New Study Shows Universe Still Expanding On Schedule

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New Study Shows Universe Still Expanding On Schedule

Posted by timothy on Thursday October 4, 2012 @10:41AM from the every-time-you-jump-it-screws-things-up dept.

The Bad Astronomer writes "A century ago, astronomers (including Edwin Hubble) discovered the Universe was expanding. Using the same methods — but this time with observations from an orbiting infrared space telescope — a new study confirms this expansion, and nails the rate with higher precision than done before. If you're curious, the expansion rate found was 74.3 +/- 2.1 kilometers per second per megaparsec — almost precisely in line with previous measurements."

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Obligatory Spelling Comment by ixnaay · 2012-10-04 10:43 · Score: 5, Funny

Not to be pedantic, but that is an impressive way to misspell 'messureents'.
1. Re:Obligatory Spelling Comment by maroberts · 2012-10-04 10:47 · Score: 2
  
  Not to be pedantic, but that is an impressive way to misspell 'messureents'.
  The part of the universe covering that word hasn't fully expanded yet..
  
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2. Re:Obligatory Spelling Comment by Anonymous Coward · 2012-10-04 10:48 · Score: 3, Insightful
  
  that is an impressive way to misspell 'messureents'
  Wrong. 'messureents' is how you spell 'messureents'.
3. Re:Obligatory Spelling Comment by wonkey_monkey · 2012-10-04 11:23 · Score: 3, Insightful
  
  Not to be pedantic
  Sorry to be pedantic, but you are being pedantic.
  
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4. Re:Obligatory Spelling Comment by slashmydots · 2012-10-04 14:57 · Score: 1
  
  Not to be pedantic, but that is an impressive way to misspell 'messureents'.
  And yet they calculated the speed of light modified by the expansion of available space to travel through at a potentially non-static rate. I'm sure they didn't make a mistake there either, lol. Okay, here's my amateur astronomer opposition theory: the rest of the universe is gone! IT'S JUST GONE! But we're still receiving light from when it was there. Prove me wrong, lol. See, anyone can make anything up that's unprovable with modern technology.
5. Re:Obligatory Spelling Comment by dudpixel · 2012-10-04 15:15 · Score: 1
  
  that is an impressive way to misspell 'messureents'
  Wrong. 'messureents' is how you spell 'messureents'.
  The summary now says "measurements", so I guess the above is correct now?
  
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6. Re:Obligatory Spelling Comment by dudpixel · 2012-10-04 15:16 · Score: 2
  
  sory to be pedantic but it's "ditto".
  
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7. Re:Obligatory Spelling Comment by elementik · 2012-10-04 18:51 · Score: 1
  
  It's
  
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8. Re:Obligatory Spelling Comment by saveferrousoxide · 2012-10-05 04:52 · Score: 1
  
  What I find really funny is that googling 'messureent' comes up with:
  "Showing results for measurements"
9. Re:Obligatory Spelling Comment by mfnickster · 2012-10-05 06:46 · Score: 1
  
  Shirley, it should be Messierments ?
  
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8 year old's question by RichardDeVries · 2012-10-04 10:43 · Score: 4, Insightful

It expands into what?

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1. Re:8 year old's question by hutsell · 2012-10-04 10:46 · Score: 3, Informative
  
  Hilbert Space
  
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2. Re:8 year old's question by UnknownSoldier · 2012-10-04 10:51 · Score: 3, Informative
  
  Nothingness. There is no space & time outside the physical universe. If that doesn't bake your noodle, I don't know what will.
  The nice thing about Religion^H^H^^H^H^ science is that it advances one funeral at a time. (With apologies to Max Planck :)
3. Re:8 year old's question by RichardDeVries · 2012-10-04 10:53 · Score: 4, Funny
  
  On behalf of all 8 year olds: thank you, that was very informative. As for myself: I'm supposed to have an IQ well above 130, but it would probably take me months to make sense of that page.
  
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4. Re:8 year old's question by RichardDeVries · 2012-10-04 11:01 · Score: 1
  
  Question 2
  
  There is no space & time outside the physical universe.
  Are you sure? How do you know?
  Etc. etc. ad infinitum. It's a good answer though, even I can understand it and it's helpful. Thanks!
  
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5. Re:8 year old's question by MightyMartian · 2012-10-04 11:02 · Score: 3, Interesting
  
  The universe could be a compact manifold, in which case it isn't expanding into anything. That would fit with the essential notion that it is space itself that is expanding.
  
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6. Re:8 year old's question by kheldan · 2012-10-04 11:03 · Score: 5, Insightful
  
  Correction: There is no space and time that we can determine with any certainty outside our physical universe.
  
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7. Re:8 year old's question by multiben · 2012-10-04 11:10 · Score: 4, Funny
  
  Milk. The universe is surrounded by milk.
8. Re:8 year old's question by arth1 · 2012-10-04 11:40 · Score: 3, Insightful
  
  Correction: There is no space and time that we can determine with any certainty outside our physical universe.
  This is imprecise at best. There is no "outside our physical universe", because dimensions becomes meaningless at the border of the universe, so there is nowhere "outside" for other universes to be. If they exist, they don't exist "outside" our universe, at least not in a dimensional sense.
  As for time, that is a purely local phenomenon, and we can not determine it even inside our universe, except right here. Every "here" will have its own rate of time.
9. Re:8 year old's question by Anonymous Coward · 2012-10-04 11:40 · Score: 5, Informative
  
  Unless you have a generic curiosity, don't try to hard to read that, as it is not related to the universe's expansion. The grandparent was just being random or joking. A Hilbert space is just what you get when you treat the set of all continuous functions as a vector space. It has several different possible basis sets of functions you can add up to make any other function, e.g. sine waves via Fourier analysis. Instead of having unit vectors like x, y, and z, you would have unit vectors like sin(x), sin(2x), sin(3x), etc. (which makes it infinite dimensional). The concept is really important to physics, especially quantum mechanics and any where else things like Fourier analysis would be done with some mathematical rigor. But it is not what the universe is expanding into.
  The typical analogy used for what the universe is expanding into is like a balloon being inflated, with that being a 2D universe on the surface of the balloon. You could ask about the third dimension it is expanding into, but that is not really relevant (at the moment at least). The only thing that really matters is the curvature of local space (how non-flat any given spot on the balloon is). Short of discovering some new theories unlike what we've seen before or something like brane theory, the equivalent of the 3D dimension in the balloon analogy would be unreachable and meaningless, as it would not be able to affect things in anyway beyond the curvature of the surface.
10. Re:8 year old's question by R3d+M3rcury · 2012-10-04 11:45 · Score: 1
  
  Other universes. It's that whole 'obesity' thing, which is why the kid should be outside running around and getting exercise rather than sitting inside and asking questions.
11. Re:8 year old's question by MightyMartian · 2012-10-04 12:01 · Score: 3, Insightful
  
  The problem with what you're saying is the word "into". It still suggests that there is some medium into which the universe expands. It's another form of the famous Hawking problem "What's north of the north pole?" If there is nothing, then the universe is not expanding into it. It is simply expanding.
  As much as anything, it is a problem that while expressable mathematically, is, at least to most peoples' brains (mine included) something impossible to imagine. It is just another way in which our common every day perceptions of the world around us don't model every aspect of reality well.
  
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12. Re:8 year old's question by turbidostato · 2012-10-04 12:14 · Score: 4, Informative
  
  "There is no space & time outside the physical universe.
  Are you sure? How do you know?"
  He doesn't need to know: that's a per-definition fact.
  A different question would be if the physical universe is composed of four dimensions or there are more.
13. Re:8 year old's question by gestalt_n_pepper · 2012-10-04 12:28 · Score: 1
  
  Hey man, I just work here, OK?
  
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14. Re:8 year old's question by Sponge+Bath · 2012-10-04 12:32 · Score: 2
  
  I guess God must be a woman... with astronomical tits.
15. Re:8 year old's question by Nostromo21 · 2012-10-04 13:17 · Score: 3, Funny
  
  "In the beginning, God created the heavens and the earth. The earth was without form and void, and darkness was over the face of the deep. And the Spirit of God was hovering over the face of the waters."
  Flame away. <BFG>
16. Re:8 year old's question by Anonymous Coward · 2012-10-04 14:00 · Score: 1
  
  This is imprecise at best. There is no "outside our physical universe", because dimensions becomes meaningless at the border of the universe, so there is nowhere "outside" for other universes to be. If they exist, they don't exist "outside" our universe, at least not in a dimensional sense.
  As for time, that is a purely local phenomenon, and we can not determine it even inside our universe, except right here. Every "here" will have its own rate of time.
  Not necessarily. At the formation of the universe and perhaps in times and places thereafter, it's possible that our universe became disjoint from other universes even though they intersected in the distant past. These universes would, if they existed, be very real and would necessarily be part of completely understanding the universe we live in. Anything in those now-separate space-times could reasonably be called "outside" the universe. Also, if there are wormholes that join places in our past with places in our future, the part of them that doesn't directly connect with now would be reasonably called "outside" the universe.
  I'm also disturbed by your use of the phrase "rate of time." What does that mean, if anything?
17. Re:8 year old's question by __aaltlg1547 · 2012-10-04 14:05 · Score: 1
  
  Wrong question. The rate of expansion is the rate at which objects in the universe are moving away from each other, in a massively averaged way.
18. Re:8 year old's question by __aaltlg1547 · 2012-10-04 14:07 · Score: 1
  
  "The universe could be a compact manifold, in which case it isn't expanding into anything. That would fit with the essential notion that it is space itself that is expanding."
  Just as easy to say that it is expanding into nothing.
  It's even easier to say the universe is self-contained, which bypasses the need to explain that the "nothing" you're using in your expression is not the same thing as empty space.
19. Re:8 year old's question by __aaltlg1547 · 2012-10-04 14:08 · Score: 2
  
  Milk. The universe is surrounded by milk.
  Unlikely. Turtles don't have milk.
20. Re:8 year old's question by dudpixel · 2012-10-04 15:18 · Score: 1
  
  Good point, are we measuring distance, or the speed of light?
  
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21. Re:8 year old's question by arth1 · 2012-10-04 15:21 · Score: 1
  
  I'm also disturbed by your use of the phrase "rate of time." What does that mean, if anything?
  For a local observer observing itself, nothing.
  Time itself bends in the presence of gravity or velocity.
  If you sit at A, which is equidistant from B and C, and observe a spaceship close to the speed of light going from B to C, you may observe that the trip took five years. However, the spacefarers aboard the vessel will swear up and down that it only took two years. And you're both right.
  The travelers who are in a different time frame has a different "rate of time" -- by your clock. Just like you have by theirs.
  And consider photons. Through vacuum, they move at c, by definition. That means that no time passes for a photon. This seems like a paradox, because if an electron moves a distance of fifteen thousand million light years, surely it takes fifteen thousand million years? Nope. That is the time an outside observer would measure, not the time for the photon. From its viewpoint, movement is always instantaneous[*].
  So from our point of view, a photon's "rate of time" is, for lack of a better phrase, "infinitely slow".
  Of course, the Bohr legacy has other ways of describing it, but not in plain ole English in four dimensions.
  [*]: This also means that the lifetime of a photon is zero. That's more of a paradox. Taken to its extreme conclusion, it could lead to photonic solipsism and string theories.
22. Re:8 year old's question by Bengie · 2012-10-04 15:30 · Score: 1
  
  "This also means that the lifetime of a photon is zero. That's more of a paradox." - I think it just means our concept of time is wrong.
23. Re:8 year old's question by Pseudonym+Authority · 2012-10-04 16:14 · Score: 1
  
  For it to not be true, relativity would have to be completely wrong. Since it's back up by math, and you assertion is backed up by an unwillingness to understand, I'm going to have to side with relativity until you show some evidence other than `It's just no common sense!'.
24. Re:8 year old's question by kheldan · 2012-10-04 17:38 · Score: 1
  
  This is imprecise at best.
  Really, you have to admit that for something purely theoretical with a high likelyhood of never being proven at all, "imprecise at best" is a moot statement -- at best. :-)
  
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25. Re:8 year old's question by RichardDeVries · 2012-10-04 19:56 · Score: 1
  
  Thanks! I've read about the balloon analogy, but it's hard for me to grasp. I'm not made for this, I guess.
  
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26. Re:8 year old's question by wonkey_monkey · 2012-10-04 21:17 · Score: 2
  
  But elephants do.
  
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27. Re:8 year old's question by Neil+Boekend · 2012-10-04 21:19 · Score: 1
  
  The flame wasn't there in the beginning. Lucifer stole it from the heavens and brought it here. That was why he was kicked out of the heaven.
  
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28. Re:8 year old's question by arth1 · 2012-10-05 00:17 · Score: 2
  
  Until we can test our models experimentally (highly unlikely for this particular case), I'd say that "uncertain" is a very precise way to describe it.
  being an outside to be uncertain about.
  You can't go five feet past the edge of the universe, because there is no space to measure five feet in. There isn't a void outside the universe where other universes can be, because that presupposes that there is a void with spatial coordinates, while those are attributes that belong to our universe.
  Yes, we want to think of what's beyond, and our intuitive thinking doesn't deal well with models that doesn't represent space as we think of it.
  The background radiation of the universe is uniform in all directions, and is believed to be so everywhere in the universe. I.e. there is no "edge" that expands. Everywhere expands.
  If there isn't an "outside" anywhere or -when for a galaxy to be, degrees of uncertainty becomes a moot point. You could as well look at whether there are universes "inside" point particles like gluons and photons, or "before" time existed.
  Or inside god's navel, for that matter.
  If we are to determine other universes, it's going to be through mathematics, not physics, which are limited to this universe.
29. Re:8 year old's question by BaronAaron · 2012-10-05 00:57 · Score: 1
  
  I like the loaf of raisin bread analogy better.
  The rest of the this wikipedia article explains things in more understandable terms.
30. Re:8 year old's question by bunratty · 2012-10-05 01:52 · Score: 1
  
  No, no, no. It's pasta sauce created from His noodly appendage.
  
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31. Re:8 year old's question by Anonymous Coward · 2012-10-05 06:38 · Score: 1
  
  You're thinking Prometheus. Who gets to have his liver eaten from his chest while chained to a rock every day for eternity.
  Luci was the Celestial Bin Laden, all insurgent up in God's face afore God went GTFO. He just gets to roam around being bad until the Apocalypse, where he gets thrown into a pit for a millenia, then gets out for a bit, presumably to stretch his legs.
  Meanwhile, Prometheus is still chained to his rock, gettin' nibbled on. For giving up a bit of fire. Old school myths punished hard.
32. Re:8 year old's question by Lucas123 · 2012-10-05 07:02 · Score: 1
  
  Another good question is if a galaxy one megaparsec away (that is, 3.26 million light years) is be moving away from us at 74.3 km/sec.How is it that a galaxy two megaparsecs away is moving at twice that speed, or 148.6 km/sec. That doesn't seem to make sense. Is the theory that the universe is expanding more quickly at the edge than at the center or are we at further out looking in?
33. Re:8 year old's question by Bengie · 2012-10-05 10:34 · Score: 1
  
  If from the photon's perspective, it lasted exactly 0 time, then it never existed as all things that have never existed also have existed a time of 0. In one frame of reference, the photon exist, but it does not exist in the other frame of reference.
34. Re:8 year old's question by RichardDeVries · 2012-10-05 16:21 · Score: 1
  
  Thanks! The article even has a heading called "What space is the universe expanding into?".
  
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Units by Anonymous Coward · 2012-10-04 10:49 · Score: 1

So, I'm probably laying out my lack of knowledge on this one, but can someone who knows about that which they speak explain kilometres per second per megaparsec?
1. Re:Units by amRadioHed · 2012-10-04 11:04 · Score: 4, Informative
  
  Due to expansion, the speed of objects accelerating away from us is proportional to the distance from us. So according to this, an object at 1 megaparsec from us will be receding at 74.3 km/s, while an object at twice the distance will be moving twice as fast.
  
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2. Re:Units by olsmeister · 2012-10-04 11:04 · Score: 1
  
  You use this constant and multiply it by the distance of an object to obtain the speed that it is receding from us. So, for instance, if a particular point in space is 1 megaparsec away from us, it is receding at 1 megaparsec * 74.3 (km/s)/megaparsec ... the megaparsecs cancel and you get 74.3 km/s. Which doesn't tell you how fast the expansion is accelerating, but does tell you how fast it's happening at this moment in time. An point 100 megaparsecs away would be receding 100 times faster or 7430 km/s. Kind of an awkward combination of units but then again it's just a factor that let's you estimate relative speed from distance.
3. Re:Units by Archangel+Michael · 2012-10-04 11:13 · Score: 1
  
  From my understanding, speed is relative, so the terms the relation of the two objects, the one being measured from and the one being measured to. As those speeds (relative) approach Light, that is when we can start seeing other interesting effects, like space curving. Space curving is what really boggles the mind, because it is, and isn't curving, depending on what you are looking at, because the "speed" is what bends our perception.
  
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4. Re:Units by gewalker · 2012-10-04 11:23 · Score: 1
  
  Yes, you appear to be slow thinking today (It happens to everybody).
  kilometers per second how fast 2 galaxies recede from each other.
  mega parsec is a really long distance (3.26 light years / 19 trillion miles / 31 trillion kilometers)
  The further away the galaxies, the faster they recede.
  E.g., if 2 galaxies are 100 MegaParsecs apart, then they should be separating from each other at about 100 * 74.3 = 7430 kilometers per second.
5. Re:Units by sconeu · 2012-10-04 11:28 · Score: 4, Interesting
  
  Interestingly, some back of the envelope calculations (using rough numbers ... 300000km/s for c, 75km/s/mpc for Hubble's Constant, and 3.25 ly/pc) gives a value of roughly 13 billion light years for the recession velocity to approach c. 13 billion years is also *ROUGHLY* the age of the visible universe.
  
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6. Re:Units by Relic+of+the+Future · 2012-10-04 11:30 · Score: 3, Interesting
  
  In the vein of xkcd-what-if #11, I wonder about the physical meaning of kilometers per second per megaparsec. Kilometer and megaparsec are both lengths, so you can divide them out by the conversion factor (1 megaparsec = 3.08567758 × 10^19 kilometers) and then you are left with "per second", i.e., a frequency. A frequency of about 240 billion gigahertz. What, if anything, does that mean?
  
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7. Re:Units by sconeu · 2012-10-04 11:30 · Score: 1
  
  Oops... that' 75km/s/Mpc, not mpc.
  
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8. Re:Units by sconeu · 2012-10-04 11:32 · Score: 3, Informative
  
  No, a *parsec* is 3.26 light years. A Megaparsec is 3.26 MILLION light years.
  
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9. Re:Units by ImprovOmega · 2012-10-04 11:53 · Score: 4, Interesting
  
  That can't be right. The universe is about 14,000 megaparsecs in radius, even if we were at the exact center that would have things traveling outward at 1.04E9 m/s or 3.46c. I'm reasonably certain they're not claiming FTL on this one so... Is it actually 74.3 m/s instead of 74.3 km/s? Or is there something else going on here?
10. Re:Units by j00r0m4nc3r · 2012-10-04 12:12 · Score: 4, Informative
  
  Space itself can expand FTL, but anything inside that space is limited to c. This also means that at any given point in the universe, there is a boundary where you can never reach beyond, because the space itself is expanding away FTL, so you can never catch up to observe anything beyond that boundary...
11. Re:Units by Anonymous Coward · 2012-10-04 12:29 · Score: 3, Insightful
  
  I think you got your final result messed up:
  (74.3 km / s / mparsec) * (1 / 3x10^19 mparsec / km) = 74.3 ? / s * 3.3x10^-20 ~ 2.4 x 10^-18 cycles per second ~ 403768506056527590 seconds per cycle ~ 12.7 billion years per cycle.
  It helps to actually include the units in your math as "unsolvable variables" that cancel each other out in your conversions. It's a fairly easy way to make sure the math comes out correct. Granted, this extremely rough number is kinda interesting because it is less than 10% off from the age of the universe. May mean absolutely nothing though.
12. Re:Units by Nostromo21 · 2012-10-04 13:13 · Score: 1
  
  So at around 4000 megaparsecs (13 billion light years) the outer rim hits the speed of light...? Hey, isn't that about the age of the Universe anyway....could I be onto something here...? ;)
13. Re:Units by LordLimecat · 2012-10-04 14:03 · Score: 1
  
  Hold on there.
  If I recall, one of the principles around c is that two things may not move apart faster than c, either. So if you have an observer with a lantern on a train moving 60mph, the light moves away from the observer at c. But! It also moves away from the train platform at c, not c + 60mph
  Now as I see it, what is being described is that the universe (spacetime) is the train in my scenario. How could you then account for the rate of expansion from the perspective of two individuals, one at each "end" of spacetime?
14. Re:Units by RegTooLate · 2012-10-04 14:07 · Score: 2
  
  whatever my ship can make the Kessel Run in less than twelve parsecs.
15. Re:Units by thrich81 · 2012-10-04 14:38 · Score: 4, Informative
  
  Space itself can expand such that the objects (events?) within it are moving apart at faster than c. Any two objects separating faster than c can't measure that -- they cannot pass any signal between them. Any light (or other signal) which leaves one will be redshifted away to nothing before it gets to the other. They are outside each other's observable universe. I'm pretty sure this has to handled using General Relativity, I don't think Special Relativity has any concept of expanding or contracting space-time. Space-time described by Special Relativity is flat and static.
16. Re:Units by sadyoshi · 2012-10-04 19:12 · Score: 1
  
  It's the ratio that space itself expands per second. Each second, space expands by a multiple of 1 + (74 km / 1 megaparsec).
17. Re:Units by f()rK()_Bomb · 2012-10-04 21:10 · Score: 1
  
  Posting to fix Accidental mod
  
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18. Re:Units by Ginger+Unicorn · 2012-10-05 00:09 · Score: 1
  
  Yes. Eventually each object in the universe will be in it's own lonely little bubble, out of range of everything else
  
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19. Re:Units by Sqr(twg) · 2012-10-05 01:38 · Score: 1
  
  You did the math wrong. 74.3 / 3.08567758e19 is approximately 2.4e-18 Hz.
  This is how frequently the universe doubles it current size at the current rate of growth.
20. Re:Units by Quirkz · 2012-10-05 02:40 · Score: 1
  
  Except I don't think the expansion applies at the galactic level, so anything in a galaxy will still have the whole galaxy with it. Now if you're talking about galaxies themselves as the objects of the universe, then that's likely true.
  
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21. Re:Units by cashdot · 2012-10-05 02:44 · Score: 1
  
  Space itself can expand such that the objects (events?) within it are moving apart at faster than c.
  correct
  
  Any two objects separating faster than c can't measure that -- they cannot pass any signal between them.
  not correct
  Let me explain: Suppose there are two points in space, A and B, which are in rest relative to eachother. The distance between A and B grows FTL as space expands.
  It is paradoxical, but nevertheless true, that travelling from A to B takes only a finite amount of time, no matter how slow the travel is. This is because the distance already traveled is expanded as well.
22. Re:Units by thrich81 · 2012-10-05 03:36 · Score: 1
  
  I'm open to discussion, but I'd say there is a flaw in your example -- if points A and B are truly 'at rest' relative to each other then by definition the distance between them is not growing (no velocity induced redshift). I think you are trying to use the definition of 'rest' as meaning no "peculiar motion" (astronomical term) on top of the motion imparted up on them by the expansion of space between them. A concrete example would be galaxies observed at a large distance -- they all have a redshift due to the expansion of space between us, on top of whatever random peculiar motions they may have, but the true measure of the velocity between us and them is the observed redshift no matter how it comes about (neglecting gravitational redshifts). If the separation velocity is greater than c then the redshift becomes infinite = no signals.
23. Re:Units by dinfinity · 2012-10-05 04:42 · Score: 1
  
  Yes, the paradox more commonly known as:
  http://en.wikipedia.org/wiki/Ant_on_a_rubber_rope (the expansion of space is explicitly referenced at the end of the article).
  It has to be said however, that the 'finite amount of time' can easily be ridiculously large.
24. Re:Units by cashdot · 2012-10-05 05:48 · Score: 1
  
  If the separation velocity is greater than c then the redshift becomes infinite = no signals
  I do not understand which theorie/formulae you indicate here
  You should not confuse redshift caused by Relativistic Doppler, which is not even defined for FTL, with Cosmological redshift
25. Re:Units by thrich81 · 2012-10-05 07:00 · Score: 1
  
  Dang, now I have to go review some GR stuff to go any further. When you get deep into GR, either on cosmological distances or strong gravity fields things get badly non-intuitive. In this particular case I think we will run into the problem of what exactly is meant by "areas of space receding from each other at faster than c". I'll leave with this one question -- if you postulate two objects separating from each other at faster than c due to the cosmological distance between them, and further assert that they will be able to "observe" each other (send a light or other signal), what is the observed doppler shift of that signal when received? Appreciated the discussion.
Gem Secretes as Superman by badford · 2012-10-04 10:50 · Score: 3, Funny

is an anagram of 'megaparsec messureents' thought you'd like to know.

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-badford
Ok. Now what is it in hogsheads per fortnight? by Nadaka · 2012-10-04 10:50 · Score: 1

ha
1. Re:Ok. Now what is it in hogsheads per fortnight? by flaming+error · 2012-10-04 11:08 · Score: 1
  
  You're units are incompatible. I think the units you wanted were football field lengths per fortnight per furlong.
2. Re:Ok. Now what is it in hogsheads per fortnight? by Nadaka · 2012-10-04 11:19 · Score: 2
  
  hmm...
  Partially right. but the universe expands in 3d, not just linearly.
  What is the answer for hogsheads per fortnight per displacement of Archimedes in a bathtub.
3. Re:Ok. Now what is it in hogsheads per fortnight? by ThreeKelvin · 2012-10-04 11:31 · Score: 1
  
  Hogshead per fortnight (equivalent to m^3/s) is the wrong unit of measurement for expressing the expansion of the universe. I'd go with 2.4 +/- 0.068 exaHz for a whimsical and opaque way of expressing it.
4. Re:Ok. Now what is it in hogsheads per fortnight? by ThreeKelvin · 2012-10-04 12:19 · Score: 1
  
  If you want the expansion as a volume you could use m^3/(s*m^3), i.e., rate of volumetric expansion per volume of space. m^3/s just gives you a rate of volumetric expansion, it doesn't say anything about the volumetric expansion being faster if you look at a larger volume, or equivalently, things move faster away from you the further away from you they are, i.e., m/(s*m), which is what Hubble's Law is all about.
  You can of course calculate the expansion of af known volume of space e.g. the entire universe* or just our galaxy in m^3/s, using the newly reported observation.
  *As far as I know, we don't know how big the universe is, or even if the universe is finite, so we couldn't actually calculate this.
Not to be pedantic by ubergeek65536 · 2012-10-04 11:09 · Score: 2, Insightful

The visible part of the universe is expanding. We have no clue what's happening to the infinitely large part we can't see.
1. Re:Not to be pedantic by countach · 2012-10-04 11:18 · Score: 4, Insightful
  
  Well, to be pedantic, its a stretch to say "we have no clue". We can make some pretty damned good guesses.
2. Re:Not to be pedantic by Anonymous Coward · 2012-10-04 12:00 · Score: 1
  
  I believe the original is talking about rest of the universe that is outside the 13.7 billion light year radius sphere that we can see.
3. Re:Not to be pedantic by dido · 2012-10-04 12:58 · Score: 1
  
  Well, there is the dark flow, a mysterious influence on the motion of distant galaxies whose cause can no longer be observed because it has presumably passed beyond the visible universe. However, we can still see the results of its effect on stuff that is still in the visible universe.
  
  --
  Qu'on me donne six lignes écrites de la main du plus honnête homme, j'y trouverai de quoi le faire pendre.
4. Re:Not to be pedantic by cain+amofni · 2012-10-04 14:01 · Score: 1
  
  yes. the prevailing conjecture seems to be at odds with a little einsteinian problem: no absolute rest, no absolute velocity. so what is expanding at that rate with respect to what? if they said the 'edge of the observable universe' then it would have meaning, but since there is a limit of observable range due to the fact that beyond a certain distance from the observer (us), a galaxy or quasar would be receding at a cumulative rate greater than the speed of light, and hence, exits the observable universe relative to our vantage point. thus, unless we are at the center of the universe - highly unlikely - then the observable universe is a subset of the total universe. so we really have no way of knowing the actual size of the universe, or whether it's infinite, in which case, saying it's expanding at a certain rate has no meaning at all.
5. Re:Not to be pedantic by Ironhandx · 2012-10-04 14:09 · Score: 1
  
  Its things like this that we've confirmed as accurate as much as we can that makes me think the universe isn't expanding at all, we're just able to see more of it all the time. The current size of the universe closely correlates with the speed of light and the time it would have taken that light to reach us... coincidence?
  Space itself is supposedly able to expand faster than the speed of light, however I'd like someone to point me to the evidence that this is happening at all.
6. Re:Not to be pedantic by Anonymous Coward · 2012-10-04 16:23 · Score: 2, Informative
  
  Doppler shift. Seriously.
  Light can experience doppler shift like sound can (well, really any wave can see a doppler shift). So if two objects are moving away from each other, light from one to the other will be red shifted. If two objects are moving closer together, the light will be blue shifted.
  Since chemicals have known spectral emission/absorption lines, you use that data compared with your observational data of distant objects to figure out the actual shift. Add in some math and you can even figure out how fast they are going. Hubble was one of the first to do the observations and noticed that *everything* outside the local group was red shifted. Andromeda and other members of the local group are gravitationally bound, including our galaxy, so you get other interesting values, including a blue-shifted Andromeda which gives us the idea that it will eventually collide with our galaxy as we more accurately measure that.
  But if the universe wasn't expanding, you'd expect that you wouldn't see such consistent and uniform redshifts in EVERY direction. And this concept has been backed up with data using a specific type of supernovae as a "standard candle" to figure out distances and confirm that the redshifts are telling us what we think they are telling us. Everything with bigger redshifts we've been able to also measure with a standard candle has been further away from things with smaller redshifts.
  The thing is, this red shift is also what allows us to measure the size of the observable universe, because this measured expansion is so uniform. And the constant used to describe this expansion is the Hubble constant. This particular bit of science isn't exactly new either. Hubble did the work almost a century ago now.
7. Re:Not to be pedantic by cain+amofni · 2012-10-05 12:09 · Score: 1
  
  I hear what you're saying but my point is that the Hubble constant is relative, not absolute. Relative to the observer in a non-absolute location. The expansion is an exponential scalar motion without any center. Even the edge of the observable universe is relative to the observer. So it's fine to talk about the universe expanding, but expanding relative to what? By definition, the size (radius) of the universe is that of only the observable universe - relative to us. Someone way over at the edge (according to us) is likely to see a different observable universe that extends 13 billion light years in all directions from their center of observation, beyond which the expansion rate is > c (again relative to us only), so quite a bit of that is invisible to us and always will be. So the limit of observability is 13 billion light years. Is it a coincidence that the calculated age of the universe (from only observables) is also 13 billion years? Of course not. Neither is the fact that the dimension of the Hubble constant is a frequency that resolves to 1/13 billion years. What is the probability of all those emerging without a common first principle? And what is the likelihood that we would happen to be at the center of the observable universe? About zero, to say nothing of the "total" universe. There is no reason at all to assume that we know the size or age of the "universe" and to throw that into the discussion of the Hubble constant (as many are on this thread) is meaningless.
what's in a name? by X10 · 2012-10-04 11:10 · Score: 2

It's not called "expansion rate". It's called "the Hubble constant".

--
no, I don't have a sig
Turtles. Duh! by Anonymous Coward · 2012-10-04 11:18 · Score: 1

Turtles. All the way out. Duh! Don't they teach kids anything these days?
Sorry for sounding stupid... by Longjmp · 2012-10-04 11:26 · Score: 1

... but shouldn't the universe expand at the speed of roughly 300,000 km/s (i.e. speed of light - and information) from any given point of the universe?
Someone enlighten me please.

--
There are fewer illiterates than people who can't read.
1. Re:Sorry for sounding stupid... by __aaltlg1547 · 2012-10-04 14:09 · Score: 1
  
  If that were the case, we wouldn't see anything when we look up at night.
2. Re:Sorry for sounding stupid... by Prof.Phreak · 2012-10-05 00:25 · Score: 1
  
  If you shine a laser pointer at the sky (not airplane), the beam leaves earth, and about 14 billion years the beam will reach the farthest galaxies we can see. What happens after another 1000 billion years? Will the beam curve back on itself? Will it slow down and go only at the rate of expansion? But, if the beam just keeps on going at c---it would be beyond the ``visible edge'' of the universe, no? Wouldn't that imply that the `non-visible' real edge of the universe has to expand at least at 'c' or else you'd have light leaving the universe, which it shouldn't :-/
  
  --
  "If anything can go wrong, it will." - Murphy
Better than ahead of schedule by Dyne09 · 2012-10-04 11:30 · Score: 1

Because, that would just be a problem.
Sure, but ... by fahrbot-bot · 2012-10-04 11:34 · Score: 1

the expansion rate found was 74.3 +/- 2.1 kilometers per second per megaparsec
... what is that in something useful, like Library of Congresses?

--
It must have been something you assimilated. . . .
Re:unit: kilometers per second per megaparsec ? by under_score · 2012-10-04 11:39 · Score: 1

I just means that over a given distance (a megaparsec) if you measure that distance every second, it will seem to have grown larger (by 47.3 +/- 2.1 kilometers). In other words, expanding space means that distance itself is growing.
Now, being a cosmology noob myself, I still can't quite wrap my head around this idea: if we look at a much smaller scale, say one meter, what are we actually observing? In our own frame of reference, does this mean that if you removed a one meter ruler from the universe for a second and then brought it back it would be measured to be slightly less than one meter? Or does it mean that the fundamental fabric of the universe that reflects relationships and fundamental constants in physics are changing so that when you bring the meter ruler back into the universe it would "pop" out to the new length of a meter?
I know that it relates to red shift... gack.

--
Helping with organizational effectiveness is our job.
Actually, it shows the Universe WAS expanding by WillAffleckUW · 2012-10-04 11:52 · Score: 1

What most of you don't realize is it started to collapse a few millenia ago, but the light and gravity waves from that haven't arrived yet.
Put on your tinfoil hats!

--
-- Tigger warning: This post may contain tiggers! --
Megaparsec? by tpstigers · 2012-10-04 12:16 · Score: 1

Never heard of them. How many in the Kessel Run?
1. Re:Megaparsec? by Neil+Boekend · 2012-10-05 00:11 · Score: 1
  
  Well, the kessel run is 18 parsecs, so that'll be 18/1,000,000=0,000018 Megaparsecs
  
  --
  Well, I might have a way, but it only works on a semi spherical planet in a vacuum.
Re:South Park by hazah · 2012-10-04 12:30 · Score: 1

It just rolls off the tongue.
Re:Units Space FTL, but information thru space? by shoor · 2012-10-04 12:42 · Score: 3, Interesting

Something I've been wondering about, but never knew quite where to ask. (Maybe this isn't the place either, but I'll give it a shot.)
i understand (or at least parse the semantic meaning) that the speed of light through space is fixed, and space can expand fasterthan that. Normally, it seems that the speed of information transmission is also tied to the speed of light, mainly I presume, because paradoxes would arise if it weren't. But can information travel across space at an effective speed uninfluenced by the expansion of space without causing paradoxes? Is it possible that information could still reach us even if light could not?

--
In theory, theory and practice are the same; in practice they're different. (Yogi Berra & A. Einstein)
The Universe has no center by seibai · 2012-10-04 13:05 · Score: 2

Just to clarify something that bothers me because so many people seem to believe it despite relativity expressly making it impossible: the universe has no center. Really, look it up. Similarly, the "big bang" does denote an explosion from a specific point.
1. Re:The Universe has no center by Anonymous Coward · 2012-10-04 17:29 · Score: 3, Insightful
  
  The center of the observable universe is exactly where I am at this moment. Beyond the observable universe, we have no idea, so we might as well assume that the center of the universe is the same as the observable universe. Me.
2. Re:The Universe has no center by Kaptain+Kruton · 2012-10-05 03:39 · Score: 1
  
  You're the center of the universe? And people say that I have a big head...
Re:unit: kilometers per second per megaparsec ? by Dan+East · 2012-10-04 13:09 · Score: 1

In terms of only km, each second the distance 415,299,808,882,907,133 km expands by 1 more km.

--
Better known as 318230.
dimensional analysis resolves to frequency by cain+amofni · 2012-10-04 13:48 · Score: 1

I find it fascinating that dimensional analysis of the expansion of space resolves to a frequency: 74.3 ((kilometers / second) / megaParsec) = 2.40789901 × 10-18 hertz http://www.google.com/#q=74.3+km/s+/+megaparsec http://www.ardeshirmehta.com/Relativity.html
1. Re:dimensional analysis resolves to frequency by sconeu · 2012-10-04 16:08 · Score: 1
  
  That frequency is 1/13billion years.
  
  --
  General Relativity: Space-time tells matter where to go; Matter tells space-time what shape to be.
2. Re:dimensional analysis resolves to frequency by wonkey_monkey · 2012-10-04 21:53 · Score: 1
  
  Is that a coincidence?
  
  --
  systemd is Roko's Basilisk.
3. Re:dimensional analysis resolves to frequency by sconeu · 2012-10-05 06:22 · Score: 1
  
  I don't know. It corresponds roughly with the age of the universe, and also with the limit at which the recession velocity approaches c.
  I'm just a dilletante. You'd have to ask an astrophysicist what the significance of that value is, if any.
  
  --
  General Relativity: Space-time tells matter where to go; Matter tells space-time what shape to be.
4. Re:dimensional analysis resolves to frequency by cain+amofni · 2012-10-05 11:33 · Score: 1
  
  If any astrophysicist knows I'd be surprised.
Re:Your problem... by MightyMartian · 2012-10-04 13:57 · Score: 1

There is a large amount of neurological heavy lifting that goes into interpreting sensory input.

--
The world's burning. Moped Jesus spotted on I50. Details at 11.
Re:Units Space FTL, but information thru space? by Andreas+Mayer · 2012-10-04 15:14 · Score: 1

But can information travel across space at an effective speed uninfluenced by the expansion of space without causing paradoxes? Is it possible that information could still reach us even if light could not?
No.
Nothing can travel faster than light and information has to be carried by *something*.
Light years please by rossdee · 2012-10-04 17:44 · Score: 1

"The universe is about 14,000 megaparsecs in radius"
A parsec is about 3.26 light years therefore a MegaParsec is 3.26 million light years
Say if you have velocity per distance thats distance per distance per time, the distances cancel out so the value would be a per time in other words a frequency
a very small frequency of course, but still could be expressed in hertz
Nope. Edwin Hubble didn't believed in Big Bang by Zdzicho00 · 2012-10-04 21:23 · Score: 1

Edwin Hubble was very sceptical about, so called "Big Bang" theory and claimed that there might be different explanation of redshift effect which he observed.
``Astronomer Edwin P. Hubble says that after a six-year study, evidence does not support what we now call the Big Bang theory, according to the Associated Press. “The universe probably is not exploding but is a quiet, peaceful place and possibly just about infinite in size.''''
Check this paper too:
http://arxiv.org/PS_cache/arxiv/pdf/1107/1107.2485v2.pdf
1. Re:Nope. Edwin Hubble didn't believed in Big Bang by negablade · 2012-10-04 22:10 · Score: 2
  
  That doesn't mean he was right. The prevailing opinion at the time was for a static, unchanging universe. And the discovery that it was expanding would have been difficult to reconcile with our understanding at the time. Prevailing opinions do change, albeit sometimes slowly, in the face of mounting evidence.
Naive question by tchi.keufte · 2012-10-05 01:08 · Score: 1

And why wouldn't we consider that the content of the Universe (including us) is shrinking, instead ?
It's... by bunratty · 2012-10-05 01:49 · Score: 2

Monty Python's Flying Circus!

--
What a fool believes, he sees, no wise man has the power to reason away.
Limits of the human mind by microbox · 2012-10-05 02:31 · Score: 1

I think it just means our concept of time is wrong.
Black and white thinking meets the limits of conception. *every* concept is wrong. It is a trivial statement. Both the concept, and its black & white categorization as right/wrong, are artefacts of the human brain. And the GP is wrong. From a photons point of view, it has zero lifetime only if it travels through a perfect vacuum. Light travels more slowly otherwise, and then observes "time" and "distance".

Another way of saying is, if a photon was generated in a distance star, and it intersected with your eye (i.e., you saw it), then from the photons point of view, this would have been instantaneous if it only travelled through a perfect vacuum.

Stated this way, it does not violate quotidian conceptions of time.

--

Like all pain, suffering is a signal that something isn't right
Hera by microbox · 2012-10-05 02:33 · Score: 1

Hera (Zeus' wife) sprayed milk across the sky -- creating a luminous strip that we still call the "Milky Way"

--

Like all pain, suffering is a signal that something isn't right
Re:Your problem... by kilfarsnar · 2012-10-05 03:15 · Score: 1

is thinking that "our common every day perceptions of the world" are somehow not reality. Model, indeed.
--
That really depends on how you define reality.

--
"What the American public doesn't know is what makes them the American public." -Ray Zalinsky (Tommy Boy)
Re:Units Space FTL, but information thru space? by painandgreed · 2012-10-05 05:40 · Score: 1

i understand (or at least parse the semantic meaning) that the speed of light through space is fixed, and space can expand fasterthan that. Normally, it seems that the speed of information transmission is also tied to the speed of light, mainly I presume, because paradoxes would arise if it weren't. But can information travel across space at an effective speed uninfluenced by the expansion of space without causing paradoxes? Is it possible that information could still reach us even if light could not?
FIrst off, don't worry about paradoxes, because physics doesn't. As much as it may hurt our brains, according to Tippler's solution for an infinitely long cylinder, Feynman diagrams and other solutions for Einstein's equations for general relativity, it seems that the physics doesn't bear out paradoxes. However, many of these cases are so extreme that we doubt we'll ever see them and its a safe bet to even say they are not actually possible (although nothing prohibits them according to the physics I have seen the math for).
One of those extremes would be a tachyon, a particle moving faster than light. Einstein's equations prohibit anything accelerating to or beyond the speed of light, but have no prohibitions about a particle being created moving at a speed greater than light. However, unless a positron is actually an electron moving backwards in time, we haven't seen any and might not even know what to look for. Last I heard that wasn't pure wishful speculation or unsubstantiated denial, tachyons might have been possible in the early universe but if they could exist, it would be evidence that the universe was at a false vacuum and they would quickly create instability and drop the universe to a more stable energy state. Let's hope we don't create one because that might be the end of the universe as we know it.
Other solutions for FTL travel involve semi-hard science fiction such as warping space, wormholes, or hyperspace. While light and everything else in space must obey the c speed limit, that is the max speed of things travelling through space, whereas space can do whatever it damn well pleases. Once again, they can come up with equations for space warping to the point that such things can happen, but those seem to be so extreme that we're not even sure if they are possible even thought the math works out. Wormholes are a related idea but you really aren't traveling faster than light, but rather taking a short cut where light has a shorter distance to travel. Imagine you are looking at a mountain and to get to the other side, you need to drive around it. Then somebody builds a tunnel through the mountain and you can instead just drive straight across. The speed limits are the same for both routes, but the tunnel (ie wormhole) is a shorter distance. Again, warping space is hard and requires a lot of energy. So much that such wormholes that might actually allow information to travel through might be impossible. There there is hyperspace which stipulates that all of our (3D) space is connected to another space and the physical laws such as c do not apply to that space, or the distances are simply shorter. Imagine the Flatlander being lifted off of Flatland and blown by a wind in 3D space faster than anything can travel in 2D space and then dropped again into Flatland.
Seeing as.... by hesaigo999ca · 2012-10-05 09:04 · Score: 1

Seeing as we can not see the edge of the universe from where we are....
how can we really tell if yesterday the edge was 1.2 km less then it is today?
Are we saying that all objects are moving away from each other at that rate?
Of course not, they have gravity and orbits and all that....
so what are they using to gauge the edge of the universe has extended from yesterday?
Seriously! I want to know
1. Re:Seeing as.... by pantaril · 2012-10-08 00:03 · Score: 1
  
  Seeing as we can not see the edge of the universe from where we are....
  how can we really tell if yesterday the edge was 1.2 km less then it is today?
  Are we saying that all objects are moving away from each other at that rate?
  Of course not, they have gravity and orbits and all that....
  so what are they using to gauge the edge of the universe has extended from yesterday?
  Our universe has probably no edge, at least not in our three dimensional space. Some studies sugest it looks like four dimensional expanding dodecahedron. What that menas is if you travel in one direction for a very long distance, you will return to the point where you started. You can imagine that quite easily if you take away one dimension and imagine three dimensional curved and expanding space i.e. inflanting air baloon. If you draw black dots on the surface of the baloon (representing galaxies), you will find out that each galaxy is traveling away from each other galaxy as the baloon inflates. Also if you walk on the surface of the balloon for a long time, you will arive to the point where you started.
  We are not measuring the expansion rate by observing the border of the universe (we cannot see any border and there is probably no border as i explained above). Instead, we look at distant galaxies. We measure the distance to far away galaxies using supernovae explosions (i.e. standart candles) and the red-shift effect which influence the light as it travels from the distant galaxy to us.
  I don't know the details here (astrophysics is just my hobby) but we know somehow that the more distant a galaxy is, the faster it travels from us. Very far galaxies are traveling faster than light from us.
2. Re:Seeing as.... by hesaigo999ca · 2012-10-09 01:25 · Score: 1
  
  I am not sure about that, who is to say how much further out the edge of the universe is from the very first galaxy that we may record, or maybe we still have yet to actually be able to see the first galaxy seeing as it is so far away, so we could be way off if we just use the distances between us and the galaxies, vs. the actual measurement of the edge to us...no?
  I am no mathematician, but it seems that everything is theoretical at this point in terms of what we THINK we know and what is fact, hence my original comment
  we do not really know...who knows, maybe the universe started to expand 1 billion years before the first galaxy showed up, would that not affect how much size the universe had already grown, and thereby give us false calculations being off by 1 billion years of expanding/speed?
3. Re:Seeing as.... by MacColossus · 2012-10-12 09:05 · Score: 1
  
  Doppler Effect on light waves http://archive.ncsa.illinois.edu/Cyberia/Bima/doppler.html
4. Re:Seeing as.... by hesaigo999ca · 2012-10-18 07:17 · Score: 1
  
  I know about this, and am very aware that this practice is used, however, I also know they estimate that the distance betwen the earth and say star 1 is at xx km per second, but 2 things pop into question.... can we use the same formula for something that does not behave the same as stars, we are not talking about an actual object moving in space, but we are talking about a virtual(is it really?) edge of the universe, from which we assume on the other is nothingness, therefor could we really say this object would be subject to the same formulas used to calculate distances for stars.
  Also the premise that the stars are moving away from the Earth at a perticular rate is a false assumption...can we say the big bang exactly started on the Earth's position...I know we think we are the center of the universe on this small rock, but it could also be we are right on the edge of the universe and not even know it,
  as we do not know the full size of the universe at this point.
  Use this same point of view to understand that all planets orbit stars (most anyways), and stars do solar systems, and solar systems do galaxies, we have a multitude of combinations of orbits that propel objects in such patterns that it would be unpredictable to know at which point one star is coming closer to us because it is coming back on its revolving orbit....have u seen 2 galaxies merge, the actual gravitational pull sends them spiraling together smashing solar systems and planets together from the sheer force of it all....would they not appear differently using this same formula to explain why one day they were further out, and the next closer to use even though their orbit was understood as pulling them away from us.....
  All in all, I know we know nothing when it comes to space, and yet we declare so many things as if fact. My point remains, you can only be absolute when you have fact in hand.and unless we have God's 2 dimensional game board or map of the universe showing exact distances of all there is in this universe from each other that we can look down at from a bird's point of view, all we have are these speculations on our part.....