Gravitic Mayhem
April 24, 2008 6:04 PM   Subscribe

" It looks as if our Milky Way will be subsumed into its giant neighbour, the Andromeda galaxy...." A (not so) little trove of images of galactic collisions has been released to mark the 18th anniversary of the Hubble telescope's launch. Gravitic Mayhem. (via)
posted by Kronos_to_Earth (20 comments total) 4 users marked this as a favorite
From the site: But galaxies have a dynamical side. They have close encounters that sometimes end in grand mergers and overflowing sites of new star birth as the colliding galaxies morph into wondrous new shapes.

Very cool site and images, thanks Kronos_to_Earth.

But I'm overcome by an insane need to take a red Sharpie and cross out the "al" from "dynamical." Arrrrgh!
posted by amyms at 6:13 PM on April 24, 2008 [1 favorite]

These images are almost as cool as your name, Kronos_to_Earth. Thanks!
posted by cosmonik at 6:53 PM on April 24, 2008

"It looks as if our Milky Way will be subsumed into its giant neighbour, the Andromeda galaxy..."

Man, that's really gonna put a crimp in my evening.
posted by flapjax at midnite at 7:01 PM on April 24, 2008 [1 favorite]

These are fantastic pics, thanks.

It's amazing to think that in such a mind-staggering sparse environment, interaction like this still occurs.
posted by Serial Killer Slumber Party at 7:04 PM on April 24, 2008

Every time I look at photos like this and read phrases like "450 million light-years" i start to feel so very small and unimportant that I want to take a nap.
posted by Bookhouse at 7:22 PM on April 24, 2008

Amyms: For reasons beyond my comprehension, the study of the motion of bodies like this and pretty much everything else which has its time evolution governed purely by coupled differential equations is called "dynamical systems." It hurts me too.
posted by Schismatic at 7:34 PM on April 24, 2008

Thanks for that, Schismatic. At least I know it's correct within its own context.

It's still making me twitch, though.
posted by amyms at 7:57 PM on April 24, 2008

I love this one. It looks like a dance (the larger galaxy is extending its hand and the smaller galaxy is being coy).
posted by amyms at 8:05 PM on April 24, 2008

I want a second opinion from any German 10 year old.
posted by Senator at 9:10 PM on April 24, 2008

This reminds me of Gravitas, which is worth downloading for the soundtrack alone.
posted by mullingitover at 10:40 PM on April 24, 2008

Does anyone know why physicists use dynamical? or when that started?

Being one, I use it too, but then friends ask me why. And I can't answer. (Although I can say the word in my mind carries a much more technical meaning than "dynamic" does. I expect "dynamic" to refer to the way a certain person speaks or acts, but dynamical would refer to some object in physics, a field or moving body or whatnot, akin to Schismatic's explanation above).

Those pictures are nifty, btw, thanks for sharing!
posted by nat at 11:19 PM on April 24, 2008

Do astrophysicists have any idea what happens on the planetary scale during a galactic 'collision'?

Do we have stars actually crashing into each other, massive energy discharges, and planets ripped out of orbit like a giant billiard game... basically, extinction for any macroscopic life that happens to be around...

Or is it more like one of those magnetic orbiting executive toys where solar systems pass within a few LY of each other, affecting orbits slightly, solar systems switching from one galaxy to the other, and from an planetary perspective, not much really happens...

(I just tried to calculate the galactical centrepetal force required to keep the sun orbiting the galactic core, and compare it to the solar centrepetal force on the earth... and got lost in a maze of zeros...)
posted by nielm at 1:57 AM on April 25, 2008

A "dynamic" equation would be one that itself moves around. A "dynamical" one would be one that has to do with dynamics.
posted by DU at 5:08 AM on April 25, 2008

amyms :

Shall we dance? Shall we dance?
On a bright cloud of music shall we fly?
Shall we dance? Shall we dance?
Or shall we say "Goodnight" and mean goodbye?
Or perchance when the last little star has left the sky?
Shall we still be together with our arms about each other
And shall you be my new romance?
On the clear understanding that
this kind of thing can happen,
Shall we dance? Shall we dance? Shall we dance?
posted by Halloween Jack at 6:58 AM on April 25, 2008 [1 favorite]

Great post, thanks!

But I'm overcome by an insane need to take a red Sharpie and cross out the "al" from "dynamical." Arrrrgh!

Does anyone know why physicists use dynamical? or when that started?

I'm not quite sure why "dynamical" is such an irritant/mystery; does "economical" bother you the same way? In any case, dynamic and dynamical are two different words. OED on the latter:

1. Of or pertaining to the science of DYNAMICS.
1812-16 PLAYFAIR Nat. Phil. (1819) II. 271 An elementary exposition of the dynamical principles employed in these investigations. 1833 HERSCHEL Astron. viii. 266 As an abstract dynamical proposition. 1869 HUXLEY in Sci. Opinion 28 Apr. 486/3 Strict deductions from admitted dynamical principles.

2. Of or pertaining to force or mechanical power
1828 WEBSTER, Dynamical, pertaining to strength or power. 1843-46 GROVE Corr. Phys. Forces (ed. 1) 15 Nor do we by any of our ordinary methods test heat in any other way than by its purely dynamical action. [...] 1862 SIR H. HOLLAND Ess. i. 14 On the mutual convertibility of heat and dynamical force. 1880 HAUGHTON Phys. Geog. iii. 96 In a permanent condition of dynamical equilibrium. 1881 SIR W. THOMSON in Nature No. 619. 435 High potential.. is the essential for good dynamical economy in the electric transmission of power. 1889 Geol. Mag. 243 Rosenbusch.. seeking to bring clearly into view the consideration that the special kind of metamorphism referred to is only produced when the mechanical forces effect movement, and thus do work, suggested the term Dynamical metamorphism or dynamometamorphism.

[Plus other definitions not relevant here.]

It looks as if our Milky Way will be subsumed into its giant neighbour, the Andromeda galaxy

Is this going to be like one of those mergers where employees of both companies are nervously wondering who's going to be let go?
posted by languagehat at 7:04 AM on April 25, 2008


1. Update on takeover of Milky Way by Andromeda galaxy. Staffing issues discussed, agreed that this was a good chance to get rid of embarrasingly-named Uranus. Memo entitled "We're firing Uranus" to be distributed to all staff.

2. New brand names considered and voted on. Milkdromeda - 2 votes. Androway - 1 vote. Alko-Wade - 10 votes.

3. Plans for future expansion presented. Current expansion target of Hubble Constant deeemed too conservative, faster expansion sought; cautious mutterings about about inflationary environment.

4. Audit report results: some 70% of galactic mass still unaccounted for. Agreed that it must be here somewhere, or else we're counting wrong.
posted by the quidnunc kid at 7:48 AM on April 25, 2008 [4 favorites]

Do astrophysicists have any idea what happens on the planetary scale during a galactic 'collision'?

From what I understand, stars or whatever crashing into each other is very rare. I'm sure there are quite a number of systems getting flung out of whichever galaxy they were in to being with but I don't know if this is necessarily catastrophic to the ejected system. And the interactions between the colliding galaxies can compress gas within each and spark a bunch of new star births.

And for your amusement: Galaxy Collision Simulator Java Applet (click on the Applet link at top left).
posted by effwerd at 12:43 PM on April 25, 2008

Astrophysicist, here (though not a galaxy guy).

To get a sense of how vast space is, take the Sun. Shrink it down to the size of a grain of sand. Now take that grain-of-sand-sized Sun and guess where the nearest star will be.

I'll wait.

It'll be 5 miles away (that's about 8 km). So, no stars won't literally collide (I'll leave it as an exercise for the reader to calculate the aspect ratio of a grain of sand at 5 miles and the likelihood that its velocity vector intersects with the capture radius of the Sun), but they may on rare occasions get close enough to perturb something in the Oort Cloud such that a comet may impact Earth someday.

Of course, by the time Andromeda and the Milky Way merge, life on Earth will have been burned to a cinder by the ever brightening Sun, so it's pretty much a non-issue for us (well, barring us colonizing some far-off world, anyway).

Now -- as a stellar astronomer -- if I really wanted to blow your mind, I would tell you to imagine how you could see that grain of sand glowing from five miles away with your naked eye! You can't actually see Proxima Centauri with your naked eye, but you can (obviously) see stars much further away.
posted by dirigibleman at 9:51 PM on April 25, 2008 [2 favorites]

But the monster black holes at the centers of the galaxies will merge, and become active again for a time. We'll most likely either be flung out into the void, or fall into the center to be eaten by the merged monster black hole, depending whether we're on the leading or trailing side of our galaxy at the time of the collision.
posted by cytherea at 12:21 AM on April 26, 2008 [1 favorite]

Wonderful. Thanks for stoking the coals in my nightmare furnace.
posted by squirrel at 2:46 PM on April 27, 2008

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