Milky Way Heavier Than Thought, and Spinning Faster 285
An anonymous reader writes "The Milky Way is spinning much faster and has 50 per cent more mass than previously believed. This means the Milky Way is equivalent in size to our neighbor Andromeda — instead of being the little sister in the local galaxy group, as had been believed. One implication of this new finding is that we may collide with Andromeda sooner than we had thought, in 2 or 3 billion years instead of 5."
The good news (Score:5, Funny)
At least now we don't have to worry about our sun going nova, we'll all die in an intergalactic traffic accident first.
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A far more stimulating demise, IMHO.
Re:The good news (Score:5, Funny)
But the night sky will look even prettier for the future cockroach decedents, if they have evolved enough to "look up" by then.
Personally, I plan on being dead in a time span that measures in decades, not billions of years.
Re:The good news (Score:5, Informative)
the future cockroach decedents
They'll be the descendants. We'll be the decedents.
rj
Re:The good news (Score:5, Funny)
Given billions of years, either word could work, and neither will be relevant
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Why plan on being dead at all? We may yet live to see the singularity...
Re:The good news (Score:5, Funny)
I was hoping to win a Darwin Award in a few billion years for 'collided with another galaxy'
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You should PLAN on being dead. Just don't die. (Score:3, Insightful)
If you don't plan on what happens after that, someone else will (no pun intended).
Planning on something isn't the same as wishing for it.
As for me, WRT "the singularity"? If I could upload "myself", would I? I don't know. Probably. But if you think about it, "you" don't get to go, only your "branch/copy" does. Are you that selfless? What if it costs money? Are you willing to pay for "his" immortality? AFAIK, the first sentence stands alone.
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There *wont* be a different between you and your copy. Your copy will do what you would do, react in the same way, make the same decision and evolve the way you do based on your daily input and ability to output, process, link, associate and store creating a dynamic internal cerbral evolution. But he or she will be able to do that. You will still be stuck in your conscience, and not being able to be transfered in a way you get to experience it. Why not? i
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Personally, I plan on being dead in a time span that measures in decades, not billions of years.
Speak for yourself--I plan to live forever.
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What type of creature are you?
And are you good to eat?
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Not sure, crunchy for your first question, well speaking for it not myself.
As to the second question the answer is tasty with a slight aftertaste burn.
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I know you're trying to be funny but when the two galaxies do meet, the odds are no stars will collide.
They've already filmed it... (Score:5, Interesting)
Because it's on youtube. http://www.youtube.com/watch?v=dJRc37D2ZZY [youtube.com]
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I hope someone has their Camcorder running with a long play tape, its going to be a hell of a show, albeit a somewhat slow one.
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It's just like human marriage: both start out as streamlined, well-defined independent spirals, but end up as one big ugly amorphous blob.
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They also tend to fling bits and pieces of themselves into the cosmic void soon after the union. Sometimes those pieces will amount to a new galaxy, but most tend to linger around in an eccentric orbit, trying to escape but never managing to achieve enough velocity.
Re:The good news (Score:5, Funny)
I hope we're insured. Imagine if the other guy sues!
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Except collapsing galaxies probably isn't as bad as it sound.
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Better start getting quotes from Geico on upgraded insurance then...
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Actually, at the rate our sun is heating up [bbc.co.uk] as a natural part of its life cycle, we've got about 500 million years to get off this rock. So, we don't get to see that firey end anyway.
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Actually, if we get far enough away, we'll get a better view of the whole thing.
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Good thing, because our local star (aka the Sun) doesn't have enough mass to go nova. It'll be a Red Giant swelling to absorb the atmospheres of the inner planets. It will then eventually shrink back down to a white dwarf and eventually die a completely lonely death. Unless we get lucky and we slam into one of those Andromedan supergiants.
I'll be counting the days (Score:5, Funny)
..on my Zune
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Timeline revisions of 2-3 Billion years are now to be expected. A patch will be made available before this becomes an issue in the year 2012000000.
hello... (Score:2, Informative)
Mass != weight
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OK, so you want to maintain scientoideological purity and claim "heavy" only has to do with gravity...so what? Two kilograms is still heavier than one kilogram, no matter what gravity you apply to them.
rj
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No, he's pointing out the pretty basic fact that mass and weight are measures of two different things.
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Of course they are. But "more mass" implies "heavier" just as much as "more weight" does!
rj
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just as much as "more weight" does
No. It implies that you're near a much larger mass. Astronaut on Moon vs astronaut on Earth.
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A massive object in near-zero gravity weighs less than a smaller object in very strong gravity... that's sort of what weight means.
I agree it's pedantry to insist that the headline be perfectly accurate, but you're still wrong.
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That's some heavy thinking. You must have a massive intellect.
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What? No. Weight is a function of gravity. An object can have near-infinite mass, but if it isn't affected by a gravitational field, it's weight remains zero.
Re:hello... (Score:4, Informative)
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Actually I think it was when I was playing catch with my Nephew... I missed the ball and it started orbiting ;)
Reassuring (Score:3, Funny)
For a while there I was worried it had dropped down to 1 billion years.
Re:Reassuring (Score:4, Insightful)
No can do.
However, we may be able to dupe this tomorrow and then again a few years from now when its on Digg.
Thanks for your understanding,
The Management
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1000 years is no less irrelevant to you than 1 billion years.
Science (Score:5, Interesting)
One thing that is great about science is that it does have a way of eventually finding errors and correcting them in the face of new evidence.
As far as galactic collisions are concerned, we are in no immediate danger. 2-3 Gy vs 5 is an academic exercise, as the Sun will most likely increase its output sufficiently by then to boil off the Earth's oceans anyway,
Besides, the density of a galaxy (outside of the core) is so low that the chance of a stellar or planetary collision is negligable anyway.
Or, by then, we would have the technology to detect it and either deflect it or GTFO of the way anyhow.
Still, it is nice to know we're not in the pipsqueak galaxy. Hoorah!?!?
Re:Science (Score:5, Funny)
Still, it is nice to know we're not in the pipsqueak galaxy. Hoorah!?!?
The Miiilky Waaay... Fuck, yeah!
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Still, it is nice to know we're not in the pipsqueak galaxy. Hoorah!?!?
Let's go to the Magellanic Clouds and look for somebody to beat up!
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True. I've heard estimates that predict in about 900 million years, the oceans will have boiled due to the increased energy output from the sun. Between that, and whatever else we could do to doom ourselves, it kind of wants to make you get into space as quickly as possible, no?
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One thing that is great about science is that it does have a way of eventually finding errors and correcting them in the face of new evidence.
It's also what makes many educated lay people suspicious when scientists categorically assert that Global Warming Is Upon Us, and We're All Going To Die, so quick, lets over-regulate every facet of everyone's lives, because We Went To University, So We Know What's Good For You.
I love the Scientific Method, and I think it's the only way to discover Reality, but we have
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I've read that a bigger risk is that of a nearby super-nova. The collision will likely trigger extreme star formation due to the stirring up of interstellar gas. Thus, it will be quite a fire-works show for a while.
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Still, it is nice to know we're not in the pipsqueak galaxy. Hoorah!?!?
Well, we never really were. The Local Group contains a few dozen galaxies, of which the Milky Way was already known to be one of the "big 3" (Andromeda, The Milky Way, and The Triangulum galaxies all being pretty big in comparison to most of the others in the group). It's just that now instead of being #2 we might just be #1 :).
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Declaration of inter-galactic hostilities (Score:5, Funny)
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Two galaxies, one cup.
Re:Declaration of inter-galactic hostilities (Score:4, Funny)
Well, that'll show those Andromedans not to attack "smaller" galaxies. Now who's laughing! We will plunder their mass...
So your saying that in the final climactic battle between forces beyond human comprehension - I'm stuck on the pirate side? Dammit!!
Ninjdromeda's gonna kick our ass...physics be damned!
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Ninjdromeda's gonna kick our ass...physics be damned!
Dude, we can see them coming 2-3 billion years in advance. I don't think they're ninjas.
last chance for backup! (Score:5, Funny)
oh well.. still leaves plenty of time to debate which is the most robust backup method after all then?
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VI! Emacs!!!! ummm... little help?
pico, there I helped
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PS3!
I for one... (Score:4, Funny)
Thought I was drunk.
Good to know it was the milky way spinning all too fast.
From TFA (Score:2)
The Earth's Solar System is located some 28,000 light years from the centre of the Milky Way. At that distance, the new measurements show that the galaxy is rotating at a speed of 965,600 km/h, compared to previous estimates of 804,672 km/h, the astronomers report.
965,600 km/h = 268 222.222 m/s or about 1/1117th of the speed of light...
Re:From TFA (Score:4, Insightful)
"...the galaxy is rotating at a speed of 965,600 km/h, compared to previous estimates of 804,672 km/h, the astronomers report."
Anyone else think it odd that the previous estimate had six significant digits, yet was apparently off by ~20%?
Re:From TFA (Score:4, Funny)
Re:From TFA (Score:4, Insightful)
The odd thing is not the estimate (500,000 mph has one significant digit) but its conversion to km/h.
Re:From TFA (Score:5, Informative)
Thank you, makes much more sense now. Agence France-Presse strikes again. They converted mph to km/hr VERY precisely.
965,600 km/h = 600,000 mph
804,672 km/h = 500,000 mph
Abstract of presentation (10aPT Tue Jan 6, if you are in Long Beach CA) is at http://tinyurl.com/9d5rec [tinyurl.com].
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The original number was probably in m/s anyway, then converted to mph, rounded, then converted to km/h and not rounded.
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Precision != Accuracy.
The previous measurement had 6 significant digits of precision.
They just happened to be inaccurate.
Note that the new estimate seems to have *less* precision (assuming that only the first 4 digits are significant), but is claimed, at least, to have more accuracy.
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Anyone else think it odd that they measured angular velocity in linear units? WTF?
Showing My Ignorance (Score:2, Insightful)
But how do you calculate the rate of rotation and mass of a galaxy that you're in? It's mind blowing that we can actually do that.
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Depends, how much time do you have to make observations? It's probably rather easy if you got a couple million years to burn.
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it seem they got it wrong at least once so far ...
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But how do you calculate the rate of rotation and mass of a galaxy that you're in? It's mind blowing that we can actually do that.
Science.
It works, Bitches [xkcd.com].
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Simple, the girl astronomers don't mind asking neighboring galaxies for directions. (Stubborn guys try to use math and stuff.)
position (Score:2)
Speed: if you know a constellation of stars is in our galaxy, then you can track it's movement speed. Especially since we have software that'll give the position of constellations right back to egyptian times, etc.
Mass: they're working this out based on the rotation speed.
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I'm no physicist, but I do know that the orbital velocity of an object depends on two things: its distance from the system's center of gravity and the mass of the system in question. Getting a more accurate measure of our orbital velocity gave us a better estimate of the mass.
Way Heavier Than Thought, and Spinning Faster (Score:5, Funny)
Ugh. Sounds like scientists just discovered my last blind date.
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Strangely appropriate. [xkcd.com]
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The Milky Way would like to respond by noting that it is not, in fact heavier, it's just that these pants makes its butt look big.
I haven't read the paper, but... (Score:2, Insightful)
I think the article oversimplifies. The Milky Way doesn't rotate as one single piece. It's made up of billions of stars (duh!) which revolve around the center at different velocities. So, the question is, is the quoted speed the speed at which the Sun revolves around the galactic center or the average speed of the arms (which move much slower than the stars)? Maybe more later if I can find the paper on arxiv.org
Re:I haven't read the paper, but... (Score:5, Interesting)
Actually the orbital velocity is (surprisingly) close to constant, as in most spiral galaxies. In fact, it is these "flat" (i.e. constant as a function of galactocentric radius) rotation curves that were some of the earliest evidence for dark matter.
That having been said, my guess is that the velocities quoted in the press release refer to the Sun's (or more accurately the Local Standard of Rest's) velocity around the Galactic center.
Couldn't find the paper on arxiv.org ...
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No wonder our neighbors keep shifting away. I thought it was because they were on to our wireless thievery.
Damn... (Score:2)
...in 2 or 3 billion years ?!? (Score:2, Funny)
Whoa, for a moment I thought you said _million_ years. No need to panic, people.
Ahah! (Score:5, Funny)
It's only a matter of time before the earth's age is readjusted to 6000 years!
So much for the snack food (Score:2)
astronomers... (Score:2)
with apologies to Randall Munroe (Score:2)
Milky Way heavier than thought? Maybe it's your mom.
Zing!
Dark Matter (Score:2)
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OK, so now that the galaxy is heavier/massive. Do we still need dark matter to explain how it works?
More than ever. Dark matter was discovered (well, supposed) because of the way the galaxy rotates in an even fashion. Loose particles (ie, atoms of water in a cup) don't do that. Dense particles (ie, atoms of plastic in a CD) do. So there must be even _more_ dark matter than previously thought.
They keep swapping the title (Score:3, Insightful)
It seems like whether the Milky Way or Andromeda is bigger changes every couple years, as this paper or that paper claims a measurement showing one or the other is actually a lot bigger than we all thought.
We used to think the Milky Way was bigger (and before that, thought Andromeda was bigger for the longest time), and then recently we got some evidence that Andromeda was actually bigger after all. And then there's this piece about the Milky Way actually be bigger after all.
Me? I'm going to sit back and let the scientists figure it out for a few more decades before deciding. All we really know is that Andromeda and the Milky Way are by far the two biggest galaxies in our Local Group, and they're probably close enough in size to make figuring out which one is really bigger a bit tricky.
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When the tax collector comes by, we tinker with the books a bit, but then put it back big for advertising reasons.
this is why I'm skeptical (Score:2, Interesting)
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You do realize that this discovery means that there is _more_ dark matter in the Milky Way, not less?
we age slower then (Score:3, Funny)
Does that mean that we age slower compared to the people in Andromeda?
Re:Good news everybody! (Score:5, Funny)
Tell that to the fat guy who got shot with a rifle round. He has a 600,000% weight advantage, yet he's still in ICU on a respirator.
Fat man 0, Remington 1.
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Tell that to the fat guy who got shot with a rifle round. He has a 600,000% weight advantage, yet he's still in ICU on a respirator.
Did you see the bullet afterward?
Heavy thoughts??? (Score:3, Funny)
Do you mean there is a problem with gravity in the future?
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Forgive the possibly stupid question, but since km/h is a measure of linear speed, is that saying that we're traveling at that speed or is the edge of the Milky Way moving that fast?
It means exactly what it says. Our Solar System is rotating at 965,600 km/h. We aren't at the edge of the Milky Way anyway as the artist's rendering on the article page shows so it isn't the latter. The "At that distance" phrase is referring to the Solar System's distance (28k light years) from the center of the galaxy. Since the Milky Way isn't being torn apart the outer edges of the galaxy are rotating faster than the inner core (outer edges have to move faster because they have more distance to travel) c
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In what universe are those rules true? Certainly not this one.
The closer we are to the galactic center of mass, as measured in terms of the centers attraction for us, the higher the gravitational pull toward the center, and the faster we have to go in order not to fall in in a few million years. The stars and other materiel 10x farther out, have required orbital speeds much lower to sustain a constant orbit. This is the reason that most galaxies are spiral shaped, and one can say with 100% certainty whic
Re:From TFA: (Score:5, Interesting)
The visble arms of our galaxy's spiral aren't a fixed buch of stars clustered togther, it's a density wave that travels around the disk. Our solar system will pass in and out of various arms (eventually) as the density wave is travelling at a different speed to the actual rotation.