Sobre O Eclipse Penumbral Do Dia 10 De Fevereiro De 2017!

Sobre o eclipse penumbral do dia 10 de fevereiro de 2017!

Subtle Lunar Eclipse

Today’s (Feb. 10) lunar activity comes in the form of a penumbral eclipse. What does that mean and how does this type differ from a total eclipse? Let’s take a look:

First off, what is a penumbra? During a lunar eclipse, two shadows are cast by the Earth. The first is called the umbra (UM bruh). This shadow gets smaller as it goes away from the Earth. It is the dark center of the eclipse shadow where the moon is completely in the shadow of the Earth.

The second shadow is called the penumbra (pe NUM bruh). The penumbra gets larger as it goes away from the Earth. The penumbra is the weak or pale part of the shadow. This occurs because the Earth is covering a portion of the sun.

Penumbral eclipses occur when only the outer shadow (the penumbra) of Earth falls on the moon’s surface. This type of eclipse is much more difficult to observe than total eclipses or when a portion of the moon passes into the umbra. That said, if you’re very observant, you may notice a dark shadow on the moon during mid-eclipse on Friday evening. You may not notice anything at all. It’s likely the moon will just look at little bit darker than normal…like this:

Earth’s penumbral shadow forms a diverging cone that expands into space in the opposite direction of the sun. From within this zone, Earth blocks part but not the entire disk of the sun. Thus, some fraction of the sun’s direct rays continues to reach the most deeply eclipsed parts of the moon during a penumbral eclipse.

For most of North America, the penumbral eclipse will begin at moonrise (sunset) on Friday, Feb. 10 and will be obscured by evening light. Here’s a guide of when to look up:

Fun fact: Aristotle (384 – 322 BCE) first proved that Earth was round using the curved umbral shadow seen at partial eclipses. In comparing observations of several eclipses, he noted that Earth’s shadow was round no matter where the eclipse took place. Aristotle correctly reasoned that only a sphere casts a round shadow from every angle.

To learn more about lunar eclipses, visit: https://svs.gsfc.nasa.gov/11828

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

Ten Interesting facts about Mercury

Mercury is the closest planet to the sun. As such, it circles the sun faster than all the other planets, which is why Romans named it after their swift-footed messenger god. He is the god of financial gain, commerce, eloquence, messages, communication (including divination), travelers, boundaries, luck, trickery and thieves; he also serves as the guide of souls to the underworld

Like Venus, Mercury orbits the Sun within Earth’s orbit as an inferior planet, and never exceeds 28° away from the Sun. When viewed from Earth, this proximity to the Sun means the planet can only be seen near the western or eastern horizon during the early evening or early morning. At this time it may appear as a bright star-like object, but is often far more difficult to observe than Venus. The planet telescopically displays the complete range of phases, similar to Venus and the Moon, as it moves in its inner orbit relative to Earth, which reoccurs over the so-called synodic period approximately every 116 days.

Mercury’s axis has the smallest tilt of any of the Solar System’s planets (about 1⁄30 degree). Its orbital eccentricity is the largest of all known planets in the Solar System; at perihelion, Mercury’s distance from the Sun is only about two-thirds (or 66%) of its distance at aphelion.

Its orbital period around the Sun of 87.97 days is the shortest of all the planets in the Solar System. A sidereal day (the period of rotation) lasts about 58.7 Earth days.

Mercury’s surface appears heavily cratered and is similar in appearance to the Moon’s, indicating that it has been geologically inactive for billions of years. Having almost no atmosphere to retain heat, it has surface temperatures that vary diurnally more than on any other planet in the Solar System, ranging from 100 K (−173 °C; −280 °F) at night to 700 K (427 °C; 800 °F) during the day across the equatorial regions. The polar regions are constantly below 180 K (−93 °C; −136 °F). The planet has no known natural satellites.

Unlike many other planets which “self-heal” through natural geological processes, the surface of Mercury is covered in craters. These are caused by numerous encounters with asteroids and comets. Most Mercurian craters are named after famous writers and artists. Any crater larger than 250 kilometres in diameter is referred to as a Basin.

The largest known crater is Caloris Basin, with a diameter of 1,550 km. The impact that created the Caloris Basin was so powerful that it caused lava eruptions and left a concentric ring over 2 km tall surrounding the impact crater.

Two spacecraft have visited Mercury: Mariner 10 flew by in 1974 and 1975; and MESSENGER, launched in 2004, orbited Mercury over 4,000 times in four years before exhausting its fuel and crashing into the planet’s surface on April 30, 2015.

It is the smallest planet in the Solar System, with an equatorial radius of 2,439.7 kilometres (1,516.0 mi). Mercury is also smaller—albeit more massive—than the largestnatural satellites in the Solar System, Ganymede and Titan.

As if Mercury isn’t small enough, it not only shrank in its past but is continuing to shrink today. The tiny planet is made up of a single continental plate over a cooling iron core. As the core cools, it solidifies, reducing the planet’s volume and causing it to shrink. The process crumpled the surface, creating lobe-shaped scarps or cliffs, some hundreds of miles long and soaring up to a mile high, as well as Mercury’s “Great Valley,” which at about 620 miles long, 250 miles wide and 2 miles deep (1,000 by 400 by 3.2 km) is larger than Arizona’s famous Grand Canyon and deeper than the Great Rift Valley in East Africa.

The first telescopic observations of Mercury were made by Galileo in the early 17th century. Although he observed phases when he looked at Venus, his telescope was not powerful enough to see the phases of Mercury.

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images: Joseph Brimacombe, NASA/JPL, Wikimedia Commons

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carlosalberthreis

9 years ago

Que o último período seja de grandes realizações!

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carlosalberthreis

7 years ago

Reinventing the Wheel

Planning a trip to the Moon? Mars? You’re going to need good tires…

Exploration requires mobility. And whether you’re on Earth or as far away as the Moon or Mars, you need good tires to get your vehicle from one place to another. Our decades-long work developing tires for space exploration has led to new game-changing designs and materials. Yes, we’re reinventing the wheel—here’s why.

Wheels on the Moon

Early tire designs were focused on moving hardware and astronauts across the lunar surface. The last NASA vehicle to visit the Moon was the Lunar Roving Vehicle during our Apollo missions. The vehicle used four large flexible wire mesh wheels with stiff inner frames. We used these Apollo era tires as the inspiration for new designs using newer materials and technology to better function on a lunar surface.

Up springs a new idea

During the mid-2000s, we worked with industry partner Goodyear to develop the Spring Tire, an airless compliant tire that consists of several hundred coiled steel wires woven into a flexible mesh, giving the tires the ability to support high loads while also conforming to the terrain. The Spring Tire has been proven to generate very good traction and durability in soft sand and on rocks.

Spring Tires for Mars

A little over a year after the Mars Curiosity Rover landed on Mars, engineers began to notice significant wheel damage in 2013 due to the unexpectedly harsh terrain. That’s when engineers began developing new Spring Tire prototypes to determine if they would be a new and better solution for exploration rovers on Mars.

In order for Spring Tires to go the distance on Martian terrain, new materials were required. Enter nickel titanium, a shape memory alloy with amazing capabilities that allow the tire to deform down to the axle and return to its original shape.

These tires can take a lickin’

After building the shape memory alloy tire, Glenn engineers sent it to the Jet Propulsion Laboratory’s Mars Life Test Facility. It performed impressively on the punishing track.

Why reinvent the wheel? It’s worth it.

New, high performing tires would allow lunar and Mars rovers to explore greater regions of the surface than currently possible. They conform to the terrain and do not sink as much as rigid wheels, allowing them to carry heavier payloads for the same given mass and volume. Also, because they absorb energy from impacts at moderate to high speeds, there is potential for use on crewed exploration vehicles which are expected to move at speeds significantly higher than the current Mars rovers.

Airless tires on Earth

Maybe. Recently, engineers and materials scientists have been testing a spinoff tire version that would work on cars and trucks on Earth. Stay tuned as we continue to push the boundaries on traditional concepts for exploring our world and beyond.

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

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carlosalberthreis

1 month ago

É um evento único, que ficará em nossas memórias.

📅 Data de registro: 5 de agosto de 2024 às 18:24

What’s Up for June 2016?

What’s Up for June? Saturn at its best! Plus, good views of Mars, Jupiter and Jupiter’s moons continue from dusk to dawn.

You don’t have to stay up late to see Jupiter, Mars and Saturn this month, because they’re all visible soon after sunset. Jupiter is the brightest of the three, visible in the western sky all evening.

The four Galilean moons are easily visible in binoculars or telescopes. If you think you’re seeing 5 moons on June 10th, you’re not. One of them is a distant star in the constellation Leo.

For telescope viewers, the time near Mars’ closest approach to Earth, May 30th this year, is the best time to try to see the two moons of Mars: Phobos and Deimos. It takes patience, very steady skies and good charts! Mars is still large and bright in early June, but it fades as speedy Earth, in its shorter orbit around the sun, passes it.

Saturn has been close to Mars recently. This month Saturn reaches opposition, when Saturn, Earth and the sun are in a straight line with Earth in the middle, providing the best and closest views of the ringed beauty and several of its moons. You’ll be able to make out cloud bands on Saturn, in delicate shades of cream and butterscotch. They’re fainter than the bands of Jupiter. Through a telescope you’ll see Saturn’s rings tilted about as wide as they get: 26 degrees.

You’ll also have a ring-side view of the Cassini division, discovered by Giovanni Domenico Cassini, namesake of our Cassini spacecraft, orbiting Saturn since 2004 and continuing through September 2017. When you look at Saturn through a telescope, you can’t help but see several of its 4 brightest moons, and maybe more. If you just see one, that’s Titan, 50% larger than our own moon. A telescope can also reveal more moons, like Saturn’s two-colored moon Iapetus. It takes 3 months to orbit Saturn, and it’s fairly easy to see.

There’s a bright comet visible this month, Comet PanSTARRS. It’s best seen from the southern hemisphere, but it’s also visible from the U.S. low in the morning sky. Comet PanSTARRS can be seen through a telescope near the beautiful Helix Nebula on June 4, but it is visible all month.

Watch the full June “What’s Up” video for more: https://youtu.be/M7RtIa9zBYA

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

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carlosalberthreis

7 years ago

Solar System: 10 Things to Know This Week

January 8: Images for Your Computer or Phone Wallpaper

Need some fresh perspective? Here are 10 vision-stretching images for your computer desktop or phone wallpaper. These are all real pictures, sent recently by our planetary missions throughout the solar system. You’ll find more of our images at solarsystem.nasa.gov/galleries, images.nasa.gov and www.jpl.nasa.gov/spaceimages.

Applying Wallpaper: 1. Click on the screen resolution you would like to use. 2. Right-click on the image (control-click on a Mac) and select the option ‘Set the Background’ or 'Set as Wallpaper’ (or similar).

1. The Fault in Our Mars

This image from our Mars Reconnaissance Orbiter (MRO) of northern Meridiani Planum shows faults that have disrupted layered deposits. Some of the faults produced a clean break along the layers, displacing and offsetting individual beds.