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Andromeda On Collision Course With the Milky Way

samzenpus posted about 2 years ago | from the demolition-galaxy dept.

NASA 217

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.'"

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217 comments

And this is news how? (1, Informative)

GodfatherofSoul (174979) | about 2 years ago | (#40176731)

Oh, you got me to click on the story. Got me again, you ad-whoring editors!

Re:And this is news how? (5, Funny)

Anonymous Coward | about 2 years ago | (#40176781)

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.

Re:And this is news how? (5, Funny)

Jeremiah Cornelius (137) | about 2 years ago | (#40176877)

Well, just in time to warn our Great^12 Grandchildren.

Maybe we could embed the message in some giant, black humming monolith, or something...

Re:And this is news how? (1)

Surt (22457) | about 2 years ago | (#40177069)

4 billion years is somewhat more than 14 generations, at least assuming that life expectancy gains don't snowball.

Re:And this is news how? (1)

X0563511 (793323) | about 2 years ago | (#40177161)

They probably will. Also, don't forget all that relativistic travel we'll get to eventually ;)

Re:And this is news how? (2)

Anonymous Coward | about 2 years ago | (#40176933)

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.

Re:And this is news how? (1, Informative)

Anonymous Coward | about 2 years ago | (#40177333)

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.

No, it's not news. I heard it 10-15 years ago. (Could be more, hard to keep track.)

Re:And this is news how? (2)

DurendalMac (736637) | about 2 years ago | (#40177341)

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.

Re:And this is news how? (2)

Anonymous Coward | about 2 years ago | (#40177927)

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...

Re:And this is news how? (1)

X0563511 (793323) | about 2 years ago | (#40177153)

Why? The text you can read on the home page (and RSS summary!) tells you the time scale involved here. The only reason you clicked the story is because of your impatience or the stupidity of jumping because of a scary headline.

770,000 parsecs? (5, Funny)

Anonymous Coward | about 2 years ago | (#40176761)

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?

Re:770,000 parsecs? (1)

The_One_Ring (599329) | about 2 years ago | (#40176773)

From Wikipedia: The parsec (symbol: pc) is a unit of length used in astronomy. It is about 3.26 light-years, which is equal to just under 31 trillion (3.1×1013) kilometres or just over 19 trillion (1.9×1013) miles.

Re:770,000 parsecs? (1)

mug funky (910186) | about 2 years ago | (#40176775)

parsec is space.

take 1 astronomical unit as the opposite side length on a right-angled-triangle, one arc-second as the angle, and the length of the adjacent side will be 1 parsec.

Re:770,000 parsecs? (2)

Jonathan A (1584455) | about 2 years ago | (#40176793)

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?

http://en.wikipedia.org/wiki/Parsec [wikipedia.org]

The parsec (symbol: pc) is a unit of length used in astronomy. It is about 3.26 light-years, which is equal to just under 31 trillion (3.1×1013) kilometres or just over 19 trillion (1.9×1013) miles.

Re:770,000 parsecs? (1)

X0563511 (793323) | about 2 years ago | (#40177169)

So. A measure of both distance and time, depending on your context.

Re:770,000 parsecs? (4, Informative)

Jappus (1177563) | about 2 years ago | (#40177681)

So. A measure of both distance and time, depending on your context.

No. A parsec is "a distance corresponding to a parallax of one second". But here, "second" does not refer to the unit of time "second" but to an "arc-second", a specific angular value. If you have a circle, and you divide it into 360 parts, a single slice covers an angle of exactly one "degree" (do note that this in turn also does not refer to temperature). If you divide that slice into 60 parts, each slice covers an angle of 1 arc-minute. If you divide such a slice into another 60 parts, you get an angle that covers 1 arc-second.

http://en.wikipedia.org/wiki/Arcsecond#Symbols_and_abbreviations [wikipedia.org]

As for what a parallax is, please read the link provided by the grandparent.

But even if you had used a unit of time to define the parsec -- like in the light-year -- what you actually define is a pure length. Do note that you can define a light-year as both "the distance light crosses in an absolute vacuum in one solar year" or "9.4605284 x 10^15 meters". See how the latter does not include any reference to time? You could even express the light-year as the distance you can drive an object of a certain mass and shape when you accelerate it with a certain energy through a perfectly uniform medium of a certain density (thus slowing down the object eventually to a standstill).

You can define a length with the help of a unit of time, but you don't need to. That is also why the 1 astronomical unit distance used in the parsec is also not a unit of time; as the fact that it derives from the rotation of the earth around the sun is unimportant as long as the ultimately defined value remains a pure time.

Re:770,000 parsecs? (2)

Jappus (1177563) | about 2 years ago | (#40177701)

[...] the ultimately defined value remains a pure time.

Please mentally replace that part with "the ultimately defined value remains a pure unit of distance."

Re:770,000 parsecs? (0)

Anonymous Coward | about 2 years ago | (#40176937)

Hi, George, loved the trilogy, could you perhaps stop remaking them every few years? Thanks the internet.

Re:770,000 parsecs? (2)

mug funky (910186) | about 2 years ago | (#40177167)

aaah, i totally whooshed on the GP post. thank you for reminding me that this was a pop culture reference and not just a weird misconception (well, it's both i suppose, but the latter is on mr lucas).

Re:770,000 parsecs? (1)

Surt (22457) | about 2 years ago | (#40177077)

Just remember that distance and time are interchangeable thanks to the speed of light.

Re:770,000 parsecs? (0)

Anonymous Coward | about 2 years ago | (#40177381)

Close. That's how long it normally takes to do the Kessel run. However, if you know the shortcut, it only takes 12.

oh noews! (4, Funny)

j-stroy (640921) | about 2 years ago | (#40176767)

can't we launch a mission to deflect it ? !

Re:oh noews! (1)

MacGyver2210 (1053110) | about 2 years ago | (#40176855)

Nope, this event is clearly unavoidable. There is no way we have enough time to relocate or divert it.

http://www.youtube.com/watch?v=qLlUgilKqms [youtube.com]

Re:oh noews! (3, Funny)

Anonymous Coward | about 2 years ago | (#40177149)

Eh, the Sun itself only has about 4.5 billion years left in it...So Andromeda slamming into us might be a welcome change by then.

Re:oh noews! (3, Funny)

Anonymous Coward | about 2 years ago | (#40177337)

Nope, this event is clearly unavoidable. There is no way we have enough time to relocate or divert it.

What if we used a crack team of roughnecks?

Re:oh noews! (1)

Hognoxious (631665) | about 2 years ago | (#40177671)

It might work, but only if the boffins get it hopelessly wrong first despite all their fancy-pants book larnin'.

Don't Panic (3, Funny)

stms (1132653) | about 2 years ago | (#40176771)

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.

The worst danger.... (1)

PapayaSF (721268) | about 2 years ago | (#40177123)

...is that it will attract the Eddorians.

Re:The worst danger.... (1)

aiht (1017790) | about 2 years ago | (#40177407)

...is that it will attract the Eddorians.

Don't worry, in another 4 billion years, surely we will have met the Arisians. Right?

Re:Don't Panic (1)

Anonymous Coward | about 2 years ago | (#40177195)

I just got off the "phone" with the Asgard. They say it's nothing to worry about.

-Jack O'Neill (two "L"s)

Watch video of simulation of this collision (5, Interesting)

gupg (58086) | about 2 years ago | (#40176785)

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 [youtube.com]

Sumit
(NVIDIA employee)

Re:Watch video of simulation of this collision (3, Informative)

Anonymous Coward | about 2 years ago | (#40176883)

Andromeda-Milky Way collision starts at 2:54, before that is a recap of the Fermi architecture.

Re:Watch video of simulation of this collision (0)

Anonymous Coward | about 2 years ago | (#40176927)

The good stuff really gets going at http://www.youtube.com/watch?feature=player_detailpage&v=aByz-mxOXJM#t=173s

Re:Watch video of simulation of this collision (1)

FrootLoops (1817694) | about 2 years ago | (#40177411)

You don't have to convert to seconds. You can use "...#t=2m53s" (or & instead of #).

Re:Watch video of simulation of this collision (3, Informative)

flimflammer (956759) | about 2 years ago | (#40177761)

You can right click a video at any time and select "Copy link at current time"

When you do that, which he likely did, it uses seconds.

Re:Watch video of simulation of this collision (2)

X0563511 (793323) | about 2 years ago | (#40177183)

Less talking more animation.

Seriously they stop the thing like 20 times to talk.

Re:Watch video of simulation of this collision (1)

FrootLoops (1817694) | about 2 years ago | (#40177505)

I'm a little confused. In the video they themselves note that around 90% of the matter in the universe is dark matter, and as far as I'm aware its configuration around our galaxies isn't well known, so... isn't the simulation basically worthless? The article doesn't clear this up either, though perhaps the papers would.

Re:Watch video of simulation of this collision (1)

Riddler Sensei (979333) | about 2 years ago | (#40177801)

Well, I was really digging the demonstration because it was a cool little piece showing Kepler and I do rather like watching these sort of simulations, but I had to sigh when the man claimed a "full scale simulation". Andromeda and the Milky Way are a far sight more than just 10 million bodies.

"Oh, look! A pedant on Slashdot!"

Still want a Kepler, however. Unfortunately finances say that my 580 is nowhere near obsolete enough to even come close to justifying it.

Interesting timing (1)

Grayhand (2610049) | about 2 years ago | (#40176797)

It's an odd coincidence that it starts to happen around the time our sun goes red giant. Not that anything resembling Homo Sapiens would be around. 5 billion years ago we hadn't made it up to the level of bacteria yet. Impossible to say what Earth life would be like by then if it survived that long. Odds are all life would be wiped out well before we go red giant. Even another billion years from now conditions will be quite harsh. Too bad because in 7 billion years we'd have a very interesting sky.

Re:Interesting timing (2)

Intrepid imaginaut (1970940) | about 2 years ago | (#40177091)

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.

Re:Interesting timing (1)

Coisiche (2000870) | about 2 years ago | (#40178003)

5 billion years ago we hadn't made it up to the level of bacteria yet.

I was under the impression that the Earth was only 4.5 billion years old.

Although I suppose you could go with panspermia and adopt the position that life here started 5 billion years ago; it just started somewhere else.

OMG! Return your library books1 (0)

Anonymous Coward | about 2 years ago | (#40176803)

Before it;s too late...

don't panic, it's just the end of the world (4, Informative)

FatLittleMonkey (1341387) | about 2 years ago | (#40176807)

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.

Re:don't panic, it's just the end of the world (0)

X0563511 (793323) | about 2 years ago | (#40177209)

I think you miss the part where that simulation was done in real-time. They didn't compute it for 8 years ;)

These GPU (is it really right to call them just GPUs anymore?) are seriously getting powerful.

Re:don't panic, it's just the end of the world (3, Funny)

Anonymous Coward | about 2 years ago | (#40177309)

In real-time?

Did the computation really take 4 billion years?

Re:don't panic, it's just the end of the world (5, Funny)

Hognoxious (631665) | about 2 years ago | (#40177689)

Yep, it was written in Java.

The first billion went while they were waiting for Eclipse to open.

Re:don't panic, it's just the end of the world (1)

toruonu (1696670) | about 2 years ago | (#40177347)

I guess my irony detector is malfunctioning or you really misunderstood the post you responded to. The impressive part is measuring the actual Andromeda galaxy lateral motion that is so tiny form our perspective and timescale that doing that accurately enough in 8 years is the impressive part. The fact that NVIDIA made an animation of it realtime or not is fully besides the point.

Though on a side note I agree that GPU's are becoming crazy fast...

Oh no! Not the Galaxy! (5, Funny)

Cyberllama (113628) | about 2 years ago | (#40176907)

That's where I keep all my stuff!

Re:Oh no! Not the Galaxy! (1)

rvw (755107) | about 2 years ago | (#40177493)

That's where I keep all my stuff!

I keep the Galaxy in my pocket. And in case it crashes, I just reboot it. What's all the fuss about?

Interesting (1)

mdenham (747985) | about 2 years ago | (#40176921)

The approach velocity is pretty low as astronomical speeds go - 187.5 m/s or 675 km/h (a bit under 420mph, for people who want non-metric numbers).

So is it actually a collision that we're headed for, or is someone with horrible depth perception trying to dock? :-)

Time stands still (1)

Anonymous Coward | about 2 years ago | (#40176925)

Andomeda will be on collision corse with the Milky Way throughout the whole history of mankind. It's just a blink of an eye for the universe.

By the time.. (0)

Anonymous Coward | about 2 years ago | (#40176929)

this will happen, this article, whatever paper is made and whatever simulations that been done will be forgotten.

Heck I can go so far and say that in probably 100 years all the stuff mentioned above will be forgotten.

The outskirts, huh? (1)

MsWhich (2640815) | about 2 years ago | (#40176931)

Typical. Some riffraff shows up in the neighborhood and instantly everyone panics and moves to the suburbs.

Anyone have the number for those SpaceX guys? I'm thinking of going early to avoid the rush.

Expanding universe? (0)

Anonymous Coward | about 2 years ago | (#40176971)

If the universe was created in a big bang, and everything expands from there on, how can two galaxies collide? Did one of them turn around or something?

Re:Expanding universe? (2)

X0563511 (793323) | about 2 years ago | (#40177215)

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.

AAAHHHHHH! (2, Funny)

Anonymous Coward | about 2 years ago | (#40176975)

AAAAHHHHHHHHHH! *pause for breath* AAAAHHHHHHHHHH!

Fear not (1)

Anonymous Coward | about 2 years ago | (#40176983)

But don't worry!!! Like all good movies only the USA will be affected...

Cool! (0)

Anonymous Coward | about 2 years ago | (#40177101)

That'll make exploring it easier sooner. 10 million years sooner!

Well then... (1)

Anonymous Coward | about 2 years ago | (#40177157)

...time to grab my towel.

Red Giant Sol? (1)

Anonymous Coward | about 2 years ago | (#40177229)

Isn't our sun expected to turn into a red giant in around the same timeframe? 4 billion years or so from now doesn't seem like it's going to be a good time for us!

Re:Red Giant Sol? (5, Insightful)

toruonu (1696670) | about 2 years ago | (#40177353)

If after 3-4 billion years we're still stuck on this rock we deserve to burn up...

whew! (2)

swell (195815) | about 2 years ago | (#40177233)

(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.

Crikey (0)

Anonymous Coward | about 2 years ago | (#40177253)

For a second there, I thought you said four MILLION years. Phew!

not a collislion course (0)

Anonymous Coward | about 2 years ago | (#40177293)

As any pilot knows, if it inches along the sky, you are not on a collission course.
Only if it remains at exactly the same spot, you are in trouble.

well.... (1)

CheshireDragon (1183095) | about 2 years ago | (#40177295)

Does this mean I can kill myself now?

Re:well.... (1)

kermidge (2221646) | about 2 years ago | (#40177697)

I figure that getting drunk and committing suicide are similar - if you need an excuse you're doing it wrong.

"collision" (0)

Anonymous Coward | about 2 years ago | (#40177335)

Actually, it will be more like the two galaxies will pass through each other and some physical objects will have their orbits disturbed. Actual collisions - like a solid object hitting another solid object are quite rare when galaxies interact simply because a galaxy is mostly empty space. What you DO see is a lot of new star formation because regions of dust are large and changes in gravity or objects passing through dust clouds can trigger a collapse and star formation etc.

Of course, if you happen to be close to either galactic core during the event then your chances of having a bad day go up quite a bit.

We're already dead in 4 billion years (1)

KarlIsNotMyName (1529477) | about 2 years ago | (#40177375)

If we still depend on the Sun in 4 billion years, we're screwed anyway. Maybe we could've burried deep underground or something, shielded from the heat and toxic atmosphere, but we need to become a lot more mobile if we intend to live on as a species (not that it's likely to be the same species as it is today).

It's coming straight at us? (0)

Anonymous Coward | about 2 years ago | (#40177587)

Yellow alert! Polarise the hullplating! Evasive maneuver pattern delta!

Damn it! another trip to Walmart... (0)

Anonymous Coward | about 2 years ago | (#40177599)

...to stock up on pasta and beans... better to be prepared hey?!

Mabe we could? (1)

Sla$hPot (1189603) | about 2 years ago | (#40177601)

If we start firering our strongest lasers at Andromeda now.
Could we.... deflect it before its too late?
Perhaps build a cloud of mirrors around the sun pointing towards the hostile galaxy.
Unless the Andromendanians have allready startet to fire their deflector beams at us.
In that case we should prepare for an even more accelerated climate change.
Maybe that explains why the climate is already so hot. Hot hot hot.
Hey SlashDot. This is a grat article. Keep up the good work.

The Perseus Galaxy (1)

neoshroom (324937) | about 2 years ago | (#40177603)

Wow, so we live in the Perseus galaxy and Andromeda really does have a rock chained to her (the M33 galaxy). Oh yeah, and for those who think I'm speaking nonsense:

Andromeda is an Ethiopian princess from Greek mythology who, as divine punishment for her mother's bragging, the Boast of Cassiopeia, was chained to a rock as a sacrifice to a sea monster. She was saved from death by Perseus, her future husband (Wikipedia [wikipedia.org] ).

Imagine (5, Interesting)

allcoolnameswheretak (1102727) | about 2 years ago | (#40177683)

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.

Re:Imagine (0, Funny)

Anonymous Coward | about 2 years ago | (#40177945)

The closer Andromeda gets, the more diffuse its structure will appear. It will just be a change in the shape of the Milky Way. I hope you will be reincarnated into a form that has no internet access. Soon.

Not an unexpected result (3, Interesting)

Michael Woodhams (112247) | about 2 years ago | (#40177721)

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.

Re:Not an unexpected result (0)

Anonymous Coward | about 2 years ago | (#40177891)

Welcome back, Michael.

Re:Not an unexpected result (0)

Anonymous Coward | about 2 years ago | (#40177903)

are you kidding?

"galactic collisions aren't expected to have bad results for life living on their planets"

oh look mom! that star is getting bigger, really quickly! uhhh, mom? uhhh.............x

Do not worry - (1)

Anonymous Coward | about 2 years ago | (#40177765)

I'm not going to be concerned until I see the Pierson's Puppeteer fleet going by in the other direction.

order of magnitude (1)

mathfeel (937008) | about 2 years ago | (#40178019)

The diameter of the sun is 1e9 meters. The distance to the closest star, Alpha Centauri, is about 4e16m (40 lightyears)...Let's put that in context:
Suppose the sun is the size of a grain of sand, say 1mm (1e-3mm), the distance to the nearest grain of sand is 40 kilometer. So a collision between galaxies is basically collision between empty spaces...

The Inhibitors already knew... (2)

Coisiche (2000870) | about 2 years ago | (#40178037)

How come nobody's mentioned Alastair Reynold's Revelation Space [wikipedia.org] 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.

Finally! (2)

CyberK (1191465) | about 2 years ago | (#40178067)

At last, mankind will have a convenient and cheap way of intergalactic travel: Wait for it to come to us.
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