For 25 years now, the Hubble Space Telescope (and many other satellites) has stimulated us with numerous jaw dropping images of space—stretching from the Great Nebula of Orion, to the Whirlpool Galaxy. They all look so huge and comprehensive, you can nearly imagine yourself moving through space, looking directly at them from up close—yet even the closest among them are unfathomably far away (the closest planet is nearly 162 million miles/261 million kilometers from sun, while the closest star is over 4 light-years distant). In a recent video, the Russian Space Agency (Roscosmos, to be exact) visualizes how our sky may look if some of these marvels were in nearer proximity to Earth. Watch the video below:
Dark matter is a hypothetical kind of matter that cannot be seen with telescopes but accounts for most of the matter in the universe. Dark matter is estimated to constitute 84.5% of the total matter in the universe. It has not been detected directly, making it one of the greatest mysteries in modern astrophysics.
Hubble Image of Galactic Collision
A study of 72 large cluster collisions shows how dark matter in galaxy clusters behaves when they collide.
Image Showing How two Galaxies Collides
Astronomers have used data from NASA’s Hubble Space Telescope and the Chandra X-ray Observatory to find that dark matter interacts with itself less than previously thought. In an effort to learn more about dark matter, astronomers observed how galaxy clusters collide with each other — an event that could hold clues about the mysterious invisible matter that makes up most of the mass of the universe.
As part of a new study, published in the journal Science on Thursday, researchers used the Hubble telescope to map the distribution of stars and dark matter after a collision. They also used the Chandra observatory to detect the X-ray emission from colliding gas clouds.
“Dark matter is an enigma we have long sought to unravel,” John Grunsfeld, assistant administrator of NASA’s Science Mission Directorate in Washington, said in a statement. “With the combined capabilities of these great observatories, both in extended mission, we are ever closer to understanding this cosmic phenomenon.”
According to scientists, galaxy clusters are made of three main components — galaxies, gas clouds and dark matter. During collisions, the gas clouds bump into each other and gradually slow down. Galaxies, on the other hand, are much less affected by this process, and because of the huge gaps between the stars within them, galaxies do not slow each other down.
“We know how gas and stars react to these cosmic crashes and where they emerge from the wreckage,” David Harvey of the École Polytechnique Fédérale de Lausanne in Switzerland, and the study’s lead author, said in the statement. “Comparing how dark matter behaves can help us to narrow down what it actually is.”
The researchers studied 72 large galaxy cluster collisions and found that, like galaxies, the dark matter continued straight through the collisions without slowing down much, meaning that dark matter do not interact with visible particles.
“There are still several viable candidates for dark matter, so the game is not over. But we are getting nearer to an answer,” Harvey said.
Source : IBT times
(Click Image to Download)
It kind of looks like a snow globe — or maybe like the glittering ornament atop a massive Christmas tree.
Or like your neighbor’s house during December, if you’re lucky enough to live next to an aggressive seasonal decorator.
But this image from the Hubble Space Telescope shows Messier 92. Messier 92 is a globular cluster, or a spherical group of old stars bound tightly together by gravity. Their density can make globular clusters appear quite bright, and this is one of the brightest in our whole galaxy.
You may even have seen this cosmic bauble before. It’s over 25,000 light years away from Earth, but with 330,000 stars packed tightly into it, it’s often visible with the naked eye. You can catch its occasional appearances in the constellation Hercules.
Astronomers know from Messier 92’s molecular composition that it isn’t just bright — it’s also very old. About as old as the universe itself, in fact.
Like this image? You could have been the one to create it. A version of this photo was submitted by Gilles Chapdelaine as part of the Hubble’s Hidden Treasures image competition. The Hubble has beamed back so much data that not all of it has been translated into visible images, but the public is welcome to sift through archives to try to find stellar shots worth sharing.Find out more at the Hubble Web site.
Source : Washington post