The Universe is Pretty Big 134
Psiolent writes "According to a recent article on Space.com, the universe is pretty big (156 billion light years across, to be more precise). Some recent research examining 'primordial radiation imprinted on the cosmos' has led to this conclusion, as well as a few others. This finding is particularly interesting considering the universe is only 13.7 billion years old (which would mean the universe has been expanding faster than light travels), but the article does a good job addressing this seeming paradox."
since light is the FASTEST moving thing (Score:2)
i.e. if the universe were 1 light year across, then it would be six months old, as it's expanded in all directions for that long?
Re:since light is the FASTEST moving thing (Score:5, Interesting)
going backward in time? (Score:2)
Re:going backward in time? (Score:3, Informative)
BIG! (Score:1)
Appologies to Mr. Adams.
Re:going backward in time? (Score:2, Insightful)
Re:going backward in time? (Score:2)
Re:going backward in time? (Score:1)
I guess that you can say that, but it is not a term/measurement used in physics. In physics you only look at one of the cars at a time (if you are using relativity), so you need to be in the other if you want
Re:going backward in time? (Score:1)
The real answer is since we cannot observe from a point moving anywhere near relativistic speeds, we don't really know.
And the only "objects" we can observe that are moving anywhere near those speeds are at the limit of our observable radius, and we can't be certain how fast they are in fact moving due to the variability of the speed of light, etc.
I'm not a physicist, so perhaps I'm stupid, or I dumbed down what has been explained to me, but don't the doppler effect(s) and some of th
Re:going backward in time? (Score:1)
I would definitely not want to call anyone here stupid, least of all someone who admits they don't know exactly what might be happening. I screw up in my posts a bit (usually with legal stuff), but I try my best.
I like how you point out that since we cannot observe from a point moving anywhere near relativistic speeds, we don't really know. So ma
Re:going backward in time?heading OT (Score:1)
Thanks
I'm reminded of course of many(NOT ALL) scientists and "experts" who claimed that bad things would happen at 762mph. And at 100mph.
I'm fascinated by the discussion, and would like to get back to studying some of the more arcane areas of physics, But whenever someone is so dogmatic about a pyramid of theories that cannot(YET I HOPE) be thoroughly tested I get that twi
Re:going backward in time?heading OT (Score:1)
Relative Velocities... (Score:2)
Don't add at high speeds. If A and B are both moving away from me in opposite directions at 0.6c, they they are NOT moving at 1.2c relative to each other.
By "fixed point" I assuemt you mean at rest in an inertial frame. There are no fixed points in special relativity.
Re:going backward in time? (Score:3, Informative)
Also, this expansion is not like plate tectonics on earth where there are a couple different areas that are expanding (while there are a couple that are receding). This expansion is happening everywhere at once. So rather than all of the extra space just appearing between New York and London somewhere in the Atlantic, it is as though the earth's diameter started to increase and New
Re:going backward in time? (Score:2)
GO TO YOUR ROOM (Score:2, Informative)
The truth is out there.
Re:since light is the FASTEST moving thing (Score:5, Informative)
Re:since light is the FASTEST moving thing (Score:2)
In other news... (Score:1, Funny)
Re:In other news... (Score:1, Troll)
A, one wonders, redundant of what? And, B, it's called wit - you lunkheads.
Lighten up. (cf. Light, speed of. Am too on-subject.)
Fine. Just give me my minus one and move along.
Re:In other news... (Score:1)
That's a minimum.... (Score:5, Informative)
It's worth pointing out that the156 billion lyrs number is a minimum size for the universe. There's nothing in the data that tells us it's only this large.
It also doesn't tell us anything about the shape of the universe. Recent studies of the microwave background have proposed that the universe has a soccer ball or even a Picard [newscientist.com] (no relation to the TV character) shape. Neither of these have been ruled out, but the minimum size for either of these shapes in our region of space would be 156 billion lyrs. This new result doesn't even tell us if there is a boundary (no, don't ask me what happens at the edge, I don't know) or if the universe "wraps" like the Asteroids game.
Re:That's a minimum.... (Score:2)
I read this and remembered that string theory predics several extra dimensions we can't percieve because they're to small.
Any possible relation here?
Mycroft
Re:That's a minimum.... (Score:2, Interesting)
First off, IANAQP. Most of my modern cosmology and quantum physics comes from SciAm, Brian Greene books [slashdot.org], and conversations with Tripoli Rocketry Association member #004. The last time I did tensor calculus was when I looked up Frank Tipler's paper "Rotating Cylinders and the Possibility of Global Causality Violation" [utas.edu.au] twenty years ago. Yes, that is the paper Larry Niven used as the name for
Re:That's a minimum.... (Score:2)
I am aware the extra dimension must be very tiny to exist. I'm more looking for the connection, if any, to the potential picard shape for the universe.
That is do the two descriptions support each other, or possibly one be the consequence of the other, or are they not re
Re:That's a minimum.... (Score:2, Interesting)
One of the important points about the Picard geometry discussed in the "horn of plenty" theory is that the universe would look different depending on where you are.
As we look around, the universe appears to be pretty much the same in any direction we look. The fine structur
Re:That's a minimum.... (Score:2)
I think just about everyones' understanding is a bit primitive compared to the likes of Hawking,Michou(sp?),Greene,Thorn, and a few others.
I'll have to look for Greene's books, I rather liked Hawkings books and few others I've read.
Most of the basic stuff I can follow about as well as anyone can w/o the math/physics skills needed to study the actuall theory. But I hadn't heard much about
Re:That's a minimum.... (Score:2)
Mycroft
Re:That's a minimum.... (Score:2)
Would have been 84 or 85 while I was still in highschool.
It was writing in basic on a commodore64. ahhh fond memories.
Eventually the birth and death rules as well as the graphics for cells could be user set as well as patterns saved and loaded.
Mycroft
Re:That's a minimum.... (Score:1)
Re:That's a minimum.... (Score:2)
The problem is I don't really have the background a REAL theoretical physicist has to know whether the feature of a picard space that curls some dimensions down tight has any significance wrt string theories shrunken dimensions or if I'm totaly of base or out at 90 to the whole thing.
obligitory Douglas Adams Quote (Score:4, Insightful)
Space is big. You just won't believe how vastly, hugely, mind- bogglingly big it is. I mean, you may think it's a long way down the road to the drug store, but that's just peanuts to space.
Douglas AdamsRe:obligitory Douglas Adams Quote (Score:4, Informative)
Re:obligitory Douglas Adams Quote (Score:4, Funny)
Re:obligitory Douglas Adams Quote (Score:1)
Re:obligitory Douglas Adams Quote (Score:2)
What an error....
Re: (Score:2)
Re:obligitory Douglas Adams Quote (Score:1)
Re:obligitory Douglas Adams Quote (Score:1)
Re: (Score:2)
Re:obligitory Douglas Adams Quote (Score:1)
Er, yes (Score:5, Informative)
Sure. There is no restriction to the rate at which spacetime can expand. Relativity only applies to the acceleration of matter.
Would this work on cops? (Score:5, Funny)
Re:Er, yes (Score:2)
but given this was modded up so strongly, when exactly do people these days get introduced into the theories of relativity? a 100 year old solution too i might add. i guess that's rhetorical. it does disappoint me to some extent. it seems all it takes is a free saturday night from the brew and tele. but wait, i'm throwing oxymorons he
Wakawakawaka... (Score:2)
A hall of mirrors could mean the universe is finite but tricks us into thinking it is infinite.
Think of it as a video game in which an object disappearing on the right side of the screen reappears on the left.
Well, shoot... thank god I tought it was just me being obtuse. I mean... at least now I know why altho it is finite, I won't hit a wall if I were to travel (or try to) 156 Billion Light Years +1 inch. Turn's out I'll just warp to the other edge... like pacman.
finite? (Score:2)
Re:finite? (Score:2)
Perfectly! What we can see of the universe is pretty uniform, suggesting that it just keeps on going in the same way presumably forever in all spatial directions, making it infinite. On the other hand, if there is a change or boundary outside the range of what we can see, how would we know?
Re:finite? (Score:1)
Re:finite? (Score:4, Informative)
To clarify, when we talk about spheres in this context we mean the surface, not the inside - hence a sphere is 2D, not 3D.
Re:finite? (Score:1)
- The universe could be:
- Finite
- Infinite with a closed topology (would this actually be a special case under finite?)
- Infinite with an open topology
Sorry if I massacred the distinctions between what is still plausible based on this discovery.Re:finite? (Score:2)
Re:finite? (Score:2)
Re:finite? (Score:2)
Universe potentially older (Score:4, Informative)
The evidence comes from the fact that older stars must fuse carbon, nitrogen and oxygen into helium, unlike their younger bretheren that fuse pure hydrogen. The slowest part of the carbon-nitrogen-oygen reaction comes during the collision of a proton with a nitrogen-14 nucleus. Using particle accelerators to mimic the interior of older stars they have determined that the reaction occurs half as fast as estimated.
Two research teams, one from the National Institute for Nuclear Physics in Padova, Italy, and the other from the University of North Carolina at Chapel Hill, have performed nearly identical experiments and their prelimiary results agree, although their findings have not yet been published.
Re:Universe potentially older (Score:2, Informative)
Re:Universe potentially older (Score:5, Interesting)
Now the argument that the referenced article is using is that less massive stars will stay on the main sequence longer, due to the reduction in CNO efficiency. Thus older globular clusters will have a bluer turnoff than previously expected.
While this will cause a systematic underestimation of the age of globulars by ~0.7-1.0 Gyr, the uncertainties are so large (+/- 1-1.5 Gyr or so), that they are still consistent with the age of the universe derived from CMB observations.
Doug
Re:Universe potentially older (Score:2)
Only space expanding? (Score:3, Interesting)
Re:Only space expanding? (Score:2)
So anyone cluefull enough who chooses to post has at least two people who would appretiate the effort.
Mycroft
Re:Only space expanding? (Score:2, Insightful)
I'm not a scientist either, so I'm just making a complete stab-in-the-dark guess, and I'm very happy to be corrected by anyone with a more researched answer.
Re:Only space expanding? (Score:2)
It's because the attractive forces overpower the expansion. At a short enough range, even gravity is strong enough to hold a galaxy in one piece and keep its stars from Hubble-expanding away from each other. It's only at the vast distances of intergalactic space that the expansion can finally overpower the fundamental forces.
Re:Only space expanding? (Score:1)
Re:Only space expanding? (Score:3, Interesting)
Yup, over large enough scales. Which is why everyone was concerned (up until a few years ago) about whether or not there might be a "Big Crunch". If the universe ever stops expanding, it must then proceed to collapse -- excepting the unlikely possibility that dark energy weakens but thereafter remains constantly balanced at the equilibrum, as Einstein originally envisioned when he proposed the Cosmological Constant.
Re:Only space expanding? (Score:1)
Re:Only space expanding? (Score:2, Informative)
Now on the scale of molecules, planets, solar systems, even galaxies, expansion is tiny still. The intermolecular forces, electric, magnetic, gravity, whatever will all overpower the expansion by many many orders of magnitude. IIRC the estimates for expa
Re:Only space expanding? (Score:2)
Take this one le
Re:Only space expanding? (Score:2, Informative)
Re:Only space expanding? (Score:3, Informative)
My source? I asked this in the context of the distance from the Sun to Pluto increasing over time of John C. Baez [ucr.edu], who works on gravity and has written books on it, so I would say he is a good authority.
His response was that space does not expand (much) near massive objects - meaning even between the Sun and Pluto the expansion w
Re:Only space expanding? (Score:3, Insightful)
This is actually a really great question. Don't let the flurry of responses fool you, the answer to something like this is not so easy or cut-and-dry.
The truth is, no one is completely sure. The replies you've gotten aren't too far off from nice, accepted answers that you might get from a physicist, but it's one of those things where no one really knows.
First, consider the statement "space is expanding". Sounds simple enough, but lets start with the simple: What is space? I mean, what is it that's exp
Re:Only space expanding? (Score:2)
OK, I'll write more, because in my last post I wanted to show people how confusing this really is, but now I'll make an attempt at an understandable explanation. It's not really a perfect explanation, but it should be understandable.
The problem with the explanation of electromagnetic and gravitational forces holding the molecules together is that it already assumes some funny things about space and matter, which isn't entirely clear. Let's say space was expanding uniformly, and space is flat. Why isn't
WTF? (Score:2, Interesting)
We can measure the distances to far off galaxies to get a "radius", but a "radius" implies a center, primarily the Earth. I have some serious problems with us, because it implies that the "Big Bang" occurred right he
Re:WTF? (Score:1)
WTF back at you (Score:2, Informative)
Re:WTF? (Score:4, Informative)
a) the concept of "radius", or "coordinate system".
b) the concept of "isotropy"
c) the concept of 4D surfaces
a) Radius here is indeed taken as distance to the earth. Cosmologists like to use a spherical coordinate system where the earth sits at the centre, simply because it is *convenient*. Let me first explain isotropy and hopefully it will become clear why this, in this case, doesn't matter:
b) Isotropy says that the *visible* universe is pretty much the same everywhere we go. Cosmologists reached this conclusion based on *observational* evidence. This means (among other things) that the universe is expanding *at the same rate* everywhere in space. This has huge implications.
Try this: Find a piece of paper and draw a series of black dots, in a grid, equally spaced. Make one of your dots red. That's the earth. Now imagine your paper is elastic and you take its four corners and pull, so that your paper gets bigger (you'd pull exactly the same amount horizontally and vertically). You'd see that the distance from the red dot to the nearest black dots had increased by a given amount, say D.
If you repeated this exercise having coloured ANY of the other dots red, you'd find the same thing. Meaning, expansion (and measured distances DUE TO EXPANSION are the SAME no matter where you sit in the Universe.
So it doesnt really matter that we're measuring distances due to expansion with a radius relative to the earth. You'd get the same answer if you were sitting on the galaxy M31, measuring distances relative to it.
c) So where is the centre of expansion? Look at your fictitional piece of paper and you'll be able to tell that it's nowhere in the piece of paper. In fact it seems to be everywhere. The right answer gets complicated due to the fact that we live on a curved 3d space. But the answer is again nowhere in our 3d space, and again it seems to be everywhere. We'd have to get into higher dimensions to explain this but the point that I would really like to get across is that there is NO centre of expansion. Not that we can visit
I hope this helped.
--r
Re:WTF? (Score:2)
Yep, and it only makes sense if the rest of the universe is also the center. Cosmology is weird, don't try to apply common sense to it.
Re:WTF? (Score:2)
I think that by definition the Big Bang occurred everywhere. Either that or everywhere occurred at the the Big Bang. Take your pick.
Re:WTF? (Score:2)
Not really. It's more analogous to the statement "the earth's circumference is at least 20,000 miles" - no matter where you are, you can go at least 20,000 miles in a straight line before you get back to where you started. That statement doesn't imply that you're at the center of the earth, just that you can treat it as the center for the purpose of describing your observations.
Re:WTF? (Score:1)
We can't identify an edge, so since we can measure in every direction from us, and light appears to move at the same speed in all directions, we OBSERVE a spherical universe surrounding us.
It doesn't mean anything other than that is what we observe and thusly how we speak. Just like sunrise... It looks like it comes up so thats how we talk.
Like the billboard used to say... (Score:1, Offtopic)
Space is dark
It's hard to find
A place to park
Burma Shave
Oh come on /.'rs I can't be the only one.... (Score:3, Informative)
Whenever life get you down, Mrs. Brown,
And things seem hard or tough.
And people are stupid, obnoxious or daft,
And you feel that you've had quite enu-hu-hu-huuuuff!
Just - re-member that you're standing on a planet that's evolving
and revolving at 900 miles an hour,
It's orbiting at 19 miles a second, so it's reckoned,
the sun that is the source of all our power.
The Sun and you and me, and all the stars that we can see,
are moving at a million miles a day,
In the outer spiral arm, at 40,000 miles an hour,
of the Galaxy we call the Milky Way.
Our Galaxy itself contains 100 billion stars,
it's 100,000 light-years side-to-side,
It bulges in the middle, 16,000 light-years thick,
but out by us it's just 3000 light-years wide.
We're 30,000 light-years from galactic central point,
we go round every 200 million years,
And our galaxy is only one of millions of billions
in this amazing and expanding universe.
The universe itself keeps on expanding and expanding,
in all of the directions it can whizz,
As fast as it can go, at the speed of light you know,
twelve million miles a minute, and that's the fastest speed there is.
So remember, when you're feeling very small and insecure,
how amazingly unlikely is your birth,
And pray that there's intelligent life somewhere up in space,
because there's bugger all down here on Earth.
Their explanation makes no sense (Score:1)
Imagine the universe just a million years after it was born, Cornish suggests. A batch of light travels for a year, covering one light-year. "At that time, the universe was about 1,000 times smaller than it is today," he said. "Thus, that one light-year has now stretched to become 1,000 light-years."
I understand the concept that everything is getting further from everything else, no
Re:The Universe is Pretty Big (Score:4, Informative)
Re:The Universe is Pretty Big (Score:2, Informative)
Re:The Universe is Pretty Big (Score:1)
Re:The Universe is Pretty Big (Score:3, Insightful)
Re:The Universe is Pretty Big (Score:2)
Re:The Universe is Pretty Big (Score:1)
News for mathematically illiterate nerds (Score:2)
Beside this, double asterisks and circumflexes are completely unnecessary kludges for web sites because HTML is completely capable of handling superscripts! A web site that describes itself as "news for nerds" and does not support superscripts and subscripts is pretty sad!
Re:News for mathematically illiterate nerds (Score:1)
Its not a klooge, its using the tool you have, effectively. And since this is news for nerds, using the standard programming notation should be fairly simple.
Re:News for mathematically illiterate nerds (Score:2)
Re:News for mathematically illiterate nerds (Score:1)
Excerpt from the Weekly World News ?!?!? (Score:2, Interesting)
Read this quote.... (which seems to provide a basis for other comments)
"The universe is about 13.7 billion years old. Light reaching us from the earliest known galaxies has been travelling, therefore, for more than 13 billion years. So one might assume that the radius of the universe is 13.7 billion light-years and that the whole shebang is double that, or 27.4 billion li
Re: Excerpt from the Weekly World News ?!?!? (Score:5, Insightful)
There's another good reason to pick Earth as the center; if the universe is 13.7 billion years old then there is no way that anything - light, gravity, particles, aliens - from farther than 13.7 billion light years has reached us. We are at the centre of a 13.7 billion light year sphere containing everything which we can possibly observe.
Not only does this not rule out the possibility of light which hasn't reached us yet, it is defined by it. This observable universe, which some have called "the cosmos", expands by 1 light year every year, as light further out has time to reach us. The entire universe could well be much larger than this; we can only theorize.
By the way, the observable universe is very symmetrical in every direction, so we can consider ourselves to be at the centre even in a literal geometric sense of the word.
not symmetrical last time I observed it... (Score:4, Insightful)
In addition to this, the observable universe has no visible boundaries which could be deemed symmetrical, as what we observe is not so much the universe itself but the contents thereof. Since the contents aren't spread symmetrically or in any particular order for that matter, any observed boundaries can't be symmetrical.
If you can't see where it ends, does that mean it ends where you no longer see it?
Re:not symmetrical last time I observed it... (Score:3, Insightful)
I have a couple more questions... which may only serve to indicate my ignorance in both posing the above issue and asking these questions....
Taking this quote into consideration:
"One seemingly paradoxical consequence of Hubble's observation is that galaxies sufficiently far away will be receding from us at a velocity faster than the speed of light. This distance is called the Hubble radius, and is commonly referred to as the horizon in analogy with a black hole horizon."
Wouldn't it be
Re:not symmetrical last time I observed it... (Score:2, Informative)
Re:not symmetrical last time I observed it... (Score:1)
Re:Excerpt from the Weekly World News ?!?!? (Score:1, Insightful)
Re:Excerpt from the Weekly World News ?!?!? (Score:2)
If it helps, think of it this way: the universe isn't actually expanding by everything moving apart. It's expanding by the distances between things getting bigger. Another way to look at it is as if everything in the universe-- the stuff, as it were-- is shrinking. Imagine two oranges side by side, touching. If those oranges shrank to the size
Re:size matters not! (Score:1)
That is what scifi fans call warping.