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Andromeda On Collision Course With the Milky Way
ananyo writes "From the Nature story: 'The Andromeda galaxy will collide with the Milky Way about 4 billion years from now, astronomers announced today. Although the Sun and other stars will remain intact, the titanic tumult is likely to shove the Solar System to the outskirts of the merged galaxies. Researchers came to that conclusion after using the Hubble Space Telescope between 2002 and 2010 to painstakingly track the motion of Andromeda as it inched along the sky. Andromeda, roughly 770,000 parsecs (2.5 million light years) away, is the nearest large spiral galaxy to the Milky Way.'"
I thought parsecs was a unit of time though? So 770,000 parsecs is about 4 billion years?
So 12 parsecs is about 20 hours?
can't we launch a mission to deflect it ? !
Stop Panicking!!! This is no time to panic... Though if you do panic try to hold on to that feeling because it is the proper response to being told that your galaxy is on a collision course with another galaxy.
This may not be news to you, but I'm thankful to know so I could cancel my tickets to The Book Of Mormon while they're still refundable.
NVIDIA showed a simulation of this collision running on their latest Tesla GPGPU based on the "Kepler" architecture
Starts at around 1:00 on this video with a great explanation of the collision itself.
http://www.youtube.com/watch?v=aByz-mxOXJM&feature=relmfu
Sumit
(NVIDIA employee)
It's been known for a long time that Andromeda had a velocity towards the Milky Way (easily measured by its blue-shift), but no one could tell what its lateral velocity was, therefore whether it was going to actually collide or whether it was in an eccentric orbit. Actually measuring such a tiny side-shift, against more distant galaxies, of a source which is not actually a single defined object, where every part of it is in separate motion, in just 8 years, is pretty fucking impressive.
Science is all about firing a drunk pig out of a cannon just to see what happens.
Well, just in time to warn our Great^12 Grandchildren.
Maybe we could embed the message in some giant, black humming monolith, or something...
"Flyin' in just a sweet place,
Never been known to fail..."
That's where I keep all my stuff!
It's news because we didn't know if Andromeda and the Milky Way were orbiting each other or on a collision course without the transverse velocity of Andromeda. Now we know. Well, we think we know. It's going to be a little while until we can actually observe the outcome.
AAAAHHHHHHHHHH! *pause for breath* AAAAHHHHHHHHHH!
Like this submission?
It really brings home an appreciation for the human race. For all the wailing and gnashing of teeth about environmental damage we really are the only chance for earth based biodiversity to survive.
They gravitate towards each other. If their "ejection angle" was close enough for them to be flying mostly-parallel they would eventually pull into each other.
For large sets, this will be our guide even unto death, for the LORD will work for each type of data it is applied to...
(wiping sweat from brow)
I thought for a moment that TFA said 4 million years.
Hey, 4 billion is a long time. No need to panic.
...omphaloskepsis often...
There is a better article from NASA:
http://www.nasa.gov/mission_pages/hubble/science/milky-way-collide.html
This. I read this in an astronomy book a long time ago. Maybe now it's more certain, but really, this isn't big news.
If after 3-4 billion years we're still stuck on this rock we deserve to burn up...
Andromeda / Star Trek crossover, about time.
Imagine how awesome the sky would look once Andromeda is near enough to dominate the view.
Imagine how awesome the sky would look with two galaxies, one of them much larger than our own, sprawling around it.
Imagine how such a view might affect the belief systems and cultures of all the advanced life forms that might be able to perceive it.
Hopefully, I will be there, billions of years in the future, and be able to experience it.
We've always been on a collision course with Andromeda.
Confucius say, "Find worm in apple - bad. Find half a worm - worse."
Isolated clusters of galaxies (such as the local group) are expected to have low total angular momentum (basically because the initial condition has low angular momentum, and in the absence of large mass anisotropy nearby, there is nothing to change this.) The mass of the local group is dominated by Andromeda and us, and hence so is the angular momentum. If the us/Andromeda pair has low angular momentum about their centre of mass (and given the pair is gravitationally bound), they will both pass close to that centre of mass - i.e., they will collide.
Of course, having an actual measurment is much more satisfying than having a theory.
Also - although they can be spectacular from outside, galactic collisions aren't expected to have bad results for life living on their planets. The biggest effect is that colliding dust clouds trigger a burst of star formation, so the night sky will be pretty.
It has been a few decades since I studied this, so I hope this is all accurate.
Quattuor res in hoc mundo sanctae sunt: libri, liberi, libertas et liberalitas.
Until now we did not know what kind of collision it would be.
It could be a partial collision or even a near-collision.
Now we know for sure it will be a head-on collision..
That's news as far as me concerns...
How come nobody's mentioned Alastair Reynold's Revelation Space series yet? Doesn't anyone here read SF?
The fact that the Milky Way and Andromeda galaxies will eventually collide is the motivation of the Inhibitors.
At last, mankind will have a convenient and cheap way of intergalactic travel: Wait for it to come to us.
At the level of pop culture maybe it's not news. On the level of science it was not known 10-15 years ago. It was known that Andromeda was approaching the Milky way but there was no information on whether it would actually hit or whether we'd sling shot past each other and (potentially) go into orbit. A detail often glossed over in pop science books, and even some science books.
The point is, people knew Andromeda was coming towards us at x km/s. But that is only the tangential component (towards us). It might have also flown at x km/s to the right at the same time, going 45 past us.
Now people observed the speed of Andromeda on the sky (a painstaking measurement). As it turns out, Andromeda will not miss our Galaxy. That was kind of expected from the masses of galaxies in our local group -- Andromeda and the Milky Way have the same mass and are much larger than all the others, so they should attract each other most.
NB: The message above might reflect my opinion right now, but not necessarily tomorrow or next year.
I was going to challenge your assumptions about the nature of empty space in regards to collisions between large bodies. I was told in school that all matter consists largely of empty space. So I examined the common element iron:
The diameter of the nucleus of an iron atom is 1.26e-8 cm. The standard atomic weight of iron is 55.845 (which is equivalent to 55.845 gm/6.022e23 atoms or 1gm/1.0783e22 atoms). The density of iron at room temperature is 7.874 gm/cm^3. So 1 cubic centimeter of iron weighs 7.874 grams, and contains 8.49e22 atoms. Assuming a cubed nucleus, and ignoring the relatively tiny electrons, each atom has a volume of 2.00e-24. Multiply by the number of atoms above and we should have a volume of 0.17cm^3. Note that a sphere occupies 52% of the volume of its enclosing cube, which would bring the estimate down to 0.089cm^3. So ultimately, solid iron is 9-17% protons and neutrons.
It appears that while matter is more empty space than it is solid, the "emptiness" is only 1 order of magnitude, whereas your example was about 7. I retract any objections.
And over there we have the labyrinth guards. One always lies, one always tells the truth, and one stabs people who ask t
OK, so if all matter came into being 14 Billion years ago in the big bang, and all space and the matter in it has been expanding since then, and new research shows that the universe will likely keep expanding as opposed to collapsing back in upon itself, how are two galaxies with the same approximate mass supposed to collide? Shouldn't we be getting further apart? I guess relatively close bodies of matter will continue to migrate towards each other even as the larger body of matter continues to expand, so matter will eventually be in larger clumps with more open space between them, but it still seems a bit counter-intuitive.
Keep passing the open windows...