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Waspie_Dwarf

Our Galaxy is Destined for Head-on Collision

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Posted (edited)

NASA'S Hubble Shows Milky Way is Destined for Head-on Collision

May 31, 2012

J.D. Harrington Headquarters, Washington 202-358-5241 j.d.harrington@nasa.gov

Ray Villard Space Telescope Science Institute, Baltimore 410-338-4514 villard@stsci.edu

RELEASE : 12-159

NASA'S Hubble Shows Milky Way is Destined for Head-on Collision

WASHINGTON -- NASA astronomers announced Thursday they can now predict with certainty the next major cosmic event to affect our galaxy, sun, and solar system: the titanic collision of our Milky Way galaxy with the neighboring Andromeda galaxy.

The Milky Way is destined to get a major makeover during the encounter, which is predicted to happen four billion years from now. 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.

"Our findings are statistically consistent with a head-on collision between the Andromeda galaxy and our Milky Way galaxy," said Roeland van der Marel of the Space Telescope Science Institute (STScI) in Baltimore.

The solution 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 STScI.

The scenario is like a baseball batter watching an oncoming fastball. Although Andromeda is approaching us more than two thousand times faster, it will take 4 billion years before the strike.

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.

To make matters more complicated, M31's small companion, the Triangulum galaxy, M33, will join in the collision and perhaps later merge with the M31/Milky Way pair. There is a small chance that M33 will hit the Milky Way first.

The universe is expanding and accelerating, and collisions between galaxies in close proximity to each other still 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.

A century ago astronomers did not realize that M31 was a separate galaxy far beyond the stars of the Milky Way. Edwin Hubble measured its vast distance by uncovering a variable star that served as a "milepost marker."

Hubble went on to discover the expanding universe where galaxies are rushing away from us, but it has long been known that M31 is moving toward the Milky Way at about 250,000 miles per hour. That is fast enough to travel from here to the moon in one hour. The measurement was made using the Doppler effect, which is a change in frequency and wavelength of waves produced by a moving source relative to an observer, to measure how starlight in the galaxy has been compressed by Andromeda's motion toward us.

Previously, it was unknown whether the far-future encounter will be a miss, glancing blow, or head-on smashup. This depends on M31’s tangential motion. Until now, astronomers had not been able to measure M31's sideways motion in the sky, despite attempts dating back more than a century. The Hubble Space Telescope team, led by van der Marel, conducted extraordinarily precise observations of the sideways motion of M31 that remove any doubt that it is destined to collide and merge with the Milky Way.

"This was accomplished by repeatedly observing select regions of the galaxy over a five-to seven-year period," said Jay Anderson of STScI.

"In the worst-case-scenario simulation, M31 slams into the Milky Way head-on and the stars are all scattered into different orbits," said Gurtina Besla of Columbia University in New York. "The stellar populations of both galaxies are jostled, and the Milky Way loses its flattened pancake shape with most of the stars on nearly circular orbits. The galaxies' cores merge, and the stars settle into randomized orbits to create an elliptical-shaped galaxy."

The space shuttle servicing missions to Hubble upgraded it with ever more-powerful cameras, which have given astronomers a long-enough time baseline to make the critical measurements needed to nail down M31's motion. The Hubble observations and the consequences of the merger are reported in three papers that will appear in an upcoming issue of the Astrophysical Journal.

For images, video, and more information about M31's collision with the Milky Way, visit:

For more information about NASA's Hubble Space Telescope, visit:

arrow3.gifSource

Edited by Waspie_Dwarf
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How fun! I can't wait! I need some excitement in my life.

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I was interested until I hit the "four billion years from now" part.

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We should start looking for an Anti-galaxy shelter..or emigrate !

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The night sky will look pretty interesting in 4 billion years time.

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I plan on being reincarnated a few more times, so I will probably get to see it!

Too bad I won't remember reading about it, though. Lol.

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wasp, can you pm me when it gets near?

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wasp, can you pm me when it gets near?

I'm afraid not, I'm going to be away that day.

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I plan on being reincarnated a few more times, so I will probably get to see it!

Too bad I won't remember reading about it, though. Lol.

Hi,Snow White did a hibernation thing,I guess we have to get an apple from the bad Queen, any idea where she lives ?

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Posted (edited)

How much do these guys get paid again?

I predict that in 3 Billion years the moon will be further away from the earth than it is today.

Now someone pay me for this earth shattering news.

Edited by Capt Amerika

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Cool animations of what would be an amazing sight if we had the time. The Earth would just be a hot rock by then anyway, oceans boiled off etc and the sun would be approaching its best before date also..

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Posted (edited)

How much do these guys get paid again?

I predict that in 3 Billion years the moon will be further away from the earth than it is today.

Now someone pay me for this earth shattering news.

There is a VAST difference between providing evidence for something that was previously suspected but not proven and making a post on an internet discussion forum.

Edited by Waspie_Dwarf

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The moon is moving away from the Earth at about 3.8 centimeters per year. After the Andromeda collision we, generally speaking, will be on another collision course with the Shapley Supercluster.

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This is old... They new about this in 2007...

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But I was just getting settled in at my new place!

Seriously, I know 4 billion years seems like a long time, but it's gonna go by in the blink of an eye!

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THIS IS A REAL DOOMSDAY PREDICTION! lucky for us its 4,000,000,000 years away. we actually have EVIDENCE this time. not like the other doomsday predictions no offense howard camping :P

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Amazing, Oh if only I could be alive to see this. It isn't doomsday but the rebirth of a solar system. Imagine this the first ever galaxy with two suns. An Earth with a oval rotation instead of rounded. Days would last a lot longer with only a few hours of darkness. We may even obtain another moon in our orbit. We would not have another ice age but a Desert Age of sands...sounds like a Sci-Fi flick...never mind me I'm just rambling.

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The real news here is that we have now been able to measure the direction and speed with absolute accuracy. 4 years ago we could see that both galaxies were moving toward each other, but now the proof is in...a direct collision. This is also proof that gravity has been attracting each other for a very long time, to the point where a direct collision is unavoidable. Gotta luv mother nature.

Any gravitational pull strong enough to pull our sun will result in the total disruption of our solar system.

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THIS IS A REAL DOOMSDAY PREDICTION! lucky for us its 4,000,000,000 years away. we actually have EVIDENCE this time. not like the other doomsday predictions no offense howard camping :P

No. This will probably not have any noticeable impact on the Earth.

Amazing, Oh if only I could be alive to see this. It isn't doomsday but the rebirth of a solar system. Imagine this the first ever galaxy with two suns. An Earth with a oval rotation instead of rounded. Days would last a lot longer with only a few hours of darkness. We may even obtain another moon in our orbit. We would not have another ice age but a Desert Age of sands...sounds like a Sci-Fi flick...never mind me I'm just rambling.

No. The Earth's orbit is unlikely to be affected. The new merged galaxy might have two galactic cores for a while, but that is about it. We will not get a new moon. It is incredibly unlikely that we will get another star.

Any gravitational pull strong enough to pull our sun will result in the total disruption of our solar system.

No. The net gravitational pull from Andromeda, while vast, will change gradually enough that it will almost certainly not disrupt our Solar system. It will just ``slide'' our Solar system smoothly and slowly to a new location within the merged galaxy.

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Posted (edited)

To add to what Sepulchrave said, the stars of both galaxies are so far apart, it is likely that most solar systems will be unaffected. Would be a nice sight in the sky though. Our sun may be a red giant around this period.

Edited by Mentalcase

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People are worrying about this now,but who knows, the human race might become extinct way before. The bigger concern is us not killing ourselves by nuclear missiles.

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Would somebody please fix the title of the article? "Andromedia" offended my eyeballs.

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I was worried we'd all die, but in 4 billion years I can't even imagine where humanity will be.

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Posted (edited)

No. This will probably not have any noticeable impact on the Earth.

No. The Earth's orbit is unlikely to be affected. The new merged galaxy might have two galactic cores for a while, but that is about it. We will not get a new moon. It is incredibly unlikely that we will get another star.

No. The net gravitational pull from Andromeda, while vast, will change gradually enough that it will almost certainly not disrupt our Solar system. It will just ``slide'' our Solar system smoothly and slowly to a new location within the merged galaxy.

I thought that the likelihood is that our system will end up near the edge of an arm giving us quite a spectacular view of the new Galaxy? Although water will be boiled of the earth around this time wont it? I thought what happens in the merge was still a little up in the air to be honest, but it gives us something other than the Sun burning out to think about I guess!

I actually had no idea this was not confirmed earlier. I thought it was some time ago. I have mentioned the event in the ET section of the forum many times, our new Milkomeda Galaxy :D when people talk about the sun burning up. The Sagittarius Dwarf Galaxy (a globular cluster with type II stars) is currently colliding with the Milky Way about 70,000 light years away from earth, and should hit the center of the galaxy in about 100,000 years. But if I had a choice, I'd like to be here in about 11 million years when Phobos will either smash into Mars of become a new ring around it.

Edited by psyche101

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Imagine a planet's, stars, ect ect passing our skies, now that'll be a sight

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