Our Galaxy Will Collide With WHAT?
HPMG News | June 11, 2012
“Our Milky Way galaxy is on a collision course with the neighboring Andromeda galaxy. This isn't speculation. NASA astronomers say with certainty it will happen. That's the bad news. The good news is that it won't happen for about four billion years - give or take.
And when the two do collide, it will be a stupendous galactic crash with the Milky Way getting a major makeover during the smashup. It is likely the sun will be flung into a new region of our galaxy, but our Earth and solar system are in no danger of being destroyed.
The findings came through painstaking NASA Hubble Space
Telescope measurements of the motion of Andromeda, which also is known as M31. The galaxy is now 2.5 million light-years away, but it is inexorably falling toward the Milky Way under the mutual pull of gravity between the two galaxies and the invisible dark matter that surrounds them both.
"After nearly a century of speculation about the future destiny of Andromeda and our Milky Way, we at last have a clear picture of how events will unfold over the coming billions of years," said Sangmo Tony Sohn of the Space Telescope Science Institute (STScI) in Baltimore, Maryland.
And that scenario is a lot like a baseball batter watching an oncoming fastball-except it's one that will take 4 billion years to connect.
Andromeda is moving toward the Milky Way at about 250,000 miles per hour. For perspective that is fast enough to travel from the Earth to the moon in one hour.
Computer simulations derived from Hubble's data show that it will take an additional two billion years after the encounter for the interacting galaxies to completely merge under the tug of gravity and reshape into a single elliptical galaxy similar to the kind commonly seen in the local universe.
Although the galaxies will plow into each other, stars inside each galaxy are so far apart that they will not collide with other stars during the encounter. However, the stars will be thrown into different orbits around the new galactic center. Simulations show that our solar system will probably be tossed much farther from the galactic core than it is today.
Why do such collisions occur? The universe is expanding and accelerating, and collisions between galaxies in close proximity to each other happen because they are bound by the gravity of the dark matter surrounding them. The Hubble Space Telescope's deep views of the universe show such encounters between galaxies were more common in the past when the universe was smaller. “
M31 is on its way to rearrange our Solar System and is gradually being pulled by gravity and there will be a giant Fourth of July kinds of explosions as Andromeda comes careening into our galaxy, the Milky Way, about four billion years from now. M31 is 2.5 million light years away, traveling at 250,000 mph, and will take about four billion years to arrive.
Although the galaxies will hit each other, the stars inside each galaxy are too far apart to cause damage, but the sun will be flung into different parts of our galaxy so our climates will change.
After the initial impact the stars will have been thrown into different orbits around a new center which will take another two billion years for it to form around a single galaxy again with the usual orbiting planets with their hosts of moons and stars.