The Gemini South massive 8-meter telescope captured a beautiful moment in a destructive dance.
Wow.
These two galaxies, individually called NGC 5426 (left) and NGC 5427 (right) are together called Arp 271. Halton Arp is an astronomer who spent quite a bit of time cataloging unusual galaxy systems, and almost all of them turned out to be interacting. In this case, the two magnificent spirals, lying 90 million light years away from Earth, are just starting to collide. Although they look intact, tell-tale signs of their mutual gravitational train-wreck are there: the spiral arms are just starting to distort, and the giant gas clouds (seen as the pinkish blobs) are more common than expected. Also, they appear to be knottier and more abundant on the sides of each galaxy closest to the other galaxy (despite appearances, I think the left side of NGC 5426 is closer to NGC 5427 which is behind the more face-on galaxy; it can be difficult to judge these things in an image though).
This means that the two galaxies are beginning the first steps of a dance that will take 100 million years to complete. They will pass each other, slow, then tangle again. This may happen several times, but in the end they will most likely merge, forming a large, puffy, elliptical galaxy. The fireworks will be spectacular as cloud collisions hugely accelerates star formation, lighting up the gas, causing frequent supernova…
… and also, perhaps, dumping gas into the central black holes no doubt lurking in the hearts of both galaxies. When that happens, the matter will heat up and glow incredibly brightly, turning this mess into an active galaxy. But eventually even that will settle down, and in the end, the signs that the one elliptical was once two stately spirals will be subtle and few.
Don’t forget: we’re headed toward the Andromeda galaxy as well. In a billion years or two, this will be us. Looking outward sometimes helps us look inward. The fate of the denizens of the universe is sometimes our own, too.
June 26th, 2008 at 11:09 am
I’m curious as to what the consequences for any life would be in these two galaxies, if any? (Aside from the obvious – getting smacked by a supernova)
June 26th, 2008 at 11:15 am
I wish I could be around to see something like that happen. Imagine living long enough to watch that kind of thing happen…
I am kind of glad I won’t be alive when we collide with Andromeda, I really can’t image that being a pleasant experience.
June 26th, 2008 at 11:22 am
Wow, that’s what I call a picture.
June 26th, 2008 at 11:34 am
I thought the jury was still out on the Andromeda Galaxy’s proper motion and whether we’d collide or not…
Also, you know what would be totally awesome? If an ordinary galaxy collides with a galaxy with a supermassive black-hole binary, then there’s the possibility of one of the three black holes getting ejected from the collision at v ~ c (it’s just the three-body problem, the relativistic effects don’t change the basic structure). Picture 10^9 solar masses cruising through space at .95c, disrupting all that cross their paths without even noticing…
June 26th, 2008 at 11:37 am
A billion years… I think I’ll be pretty gone by then.
Oh well, let’s just admire the other fancy galaxies playing bullies.
June 26th, 2008 at 11:47 am
Edmund
Good job setting up BA for a book plug. Well, is it still a plug if you do it on your own site?
I’ll beat you to it.
Buy “Death from Above”
June 26th, 2008 at 11:51 am
Actually…I wonder if you could use such a thing as the core for a Bussard ramjet that eats globular clusters?
June 26th, 2008 at 12:03 pm
I’m guessing there wouldn’t be much in the way of consequences for life in either galaxy. They’re mostly empty space right? So we wouldn’t have many stars colliding? I dunno, just guessing.
June 26th, 2008 at 12:22 pm
Good stuff.
Phil, a link you may like.
June 26th, 2008 at 12:27 pm
Totally Kewl!
June 26th, 2008 at 12:36 pm
mikeb302000 took the words right out of my mouth. What a picture!!
Any my first thoughs on the effects of a galactic collission (Milky Way plowing into Andromeda) were along the lines of Shane’s. The two galaxies are mostly empty space, and two starts would have to pass pretty close to each other for any major impact on a planetary system orbiting either star. I guess we can infer this from the traces of the occassional dwarf galaxy I understand the Milky Way has for lunch once in a while.
June 26th, 2008 at 12:38 pm
Very nice, Phil! This has to be a Basic Astronomy 101 type question, but I hope you may be able to provide an explanation. In images such as this one, we always see many stars, with a wide range of diameters. Are these images of larger-diameter stars really just nearby stars (in our own galaxy) that are out of focus? Do any of our telescopes have enough resolution to image the true diameters of stars in our galaxy? Or are we really seeing images in which the apparent star diameters are just representative of either inappropriate focus (for those particular objects) or light scattering within the optics of the telescopes, or some other type of “aliasing”?
I did try to search the site for an answer but was not successful. Party on, BA!
June 26th, 2008 at 12:44 pm
Here is Galaxy Crash from Case Western Reserve University.
Java Model
June 26th, 2008 at 1:12 pm
I still have a hard time believing that stars don’t collide when galaxies merge ( or at least I’ve read where it was a VERY small number that actually collide). I have to think at least a few percent collide. I’d love to see thats, it’d really look sweet
June 26th, 2008 at 1:30 pm
I think the biggest problem for life in a colliding galaxy would be radiation…with the merger you’ll get starbursts and so X-rays coming out of that, and I don’t think an active galactic nucleus is something you want to be near if you like your DNA.
June 26th, 2008 at 1:33 pm
Michael L,
“I’m curious as to what the consequences for any life would be in these two galaxies, if any? (Aside from the obvious – getting smacked by a supernova)”
I think you are right about being hammered by a supernova, or even eventually getting lots of radiation from the central AGN, if nearby when one lights up. But yeah, stellar collisions are ridiculously rare, stars just interact gravitationally and smoothly. The gas collisions, that’s the pretty part. Hence the star formation and hence the supernovae…
That could be a chapter in “Death from the Skies” as hambr pointed out, living in a starburst galaxy, or living in an interacting galaxy!
As far as stars not colliding, when you look at the density of stars in a galaxy (handwavy approximation with the size if our sun and distance to the next star gives a volume filling factor of something like 10^-21) the chances of collision are so tiny as to make such collisions unimportant. Not to say that two stars have never collided, surely that would be awesome. The only instance I can think of is with two stars in a binary coalescing.
Great article and pretty, pretty picture! Also, I think one of those galaxies is already a Seyfert 2, so the fun has already begun in the AGN department…
June 26th, 2008 at 1:35 pm
You guys got to my statement/question before I did. I wonder what does happen to life in these two galaxies. And if there is highly intelligent life, what could they come up with to save themselves? Stargates???
June 26th, 2008 at 1:42 pm
Wow, I really screwed up my last post. The book is “Death from the Skies”, not “Death from Above”. Sorry BA and thanks for getting it right Nicole (and not making an ass out of me).
June 26th, 2008 at 1:56 pm
Haha, I don’t think I even noticed. What is really important is, which sounds more sinister and destructive? … bwah haha…
I don’t follow Stargate anymore, does the one in Atlantis reside in the Andromeda Galaxy? (I think they say “Perseus” or “Pegasus” one of the nearby constellations to Andromeda…) In which case, you are still in the mess of it!
June 26th, 2008 at 2:19 pm
Just out of curiousity how far away are these galaxies?
June 26th, 2008 at 2:34 pm
I don’t think there would be dire consequenses for life. Stars in interacting galaxies affect each other as much as two flies in the Grand Canyon. Astronomers might notice a lot of nebulae but on that timescale it wouldn’t seem abnormal.
KP
June 26th, 2008 at 2:46 pm
Imagine being on a planet on the rim of the right hand galaxy. You’d live your life with that left hand galaxy dominating the night sky 6 months of the year…
If I’ve got the geometry right, a 100k LY diameter galaxy at 50k LY distance would appear as a 90 degree object in the night sky…
June 26th, 2008 at 2:51 pm
BA, assuming the Gemini page you’ve linked is correct, I think you’ve switched NGC 5426 and 5427.
Like Edmund I’d be interested to know how we can measure the transverse motion of M31. Or doesn’t it matter, because we are already gravitationally locked for any reasonable value of the speed?
I love the phrase, too, on the Gemini site: “strong tidal forces have broken the arm in two, causing it to bleed starlight.”
Jim Shaver, I think the larger blobs in this particular picture are galaxies in their own right, presumably more distant ones. Some of the smaller dots may be globular clusters belonging to the main pair. There’s another interacting pair right at the top, above NGC 5426 (you need to download the full resolution image to see).
June 26th, 2008 at 2:52 pm
i.e. it would be awesome and the poets of that planet would also be awesome. All we’ve got is a stupid moon.
June 26th, 2008 at 3:03 pm
Hey Centipede, some of us like the moon
June 26th, 2008 at 3:22 pm
These two galaxies are clearly getting it on.
Maybe we should let them have their privacy, rather than
post the pictures of their sordid intergalactic love affair
all over the Internet.
First Britney Spears and now Arp 271. Is there no deceny,
no shame left in the Cosmos?
June 26th, 2008 at 3:34 pm
Vagueofgodalming (Mr. Vague?):
Thanks for taking a stab. Actually, I’m not referring to the other distant galaxies or the star clusters or nebulae in the image. Surely, some of those dots are stars, and they have many different diameters in the image. I’m just trying to learn whether the diameters of the stars in the image are real properties of those stars or just artifacts that have more to do with how the image was taken.
I know the BA could explain it, if he has time.
June 26th, 2008 at 5:53 pm
Very beautiful.
June 26th, 2008 at 8:37 pm
Arp said
What? no intergalactic porn? Sheesh! Some of us like seein’ galaxies get it on!
June 26th, 2008 at 9:00 pm
Blackravyn, Phil mentions it in the post: 90 million light years. Approx 8.5×10^20 km. Probably off the main bus routes.
June 26th, 2008 at 10:06 pm
What is the chance that the sun will be thrown off by 2-3 billions of years from now by collision with andromeda?
June 27th, 2008 at 6:40 am
@ARP1234: You have a naughty mind. I like that.
June 27th, 2008 at 7:48 am
Dear Naked Bunny with a Whip – apparently so do you. :^)
Entertain the thought, just for a moment, that galaxies are
living beings in a manner and on a scale we puny little creatures
are not used to.
Would their mergers be a form of reproduction? Or actual
cannibalism as astronomers call it? Or just a really long version
of our one night stands?
June 27th, 2008 at 9:00 am
90 million light years away — 100 million years to complete the coalescence. This dance should pretty much be over by now; we just aren’t able to see the final steps. Anybody modeled it digitally?
June 27th, 2008 at 9:57 am
Anyone know what if any, gravitational forces etc would be felt on the far side of either galaxy? Or, is the distance so great that they wouldn’t feel a thing?
June 27th, 2008 at 12:27 pm
Firemancarl, when the shockwaves from the galactic impact
hit us, we will be knocked around like the crew of the Starship
Enterprise when they get hit by a Klingon disruptor beam and
aren’t wearing any seatbelts! This will be accompanied by
dramatic orchestral music to set the mood.
Beware the concussion!
June 27th, 2008 at 12:44 pm
Yeah, but I want the scene to be set to O Fortuna!
http://www.youtube.com/watch?v=xuERh0jBjh8
June 27th, 2008 at 12:48 pm
Gary:
See the Galaxy Crash reference above. Its not Arp271, but it will give you a good idea of what happens. Visit the Case Western web site, and you probably could model it with their software.
June 27th, 2008 at 2:15 pm
“…the two magnificent spirals, lying 90 million light years away from Earth, are just starting to collide.”
“…the first steps of a dance that will take 100 million years to complete.”
So in “present day” terms this collision is almost over.
June 27th, 2008 at 2:58 pm
Good point Owl. Too bad it’ll be millions of years to see the result!
June 27th, 2008 at 3:14 pm
I suggest instead of beaming Doritos ads and Beatles songs
into our galaxy, that we transmit Barry White to Arp 271 to,
you know, help them set the mood.
At the very least, any aliens in those galaxies, if not the very
galaxies themselves, will know we are a really cool species.
June 27th, 2008 at 5:20 pm
I thought we were colliding with Andromeda in 5 billion years….was it refined to 1-2 billion years recently?
June 28th, 2008 at 3:26 am
Very nice
June 28th, 2008 at 7:38 am
Breathtaking, superluminous image!
Thankyou Dr Phil Plait Just thankyou …
… & that must surely be a top three contender for this years best photos / images.
____________________________________________
“Yet here we are with our eyes and our minds and our curiosity, six billion passengers aboard a tiny blue boat, bobbing and wheeling our way around one vast Catherine wheel among many.”
- P.246, Ferris, ‘Seeing in the Dark’, Simon & Schuster, 2002.
June 28th, 2008 at 7:41 am
On the topic of collisions bewteen the stars within these galaxies its worth reading this quote :
***
“If you put three grains of sand inside a vast cathedral, that cathedral will be more densely packed with grains of sand than stars are found apart in the space.”
***
By Sir James Jeans, British astronomer, quoted on page 28, ‘Skywatching’, David H. Levy, Ken Fin Books, 1995.
June 28th, 2008 at 8:15 am
andrew on 27 Jun 2008 at 5:20 pm :
“I thought we were colliding with Andromeda in 5 billion years….was it refined to 1-2 billion years recently?”
There’s an article – the cover article actually – on this topic in the june 2008 issue of Astronomy magazine :
“Our Galaxy’s date with destruction” by Abraham Loeb & T.J. Cox, Pages 28-33.
They include a simulation showing the collision between the Milky Way and Andromeda starting in 2 billion years time and concluding in 5.5 billion years time. Its a long drawn out collision beginning with approach and interaction and ending up in a fusion of the two spiral galaxies into a single “Milkomeda” elliptical galaxy.
Jim Shaver on 26 Jun 2008 at 12:38 pm :
“Very nice, Phil! This has to be a Basic Astronomy 101 type question, but I hope you may be able to provide an explanation. In images such as this one, we always see many stars, with a wide range of diameters. Are these images of larger-diameter stars really just nearby stars (in our own galaxy) that are out of focus? Do any of our telescopes have enough resolution to image the true diameters of stars in our galaxy? Or are we really seeing images in which the apparent star diameters are just representative of either inappropriate focus (for those particular objects) or light scattering within the optics of the telescopes, or some other type of “aliasing”?
I did try to search the site for an answer but was not successful. Party on, BA!”
If you happen to see this : try checking out James B. Kaler’s awesome Stars website :
http://www.astro.uiuc.edu/~kaler/sow/sowlist.html
Yes, several stars have had thediameters measured and at least one – Betelgeux – has even been photographed. Check Hamal (Alpha Arietis) and one other star which have had limb darkening I think it was detected for them ..
I’ll try and answer your questions here :
1) Are these images of larger-diameter stars really just nearby stars (in our own galaxy) that are out of focus?
SCR (me) : I think so usually yes – But what you’re seeing with the stars in the image here isn’t actually diameter but instead just the relative brightness or apparent magnitude of the individual star – I think.
Although some of these “stars” esp. the fuzziest looking ones – may actually be distant background galaxies : Eg. notably galaxies present in an image of the Helix Nebula in Aquarius! (NGC 7293)
2) Do any of our telescopes have enough resolution to image the true diameters of stars in our galaxy?
SCR : There have been images taken of the red supergiant Betelgeux (aLpjha Orionis – the 10th brightest star as seen from our skies) although they used a specialtechnique called interferometry to capture the image. So yes. Again, check on Kaler’s website & is shown in his books and some other astronomical texts.
3) Or are we really seeing images in which the apparent star diameters are just representative of either inappropriate focus (for those particular objects) or light scattering within the optics of the telescopes, or some other type of “aliasing”?
SCR : Hmm .. Not quite sure what you are meaning here tobe quite honest but very probably yes. I think it has a lot to do with how the light (photons) build up quicker from brighter stars on photographic film and CCD chips but I’m not quite sure. Maybe somebody else can clarify further? I’d think if itwasan out offocus issue then it’d look more out of focus & you may expect more smearing and lack of sharpness? pretty sure that light is lost within some telescope designs (esp. reflectors) but more than that …? Well I’d have to do more research on that …
June 28th, 2008 at 8:22 am
CORRECTION : For italicising stuff up. Sigh. Please BA let us edit these posts!
________________________________
…
“Our Galaxy’s date with destruction” by Abraham Loeb & T.J. Cox, Pages 28-33, Astronomy magazine June 2008.
They include a simulation showing the collision between the Milky Way and Andromeda starting in 2 billion years time and concluding in 5.5 billion years time. Its a long drawn out collision beginning with approach and interaction and ending up in a fusion of the two spiral galaxies into a single “Milkomeda” elliptical galaxy.
…. SCR : There have been images taken of the red supergiant Betelgeux (Alpha Orionis – the 10th brightest star as seen from our skies) although they used a special technique called interferometry to capture the image. So yes. Again, check on Kaler’s website & is shown in his books and some other astronomical texts.
…I’d think if it was an out of focus issue then it’d look more out of focus & you may expect more smearing and lack of sharpness? Pretty sure that light is lost within some telescope designs (esp. reflectors) but more than that …?
June 28th, 2008 at 11:52 am
Andrew said..
Pssst dude! It’s all cause of galactic warming!
July 7th, 2008 at 1:11 pm
grand canyon train