Sun - Blog Posts

New Science from our Mission to Touch the Sun

In August 2018, our Parker Solar Probe mission launched to space, soon becoming the closest-ever spacecraft from the Sun. Now, scientists have announced their first discoveries from this exploration of our star!

The Sun may look calm to us here on Earth, but it's an active star, unleashing powerful bursts of light, deluges of particles moving near the speed of light and billion-ton clouds of magnetized material. All of this activity can affect our technology here on Earth and in space.

Parker Solar Probe's main science goals are to understand the physics that drive this activity — and its up-close look has given us a brand-new perspective. Here are a few highlights from what we've learned so far.

1. Surprising events in the solar wind

The Sun releases a continual outflow of magnetized material called the solar wind, which shapes space weather near Earth. Observed near Earth, the solar wind is a relatively uniform flow of plasma, with occasional turbulent tumbles. Closer to the solar wind's source, Parker Solar Probe saw a much different picture: a complicated, active system. 

One type of event in particular drew the eye of the science teams: flips in the direction of the magnetic field, which flows out from the Sun, embedded in the solar wind. These reversals — dubbed "switchbacks" — last anywhere from a few seconds to several minutes as they flow over Parker Solar Probe. During a switchback, the magnetic field whips back on itself until it is pointed almost directly back at the Sun.

The exact source of the switchbacks isn't yet understood, but Parker Solar Probe's measurements have allowed scientists to narrow down the possibilities — and observations from the mission's 21 remaining solar flybys should help scientists better understand these events. 

2. Seeing tiny particle events

The Sun can accelerate tiny electrons and ions into storms of energetic particles that rocket through the solar system at nearly the speed of light. These particles carry a lot of energy, so they can damage spacecraft electronics and even endanger astronauts, especially those in deep space, outside the protection of Earth's magnetic field — and the short warning time for such particles makes them difficult to avoid.

Energetic particles from the Sun impact a detector on ESA & NASA's SOHO satellite.

Parker Solar Probe's energetic particle instruments have measured several never-before-seen events so small that all trace of them is lost before they reach Earth. These instruments have also measured a rare type of particle burst with a particularly high number of heavier elements — suggesting that both types of events may be more common than scientists previously thought.

3. Rotation of the solar wind

Near Earth, we see the solar wind flowing almost straight out from the Sun in all directions. But the Sun rotates as it releases the solar wind, and before it breaks free, the wind spins along in sync with the Sun's surface. For the first time, Parker was able to observe the solar wind while it was still rotating – starting more than 20 million miles from the Sun.

The strength of the circulation was stronger than many scientists had predicted, but it also transitioned more quickly than predicted to an outward flow, which helps mask the effects of that fast rotation from the vantage point where we usually see them from, near Earth, about 93 million miles away. Understanding this transition point in the solar wind is key to helping us understand how the Sun sheds energy, with implications for the lifecycles of stars and the formation of protoplanetary disks.

4. Hints of a dust-free zone

Parker also saw the first direct evidence of dust starting to thin out near the Sun – an effect that has been theorized for nearly a century, but has been impossible to measure until now. Space is awash in dust, the cosmic crumbs of collisions that formed planets, asteroids, comets and other celestial bodies billions of years ago. Scientists have long suspected that, close to the Sun, this dust would be heated to high temperatures by powerful sunlight, turning it into a gas and creating a dust-free region around the Sun.

For the first time, Parker's imagers saw the cosmic dust begin to thin out a little over 7 million miles from the Sun. This decrease in dust continues steadily to the current limits of Parker Solar Probe's instruments, measurements at a little over 4 million miles from the Sun. At that rate of thinning, scientists expect to see a truly dust-free zone starting a little more than 2-3 million miles from the Sun — meaning the spacecraft could observe the dust-free zone as early as 2020, when its sixth flyby of the Sun will carry it closer to our star than ever before.

These are just a few of Parker Solar Probe's first discoveries, and there's plenty more science to come throughout the mission! For the latest on our Sun, follow @NASASun on Twitter and NASA Sun Science on Facebook.

Watch Mercury Transit the Sun on Nov. 11

On Nov. 11, Earthlings will be treated to a rare cosmic event — a Mercury transit.

For about five and a half hours on Monday, Nov. 11 — from about 7:35 a.m. EST to 1:04 p.m. EST — Mercury will be visible from Earth as a tiny black dot crawling across the face of the Sun. This is a transit and it happens when Mercury lines up just right between the Sun and Earth.

Mercury transits happen about 13 times a century. Though it takes Mercury only about 88 days to zip around the Sun, its orbit is tilted, so it's relatively rare for the Sun, Mercury and Earth to line up perfectly. The next Mercury transit isn't until 2032 — and in the U.S., the next opportunity to catch a Mercury transit is in 2049!

How to watch

Our Solar Dynamics Observatory satellite, or SDO, will provide near-real time views of the transit. SDO keeps a constant eye on the Sun from its position in orbit around Earth to monitor and study the Sun's changes, putting it in the front row for many eclipses and transits.

Visit mercurytransit.gsfc.nasa.gov to tune in!

Our Solar Dynamics Observatory also saw Mercury transit the Sun in 2016.

If you're thinking of watching the transit from the ground, keep in mind that it is never safe to look directly at the Sun. Even with solar viewing glasses, Mercury is too small to be easily seen with the unaided eye. Your local astronomy club may have an opportunity to see the transit using specialized, properly-filtered solar telescopes — but remember that you cannot use a regular telescope or binoculars in conjunction with solar viewing glasses.

Transits in other star systems

Transiting planets outside our solar system are a key part of how we look for exoplanets.

Our Transiting Exoplanet Survey Satellite, or TESS, is NASA’s latest planet-hunter, observing the sky for new worlds in our cosmic neighborhood. TESS searches for these exoplanets, planets orbiting other stars, by using its four cameras to scan nearly the whole sky one section at a time. It monitors the brightness of stars for periodic dips caused by planets transiting those stars.

This is similar to Mercury’s transit across the Sun, but light-years away in other solar systems! So far, TESS has discovered 29 confirmed exoplanets using transits — with over 1,000 more candidates being studied by scientists!

Discover more transit and eclipse science at nasa.gov/transit, and tune in on Monday, Nov. 11, at mercurytransit.gsfc.nasa.gov.

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Galactic Ghouls and Stellar Screams

A quiet, starry night sky might not seem like a very eerie spectacle, but space can be a creepy place! Monsters lurk in the shadowy depths of the universe, sometimes hidden in plain sight. Many of them are invisible to our eyes, so we have to use special telescopes to see them. Read on to discover some of these strange cosmic beasts, but beware — sometimes fact is scarier than fiction.

Monster Black Holes ⚫

You know those nightmares where no matter how fast you try to run you never seem to get anywhere? Black holes are a sinister possible version of that dream — especially because they’re real! If you get too close to a black hole, there is no possibility of escape.

Just last year our Fermi Gamma-ray Space Telescope traced an otherworldly ghost particle back to one of these monster black holes, providing additional insight into the many signals we’re picking up from some of the most feared creatures in the cosmic deep.

But it gets worse. Our Hubble Space Telescope revealed that these things are hidden in the hearts of nearly every galaxy in the universe. That means supermassive black holes lurk in the shadows of the night sky in every direction you look!

A Hazy Specter 👻

This fiendish specter lives in the center of the Milky Way, haunting our galaxy’s supermassive black hole. But it’s not as scary as it looks! Our SOFIA observatory captured streamlines tracing a magnetic field that appears to be luring most of the material quietly into orbit around the black hole. In other galaxies, magnetic fields seem to be feeding material into hungry black holes — beware! Magnetic fields might be the answer to why some black holes are starving while others are feasting.

Bats in the Belfry 🦇

The universe has bats in the attic! Hubble spotted the shadow of a giant cosmic bat in the Serpens Nebula. Newborn stars like the one at the center of the bat, called HBC 672, are surrounded by disks of material, which are hard to study directly. The shadows they cast, like the bat, can clue scientists in on things like the disk’s size and density. Our solar system formed from the same type of disk of material, but we can only see the end result of planet building here — we want to learn more about the process!

Jack-o-lantern Sun 🎃

A jack-o-lantern in space?! Our Solar Dynamics Observatory watches the Sun at all times, keeping a close eye on space weather. In October 2014, the observatory captured a chilling image of the Sun with a Halloweenish face!

Skull Comet 💀

On Halloween a few years ago, an eerie-looking object known as 2015 TB145 sped across the night sky. Scientists observing it with our Infrared Telescope Facility determined that it was most likely a dead comet. It’s important to study objects like comets and asteroids because they’re dangerous if they cross Earth’s path — just ask the dinosaurs!

Halloween Treat 🍬

Trick-or-treat! Add a piece of glowing cosmic candy to your Halloween haul, courtesy of Hubble! This image shows the Saturn Nebula, formed from the outer layers ejected by a dying star, destined to be recycled into later generations of stars and planets. Our Sun will experience a similar fate in around five billion years.

Witch’s Broom Nebula 🧹

Massive stars are in for a more fiery fate, as the Witch's Broom Nebula shows. Hubble’s close-up look reveals wisps of gas — shrapnel leftover from a supernova explosion. Astronomers believe that a couple of supernovae occur each century in galaxies like our own Milky Way.

Zombie Stars 🧟

Supernovae usually herald the death of a star, but on a few occasions astronomers have found “zombie stars” left behind after unusually weak supernovae. Our Nuclear Spectroscopic Telescope Array (NuSTAR) has even spotted a mysterious glow of high-energy X-rays that could be the “howls” of dead stars as they feed on their neighbors.

Intergalactic Ghost Towns 🏚️

The universe is brimming with galaxies, but it’s also speckled with some enormous empty pockets of space, too. These giant ghost towns, called voids, may be some of the largest things in the cosmos, and since the universe is expanding, galaxies are racing even farther away from each other all the time! Be grateful for your place in space — the shadowy patches of the universe are dreadful lonely scenes.

Mysterious Invisible Force 🕵️‍♀️

Some forces are a lot creepier than floorboards creaking or a door slamming shut unexpectedly when you’re home alone. Dark energy is a mysterious antigravity pressure that our Wide Field Infrared Survey Telescope (WFIRST) is going to help us understand. All we know so far is that it’s present everywhere in the cosmos (even in the room with you as you read this) and it controls the fate of the universe, but WFIRST will study hundreds of millions of galaxies to figure out just what dark energy is up to.

Want to learn some fun ways to celebrate Halloween in (NASA) style? Check out this link!

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Farewell to the Van Allen Probes

After seven years of studying the radiation around Earth, the Van Allen Probes spacecraft have retired.

Originally slated for a two-year mission, these two spacecraft studied Earth's radiation belts — giant, donut-shaped clouds of particles surrounding Earth — for nearly seven years. The mission team used the last of their propellant this year to place the spacecraft into a lower orbit that will eventually decay, allowing the Van Allen Probes to re-enter and burn up in Earth's atmosphere.

Earth's radiation belts exist because energized charged particles from the Sun and other sources in space become trapped in our planet's huge magnetic field, creating vast regions around Earth that teem with radiation. This is one of the harshest environments in space — and the Van Allen Probes survived more than three times longer than planned orbiting through this intense region.

The shape, size and intensity of the radiation belts change, meaning that satellites — like those used for telecommunications and GPS — can be bombarded with a sudden influx of radiation. The Van Allen Probes shed new light on what invisible forces drive these changes — like waves of charged particles and electromagnetic fields driven by the Sun, called space weather. 

Here are a few scientific highlights from the Van Allen Probes — from the early days of the mission to earlier this year:

The Van Allen belts were first discovered in 1958, and for decades, scientists thought there were only two concentric belts. But, days after the Van Allen Probes launched, scientists discovered that during times of intense solar activity, a third belt can form.

The belts are composed of charged particles and electromagnetic fields and can be energized by different types of plasma waves. One type, called electrostatic double layers, appear as short blips of enhanced electric field. During one observing period, Probe B saw 7,000 such blips repeatedly pass over the spacecraft in a single minute!

During big space weather storms, which are ultimately caused by activity on the Sun, ions — electrically charged atoms or molecules — can be pushed deep into Earth’s magnetosphere. These particles carry electromagnetic currents that circle around the planet and can dramatically distort Earth’s magnetic field.

Across space, fluctuating electric and magnetic fields can create what are known as plasma waves. These waves intensify during space weather storms and can accelerate particles to incredible speeds. The Van Allen Probes found that one type of plasma wave known as hiss can contribute greatly to the loss of electrons from the belts.

The Van Allen belts are composed of electrons and ions with a range of energies. In 2015, research from the Van Allen Probes found that, unlike the outer belt, there were no electrons with energies greater than a million electron volts in the inner belt.

Plasma waves known as whistler chorus waves are also common in our near-Earth environment. These waves can travel parallel or at an angle to the local magnetic field. The Van Allen Probes demonstrated the two types of waves cannot be present simultaneously, resulting in greater radiation belt particle scattering in certain areas.

Very low frequency chorus waves, another variety of plasma waves, can pump up the energy of electrons to millions of electronvolts. During storm conditions, the Van Allen Probes found these waves can hugely increase the energy of particles in the belts in just a few hours.  

Scientists often use computer simulation models to understand the physics behind certain phenomena. A model simulating particles in the Van Allen belts helped scientists understand how particles can be lost, replenished and trapped by Earth’s magnetic field.

The Van Allen Probes observed several cases of extremely energetic ions speeding toward Earth. Research found that these ions’ acceleration was connected to their electric charge and not to their mass.

The Sun emits faster and slower gusts of charged particles called the solar wind. Since the Sun rotates, these gusts — the fast wind — reach Earth periodically. Changes in these gusts cause the extent of the region of cold ionized gas around Earth — the plasmasphere — to shrink. Data from the Van Allen Probes showed that such changes in the plasmasphere fluctuated at the same rate as the solar rotation — every 27 days.

Though the mission has ended, scientists will use data from the Van Allen Probes for years to come. See the latest Van Allen Probes science at nasa.gov/vanallen.

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We’re On a Mission to Study The Zone Where Earth Meets Space!

We’re launching ICON — short for Ionospheric Connection Explorer — a mission to explore the dynamic region where Earth meets space: the ionosphere!

Earth’s ionosphere stretches from 50 to 400 miles above the ground, overlapping the top of our atmosphere and the very beginning of space. The Sun cooks gases there until they lose an electron (or two or three), creating a sea of electrically charged particles. But, the ionosphere also responds to weather patterns from Earth rippling up. These changes are complex and tricky to understand.

That’s why we’re launching ICON! Changes in the ionosphere can affect astronauts, satellites and communications signals we use every day, like radio or GPS. Understanding these changes could help us eventually predict them — and better protect our technology and explorers in space.

ICON will track changes in the ionosphere by surveying airglow. It’s a natural feature of Earth’s that causes our atmosphere to constantly glow. The Sun excites gases in the upper atmosphere, so they emit light. From 360 miles above Earth, ICON will photograph airglow to measure the ionosphere’s winds, composition and temperature. ICON also carries an instrument that will capture and measure the particles directly around the spacecraft.

ICON is scheduled to launch on Oct. 10, on a Northrop Grumman Pegasus XL rocket. The night of launch, the rocket is flown up to the sky by Northrop Grumman’s L-1011 Stargazer airplane, which takes off from Cape Canaveral Air Force Station in Florida. From 40,000 feet above the open ocean, the Pegasus XL rocket drops from the plane and free-falls for about five seconds before igniting and carrying ICON into orbit.   

NASA TV coverage of the launch starts at 9:15 p.m. EDT on Oct. 10 at nasa.gov/live. You can also follow along on Twitter, Facebook or at nasa.gov/icon.

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What do *you* think is inside a black hole? Or If they sun was a black hole what would we see in the sky? Thanks!

Say hello to the Saturn Nebula 👋

Garden-variety stars like the Sun live fairly placid lives in their galactic neighborhoods, casually churning out heat and light for billions of years. When these stars reach retirement age, however, they transform into unique and often psychedelic works of art. This Hubble Space Telescope image of the Saturn Nebula shows the result, called a planetary nebula. While it looks like a piece of wrapped cosmic candy, what we see is actually the outer layers of a dying star.

Stars are powered by nuclear fusion, but each one comes with a limited supply of fuel. When a medium-mass star exhausts its nuclear fuel, it will swell up and shrug off its outer layers until only a small, hot core remains. The leftover core, called a white dwarf, is a lot like a hot coal that glows after a barbecue — eventually it will fade out. Until then, the gaseous debris fluoresces as it expands out into the cosmos, possibly destined to be recycled into later generations of stars and planets.

Using Hubble’s observations, scientists have characterized the nebula’s composition, structure, temperature and the way it interacts with surrounding material. Studying planetary nebulas is particularly interesting since our Sun will experience a similar fate around five billion years down the road.

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Twinkle, twinkle, little star, How I wonder what you are. Up above the world so high, Like a diamond in the sky. 🌟 The final stages of a star’s life allow us a glimpse into the future of our own solar system. This image from our Hubble Space Telescope shows what’s left of a star 10,000 light-years from Earth.

A star like our Sun will, at the end of its life, transform into a red giant. The core of the star will eventually collapse in on itself, ejecting the surface layers outward. After that, all that remains of the star is what we see here: glowing outer layers surrounding a white dwarf star. In just a few thousand years they will have dissipated, and all that will be left to see is the dimly glowing white dwarf. More on this image, here. 

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Our Newest Solar Scope Is Ready for a Balloon Ride 🎈

Along with the Korea Astronomy and Space Science Institute, or KASI, we're getting ready to test a new way to see the Sun, high over the New Mexico desert.

A balloon — which looks a translucent white pumpkin, but large enough to hug a football field — will soon take flight, carrying a solar scope called BITSE. BITSE is a coronagraph, a special kind of telescope that blocks the bright face of the Sun to reveal its dimmer atmosphere, called the corona. BITSE stands for Balloon-borne Investigation of Temperature and Speed of Electrons in the corona.

Its goal? Explaining how the Sun spits out the solar wind, the stream of charged particles that blows constantly from the Sun. Scientists generally know it forms in the corona, but exactly how it does so is a mystery.

The solar wind is important because it’s the stuff that fills the space around Earth and all the other planets in our solar system. And, understanding how the solar wind works is key to predicting how solar eruptions travel. It’s a bit like a water slide: The way it flows determines how solar storms barrel through space. Sometimes, those storms crash into our planet’s magnetic field, sparking disturbances that can interfere with satellites and communications signals we use every day, like radio or GPS.

Right now, scientists and engineers are in Fort Sumner, New Mexico, preparing to fly BITSE up to the edge of the atmosphere. BITSE will take pictures of the corona, measuring the density, temperature and speed of negatively charged particles — called electrons — in the solar wind. Scientists need these three things to answer the question of how the solar wind forms.

One day, scientists hope to send an instrument like BITSE to space, where it can study the Sun day in and day out, and help us understand the powerful forces that push the solar wind out to speeds of 1 million miles per hour. BITSE’s balloon flight is an important step towards space, since it will help this team of scientists and engineers fine-tune their tech for future space-bound missions.  

Hours before sunrise, technicians from our Columbia Scientific Balloon Facility’s field site in Fort Sumner will ready the balloon for flight, partially filling the large plastic envelope with helium. The balloon is made of polyethylene — the same stuff grocery bags are made of — and is about as thick as a plastic sandwich bag, but much stronger. As the balloon rises higher into the sky, the gas in the balloon expands and the balloon grows to full size.

BITSE will float 22 miles over the desert. For at least six hours, it will drift, taking pictures of the Sun’s seething hot atmosphere. By the end of the day, it will have collected 40 feature-length movies’ worth of data.

BITSE’s journey to the sky began with an eclipse. Coronagraphs use a metal disk to mimic a total solar eclipse — but instead of the Moon sliding in between the Sun and Earth, the disk blocks the Sun’s face to reveal the dim corona. During the Aug. 21, 2017, total eclipse, our scientists tested key parts of this instrument in Madras, Oregon.

Now, the scientists are stepping out from the Moon’s shadow. A balloon will take BITSE up to the edge of the atmosphere. Balloons are a low-cost way to explore this part of the sky, allowing scientists to make better measurements and perform tests they can’t from the ground.

BITSE carries several important technologies. It’s built on one stage of lens, rather than three, like traditional coronagraphs. That means it’s designed more simply, and less likely to have a mechanical problem. And, it has a couple different sets of specialized filters that capture different kinds of light: polarized light — light waves that bob in certain directions — and specific wavelengths of light. The combination of these images provides scientists with information on the density, temperature and speed of electrons in the corona.

More than 22 miles over the ground, BITSE will fly high above birds, airplanes, weather and the blue sky itself. As the atmosphere thins out, there are less air particles to scatter light. That means at BITSE’s altitude, the sky is dimmer. These are good conditions for a coronagraph, whose goal is taking images of the dim corona. But even the upper atmosphere is brighter than space.

That’s why scientists are so eager to test BITSE on this balloon, and develop their instrument for a future space mission. The solar scope is designed to train its eyes on a slice of the corona that’s not well-studied, and key to solar wind formation. One day, a version of BITSE could do this from space, helping scientists gather new clues to the origins of the solar wind.  

At the end of BITSE’s flight, the crew at the Fort Sumner field site will send termination commands, kicking off a sequence that separates the instrument and balloon, deploys the instrument’s parachute, and punctures the balloon. An airplane circling overhead will keep watch over the balloon’s final moments, and relay BITSE’s location. At the end of its flight, far from where it started, the coronagraph will parachute to the ground. A crew will drive into the desert to recover both the balloon and BITSE at the end of the day.

For more information on how we use balloons for high-altitude science missions, visit: https://www.nasa.gov/scientificballoons

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Say hello to the Butterfly Nebula 👋

It looks like our Hubble Space Telescope captured an image of a peaceful, cosmic butterfly unfurling its celestial wings, but the truth is vastly more violent. In the Butterfly Nebula, layers of gas are being ejected from a dying star. Medium-mass stars grow unstable as they run out of fuel, which leads them to blast tons of material out into space at speeds of over a million miles per hour!

Streams of intense ultraviolet radiation cause the cast-off material to glow, but eventually the nebula will fade and leave behind only a small stellar corpse called a white dwarf. Our middle-aged Sun can expect a similar fate once it runs out of fuel in about six billion years.

Planetary nebulas like this one aren’t actually related to planets; the term was coined by astronomer William Herschel, who actually discovered the Butterfly Nebula in 1826. Through his small telescope, planetary nebulas looked like glowing, planet-like orbs. While stars that generate planetary nebulas may have once had planets orbiting them, scientists expect that the fiery death throes these stars undergo will ultimately leave any planets in their vicinity completely uninhabitable.

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That star stuff you see here? That's what you're made of. You possess the elements ✨ ⁣

This composite image from our Chandra X-ray Observatory, the Spitzer Space Telescope and the Isaac Newton Telescope shows high-energy X-rays emitted by young, massive stars in the star cluster Cygnus OB2. This year we're celebrating the 20th anniversary of Chandra's launch. Want to dive deeper? Click here

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GALAXY BRAIN 🧠

Our Hubble Space Telescope spotted this planetary nebula in the constellation of Orion. It's really a vast orb of gas in space, with its aging star in the center... but what does it look like to you? 🤔

When stars like the Sun grow advanced in age, they expand and glow red. These so-called red giants then begin to lose their outer layers of material into space. More than half of such a star's mass can be shed in this manner, forming a shell of surrounding gas. At the same time, the star's core shrinks and grows hotter, emitting ultraviolet light that causes the expelled gases to glow.

#InternationalCatDay? Try #IntergalacticCatDay. 

Check out features of our feline friends that have come to life as interstellar phenomena! 

Pictured first, the Cat’s Paw Nebula is located about 4,200-5,500 light-years from Earth – situated in our very own Milky Way Galaxy. It was named for the large, round features that create the impression of a feline footprint and was captured by our Spitzer Space Telescope. After gas and dust inside the nebula collapse to form stars, the stars may in turn heat up the pressurized gas surrounding them. This process causes the gas to expand into space and form the bright red bubbles you see. The green areas show places where radiation from hot stars collided with large molecules called "polycyclic aromatic hydrocarbons," causing them to fluoresce.

Next, you’ll find the Cat’s Eye Nebula. Residing 3,000 light-years from Earth, the Cat’s Eye represents a brief, yet glorious, phase in the life of a sun-like star. This nebula's dying central star may have produced the simple, outer pattern of dusty concentric shells by shrugging off outer layers in a series of regular convulsions. To create this view, Hubble Space Telescope archival image data have been reprocessed. Compared to well-known Hubble pictures, the alternative processing strives to sharpen and improve the visibility of details in light and dark areas of the nebula and also applies a more complex color palette. Gazing into the Cat's Eye, astronomers may well be seeing the fate of our sun, destined to enter its own planetary nebula phase of evolution ... in about 5 billion years.

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Say hello to the Eskimo Nebula 👋 

This nebula began forming about 10,000 years ago when a dying star started flinging material into space. When Sun-like stars exhaust their nuclear fuel, they become unstable and blast their outer layers of gas away into space (bad news for any planets in the area). This Hubble Space Telescope image shows a snapshot of the unworldly process.

Streams of high-energy ultraviolet radiation cause the expelled material to glow, creating a beautiful planetary nebula — a term chosen for the similarity in appearance to the round disk of a planet when viewed through a small telescope.

The Eskimo Nebula got its nickname because it resembles a face surrounded by a fur parka. The “parka” is a disk of material embellished by a ring of comet-shaped objects with their tails streaming away from the central, dying star. In the middle of the nebula is a bubble of material that is being blown outward by the star’s intense “wind” of high-speed material.

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When the Moon's Shadow Falls on Earth

On July 2, 2019, a total solar eclipse will pass over parts of Argentina and Chile.

Solar eclipses happen when the Moon passes directly between the Sun and Earth, casting its shadow onto Earth's surface. Because the Moon’s orbit isn't perfectly in line with the Sun and Earth, its shadow usually passes above or below Earth. But when it lines up just right, we get a solar eclipse!

People in the inner part of the Moon's shadow — the umbra — have the chance to witness a total solar eclipse, while those in the outer part of the shadow — the penumbra — experience a partial solar eclipse.

The path of the total solar eclipse stretches across parts of Chile and Argentina. People outside this path may see a partial eclipse or no eclipse at all.

During a total solar eclipse, the Moon blocks out the Sun's bright face, revealing its comparatively faint outer atmosphere, the corona. The corona is a dynamic region that is thought to hold the answers to questions about the fundamental physics of the Sun — like why the corona is so much hotter than the Sun's surface and how the Sun's constant outflow of material, the solar wind, is accelerated to such high speeds. 

Image Credit: Miloslav Druckmüller, Peter Aniol, Shadia Habbal

Our Parker Solar Probe and the upcoming Solar Orbiter mission from the European Space Agency are exploring these questions by flying through the corona itself and taking unprecedented measurements of the conditions there. Plus, our newly-chosen PUNCH mission will create tiny, artificial eclipses in front of its cameras — using an instrument called a coronagraph — to study structures in the Sun's corona and examine how it generates the solar wind.

Watching the eclipse

It’s never safe to look directly at the uneclipsed or partially eclipsed Sun – so you’ll need special solar viewing glasses or an indirect viewing method, like pinhole projection, to watch the eclipse. 

For people in the path of totality, there will be a few brief moments when it is safe to look directly at the eclipse. Only once the Moon has completely covered the Sun and there is no sunlight shining is it safe to look at the eclipse. Make sure you put your eclipse glasses back on or return to indirect viewing before the first flash of sunlight appears around the Moon’s edge.

No matter where you are, you can watch the eclipse online! The Exploratorium will be streaming live views of the eclipse with commentary in both English and Spanish starting at 4 p.m. EDT / 1 p.m. PDT on July 2. Watch with us at nasa.gov/live!

Para más información e actualizaciones en español acerca del eclipse, sigue a @NASA_es en Twitter o vea esta hoja de hechos.

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What Space Weather Means for You

In space, invisible, fast-moving particles from the Sun and other sources in deep space zip around, their behavior shaped by dynamic electric and magnetic fields. There are so few of these particles that space is considered a vacuum, but what’s there packs a punch. Together, we call all of this invisible activity space weather — and it affects our technology both in space and here on Earth.

This month, two new missions are launching to explore two different kinds of space weather.

Scrambled signals

Many of our communications and navigation systems — like GPS and radio — rely on satellites to transmit their signals. When signals are sent from satellites down to Earth, they pass through a dynamic zone on the upper edge of Earth's atmosphere called the ionosphere.

Gases in the ionosphere have been cooked into a sea of positive- and negative-charged particles by solar radiation. These electrically charged particles are also mixed in with neutral gases, like the air we breathe. The charged particles respond to electric and magnetic fields, meaning they react to space weather. Regular weather can also affect this part of the atmosphere.

Influenced by this complicated web of factors, structured bubbles of charged gas sometimes form in this part of the atmosphere, particularly near the equator. When signals pass through these bubbles, they can get distorted, causing failed communications or inaccurate GPS fixes.

Right now, it's hard to predict just when these bubbles will form or how they'll mess with signals. The two tiny satellites of the E-TBEx mission will try to shed some light on this question.

As these CubeSats fly around Earth, they'll send radio signals to receiving stations on the ground. Scientists will examine the signals received in order to see whether — and if so, how much — they were jumbled as they traveled through the upper atmosphere and down to Earth.

All together, this information will give scientists a better idea of how these bubbles form and change and how much they disrupt signals — information that could help develop strategies for mitigating these bubbles' disruptive effects.

Damaged satellites

The high-energy, fast-moving particles that fill space are called radiation. Every single spacecraft — from scientific satellites sprinkled throughout the solar system to the communications satellites responsible for relaying the GPS signals we use every day — must weather the harsh radiation of space.

Strikes from tiny, charged particles can spark memory damage or computer upsets on spacecraft, and over time, degrade hardware. The effects are wide-ranging, but ultimately, radiation can impact important scientific data, or prevent people from getting the proper navigation signals they need.

Space Environment Testbeds — or SET, for short — is our mission to study how to better protect satellites from space radiation.

SET aims its sights on a particular neighborhood of near-Earth space called the slot region: the gap between two of Earth’s vast, doughnut-shaped radiation belts, also known as the Van Allen Belts. The slot region is thought to be calmer than the belts, but known to vary during extreme space weather storms driven by the Sun. How much it changes exactly, and how quickly, remains uncertain.

The slot region is an attractive one for satellites — especially commercial navigation and communications satellites that we use every day — because from about 12,000 miles up, it offers not only a relatively friendly radiation environment, but also a wide view of Earth. During intense magnetic storms, however, energetic particles from the outer belt can surge into the slot region. 

SET will survey the slot region, providing some of the first day-to-day weather measurements of this particular neighborhood in near-Earth space. The mission also studies the fine details of how radiation damages instruments and tests different methods to protect them, helping engineers build parts better suited for spaceflight. Ultimately, SET will help other missions improve their design, engineering and operations to avoid future problems, keeping our space technology running smoothly as possible.

For more on our space weather research, follow @NASASun on Twitter and NASA Sun Science on Facebook.

Meet the other NASA missions launching on the Department of Defense's STP-2 mission and get the latest updates at nasa.gov/spacex.

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6 Things You Didn’t Know About Our ‘First’ Space Flight Center

When NASA began operations on Oct. 1, 1958, we consisted mainly of the four laboratories of our predecessor, the National Advisory Committee for Aeronautics (NACA). Hot on the heels of NASA’s first day of business, we opened the Goddard Space Flight Center. Chartered May 1, 1959, and located in Greenbelt, Maryland, Goddard is home to one of the largest groups of scientists and engineers in the world. These people are building, testing and experimenting their way toward answering some of the universe’s most intriguing questions.

To celebrate 60 years of exploring, here are six ways Goddard shoots for the stars.

For the last 60 years, we’ve kept a close eye on our home planet, watching its atmosphere, lands and ocean.

Goddard instruments were crucial in tracking the hole in the ozone layer over Antarctica as it grew and eventually began to show signs of healing. Satellites and field campaigns track the changing height and extent of ice around the globe. Precipitation missions give us a global, near-real-time look at rain and snow everywhere on Earth. Researchers keep a record of the planet’s temperature, and Goddard supercomputer models consider how Earth will change with rising temperatures. From satellites in Earth’s orbit to field campaigns in the air and on the ground, Goddard is helping us understand our planet.

We seek to answer the big questions about our universe: Are we alone? How does the universe work? How did we get here?

We’re piecing together the story of our cosmos, from now all the way back to its start 13.7 billion years ago. Goddard missions have contributed to our understanding of the big bang and have shown us nurseries where stars are born and what happens when galaxies collide. Our ongoing census of planets far beyond our own solar system (several thousand known and counting!) is helping us hone in on which ones might be potentially habitable.

We study our dynamic Sun.

Our Sun is an active star, with occasional storms and a constant outflow of particles, radiation and magnetic fields that fill the solar system out far past the orbit of Neptune. Goddard scientists study the Sun and its activity with a host of satellites to understand how our star affects Earth, planets throughout the solar system and the nature of the very space our astronauts travel through.

We explore the planets, moons and small objects in the solar system and beyond. 

Goddard instruments (well over 100 in total!) have visited every planet in the solar system and continue on to new frontiers. What we’ve learned about the history of our solar system helps us piece together the mysteries of life: How did life in our solar system form and evolve? Can we find life elsewhere?

Over 60 years, our communications networks have enabled hundreds of NASA spacecraft to “phone home.”

Today, Goddard communications networks bring down 98 percent of our spacecraft data – nearly 30 terabytes per day! This includes not only science data, but also key information related to spacecraft operations and astronaut health. Goddard is also leading the way in creating cutting-edge solutions like laser communications that will enable exploration – faster, better, safer – for generations to come. Pew pew!

Exploring the unknown often means we must create new ways of exploring, new ways of knowing what we’re “seeing.” 

Goddard’s technologists and engineers must often invent tools, mechanisms and sensors to return information about our universe that we may not have even known to look for when the center was first commissioned.

Behind every discovery is an amazing team of people, pushing the boundaries of humanity’s knowledge. Here’s to the ones who ask questions, find answers and ask questions some more!

Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com.

High-Flying Spacecraft Finish 1000th Lap Around Earth!

The quadruplet spacecraft of the Magnetospheric Multiscale mission have just returned from their first adventure into the solar wind — sailing through the most intense winds of their journey so far.

These spacecraft were designed to study Earth’s giant magnetic system, which shields our planet from the majority of the Sun’s constant outflow of material — what we call the solar wind.

Usually, the Magnetospheric Multiscale spacecraft — MMS for short — take their measurements from inside Earth’s protective magnetic environment, the magnetosphere. But in February and March, the MMS spacecraft ventured beyond this magnetic barrier to measure that solar wind directly — a feat that meant they had to change up how they fly in a whole new way.

Outside of Earth's protective magnetic field, the spacecraft were completely immersed in the particles and magnetic fields of the solar wind. As they flew through the stream of material, the spacecraft traced out a wake behind each instrument, just like a boat in a river. To avoid measuring that wake, each spacecraft was tilted into the wind so the instruments could take clean measurements of the pristine solar wind, unaffected by the wake.

Within the magnetosphere, the MMS spacecraft fly in a pyramid-shaped formation that allows them to study magnetic fields in 3D. But to study the solar wind, the mission team aligned spacecraft in a straight line at oddly spaced intervals. This string-of-pearls formation gave MMS a better look at how much the solar wind varies over different scales.

Because the four spacecraft fly so close together, MMS relies on super-accurate navigation from GPS satellites. This venture into the solar wind took the spacecraft even farther from Earth than before, so MMS broke its own world record for highest-ever GPS fix. The spacecraft were over 116,000 miles above Earth — about halfway to the Moon — and still using GPS!

Now, just in time for the 1,000th orbit of their mission — which adds up to 163 million miles flown! — the spacecraft are back in Earth's magnetosphere, flying in their usual formation to study fundamental processes within our planet’s magnetic field.

Keep up with the latest MMS research at nasa.gov/mms, on Twitter @NASASun or with NASA Sun Science on Facebook.

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Five Facts About the Kepler Space Telescope That Will Blow You Away!

Ten years ago, on March 6, 2009, a rocket lifted off a launch pad at Cape Canaveral Air Force Station in Florida. It carried a passenger that would revolutionize our understanding of our place in the cosmos--NASA’s first planet hunter, the Kepler space telescope. The spacecraft spent more than nine years in orbit around the Sun, collecting an unprecedented dataset for science that revealed our galaxy is teeming with planets. It found planets that are in some ways similar to Earth, raising the prospects for life elsewhere in the cosmos, and stunned the world with many other first-of-a-kind discoveries. Here are five facts about the Kepler space telescope that will blow you away:

Kepler observed more than a half million stars looking for planets beyond our solar system.

It discovered more than 2,600 new worlds…

…many of which could be promising places for life.

Kepler’s survey revealed there are more planets than stars in our galaxy.

The spacecraft is now drifting around the Sun more than 94 million miles away from Earth in a safe orbit.

NASA retired the Kepler spacecraft in 2018. But to this day, researchers continue to mine its archive of data, uncovering new worlds.

*All images are artist illustrations. Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com

Our Favorite Valentines Throughout the Universe

Today is Valentine’s Day. What better way to express that you love someone than with an intergalactic love gram? Check out some of our favorites and send them to all of your cosmic companions:

Your love is galactic

The Hubble Space Telescope revolutionized nearly all areas of astronomical research — and captured some truly lovely images. Here, a pair of intersecting galaxies swirl into the shape of a rose as a result of gravitational tidal pull. What type of roses are you getting for your love — red or galactic?

I think you’re n{ice}

IceBridge is the largest airborne survey of Earth’s polar ice ever flown. It captures 3-D views of Arctic and Antarctic ice sheets, ice shelves and sea ice. This lovely heart-shaped glacier feature was discovered in northwest Greenland during an IceBridge flight in 2017. Which of your lover’s features would you say are the coolest?

You’re absolutely magnetic

Even though we can't see them, magnetic fields are all around us. One of the solar system’s largest magnetospheres belongs to Jupiter. Right now, our Juno spacecraft is providing scientists with their first glimpses of this unseen force. Is your attraction to your loved one magnetic?

You’re MARS-velous

This heart-shaped feature on the Martian landscape was captured by our Mars Reconnaissance Orbiter. It was created by a small impact crater that blew darker material on the surface away. What impact has your loved one had on you?

I <3 you

From three billion miles away, Pluto sent a “love note” back to Earth, via our New Horizons spacecraft. This stunning image of Pluto's "heart" shows one of the world's most dominant features, estimated to be 1,000 miles (1,600 km) across at its widest point. Will you pass this love note on to someone special in your life?

Light of my life

Our Solar Dynamics Observatory keeps an eye on our closest star that brings energy to you and your love. The observatory helps us understand where the Sun's energy comes from, how the inside of the Sun works, how energy is stored and released in the Sun's atmosphere and much more. Who would you say is your ray of sunshine?

Do any of these cosmic phenomena remind you of someone in your universe? Download these cards here to send to all the stars in your sky.

Want something from the Red Planet to match your bouquet of red roses? Here is our collection of Martian Valentines.

Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com

55 Cancri e: Where Skies Sparkle Above a Never-ending Ocean of Lava

We’ve discovered thousands of exoplanets – planets beyond our solar system – so far. These worlds are mysterious, but observations from telescopes on the ground and in space help us understand what they might look like.

Take the planet 55 Cancri e, for instance. It’s relatively close, galactically speaking, at 41 light-years away. It’s a rocky planet, nearly two times bigger than Earth, that whips around its star every 18 hours (as opposed to the 365 days it takes our planet to orbit the Sun. Slacker).

The planet’s star, 55 Cancri, is slightly smaller than our Sun, but it’s 65 times closer than the Sun is to Earth. Imagine a massive sun on the horizon! Because 55 Cancri e is so close to its star, it’s tidally locked just like our Moon is to the Earth. One side is always bathed in daylight, the other is in perpetual darkness. It’s also hot. Really hot. So hot that silicate rocks would melt into a molten ocean of melted rock. IT’S COVERED IN AN OCEAN OF LAVA. So, it’s that hot (between 3,140 degrees and 2,420 degrees F).

Scientists think 55 Cancri e also may harbor a thick atmosphere that circulates heat from the dayside to the nightside. Silicate vapor in the atmosphere could condense into sparkling clouds on the cooler, darker nightside that would reflect the lava below. It’s also possible that it would rain sand on the nightside, but … sparkling skies!

Check out our Exoplanet Travel Bureau's latest 360-degree visualization of 55 Cancri e and download the travel poster at https://go.nasa.gov/2HOyfF3.

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Extreme Science: Launching Sounding Rockets from The Arctic

This winter, our scientists and engineers traveled to the world's northernmost civilian town to launch rockets equipped with cutting-edge scientific instruments.

This is the beginning of a 14-month-long campaign to study a particular region of Earth's magnetic field — which means launching near the poles. What's it like to launch a science rocket in these extreme conditions?

Our planet is protected by a natural magnetic field that deflects most of the particles that flow out from the Sun — the solar wind — away from our atmosphere. But near the north and south poles, two oddities in Earth's magnetic field funnel these solar particles directly into our atmosphere. These regions are the polar cusps, and it turns out they're the ideal spot for studying how our atmosphere interacts with space.

The scientists of the Grand Challenge Initiative — Cusp are using sounding rockets to do their research. Sounding rockets are suborbital rockets that launch to a few hundred miles in altitude, spending a few minutes in space before falling back to Earth. That means sounding rockets can carry sensitive instruments above our atmosphere to study the Sun, other stars and even distant galaxies.

They also fly directly through some of the most interesting regions of Earth's atmosphere, and that's what scientists are taking advantage of for their Grand Challenge experiments.

One of the ideal rocket ranges for cusp science is in Ny-Ålesund, Svalbard, off the coast of Norway and within the Arctic circle. Because of its far northward position, each morning Svalbard passes directly under Earth's magnetic cusp.

But launching in this extreme, remote environment puts another set of challenges on the mission teams. These launches need to happen during the winter, when Svalbard experiences 24/7 darkness because of Earth's axial tilt. The launch teams can go months without seeing the Sun.

Like for all rocket launches, the science teams have to wait for the right weather conditions to launch. Because they're studying upper atmospheric processes, some of these teams also have to wait for other science conditions, like active auroras. Auroras are created when charged particles collide with Earth’s atmosphere — often triggered by solar storms or changes in the solar wind — and they're related to many of the upper-atmospheric processes that scientists want to study near the magnetic cusp.

But even before launch, the extreme conditions make launching rockets a tricky business — it's so cold that the rockets must be encased in styrofoam before launch to protect them from the low temperatures and potential precipitation.

When all is finally ready, an alarm sounds throughout the town of Ny-Ålesund to alert residents to the impending launch. And then it's up, up and away! This photo shows the launch of the twin VISIONS-2 sounding rockets on Dec. 7, 2018 from Ny-Ålesund.

These rockets are designed to break up during flight — so after launch comes clean-up. The launch teams track where debris lands so that they can retrieve the pieces later.

The next launch of the Grand Challenge Initiative is AZURE, launching from Andøya Space Center in Norway in March 2019.

 For even more about what it's like to launch science rockets in extreme conditions, check out one scientist's notes from the field: https://go.nasa.gov/2QzyjR4

For updates on the Grand Challenge Initiative and other sounding rocket flights, visit nasa.gov/soundingrockets or follow along with NASA Wallops and NASA heliophysics on Twitter and Facebook.

@NASA_Wallops | NASA’s Wallops Flight Facility | @NASASun | NASA Sun Science

The Kepler space telescope has shown us our galaxy is teeming with planets — and other surprises

The Kepler space telescope has taught us there are so many planets out there, they outnumber even the stars. Here is a sample of these wondrous, weird and unexpected worlds (and other spectacular objects in space) that Kepler has spotted with its “eye” opened to the heavens.

Kepler has found that double sunsets really do exist.

Yes, Star Wars fans, the double sunset on Tatooine could really exist. Kepler discovered the first known planet around a double-star system, though Kepler-16b is probably a gas giant without a solid surface.

Kepler has gotten us closer to finding planets like Earth.

Nope. Kepler hasn’t found Earth 2.0, and that wasn’t the job it set out to do. But in its survey of hundreds of thousands of stars, Kepler found planets near in size to Earth orbiting at a distance where liquid water could pool on the surface. One of them, Kepler-62f, is about 40 percent bigger than Earth and is likely rocky. Is there life on any of them? We still have a lot more to learn.

This sizzling world is so hot iron would melt!

One of Kepler’s early discoveries was the small, scorched world of Kepler-10b. With a year that lasts less than an Earth day and density high enough to imply it’s probably made of iron and rock, this “lava world” gave us the first solid evidence of a rocky planet outside our solar system. 

If it’s not an alien megastructure, what is this oddly fluctuating star?

When Kepler detected the oddly fluctuating light from “Tabby’s Star,” the internet lit up with speculation of an alien megastructure. Astronomers have concluded it’s probably an orbiting dust cloud.  

Kepler caught this dead star cannibalizing its planet.

What happens when a solar system dies? Kepler discovered a white dwarf, the compact corpse of a star in the process of vaporizing a planet.

These Kepler planets are more than twice the age of our Sun!

The five small planets in Kepler-444 were born 11 billion years ago when our galaxy was in its youth. Imagine what these ancient planets look like after all that time?

Kepler found a supernova exploding at breakneck speed.

This premier planet hunter has also been watching stars explode. Kepler recorded a sped-up version of a supernova called a “fast-evolving luminescent transit” that reached its peak brightness at breakneck speed. It was caused by a star spewing out a dense shell of gas that lit up when hit with the shockwave from the blast. 

* All images are artist illustrations.

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How Airglow Can Help Us Understand the Sun’s Influence on Earth

You may have seen the famous blue marble or pale blue dot images showing Earth from 18,000 and 3.7 billion miles away, respectively. But closer to home — some 300 miles above Earth's surface — you might encounter an unfamiliar sight: vibrant swaths of red and green or purple and yellow light emanating from the upper atmosphere.

This light is airglow.

Airglow is created when atoms and molecules in the upper atmosphere, excited by sunlight, emit light to shed excess energy. Or, it can happen when atoms and molecules that have been ionized by sunlight collide with and capture a free electron. In both cases, these atmospheric particles emit light in order to relax again. The process is similar to how auroras are created, but while auroras are driven by high-energy solar wind, airglow is energized by day-to-day solar radiation.

Since sunlight is constant, airglow constantly shines throughout Earth’s atmosphere, and the result is a tenuous bubble of light that closely encases our planet. Its light is too dim to see easily except in orbit or on the ground with clear, dark skies and a sensitive camera — it’s one-tenth as bright as the light given off by all the stars in the night sky.  

Airglow highlights a key part of our atmosphere: the ionosphere. Stretching from roughly 50 to 400 miles above Earth’s surface, the ionosphere is an electrified layer of the upper atmosphere generated by extreme ultraviolet radiation from the Sun. It reacts to both terrestrial weather below and solar energy streaming in from above, forming a complex space weather system. Turbulence in this ever-changing sea of charged particles can manifest as disruptions that interfere with Earth-orbiting satellites or communication and navigation signals.

Understanding the ionosphere’s extreme variability is tricky because it requires untangling interactions between the different factors at play — interactions of which we don’t have a clear picture. That’s where airglow comes in. Each atmospheric gas has its own favored airglow color, hangs out at a different height and creates airglow by a different process, so we can use airglow to study different layers of the atmosphere.

Airglow carries information on the upper atmosphere’s temperature, density, and composition, but it also helps us trace how particles move through the region itself. Vast, high-altitude winds sweep through the ionosphere, pushing its contents around the globe — and airglow’s subtle dance follows their lead, highlighting global patterns.

Two NASA missions take advantage of precisely this effect to study the upper atmosphere: ICON — short for Ionospheric Connection Explorer — and GOLD — Global-scale Observations of the Limb and Disk.

ICON focuses on how charged and neutral gases in the upper atmosphere behave and interact, while GOLD observes what drives change — the Sun, Earth’s magnetic field or the lower atmosphere — in the region.

By imaging airglow, the two missions will enable scientists to tease out how space and Earth’s weather intersect, dictating the region’s complex behavior.

Keep up with the latest in NASA's airglow and upper atmosphere research on Twitter and Facebook or at nasa.gov/sunearth.

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10 Things to Know About Parker Solar Probe

On Aug. 12, 2018, we launched Parker Solar Probe to the Sun, where it will fly closer than any spacecraft before and uncover new secrets about our star. Here's what you need to know.

1. Getting to the Sun takes a lot of power

At about 1,400 pounds, Parker Solar Probe is relatively light for a spacecraft, but it launched to space aboard one of the most powerful rockets in the world, the United Launch Alliance Delta IV Heavy. That's because it takes a lot of energy to go to the Sun — in fact, 55 times more energy than it takes to go to Mars.

Any object launched from Earth starts out traveling at about the same speed and in the same direction as Earth — 67,000 mph sideways. To get close to the Sun, Parker Solar Probe has to shed much of that sideways speed, and a strong launch is good start.

2. First stop: Venus!

Parker Solar Probe is headed for the Sun, but it's flying by Venus along the way. This isn't to see the sights — Parker will perform a gravity assist at Venus to help draw its orbit closer to the Sun. Unlike most gravity assists, Parker will actually slow down, giving some orbital energy to Venus, so that it can swing closer to the Sun.

One's not enough, though. Parker Solar Probe will perform similar maneuvers six more times throughout its seven-year mission!

3. Closer to the Sun than ever before

At its closest approach toward the end of its seven-year prime mission, Parker Solar Probe will swoop within 3.83 million miles of the solar surface. That may sound pretty far, but think of it this way: If you put Earth and the Sun on opposite ends of an American football field, Parker Solar Probe would get within four yards of the Sun's end zone. The current record-holder was a spacecraft called Helios 2, which came within 27 million miles, or about the 30 yard line. Mercury orbits at about 36 million miles from the Sun.

This will place Parker well within the Sun's corona, a dynamic part of its atmosphere that scientists think holds the keys to understanding much of the Sun's activity.

4. Faster than any human-made object

Parker Solar Probe will also break the record for the fastest spacecraft in history. On its final orbits, closest to the Sun, the spacecraft will reach speeds up to 430,000 mph. That's fast enough to travel from New York to Tokyo in less than a minute!

5. Dr. Eugene Parker, mission namesake

Parker Solar Probe is named for Dr. Eugene Parker, the first person to predict the existence of the solar wind. In 1958, Parker developed a theory showing how the Sun’s hot corona — by then known to be millions of degrees Fahrenheit — is so hot that it overcomes the Sun’s gravity. According to the theory, the material in the corona expands continuously outwards in all directions, forming a solar wind.

This is the first NASA mission to be named for a living person, and Dr. Parker watched the launch with the mission team from Kennedy Space Center in Florida.

6. Unlocking the secrets of the solar wind

Even though Dr. Parker predicted the existence of the solar wind 60 years ago, there's a lot about it we still don't understand. We know now that the solar wind comes in two distinct streams, fast and slow. We've identified the source of the fast solar wind, but the slow solar wind is a bigger mystery.

Right now, our only measurements of the solar wind happen near Earth, after it has had tens of millions of miles to blur together, cool down and intermix. Parker's measurements of the solar wind, just a few million miles from the Sun's surface, will reveal new details that should help shed light on the processes that send it speeding out into space.

7. Studying near-light speed particles

Another question we hope to answer with Parker Solar Probe is how some particles can accelerate away from the Sun at mind-boggling speeds — more than half the speed of light, or upwards of 90,000 miles per second. These particles move so fast that they can reach Earth in under half an hour, so they can interfere with electronics on board satellites with very little warning.

8. The mystery of the corona's high heat

The third big question we hope to answer with this mission is something scientists call the coronal heating problem. Temperatures in the Sun's corona, where Parker Solar Probe will fly, spike upwards of 2 million degrees Fahrenheit, while the Sun's surface below simmers at a balmy 10,000 F. How the corona gets so much hotter than the surface remains one of the greatest unanswered questions in astrophysics.

Though scientists have been working on this problem for decades with measurements taken from afar, we hope measurements from within the corona itself will help us solve the coronal heating problem once and for all.

9. Why won't Parker Solar Probe melt?

The corona reaches millions of degrees Fahrenheit, so how can we send a spacecraft there without it melting?

The key lies in the distinction between heat and temperature. Temperature measures how fast particles are moving, while heat is the total amount of energy that they transfer. The corona is incredibly thin, and there are very few particles there to transfer energy — so while the particles are moving fast (high temperature), they don’t actually transfer much energy to the spacecraft (low heat).

It’s like the difference between putting your hand in a hot oven versus putting it in a pot of boiling water (don’t try this at home!). In the air of the oven, your hand doesn’t get nearly as hot as it would in the much denser water of the boiling pot.

10. Engineered to thrive in an extreme environment

Make no mistake, the environment in the Sun's atmosphere is extreme — hot, awash in radiation, and very far from home — but Parker Solar Probe is engineered to survive.

The spacecraft is outfitted with a cutting-edge heat shield made of a carbon composite foam sandwiched between two carbon plates. The heat shield is so good at its job that, even though the front side will receive the full brunt of the Sun's intense light, reaching 2,500 F, the instruments behind it, in its shadow, will remain at a cozy 85 F.

Even though Parker Solar Probe's solar panels — which provide the spacecraft's power — are retractable, even the small bit of surface area that peeks out near the Sun is enough to make them prone to overheating. So, to keep its cool, Parker Solar Probe circulates a single gallon of water through the solar arrays. The water absorbs heat as it passes behind the arrays, then radiates that heat out into space as it flows into the spacecraft’s radiator.

For much of its journey, Parker Solar Probe will be too far from home and too close to the Sun for us to command it in real time — but don't worry, Parker Solar Probe can think on its feet. Along the edges of the heat shield’s shadow are seven sensors. If any of these sensors detect sunlight, they alert the central computer and the spacecraft can correct its position to keep the sensors — and the rest of the instruments — safely protected behind the heat shield.

Read the web version of this week’s “Solar System: 10 Things to Know” article HERE.

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In Conversation with the Sun: Parker Solar Probe Communications

Our Sun powers life on Earth. It defines our days, nourishes our crops and even fuels our electrical grids. In our pursuit of knowledge about the universe, we’ve learned so much about the Sun, but in many ways we’re still in conversation with it, curious about its mysteries.

Parker Solar Probe will advance this conversation, flying through the Sun’s atmosphere as close as 3.8 million miles from our star’s surface, more than seven times closer to it than any previous spacecraft. If space were a football field, with Earth at one end and the Sun at the other, Parker would be at the four-yard line, just steps away from the Sun! This journey will revolutionize our understanding of the Sun, its surface and solar winds.

Supporting Parker on its journey to the Sun are our communications networks. Three networks, the Near Earth Network, the Space Network and the Deep Space Network, provide our spacecraft with their communications, delivering their data to mission operations centers. Their services ensure that missions like Parker have communications support from launch through the mission.

For Parker’s launch on Aug. 12, the Delta IV Heavy rocket that sent Parker skyward relied on the Space Network. A team at Goddard Space Flight Center’s Networks Integration Center monitored the launch, ensuring that we maintained tracking and communications data between the rocket and the ground. This data is vital, allowing engineers to make certain that Parker stays on the right path towards its orbit around the Sun.

The Space Network’s constellation of Tracking and Data Relay Satellites (TDRS) enabled constant communications coverage for the rocket as Parker made its way out of Earth’s atmosphere. These satellites fly in geosynchronous orbit, circling Earth in step with its rotation, relaying data from spacecraft at lower altitudes to the ground. The network’s three collections of TDRS over the Atlantic, Pacific and Indian oceans provide enough coverage for continuous communications for satellites in low-Earth orbit.

The Near Earth Network’s Launch Communications Segment tracked early stages of Parker's launch, testing our brand new ground stations’ ability to provide crucial information about the rocket’s initial velocity (speed) and trajectory (path). When fully operational, it will support launches from the Kennedy spaceport, including upcoming Orion missions. The Launch Communications Segment’s three ground stations are located at Kennedy Space Center; Ponce De Leon, Florida; and Bermuda. 

When Parker separated from the Delta IV Heavy, the Deep Space Network took over. Antennas up to 230 feet in diameter at ground stations in California, Australia and Spain are supporting Parker for its 24 orbits around the Sun and the seven Venus flybys that gradually shrink its orbit, bringing it closer and closer to the Sun. The Deep Space Network is delivering data to mission operations centers and will continue to do so as long as Parker is operational.

Near the Sun, radio interference and the heat load on the spacecraft’s antenna makes communicating with Parker a challenge that we must plan for. Parker has three distinct communications phases, each corresponding to a different part of its orbit.

When Parker comes closest to the Sun, the spacecraft will emit a beacon tone that tells engineers on the ground about its health and status, but there will be very little opportunity to command the spacecraft and downlink data. High data rate transmission will only occur during a portion of Parker’s orbit, far from the Sun. The rest of the time, Parker will be in cruise mode, taking measurements and being commanded through a low data rate connection with Earth.

Communications infrastructure is vital to any mission. As Parker journeys ever closer to the center of our solar system, each byte of downlinked data will provide new insight into our Sun. It’s a mission that continues a conversation between us and our star that has lasted many millions of years and will continue for many millions more.

For more information about NASA’s mission to touch the Sun: https://www.nasa.gov/content/goddard/parker-solar-probe

For more information about our satellite communications check out: http://nasa.gov/SCaN

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Parker Solar Probe is Go for Launch

Tomorrow, Aug. 11, we're launching a spacecraft to touch the Sun.

The first chance to launch Parker Solar Probe is 3:33 a.m. EDT on Aug. 11 from Space Launch Complex 37 at Cape Canaveral Air Force Station in Florida. Launch coverage on NASA TV starts at 3 a.m. EDT at nasa.gov/live.

After launch, Parker Solar Probe begins its daring journey to the Sun’s atmosphere, or corona, going closer to the Sun than any spacecraft in history and facing brutal heat and radiation.

Though Parker Solar Probe weighs a mere 1,400 pounds — pretty light for a spacecraft — it's launching aboard one of the world's most powerful rockets, a United Launch Alliance Delta IV Heavy with a third stage added.

Even though you might think the Sun's massive means things would just fall into it, it's surprisingly difficult to actually go there. Any object leaving Earth starts off traveling at about 67,000 miles per hour, same as Earth — and most of that is in a sideways direction, so you have to shed most of that sideways speed to make it to the Sun. All that means that it takes 55 times more launch energy to go to the Sun than it does to go to Mars. On top of its powerful launch vehicle, Parker Solar Probe will use seven Venus gravity assists to shed sideways speed.

Even though Parker Solar Probe will lose a lot of sideways speed, it'll still be going incredibly fast as its orbit draws closer to the Sun throughout its seven-year mission. At its fastest, Parker Solar Probe will travel at 430,000 miles per hour — fast enough to get from Philadelphia to Washington, D.C. in one second — setting the record for the fastest spacecraft in history.

But the real challenge was to keep the spacecraft from frying once it got there.

We’ve always wanted to send a mission to the corona, but we literally haven’t had the technology that can protect a spacecraft and its instruments from its scorching heat. Only recent advances have enabled engineers to build a heat shield that will protect the spacecraft on this journey of extremes — a tricky feat that requires withstanding the Sun’s intense radiation on the front and staying cool at the back, so the spacecraft and instruments can work properly.

The 4.5-inches-thick heat shield is built like a sandwich. There’s a thin layer of carbon material like you might find in your golf clubs or tennis rackets, carbon foam, and then another thin piece of carbon-carbon on the back. Even while the Sun-facing side broils at 2,500 degrees Fahrenheit, the back of the shield will remain a balmy 85 degrees — just above room temperature. There are so few particles in this region that it's a vacuum, so blocking the Sun's radiation goes a long way towards keeping the spacecraft cool.

Parker Solar Probe is also our first mission to be named after a living individual: Dr. Eugene Parker, famed solar physicist who in 1958 first predicted the existence of the solar wind.

"Solar wind" is what Dr. Parker dubbed the stream of charged particles that flows constantly from the Sun, bathing Earth and our entire solar system in the Sun’s magnetic fields. Parker Solar Probe’s flight right through the corona allows it to observe the birth of the very solar wind that Dr. Parker predicted, right as it speeds up and over the speed of sound.  

The corona is where solar material is heated to millions of degrees and where the most extreme eruptions on the Sun occur, like solar flares and coronal mass ejections, which fling particles out to space at incredible speeds near the speed of light. These explosions can also spark space weather storms near Earth that can endanger satellites and astronauts, disrupt radio communications and, at their most severe, trigger power outages.

Thanks to Parker Solar Probe’s landmark mission, solar scientists will be able to see the objects of their study up close and personal for the very first time.

Up until now, all of our studies of the corona have been remote — that is, taken from a distance, rather than at the mysterious region itself. Scientists have been very creative to glean as much as possible from their remote data, but there’s nothing like actually sending a probe to the corona to see what’s going on.

And scientists aren’t the only ones along for the adventure — Parker Solar Probe holds a microchip carrying the names of more than 1.1 million people who signed up to send their name to the Sun. This summer, these names and 1,400 pounds of science equipment begin their journey to the center of our solar system.

Three months later in November 2018, Parker Solar Probe makes its first close approach to the Sun, and in December, it will send back the data. The corona is one of the last places in the solar system where no spacecraft has visited before; each observation Parker Solar Probe makes is a potential discovery.

Stay tuned — Parker Solar Probe is about to take flight.

Keep up with the latest on the mission at nasa.gov/solarprobe or follow us on Twitter and Facebook.

Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com. 

Spilling the Sun’s Secrets

You might think you know the Sun: It looks quiet and unchanging. But the Sun has secrets that scientists have been trying to figure out for decades.  

One of our new missions — Parker Solar Probe — is aiming to spill the Sun’s secrets and shed new light on our neighbor in the sky.

Even though it’s 93 million miles away, the Sun is our nearest and best laboratory for understanding the inner workings of stars everywhere. We’ve been spying on the Sun with a fleet of satellites for decades, but we’ve never gotten a close-up of our nearest star.

This summer, Parker Solar Probe is launching into an orbit that will take it far closer to the Sun than any instrument has ever gone. It will fly close enough to touch the Sun, sweeping through the outer atmosphere — the corona — 4 million miles above the surface.

This unique viewpoint will do a lot more than provide gossip on the Sun. Scientists will take measurements to help us understand the Sun’s secrets — including those that can affect Earth.

Parker Solar Probe is equipped with four suites of instruments that will take detailed measurements from within the Sun's corona, all protected by a special heat shield to keep them safe and cool in the Sun's ferocious heat.

The corona itself is home to one of the Sun’s biggest secrets: The corona's mysteriously high temperatures. The corona, a region of the Sun’s outer atmosphere, is hundreds of times hotter than the surface below. That's counterintuitive, like if you got warmer the farther you walked from a campfire, but scientists don’t yet know why that's the case.

Some think the excess heat is delivered by electromagnetic waves called Alfvén waves moving outwards from the Sun’s surface. Others think it might be due to nanoflares — bomb-like explosions that occur on the Sun’s surface, similar to the flares we can see with telescopes from Earth, but smaller and much more frequent. Either way, Parker Solar Probe's measurements direct from this region itself should help us pin down what's really going on.

We also want to find out what exactly accelerates the solar wind — the Sun's constant outpouring of material that rushes out at a million miles per hour and fills the Solar System far past the orbit of Pluto. The solar wind can cause space weather when it reaches Earth — triggering things like the aurora, satellite problems, and even, in rare cases, power outages.

We know where the solar wind comes from, and that it gains its speed somewhere in the corona, but the exact mechanism of that acceleration is a mystery. By sampling particles directly at the scene of the crime, scientists hope Parker Solar Probe can help crack this case.

Parker Solar Probe should also help us uncover the secrets of some of the fastest particles from the Sun. Solar energetic particles can reach speeds of more than 50% the speed of light, and they can interfere with satellites with little warning because of how fast they move. We don't know how they get so fast — but it's another mystery that should be solved with Parker Solar Probe on the case.  

Parker Solar Probe launches summer 2018 on a seven-year mission to touch the Sun. Keep up with the latest on the Sun at @NASASun on Twitter, and follow along with Parker Solar Probe's last steps to launch at nasa.gov/solarprobe.

Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com.

Why Won’t Our Parker Solar Probe Melt?

This summer, our Parker Solar Probe will launch to travel closer to the Sun than any mission before it, right into the Sun’s outer atmosphere, the corona.

The environment in the corona is unimaginably hot: The spacecraft will travel through material with temperatures greater than 3 million degrees Fahrenheit. 

So…why won’t it melt? 

The Difference Between Heat and Temperature

Parker Solar Probe was designed from the ground up to keep its instruments safe and cool, but the nature of the corona itself also helps. The key lies in the difference between heat and temperature.

Temperature measures how fast particles are moving, while heat is the total amount of energy that they transfer. The corona is an incredibly thin and tenuous part of the Sun, and there are very few particles there to transfer energy – so while the particles are moving fast (high temperature), they don't actually transfer much energy to the spacecraft (low heat).

It's like the difference between putting your hand in a hot oven versus putting it in a pot of boiling water (don’t try this at home!). In the air of the oven, your hand doesn't get nearly as hot as it would in the much denser water of the boiling pot. 

So even though Parker Solar Probe travels through a region with temperatures of several million degrees, the surface of its heat shield will reach only about 2,500 F.

The Heat Shield

Of course, thousands of degrees Fahrenheit is still way too hot for scientific instruments. (For comparison, lava from volcano eruptions can be anywhere between 1,300 to 2,200 F.) 

To withstand that heat, Parker Solar Probe is outfitted with a cutting-edge heat shield, called the Thermal Protection System. This heat shield is made of a carbon composite foam sandwiched between two carbon plates. The Sun-facing side is covered with a specially-developed white ceramic coating, applied as a plasma spray, to reflect as much heat as possible.

The heat shield is so good at its job that even though the Sun-facing side of the shield will be at 2,500 F, the instruments in its shadow will remain at a balmy 85 F.

Parker Solar Probe Keeps its Cool

Several other designs on the spacecraft help Parker Solar Probe beat the heat. 

Parker Solar Probe is not only studying the Sun – it's also powered by it. But even though most of the surface area of its solar arrays can be retracted behind the heat shield, even that small exposed segment would quickly make them overheat while at the Sun.  

To keep things cool, Parker Solar Probe circulates a single gallon of water through its solar arrays. The water absorbs heat as it passes behind the arrays, then radiates that heat out into space as it flows into the spacecraft's radiator. 

It's also important for Parker Solar Probe to be able to think on its feet, since it takes about eight minutes for information to travel between Earth and the Sun. If we had to control the spacecraft from Earth, by the time we knew something went wrong, it would be too late to fix it. 

So Parker Solar Probe is smart: Along the edges of the heat shield's shadow are seven sensors. If any of these sensors detect sunlight, they alert the central computer and the spacecraft can correct its position to keep the sensors – and the rest of the instruments – safely protected behind the heat shield.

Over the course of its seven-year mission, Parker Solar Probe will make 24 orbits of our star. On each close approach to the Sun, it will sample the solar wind, study the Sun’s corona, and provide unprecedentedly close up observations from around our star – and armed with its slew of innovative technologies, we know it will keep its cool the whole time. 

Parker Solar Probe launches summer 2018 on its mission to study the Sun. Keep up with the latest on the mission at nasa.gov/solarprobe or follow us on Twitter and Facebook.

Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com

Tools of the Trade: How Parker Solar Probe Will Study the Sun

Our Parker Solar Probe will get closer to the Sun than any spacecraft has ever gone – it will fly right through the Sun's corona, part of the Sun's atmosphere.

This spacecraft is full of cutting-edge technology, from its heat shield down to its guidance and control systems. It also carries four suites of advanced instruments designed to study the Sun in a multitude of ways.  

1. Measuring particles

Two of Parker Solar Probe's instrument suites are focused on measuring particles – electrons and ions – within the corona.

One of these particle-measuring instrument suites is SWEAP (Solar Wind Electrons Alphas and Protons). SWEAP counts the most common particles in the solar wind – the Sun's constant outflow of material – and measures their properties, like velocity, density and temperature. Gathering this information about solar wind particles will help scientists better understand why the solar wind reaches supersonic speeds and exactly which part of the Sun the particles come from.

One instrument in the SWEAP suite is the Solar Probe Cup. Most of the instruments on Parker Solar Probe stay safe and cool in the shadow of the heat shield, but the Solar Probe Cup is one of the few that sticks out. That's so it can capture and measure particles streaming straight out from the Sun, and it had to go through some intense testing to get ready for this position in the Sun's incredibly hot corona.  

Credit: Levi Hutmacher/Michigan Engineering

The ISʘIS suite (pronounced EE-sis, and including the symbol for the Sun in its acronym) also measures particles. ISʘIS is short for Integrated Science Investigation of the Sun, and this instrument suite measures particles that move faster – and therefore have more energy – than the solar wind.

These measurements will help scientists understand these particles' lifecycles – where they came from, how they got to be traveling so fast (these particles can reach speeds more than half the speed of light!) and what path they take as they travel away from the Sun and into interplanetary space.

2. Taking pictures – but not of the Sun's surface.

WISPR (Wide-Field Imager for Parker Solar Probe) has the only two cameras on Parker Solar Probe – but they're not pointed directly at the Sun. Instead, WISPR looks out the side of the spacecraft, in the direction it's traveling, looking at the space Parker Solar Probe is about to fly through. From that vantage point, WISPR captures images of structures within the corona like coronal mass ejections, or CMEs. CMEs are clouds of solar material that occasionally explode from the Sun at millions of miles per hour. Because this solar material is magnetized, CMEs can trigger geomagnetic storms when they reach Earth – which, in turn, can cause effects like auroras and even, in extreme cases, power outages.  

Right now, our observations of events like these come from satellites orbiting near Earth, so WISPR will give us a whole new perspective. And, scientists will be able to combine WISPR's images with Parker Solar Probe's direct particle measurements to get a better idea of how these structures change as they travel.

3. Studying electric & magnetic fields

The FIELDS instrument suite is appropriately named: It's what scientists will use to study the electric and magnetic fields in the corona.

Electric and magnetic fields are key to understanding what happens, not only on the Sun, but throughout space, because they are the primary driver accelerating charged particles. In particular, a process called magnetic reconnection – when magnetic field lines explosively realign, sending particles rocketing away at incredible speeds – is thought to drive solar explosions, as well as space weather effects on Earth, like the aurora.

FIELDS measures electric and magnetic field at high time resolution, meaning it takes lots of measurements in a short amount of time, to track these processes and shed some light on the mechanics underlying the Sun's behavior. FIELDS' measurements are precisely synced up with those of the SWEAP suite (one of the sets of instruments studying particles) so that scientists can match up the immediate effects that electric and magnetic fields have on the material of the solar wind.

Parker Solar Probe launches summer 2018 on its mission to study the Sun. Keep up with the latest on the mission at nasa.gov/solarprobe or follow us on Twitter and Facebook.

Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com.