Our galaxy probably contains 100 to 400 billion stars, and is about 100,000 light-years across.
The Milky Way is about 1,000,000,000,000,000,000 km (about 100,000 light years or about 30 kpc) across. The Sun does not lie near the center of our Galaxy.
The Sun is situated about halfway from the centre and is near the middle of the disk in the vertical direction. So, to leave our Galaxy, we would have to travel about 500 light-years vertically, or about 25,000 light-years away from the galactic centre.
Galaxies may exist at that distance, but their light would be too faint for our telescopes to see. C. Because looking 15 billion light-years away means looking to a time before the universe existed.
Some galaxies will have fallen over the cosmic horizon, where no amount of time would ever let you reach them. If you wanted to travel 100 trillion light years away, you could make the journey in 62 years.
Astronomers have discovered what may be the oldest and most distant galaxy ever observed. The galaxy, called HD1, dates from a bit more than 300 million years after the Big Bang that marked the origin of the universe some 13.8 billion years ago, researchers said on Thursday.
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.
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.
“When two galaxies start to merge, their central supermassive black holes sink to the center of this newly formed galaxy and eventually merge” into a single, bigger black hole, Chiara Mingarelli, an astrophysicist at the University of Connecticut and the Flatiron Institute's Center for Computational Astrophysics who ...
Our Milky Way will have lost its identity long ago through merging with the Andromeda galaxy, M31. The resulting giant elliptical galaxy will be devoid of dust and gas. The night sky will be a largely homogeneous sprinkling of stars. Stellar density will concentrate toward the galactic core.
Proxima Centauri is 4.2 light-years from Earth, a distance that would take about 6,300 years to travel using current technology. Such a trip would take many generations.
There are likely to be many more planetary systems out there waiting to be discovered! Our Sun is just one of about 200 billion stars in our galaxy.
"Black holes form inside their host galaxies and grow inproportion to them, forming an accretion disc which will eventually destroy thehost," he added. "In this sense they can be described as viral innature."
Located just under 1,600 light-years away, the discovery suggests there might be a sizable population of dormant black holes in binary systems. The black hole Gaia BH1, seen in this artist's concept near its Sun-like companion star, is the closest black hole to Earth discovered so far.
Astronomers believe that supermassive black holes lie at the center of virtually all large galaxies, even our own Milky Way. Astronomers can detect them by watching for their effects on nearby stars and gas.
The Andromeda galaxy is currently racing toward our Milky Way at a speed of about 70 miles (113 km) per second. With this in mind, our merger will occur five billion years from now.
How long would it take to get to the Andromeda Galaxy? Forget it! Although it may be one of the closest galaxies to our own, since the Andromeda Galaxy is 2.5 million light years distant it would take 2.5 million years to get there if (and it's a huge 'if') we could travel at the speed of light.
Most of the elements of our bodies were formed in stars over the course of billions of years and multiple star lifetimes. However, it's also possible that some of our hydrogen (which makes up roughly 9.5% of our bodies) and lithium, which our body contains in very tiny trace amounts, originated from the Big Bang.
Scientists now consider it unlikely the universe has an end – a region where the galaxies stop or where there would be a barrier of some kind marking the end of space. But nobody knows for sure.
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.
22 billion years in the future is the earliest possible end of the Universe in the Big Rip scenario, assuming a model of dark energy with w = −1.5. False vacuum decay may occur in 20 to 30 billion years if the Higgs field is metastable.
Only 1-in-10,000 galaxies fall into the rarest category of all: ring galaxies. With a dense core consisting of old stars, and a circular or elliptical ring consisting of bright, blue, young stars, the first ring was only discovered in 1950: Hoag's object.
In a new study, Stanford physicists Andrei Linde and Vitaly Vanchurin have calculated the number of all possible universes, coming up with an answer of 10^10^16.
That's about the same amount of energy in 10 trillion trillion billion megaton bombs! These explosions generate beams of high-energy radiation, called gamma-ray bursts (GRBs), which are considered by astronomers to be the most powerful thing in the universe.