The latest results from the “Cheshire Cat” group of galaxies show how manifestations of Einstein’s 100-year-old theory can lead to new discoveries today. Astronomers have given the group this name because of the smiling cat-like appearance. Some of the feline features are actually distant galaxies whose light has been stretched and bent by the large amounts of mass, most of which is in the form of dark matter detectable only through its gravitational effect, found in the system.
Image credit: NASA / STScI / Chandra & Hubble
❝Sou o povo a triunfar
Sou a força popular
Sou raiz, tradição e saber
A festa do meu boi bumbá❞
Ainda estamos em 2015!! hahahah...
Que o último período seja de grandes realizações!
This month the new year’s first meteor shower fizzles, Mars meets Jupiter in the morning sky and the U.S. will enjoy a total lunar eclipse!
Most meteor showers radiate from recognizable constellations. Like the Leonids, Geminids and Orionids.
But the Quadrantids are meteors that appear to radiate from the location of the former Quadrans Muralis constellation, an area that’s now part of the constellation Bootes.
The Quadrantids’ peak lasts for just a few hours, and sadly, this year their timing coincides with a very bright, nearly full moon that will wash out most of the meteors.
You can look in any direction to see all the meteor showers. When you see one of these meteors, hold a shoestring along the path it followed. The shoestring will lead you back to the constellation containing the meteor’s origin.
On the morning of January 6th, look in the south-southeast sky 45 minutes before sunrise to see Jupiter and fainter Mars almost as close as last month’s Jupiter and Venus close pairing.
Mars is only one-sixth the apparent diameter of Jupiter, but the two offer a great binocular and telescopic view with a pretty color contrast. They remain in each other’s neighborhood from January 5th through the 8th.
Finally, to end the month, a great total lunar eclipse favors the western U.S., Alaska, and Hawaii and British Columbia on January 31st. Australia and the Pacific Ocean are well placed to see a major portion of the eclipse–if not all of it.
Watch the full What’s Up for January Video:
There are so many sights to see in the sky. To stay informed, subscribe to our What’s Up video series on Facebook. Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com.
Nessa semana, aqui em Parintins, costuma ser bastante movimentado.
Porém, devido a pandemia, quando eu fui comprar pão no final da tarde de ontem. Eu percebi que a cidade estava irreconhecível... Sem visitantes, sem sons de toadas, sem alegorias.
This new NASA/ESA Hubble Space Telescope image shows the center of the Lagoon Nebula, an object with a deceptively tranquil name, in the constellation of Sagittarius. The region is filled with intense winds from hot stars, churning funnels of gas, and energetic star formation, all embedded within an intricate haze of gas and pitch-dark dust.
Image Credit: NASA/JPL/ESA/J. Trauger
This photograph of Neptune was reconstructed from two images taken by Voyager 2’s narrow-angle camera, through the green and clear filters. At the north (top) is the Great Dark Spot, accompanied by bright, white clouds that undergo rapid changes in appearance.
Credit: NASA
Gravitational waves are ‘ripples’ in the fabric of space-time caused by some of the most violent and energetic processes in the Universe. Albert Einstein predicted the existence of gravitational waves in 1916 in his general theory of relativity.
Einstein’s mathematics showed that massive accelerating objects (such as neutron stars or black holes orbiting each other) would disrupt space-time in such a way that ‘waves’ of distorted space would radiate from the source (like the movement of waves away from a stone thrown into a pond). Furthermore, these ripples would travel at the speed of light through the Universe, carrying with them information about their cataclysmic origins, as well as invaluable clues to the nature of gravity itself.
The strongest gravitational waves are produced by catastrophic events such as colliding black holes,
the collapse of stellar cores (supernovae), coalescing neutron stars or white dwarf stars, the slightly wobbly rotation of neutron stars that are not perfect spheres, and the remnants of gravitational radiation created by the birth of the Universe itself.
hough gravitational waves were predicted to exist in 1916, actual proof of their existence wouldn’t arrive until 1974, 20 years after Einstein’s death. In that year, two astronomers working at the Arecibo Radio Observatory in Puerto Rico discovered a binary pulsar–two extremely dense and heavy stars in orbit around each other. This was exactly the type of system that, according to general relativity, should radiate gravitational waves. Knowing that this discovery could be used to test Einstein’s audacious prediction, astronomers began measuring how the period of the stars’ orbits changed over time. After eight years of observations, it was determined that the stars were getting closer to each other at precisely the rate predicted by general relativity. This system has now been monitored for over 40 years and the observed changes in the orbit agree so well with general relativity, there is no doubt that it is emitting gravitational waves.
Since then, many astronomers have studied the timing of pulsar radio emissions and found similar effects, further confirming the existence of gravitational waves. But these confirmations had always come indirectly or mathematically and not through actual 'physical’ contact.
That was the case up until September 14, 2015, when LIGO, for the first time, physically sensed distortions in spacetime itself caused by passing gravitational waves generated by two colliding black holes nearly 1.3 billion light years away! LIGO and its discovery will go down in history as one of the greatest human scientific achievements.
When a gravitational wave passes by Earth, it squeezes and stretches space. LIGO can detect this squeezing and stretching. Each LIGO observatory has two “arms” that are each more than 2 miles (4 kilometers) long. A passing gravitational wave causes the length of the arms to change slightly. The observatory uses lasers, mirrors, and extremely sensitive instruments to detect these tiny changes. Watch the animation below to see how this works!
Lucky for us here on Earth, while the origins of gravitational waves can be extremely violent, by the time the waves reach the Earth they are millions of times smaller and less disruptive. In fact, by the time gravitational waves from the first detection reached LIGO, the amount of space-time wobbling they generated was thousands of times smaller than the nucleus of an atom! Such inconceivably small measurements are what LIGO was designed to make. To find out how LIGO can achieve this task, visit LIGO’s Interferometer.
Source: LIGO & spaceplace.nasa.gov
Image credit: LIGO/VIRGO (SXS, the Simulating eXtreme Spacetimes) & NASA/Goddard Space Flight Center