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Hubble Captures Colliding Galaxies
ackthpt writes: "I used to enjoy simulating model galactic collisions on my desktop but, CNN is featuring a find for the Hubble Space Telescope -- a collision between two galaxies 206 million lightyears away in the direction of the constellation Lyra. The picture is spectacular." It's this sort of thing that makes the Hubble's continued success, in light of it's famous earlier misadventures.
206 million lightyears away ???
Are we sure? Didn't General Motors make the mirrors in the Telescope? Did they take into account that "OBJECTS IN MIRROR ARE CLOSER THAN THEY APPEAR"?
Hahahahahaha, I kill me.
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"Outlook not so good." That magic 8-ball knows everything! I'll ask about Exchange Server next.
Heck, at 0.9c, would stars even exist? Cold, hard planets, maybe, but I think even a small gas giant would be impossible.
Even if galaxies could stay together at this speed, relatively won't matter; the probably outcomes of a galaxy that is moving at another at 0.9c (fixed reference point) is probably the same as both galaxies moving at each other at 0.9c (fixed reference point) (which in this case is simply as if one galaxy as moving at the other at 0.9x c assuming the other galaxy was fixed in space). Exactly the outcome probably is dependant on if it's a direct hit or close shave.
"Pinky, you've left the lens cap of your mind on again." - P&TB
"I can see my house from here!" - ST:
Helluva way to sell a science project.
is here
:)
Lots of great pictures and hubble info. Of course, this should be in the related links.
I thought he was referring to: "Scientists with the Hubble Heritage created the image using archive data recorded by the Hubble telescope in 1996."
I was curious about the same thing.
thanks for the link
EverCode
Geeeeze I hate that. At least link to the source of the item, not some lame news story.
Oh well I guess Tim's time is better spent doing important things ;).
CC
Intellectual Property IS Theft.
Yeah, but what a way to go! =)
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A feeling of having made the same mistake before: Deja Foobar
Is it me... Or does that photo look like the head of (some of) our beloved Linux Penguin????
Leave me alone, I'm drunk.
another lawsuit against Firestone tires.
"Pinky, you've left the lens cap of your mind on again." - P&TB
"I can see my house from here!" - ST:
It is a general misconception that the BB gives a "momentum impulse" the causes the expansion of the universe. Expansio of the U is expansion of space itself, whicih has nothing to do with "total momentum" or things like that.
Also there is no "point zero" in a BB for the current "favourite" flat universe model. The idea of a BB "exploding from a point into void" is also false. In the current Omega=1 (i.e. asymtotically expanding) universe, there is not even a concept of a "single point", i.e. the Universe came into being as infinite space in the BB (hard to visualize, but true). The simple proof is that an Omega=1 U is an infinite U, so extrapolating infinite back a finite amount of time (i.e. the age of the Universe) will still lead to an infinite universe. So the Universe has no boundaries (a single point, on the other hand, has a one-dimensional boundary so to speak very loosely).
Now, to answer the question of the original poster :
Colliding galaxies are common place. During the early universe, purturbations in the density field "seeded" the universe, causing stars and galaxies to form. Some purturbations are larger than others, and those which is larger than the so called "Jeans Mass" will collapse to form objects in the universe, creating a local overdensity of mass whose gravitational effects overcome the inherent "expansion" of space. Thus, we see many so called "galaxy clusters" in space, of which Virgo is the closest. In such clusters, galaxies are gravitationally bounded to each other, and eventually will collide to form one gigantic galaxy. (Such gigantic galaxies which are >1000 times more massive the the Milky Way are called cD galaxies and are not uncommon.)
Mode (3) smart-aleck mode. Press * to return to main menu.
It really won't matter, because the odds that any star would come close enough to our system to either A) directly hit anything, or B) even disturb the orbits of any planet with gravitional pulls, would be so remote that it would not be worth calculating.
As well, the "collision" would probably take several hundred thousand years, so defining a point of collision would be relatively pointless.
Lastly, if anything negative (IE: the Earth was going to be creamed by a slow moving star) was going to happen, we would have a simply goofy amount of time to do anything we could. On the flip side, there really isn't anything you can do to stop a star from doing whatever it wants to (stars are stubborn that way, something to do with the "inertia section" in their "Laws and Code of Honour For Stars" book). Aside from a *mass* migration (to, say, somewhere nearby, like the Greater Magellanic cloud), the human race would simply have to put their collective heads between their collective knees and kiss their collective asses goodbye. In about half a million years.
My question is this: how do galaxies collide? I mean, I thought that everything started at point A, there was this Big Bang thingy, and everything flew apart from the point A. If that was the case, it should be impossible that anything flung out of the explosion should be on an intersecting path with anything else from the explosion. Think of it this way: isn't it impossible for the light from the sun to "collide" with other sun light, because they start at the same point, and move outward and apart from each other. Why do the paths of galaxies cross?
"Don't mind me cutting myself on Occam's Razor"
This totally reminds me of something I once saw on xscreensaver!
did what we're seeing occur 206 million years ago?
Short answer: yup :-)
Does the expansion of the universe affect that amount of time?
Overly simplistic answer: not really. If you have the math, you might want to look at a book on general relativity, find the chapter on the Robertson-Walker-Friedmann cosmological model, skip the section on solving the Einstein equations, and read up about comoving coordinates.
Slightly better answer: For "comoving" observers, the time on their clock is the same as the time it takes light to travel a given number of light-times (light-minutes, light-seconds, etc...). Thus, if we were comoving, the light-time would be exactly the clock time. We aren't actually comoving observers, but we aren't moving too fast, so it is a good approximation to pretend that we are.
In other words, is our "now" the same as the "now" currently at that point in space?
Yes, if we are both comoving. Both "nows" are at the same cosmic time, but it makes no practical difference, since their "now" won't be apparent to us for 206 million years. Now, if both are non-comoving, then no, the times their clocks would measure would differ.
I guess what I'm trying to ask is can you compare clocks that are 206 million light years apart
You can send a signal from one clock to the other (Einstein, among others, invented a procedure to allow comoving observers to do so), but light must still travel the distance between them, so there is no instantaneous way to do so.
So, like the rest of your question asked, if both clocks are synchronized and are comoving, they will always remain synchronized. Otherwise, no.
I don't know if I'm phrasing this comprehensibly
I'm almost certainly positive that my answers aren't comprehensible, so it doesn't much matter :-)
The question, as I understand it, relates to two galaxies coliding at 0.9c relative to each other (that is, my galaxy is standing still, but I think yours is about to run into me at 0.9c).
Well, for one thing, it's space itself that is expanding. Things aren't flying away from each other in the same way that a billiard ball flies away from the tip of the cue.
Now, in this expanding space, it is certainly possible for objects - whether they be galaxies or billiard balls - to collide with each other. It's just that galaxies are a little further apart than billiard balls.
Unlimited growth == Cancer.
As a side note, people have tried to create maps of the "acceleration vectors" of galaxies in the local universe, but not by studying motions over time -- rather, you look at the density distribution of matter and try to infer a potential and acceleration field. Yes, it's a little sketchy.
Satellites, including the Hubble Space Telescope, can collect so much data that it may take years for scientist to get around to it. For example the Voyager spacecrafts visited Saturn in the early 80s, (1981 I think), and discovered a couple new moons. In 1990, while digging through and examining the data from the Voyagers' visits, they found a another new moon. The Clemintine spacecraft which orbited the moon a few years ago, if my memory serves me, collected THOUSANDS of images a day. Do you think they have thousands of paid scientist working around the collect to look at and analyze all the data in real time?
There is no point zero. Space itself is expanding. There is no momentum in the conventional sense here.
It's not like an explosion; in an explosion you can identify the point at the center that everything started at. There is no `central point' in the universe that identifies a `location' for the initial singularity (the Big Bang).
Unlimited growth == Cancer.
> the gas should probably behave in some
> interesting ways
Like a cosmic wind that literally blows the Earth off course?
The shocks would be very interesting; I am assuming you mean the earth being hit with what would amount to a cosmic wind gust.
I understand your points, and how this could be devastating, but is the density of the ISM really that powerful? Granted that all of the arguements you have put forth are based on the density of the ISM being sufficient, but, in your opinion, do you think the ISM is that dense. I would not, at least, for *most* of the effects.
"it's a little sketchy" - Yes, but brilliant, nonetheless?
Thanks for the response! You are making me think; which, outside of comments in this article, is something that no-one else today can claim today.
"Don't mind me cutting myself on Occam's Razor"
Actually, if you look at this link it looks like a computer generated image. In fact when I take a second look at it, most CGI planets look better!
End result: certainly I agree with you that media other than imaging have their place -- spectroscopy is the way to go for a lot of things. And other wavelength bands (as you say, IR, UV, x-ray, etc.) are important, too -- but don't knock the visual band! :-) And "nice pictures" and nice science aren't necessarily mutually exclusive.
registered the domain yet?
so this thing happened 206 million years ago - how does one proof the theory of "light years" in any case? surely, they can calculate it using a bunch of mathematical expressions - but how does gravity affect the "line of sight" concept? maybe the light rays are being warped in some manner such that they seem to be further away than they really are?
the questions you pose don't have straightforward answers -- at least not ones that appear straightforward to me. But you can come up with some broad estimates.
A rough estimate of interstellar gas density is on the order of 1 particle per cm^3 -- a bit lower (0.1) between clouds, a bit higher (20) in diffuse clouds, much higher (10^3 - 10^6) in molecular clouds.
At these densities, it turns out that the likely effect of galaxy - galaxy collisions may be to strip out a large portion of the gas in both galaxies. Certainly the large-scale effects are enormous, and you can see them in our own Milky Way -- the galactic disk is "warped" upwards by as much as 4Kpc (12,000 light years) at large (20 kpc) distances from the nucleus, and this is thought to be a result of a tidal interaction long ago with the Large/Small Magellanic Clouds. Also, one of the most popular theories for how elliptical galaxies (or at least some elliptical galaxies) form is via collisions between spirals -- ellipticals have very little gas and dust. This theory is borne out somewhat by the fact that the concentration of ellipticals is much higher in rich clusters of galaxies than it is in the "field" -- as the density goes up, you would expect more collisions, hence more formation of ellipticals.
And hey, while we're at it, the process of gas stripping is a fundamental issue in the study of clusters of galaxies. As galaxies in a rich cluster move through the (very hot) intracluster medium, a shock develops and basically pushes a bunch of the gas out -- for a relatively simple physical analysis of this situation, see for instance Shore's book on Astrophysical Hydrodynamics.
But to get back to the original issue: if we were sitting on Earth when the MW collided with Andromeda, what would it be like? The answer is that I don't really know -- my hunch is that the local (in both space and time) effects would not be all that great; life around the Sun would probably get along just fine. But I don't know, because I'm too lazy to work out the problem. :-) (I'm sure this is in the literature somewhere, if you're truly dedicated -- try the Astronomy and Astrophysics data abstract service,.) Certainly the very long-term effects would be enormous, though.
Hope that helped clear things up...
While I'm far from an astronmer, I was wondering if we could somehow use the Hubble Space Telescope to study the planets in our solar system? Would Hubble give us a good view of the Outer planets, especially ones we haven't studied like Pluto or the new Kuiper belt object, or are they too close to us for Hubble to focus in on?
Doh!
Check out this link for a spectacular HST image of colliding galaxies taken in 1995.
Which is why we're not sure if there will be a big crunch or if the universe simply wimpers out spread out over an amazing distance. The balance between momentum and gravity is not well understood and without being able to accurate map all major bodies in space, there's no way to easily predict it.
And when the galaxies are done colliding, there's a lot of outcomes (I remember a good segment in Cosmos) -- One could 'eat' the other, as the picture in this article shows (where the core of one would be destroyed), they could combine cores if their movement vectors are slow enough, or both could completely kill each other leaving only a dense core of stars and several more flying away from each other and the core well above the rate which gravity could recapture them.
To me, what's amazing is the fact that there are no significant stellar events associated with the collision: no novas or the like, though I'm sure any local solar systems are majorly distributed.
"Pinky, you've left the lens cap of your mind on again." - P&TB
"I can see my house from here!" - ST:
Sorry, i don't have a physics doctorate, but your conception of "everything moving outward" isn't quite right. Our universe right now has a gradient towards moving outwards, but that doesn't mean everything is moving in a straight line from a single point. Remember, our universe is BIG. Try to imagine the imensity... No, bigger than that. Yet bigger than that. Now take that and raise it to the power of a hundred. Now what you're imagining is just our neighborhood. You see, when you have something that big, stuff gets pulled around and it goes in all directions. Since the biggest bang of them all (affectionately known as "The Big Bang", amazingly enough) was so powerful, everyone is still moving in a net outward direction, but that still leaves a variance. Think of an atomic explosion: everything is moving outwards very rapidly, but eventually it runs into stuff and changes direction. Okay, not the best analogy, but i think you can get the point by now.
~Chad
Flynt has only alleged this and has no evidence to back the claim since the informant and him could not agree on a price. The woman at the center of the controversy denied ever having intercourse with Bush has blasted Flynt telling him to "put up, or shut up" with the facts on the Drudge Report last week.
Asteroids, gamma ray blasts, mass insanity, deadly viruses, divine intervention, etc.
Now we have to worry about colliding with another galaxy. What next?
Oh shit, there's an election next week.
I'm not a PhD yet, but I am an astrophysics graduate student - and my research is in galaxy formation. As one of the other responses said, this is a pretty complicated (and not totally solved problem), but the general idea is known, thanks to some really interesting theories and lots and lots of computer simulations.
It all goes back to the big bang. After recombination (when quarks and other fundamental particles recombined to make hydrogen, helium, etc.), the distribution of matter in space wasn't completely uniform (ie some parts were denser than others), and as the universe expanded and things cooled off, these denser areas became centers of gravitational attraction and became the first stars and clumps of stars. In turn, these clumps attracted each other and formed galaxies, and so on and so forth, giving the really cool hierarchical structure that we observe today. This is known as the bottom-up theory of galaxy formation, by the way. For more information, and if you like math, check out _Physical Cosmology_ by Peebles. Another excellent book is _A Short History of the Universe_ by Joseph Silk. It's at the level of Stephen Hawking's popular books, and really interesting.
Anyhow, things that are relatively close together (such as our galaxy and those in our local group, and other clusters of galaxies) will stay near each other, since the gravitational potential holding them together is much, much stronger than the expansion of the universe. Since all of the galaxies in a cluster are moving around as well as being attracted to all of the other galaxies, their orbits are generally very complicated and can't be modelled analytically. Probability dictates that it is practically inevitable that a few will hit each other. As a matter of fact, the general consensus in the cosmology community is that most large galaxies (such as Andromeda) were created when smaller galaxies collided.
As far as the fates of the colliding galaxies, individual stars are generally unaffected since, after all, there's a lot of empty space in a galaxy. However, tidal forces typically distort or completely destroy at least one of the galaxies, or make them into one larger galaxy. Another interesting effect is that the hydrogen gas clouds in the galaxies are disturbed, which causes lots of new stars to form during or right after the collisions. A huge singularity wouldn't form because the density of stars, gas, etc. isn't high enough (by many orders of magnitude) for that to happen. If two big stars happen to collide, it is entirely possible that a black hole will form, though I don't know how probable that is.
Of course, what I have said is merely the "prevailing wisdom" of cosmologists. Computer simulations (including my own) support this theory, but the debate certainly isn't over.
-Brian
Why are NASA's pics so small and low quality.. give us some DECENT high quality digital images!!
They jammed our radar!
"Don't mind me cutting myself on Occam's Razor"
I'm guessing the stars with lens flare are nearby (relatively) stars -- part of our own galaxy -- that are "in the way". Because they are closer, they seem much brighter, so they are overexposed.
That's right, our galaxy is currently in the process of merging with the Large Magellanic Cloud, an irregular dwarf galaxy visible in the southern hemisphere. .^
^.
Simple question: What is the nature of time? [heh]
Since the collision is 206 million light years away, then did what we're seeing occur 206 million years ago? Does the expansion of the universe affect that amount of time?
[Warning: I'm not sure exactly how to phrase what I'm thinking for the following] And more esoterically, I know that time and space are intertwined in complex ways. Does it make sense to talk about what is happening at that point in space "now" in time, relativistically speaking? In other words, is our "now" the same as the "now" currently at that point in space?
I guess what I'm trying to ask is can you compare clocks that are 206 million light years apart, or does the nature of space/time make it that two clocks are considered synchronized when you can compare the signals from two clocks received at light speed? [ugh -- I don't know if I'm phrasing this comprehensibly].
--
Sometimes it's best to just let stupid people be stupid.
We'd have enough time to hire a bunch of oil drillers, throw them into two spacecraft...
Okay, I've had my fun. I'll stop now.
It may look like I'm doing nothing, but I'm actively waiting for my problems to go away.
--Scott Adams
Gravity sucks.
As for them ending up as a double-galaxy singularit, I don't think that they'll become a singularity, but current theory considers the probability/liklihood, that most normal galaxies contain a central black hole. Becomming a black hole would require more than two black holes passing through each other on a cyclical basis.
I would expect that they'll end up intertwining over time. If we're alive a couple hundred million years from now, we might even see the next iteration. (presuming that the sun hasn't melted down by then). I guess that that leads to the next question:
Are there any signs of globular clusters (or whatever galexies turn into post-collision) going for a second try?
`ø,,ø`ø,,ø!
Free Software: Like love, it grows best when given away.
Erm, "friction"? With what?
"Gravitional acceration from the galaxies"
Assume you mean "accreation", how would accreation slow anything down to a measurable degree? And where are the galaxies picking up this extra mass? Pre "Big Bang" proto matter litter?
So, at the end of your first paragraph, you are saying, that the galaxies are NOT colliding head on, but are "glancing through each other", so to speak.
Galaxy self-canabilism, on the grandest scale, in the end, would cause another Big-Bang type singularity, correct?
I thought we had a rather detailed map of all of the galaxies in a 20 megaparsec sphere, including a lot of information regarding their velocity vectors and mass. Admittedly, acceleration vectors would take a tremendous amount of time gather.
>though I'm sure any local solar systems are
> majorly distributed.
Actually, I would disagree with you on that point. We don't feel any a affects of the tritary system only 4-5 light years away (the Centauri system). Ergo, calculate the odds of any star of, let's say, three times the sun's mass of the star coming within 5 light years of the Sun during a collision. Change the numbers to fit this equation:
Force of Gravity = product of masses * the gravitational constant / the distance squared
OR:
F = KmM/(d^2)
with:
F = force needed to affect the earth's orbit
M = mass of rogue star
m = mass of earth,
K = gravitational constant (what ever it is)
d = distance between the two
Assume the F to move the earth out of orbit by, say 0.1% is a constant (and average and scalar, for now), we would have
d^2 = (mK/F) * M
To make matters ease, we replace mK/F, all constants, with one constant, X.
d^2 = X*M
OR (d^2)/M = X
Now, with M = 3*our sun's mass, d = 5 light years, which is the minimum safe distance/mass ratio:
25/3*SunMass = X
So as long as the ratio between the distance of the rogue star and the rogue star mass is less or equal to 25 light years squared divided by three times the sun's mass, everything is okay (keep those units straight!).
"Don't mind me cutting myself on Occam's Razor"
First of all, the Big Bang isn't a matter of everything in the universe exploding from point A. The Big Bang didn't happen at a point, it's the universe itself (not just the stuff in it, but spacetime itself) expanding everywhere at once. A common 2-D analogy is spots on the surface of a balloon, when you inflate the balloon the spots get further apart, the surface of the balloon has no center, every point is moving away from every other.
As for why the paths of galaxies cross, although the universe is expanding and most galaxies are moving away from any given galaxy, locally that can be different, as gravitational attraction can bring things together if they are close enough to begin with.
"I believe that the cult of the particular brings only death - for it bases order on likeness." St.-Exupery
You are right on that account, but it still rules out head-on collisions.
"Don't mind me cutting myself on Occam's Razor"
How do galaxies collide? Why do the paths of galaxies cross?
If the galaxies are close enough to each other to start with, gravitational attraction will be sufficient to overcome the separation caused by cosmic expansion.
Don't think of an explosion...the BB wasn't an explosion. Things aren't flung outward. In a certain very well defined sense, nothing in the universe is moving. It is the stuff (space) between the stuff (galaxies, etc) that is expanding, but it isn't "pushing" the galaxies apart. In a certain rigorous sense, to first approximation, the galaxies aren't moving (their cosmic coordinates are not changing with time, but the space between coordinates is increasing).
Beyond the first approximation, since galaxies are kind of heavy, they are gravitationally attracted to each other. If when they were formed they were close enough to each other, their mutual attraction would cause them to be drawn together faster than the space between them could stretch, and they would gain speed towards each other.
> Why are NASA's pics so small and low quality..
You are mistaken sir. It's CNN and CBS who are the bandwidth cheapskates.
NASA's pics are huge.
Turn the hearts of our children dark? George Bush is *definitely* not up on the technology. Hearts are made of meat, and the way to keep meat looking nice and red in the butcher shop display case is to add a small amount of sulfites to it. Duh.
The internet doesn't cause it. Exposure to oxygen causes hearts of children, cows, and pigs dark.
If tits were wings it'd be flying around.
If you are talking about the cross-shaped spikes of light that come from the brighter stars, those are actually diffraction effects caused by the secondary mirror holder in the telescope. the smaller secondary is held in place by a mount shape like a + and this causes the diffraction spikes. they don't show up on the fainter stars so well because they are, um, fainter. .^
^.
Is this the height of arrogance or what? They turned an entire galaxy (two, in fact) upside down just because it looks nicer!
This happened years ago. Why are we only hearing about it now?
They both must report to their respective insurance companies of course. If the companies can insure SUVs it can't be that much more expensive to insure galaxies.
"Obtuse Anger is that which is greater than Right Anger" - Lewis Carroll
The really interesting part about this is that two galaxies can collide and the stars inside feel almost 0 difference. The reason being that the space between individual stars in a galaxy is so expansive compared to the actual mass of the star (and hence any sort of significant gravitational pull).
Moo
We have our own collision coming up, with Andromeda, fairly soon (possibly within the lifetime of our own sun, something like 5 billion years from now). I wonder if it will look this cool, and who will be watching?
t ml has some more info, although I think this page is getting a bit dated.
http://oposite.stsci.edu/pubinfo/pr/97/34/af1.h
Pacer
What a marvellous image from the Hubble crew, yet again!
And yet.. the scentists totally overlooked one of the most inspiring and self-validating discoveries about this cataclysm: they rotated the image Too Far! Yes, rotating the image just 90 degrees to the right instead of 180 degrees, the photo is quite obviously Tux.
It may be interpreted as an Emperor penguin staring regally off into the reaches of space, or (more likely) his wings close against his body after their downbeat against the freezing depths he swims, our mascot is about to swallow a most appealing morsel of a miniature galaxy.
Come to think of it, no matter which way you rotate this pic it is most definitely a penguin. Where did those scientists learn taxonomy? A golf club? Feh! Maybe they need to rethink their choice of OS?... And how do they know it wasn't just a penguin galaxy to start off with? The dopplers should show the little fishie galaxy fleeing most convincingly.
Oh wait, that wasn't colliding galaxies..someone smeared grape jelly on the lens!
SL33ZE - Artificial Intelligence is No Match For Natural Stupidity -
Wow, that site is really cool. I remember going to it a long time ago, they certainly have kept it going.
Anyway, here's another great pic of 2 more galaxies collding.
http://www.phy.mtu.edu/apod/ap991109.h tmlAnd hell, I might as well borrow their html of the description:
Billions of years from now, only one of these two galaxies will remain. Until then, spiral galaxies NGC 2207 and IC 2163 will slowly pull each other apart, creating tides of matter, sheets of shocked gas, lanes of dark dust, bursts of star formation, and streams of cast-away stars. Astronomers predict that NGC 2207, the larger galaxy on the left, will eventually incorporate IC 2163, the smaller galaxy on the right. In the most recent encounter that peaked 40 million years ago, the smaller galaxy is swinging around counter-clockwise, and is now slightly behind the larger galaxy. The space between stars is so vast that when galaxies collide, the stars in them usually do not collide.
How much warning time do you think we would have?
I simple question for the physics docterates here in /.
;)
How does this phenomenon fit into the expanding universe model? Perhaps my understanding of the model is too simplistic or flawed, but I would have thought that in general the galaxies would all be flying apart from eachother at some relatively high speed - making this apparent head on colosion a bit improbable.
Would it require that the two clusters have a similar enough trajectory and have just pulled towards eachother via combined gravitational effects over eons?
Is it likely that - even though stars won't colide - the two galaxies will become one double dense one - perhaps collapsing inward to a singularity?
Yes, this is probably better suited for Ask Slashdot, but there's no way that would ever get accepted let alone on the front page
All pretty facinating though...
Ad in classifieds: Pandora's Box (no box) $5
So how come some stars show lens flare, and
other stars are perfectly clear????
Is the lens flare caused by the Hubble optics, or
is it something in the path between the star and
us???
Thanks in advance!
-Jim
Celebrate Excellence!
In most situations I don't think you would have a galaxy collision at that high of a speed. Since the universe is supposidly expanding, we measure most things as moving away from us with velocities close to c and sometimes for the really far objects many times greater than c (redshift in the light). The concept to note here is that it is the actual space that is expanding, and hence it looks like the galaxies are travelling that much faster. So I guess you probably wouldn't find galaxies colliding at near-c speeds. Maybe if the universe starts to contract it might become more common ;)
Now, If you could get two galaxies to approach each other at near the speed of light you would definately have to take relativity into account. What that would entail exactly is far above my head, since it lies in the domain of general relativity (of which I'm not well versed) but suffice to say I wouldn't expect anything less than an interesting situation - one of the interesting problems in physics is the n-body problem, which is just the problem of describing the motion of n different objects under the laws of general relativity. Suffice to say it hasn't been solved for even 3 objects, so I would suggest that relativistic galaxy collisions are probably pretty complicated events.
UBU
of the material universe is as yet unsolved.
In the vernacular of the profession it is refered to as " not well understood," which is code for " We havn't the slightest fscking idea."
Your question is thus actually not only not a trivial one, but a rather profound one that is one of the major questions that actual cosmologists wrestle with.
If the universe is expanding evenly, and all evidence shows that it is, WHY isn't the matter in it evenly distributed? Especially taking into account that for some time after the big bang all matter had so much energy and was composed of such small particles that no known attractive force would have had any significant effect on them.
Good question. DAMN good question. Its solution is left as an exercise for the student, and when you find it teacher wants a good look at it because he wants to know too.
I'll offer you my own best guess though. In the nanoseconds after the big bang space itself was 'clumpy,'which naturally created 'pockets' of congregated matter. As the universe expanded these 'clumps' of space and matter expanded into each other and evened out, leaving space a single entity, but leaving the clumps of matter, now attracting under subatomic, and then later, gravitational forces.
What made space 'clumpy.'
Glad you asked. That'll be 90% of your final grade because I havn't got an fscking clue.
We'd have enough time to launch an anti-galaxy nuclear missile and destroy the rogue galaxy before it has a chance to collide with us and possibly wipe out all life on Earth.
(note: it's funny)
--
Pretend there is some witty statement here.
Was Captain Hazelwood at the wheel?
We all get lots of cool desktop wallpaper out of the deal.
Judging by this story scientists get lots of entertainment value out it as well as they all try to decide what terrestrial or supernatural image the space photos most look like.
Kinda like playing "clouds" with a multi billion dollar budget.
They could save time and money by working smarter, not harder, if they all had their analysts sit on the arguments of image interpretation as well.
Hey, maybe I should patent that idea.
Wow from the looks of it, the yellow one kicked the purple one's ass up and down the quadrant!
here you can find higher quality images you can scale down for your desktop:
p hotos.html
http://oposite.stsci.edu/pubinfo/PR/2000/34/pr-
I bet their insurance rates are gonna go WAYYYYY up. Maybe the two galaxies can settle without telling their insurance agencies... or maybe not since it's on CNN and they've probably already heard about it. Damn CNN...
:)
Since the universe is supposidly expanding, we measure most things as moving away from us with velocities close to c and sometimes for the really far objects many times greater than c (redshift in the light).
From what I understood of my Quantum I class, we cannot measure anything moving away from us at many times c. (Except, IIRC, for weird particles like neutrinos, which travel faster than c but never drop below it). The simple Einstein velocity addition formula states that v=(u1+u2)/(1+u1*u2/c^2). Thus, nothing is ever faster than c, no matter how many times you speed it up.
It may look like I'm doing nothing, but I'm actively waiting for my problems to go away.
--Scott Adams
More information on this can be found here.
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*Condense fact from the vapor of nuance*
25: ten.knilrevlis@wkcuhc
*Condense fact from the vapor of nuance*
Isn't science great!
We should also ban the public use of those nasty space words like: "moon", "black hole" or even "venus" 'cause it makes a link to nudity. Those scientists are a menace for the peaceful society.
:)
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1% APY, No fees, Online Bank https://captl1.co/2uIErYq Don't let your $$$ sit in a no-interest acct.
>You've got the competition from the momentum generated from the Big Bang...
> While within the first few nanoseconds after the BB...
But it is still a theory. A theory with, apparently, very little hard evidence to back it up. And that's interesting becasue poeple have been studing it for a generation.
Did you know that most universe scale computer models only take into account gravity. What about electromagnatism? "Nope".
Check out The Big Bang Never Really Happened by Eric J. Learner for more info.
"Lerner does a fine job poking holes in Big Bang thinking and provides a historical perspective as well, linking scientific theories to trends in philosophy, politics, religion and even economics...a most readable book." -- Chicago Tribune
Yes, Bush had his girlfriend have an abortion, but you can't blame Bush for it. He was high on cocaine.
...and George Pal is dead so can't make a movie about it....
Hacker: A criminal who breaks into computer systems
"Information wants to be paid"
For fans of these kinds of pictures, Astronomy Picture of the Day is hard to beat. They have a this same picture for today.
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Infuriate left and right
After switching to another glass cleaner, scientists discovered that the galaxies were no more than large deposits of space-bird poop on the main lens. Apparently, the birds had recently migrated to Mercury and had passed the telescope after ingesting too much Martian Beef Ravioli...
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No sig
What this is going to do to their insurance premiums...
+++ ATH0 +++
Not really. If we came up with a word for "The time of one rotation around the galactic center", it might be able to ruin one of those.
-- The act of censorship is always worse than whatever is being censored. Always.
Man, first we see a skull in outer space, and now we see a violent collision between galaxies. Doesn't anyone think of the children? We need to ban these violent space images before they turn the hearts of our children dark!
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Private Essayist
What would happen if the galaxy movement was greatly sped up, like .9c (where c is the speed of light)? Would relativity become a greater factor?
- I don't care if they globalize against free speech. All my best free thoughts are done in my head.
He has worked on simulation programs that model this exact situation - the most interesting is the example showing the collision of our poor galaxy with Andromeda! (It's actually going to happen - don't worry though, it won't be for a long time...)
UBU
if the matter anti matter proportion was off by only one one hundreth of one percent then matter and anti matter could have simply anihilated each other conventionally and still left the matter we find in the universe today.
Which you ought to able to tell from my previous post is the scenario I personally prefer.
Tell you what, I'll flip you for it, since neither of us knows for sure.
You are so close to the answer, but you haven't hit the nail on the head.
.9c, you will never see it form. This is not because the gravity acts 'slowly', it is because time is so dilated, the galaxy forms in incredibly slow motion. From an observer in the other galaxy, your own will also never form.
.9c away, that is a different matter.
If a galaxy is headed away from you at
As to the galaxy remaining cohesive, that is difficult to say. From it's own reference point, yes, it will remain cohesive, but from a reference point moving
Because simultaniety of events will not transfer between the reference points, the position of the stars/star clusters relative to each other change radically between external reference points. Due to this, the galaxy will appear much larger and less dense than to a native moving with the galaxy.
A couple of points:
Neutrinos don't travel faster than c. In fact, since recent evidence from SuperKamiokande (spelling?) and other neutrino detectors suggests that neutrinos have mass, they must travel at speeds strictly less than c. You might be thinking of tachyons, which are purely theoretical particles that travel at speeds greater than c (but never less than c).
Yes, according to special relativity the speed of light is a strict speed limit for moving particles, but the important clarification is that the speed limit is enforced relative to the local space around that particle. I can only reach a particular speed while running 100m on a track, but I'll get a boost if the actual space between me and the start line is expanding as I run; I'm still running at my top speed relative to the track under my feet, but I appear to be moving away from the start line much faster because of the combined effect of my velocity and the expansion of space. Similarly, a distant star that's moving away from us can appear to be receding at speeds greater than c (as determined by measurements of redshift of light coming from it) if its velocity relative to its local space, combined with the expansion of space in between, is high enough.
-Gabe
John Walsh takes you 200 million light years and shows what happens when galaxies go bad.
Did anyone else notice that it looks kind of like a huge penguin diving through space??
Galaxy collisions are very common, actually. Not only is the Milky Way absorbing the Large Magellenic Cloud (why do you think it looks so large? It's friggin' close) over time - they're inspiraling, that is - but the Milky Way is also currently devouring a smaller irregular galaxy - or, to be more specific, *has* devoured, we're just seeing it now.
I wish I could provide URLs for proof for those, but I mainly remember them from the papers, which were published about two years ago (the small irregular galaxy, that is, the LMC's fate is well known).
But those are kindof like speed bumps for a galaxy- in fact, that's how they grow - and evolve, actually, which of course, makes sense. What about a major collision between us, and say, Andromeda?
Wait a few billion years - it's happening. Give it a few billion more, and the Milky Way and Andromeda will be one very large elliptical galaxy. Of course, the Sun could just as easily become ejected from the merging galaxies, and that's not entirely out of the question, since we're near the rim and have significant angular momentum about one of the colliding centers of mass.
But, then the question comes, who cares? What does it matter? The answer is, truly, very little. Being in a galaxy is great for forming stars, but once a star is formed, it has no more need to stick around in a galaxy. So, being ejected doesn't matter. Neither does the impending galactic collision - considering the massive amount of space involved, the main effect of galactic collision is nothing more than heating up a bit of space dust.
HELLÓ! Does nobody here read Astronomy Picture of the Day? It has new picture every day and a detailed description by a professonal astronomer. Put it in a bookmark NOW! And you call yourself geeks, sheesh!
A colliding galaxy can really ruin your day...
I am !amused.
What I want to know about is the Cult3D plugin (see the Hubble model for a link). I was quite pleasantly suprised to see that they have a linux version of the plugin, so I downloaded and installed it and it shows up in about:plugins and... going to the Hubble model makes Netscape crash now.
Anyone have this working on linux? FWIW I'm running 2.4.0-test9 and Netscape 4.74