NASA has discovered at least one massive galaxy that has been deemed to be completely dead. The galaxy in question, MACS 2129–1, is over 22 billion lightyears from Earth. The only reason the researchers at NASA were able to detect such a distant object was thanks to a phenomenon known as a gravitational lens.
The Hubble Space Telescope has found not one or two, but as many as 6 galaxies that are dead, as far as their role of birthing stars is concerned. The Hubble Telescope was looking back in time to a period when the universe was some 3 billion years old.
One such estimate says that there are between 100 and 200 billion galaxies in the observable universe. Other astronomers have tried to estimate the number of 'missed' galaxies in previous studies and come up with a total number of 2 trillion galaxies in the universe.
"Dead" galaxies mysteriously ran out of fuel to make stars early in the universe. "Live fast, die young" could be the motto of six early, massive, "dead" galaxies that ran out of the cold hydrogen gas needed to make stars early in the life of the universe.
The Andromeda galaxy, our nearest massive spiral galaxy, is in the green valley and likely began its decline eons ago: it is a zombie galaxy, according to our latest research.
The eventual merger is still at least 2.5 billion years away. So our home planet and the solar system is safe until then. But after that, it is bad news for Earth. Depending on the position of the solar system, Earth can be exposed to more radiation from nearby stars resulting in inhospitable temperatures.
The technology required to travel between galaxies is far beyond humanity's present capabilities, and currently only the subject of speculation, hypothesis, and science fiction. However, theoretically speaking, there is nothing to conclusively indicate that intergalactic travel is impossible.
Located in the constellation Triangulum Australe, galaxy ESO 137-001 looks amazingly like a jellyfish swimming amid a sea of stars. The galaxy is a barred spiral galaxy — together, its stars form a spiral shape with a bar-shaped center — with a twist: streamers of stars that seem to drift like jellyfish tentacles.
The 'ghost galaxy' falls in the category of ultra-diffuse galaxies that are known for their extremely low density. Compared to the Milky Way galaxy — which itself amazed astronomers recently with a broken arm anomaly — the NGC 1052-DF2 galaxy has roughly the same volume, but only has about 0.5 percent star density.
The life cycle of galaxies
As galaxies fall through clusters, the intergalactic plasma can rapidly remove their gas in a violent process called ram pressure stripping. When you remove the fuel for star formation, you effectively kill the galaxy, turning it into a dead object in which no new stars are formed.
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There's a limit to how much of the universe we can see. The observable universe is finite in that it hasn't existed forever. It extends 46 billion light years in every direction from us.
"So a number like 200 billion [galaxies] is probably it for our observable universe."
Firstly, it is a future collision with another galaxy, Andromeda. The galaxies will pass through each other, merge into one gigantic galaxy and all star clouds will flash into a star formation. But there are also some issues, for instance, hot large blue stars, a blasting gas, a quasar, radiation.
When all of the stars in a galaxy die, and new ones are no longer forming, the galaxy itself ceases to exist. This occurs when all of the galaxy's gas is ejected, making it impossible for new stars to form.
For the most part, the stars you see with the naked eye (that is, without a telescope) are still alive. These stars are usually no more than about 10,000 light years away, so the light we see left them about 10,000 years ago.
Compared to other types of galaxies, elliptical galaxies have smaller portions of gas and dust, contain older stars, and don't form many new stars. The largest and rarest of these galaxies – known as giant ellipticals – are about 300,000 light-years across.
An extragalactic planet, also known as an extragalactic exoplanet or an extroplanet, is a star-bound planet or rogue planet located outside of the Milky Way Galaxy. Due to the immense distances to such worlds, they would be very hard to detect directly. However, indirect evidence suggests that such planets exist.
Black holes are the darkest things in our universe because they emit no light whatsoever in any wavelength.
The small galaxy of IC 1613, which is 2.3 million light-years away is notable for its lack of cosmic dust swirling among its scattered stars and the bright pink gas that gives it its unique color.
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Now the Andromeda galaxy can be seen with the naked eye, like a tiny dot in the sky. But in three billion years it will be so clearly visible to the naked eye that it will even be possible to see individual spiral arms in it.
Andromeda–Milky Way collision
The merger will totally alter the night sky over Earth but will likely leave the solar system unharmed, according to NASA.
The trite answer is that both space and time were created at the big bang about 14 billion years ago, so there is nothing beyond the universe. However, much of the universe exists beyond the observable universe, which is maybe about 90 billion light years across.