Do you know how big the universe is?

[Kurt_and_Hunter]

The universe is about 14 billion years old.

The universe started at a point and nothing can travel faster than light so the universe has to be less than 28 billion light years across.

Except it is a lot larger than that. Like... a lot larger than that.

How is this possible? because even though nothing can travel faster than light through space, space itself can expand way faster than the speed of light, and did so early in the universe's history. (And is still expanding at a decent clip today)

Th part of the universe that we can detect is just a tiny corner of the thing, but still huge. About 92 billion light years across. That's way more than 28 billion, but the light from distant galaxies has itself been stretched as space expanded at incredible speed... or something like that.


It is comforting, in a strange way.

[Lyric]

1. Well it certainly puts ones problems into perspective.

Now if only we could stop fighting each other constantly for the same reasons. :(

[Kurt_and_Hunter]

2. More than 100 Billion galaxies in the observable universe...

...and ours is the only one where beings don't use their turn signals!

[rurallib]

3. so if a rocket ship travelling at 17,000 miles an hour were to travel

across the universe, how many Huggies would David Vitter need to pack for the trip?

[Kurt_and_Hunter]

6. That's hard to say... he uses them for so many purposes

[ikri]

62. Depends (geddit) how often he changes

But the stack would probably be bigger than Jupiter

[denem]

4. The Big Rip is far from comforting.

First the Galaxies are pulled apart, thne clusters of stars, then solar systems, the sun and planets theselves, and finally atoms until theres nothing.

[derby378]

7. That's one possible outcome

You're getting deep into the mysteries of quantum physics and dark energy at that point, but yes, that is a possible outcome - the universe could just wink out like a spent firecracker, only this time we'll be lucky if there's any subquantum ash.

[rurallib]

10. I blame it on the Republicans.

[denem]

13. Black hole points of singularity would remain:

They by definition occupy no space, until hawking radiation fishes them off too, then zilch.

[pinboy3niner]

54. So some see the Big Rip as half-empty, some see it as half-full?

:evilgrin:

[derby378]

5. And therein lies one of the great conundrums of astronomy

The Hubble, Keck, and other telescopes have given us an expanded view of the universe which is our only window on the faraway cosmos.

At the same time, that image is also a lie.

Many of the objects we are seeing emitted that light over 10 billion years ago. By now, these objects may have dramatically shifted position, collided with each other, or just faded out of the heavens completely. But we cannot know with any certainty their current position or ultimate fate. Not until the light from those distant reaches finally finds its way to Earth.

Maddening, isn't it?

[Xipe Totec]

9. It's even beyond that

There are objects out there receding faster than light can travel.

So we will never, ever, see them.

[the redcoat]

8. We can only detect a 14 billion light year radius.

If the universe is 14 billion years old, then we can only see light 14 billion light years away.


If the universe is 92 billion light years wide, then that creates a 46 billion light year radius (if we are in the center, which is best case scenario but not likely). But if we agree that the universe is 14 billion years old, then light from 40 billion light years away has not reached us yet, which explains why we can't see 92 billion light years across.

[Kurt_and_Hunter]

11. Or so it would seem...

"The most precise estimate of the universe's age is 13.73±0.12 billion years old"

"The universe is very large and possibly infinite in volume. The region visible from Earth (the observable universe) is about 92 billion light years across"

http://en.wikipedia.org/wiki/Universe#Size.2C_age.2C_contents.2C_structure.2C_and_laws



The universe is a weird place.

[derby378]

15. I don't know about the "infinite volume" part

If the entirety of the universe once fit into a sphere smaller than the size of a pea, and the inflation of this primordial fireball seems to follow a definite progression, then the universe must by definition have borders and therefore a center - although floating in the center of the universe would be rather pointless, really, unless there was some new evidence for either a cyclic universe or Hoyle's old "steady state" model.

[Kurt_and_Hunter]

21. I'm with you. I had a problem with that as well.

Maybe it's a philosophical/science thing where it cannot be proven that it is finite, but it sure seems to have a practical proof of being finite insofar as it was once finite...

Or perhaps "volume" is the key. Is this some of that 17 dimensions stuff? Finite width, infinite volume...

Beats me.

[Commie Pinko Dirtbag]

25. "must by definition have borders and therefore a center" -- No. Follow me.

Imagine beings who live not in three, but in two dimensions. In this case, the Universe expands as a normal (for us) expanding three-dimensional balloon shape. For the flatlanders, every point in their universe is equivalent. No boundaries, no center. If one flatscientist tries to tell flatpeople they live in a "three-dimensional balloon", they'll all be baffled. Some will ask, "is it like a circle?" The flatscientist will say, "yes, but with one more dimension, perpendicular to our known two." The layman flatpeople will say, "my head hurts."

[Kurt_and_Hunter]

26. And a sphere contains an infinity of circular sections....

...is that where this is going?

[Commie Pinko Dirtbag]

28. Make sure you understand the flatpeople's scenario first.

What I'm saying is, our supposedly "all-encompassing" 3-D space might be only the surface of a hyper-sphere, so the supposed "center" actually lies outside of the Universe, and the "boundary" is the entirety of space.

Just like the 2-D spherical surface the flatpeople think is everything, is actually only the boundary of a 3-D sphere. They, of course, can't comprehend 3-D. At most, their nerdy physicists can abstract it and manipulate it mathematically.

Just like our nerdy physicists do with 4-D.

[derby378]

33. That 3D balloon shape, however, still has a center

It matters not whether the flatlanders are capable of evolving the necessary "up" and "down" concept to perceive the center of this shape - even if every point on the surface is equivalent, you're only talking about the surface. Underneath the surface, there is volume and therefore a center of some sort.

It's the same with us. Even if in our 4D spacetime universe all points are likewise moving away from each other with the same equivalence, that still implies the existence of at least one extra spatial dimension that you and I may never hear of, let alone experience, but that doesn't mean it isn't there.

The whole notion of extra dimensions has been with the scientific community for some time, with the Calabi-Yau manifolds being the most prominent theory of extra dimensions, and it is hoped that some of the particle research at CERN's Large Hadron Collider may shed light on whether such dimensions actually exist.

[the redcoat]

29. You're ignoring the most important part of the sentence you quoted:

"...based on where the expansion of space has taken the most distant objects observed."

This is completely different from saying we can see 92 billion light years across. It is saying that objects now 92 billion light years away were at one point much closer, but the universe "carried" them away from us.

The result is that we can "see" that far because the light from those objects originally emanated from less than 14 billion light years away.


Take the age of 14 billion year old light and multiply it by the speed we believe the universe is expanding, and that's how you get 92 billion light years. You don't get it by saying we can literally "see" 92 billion light years away. For this to be possible, light would have to travel faster than the speed of...light.

[Obamanaut]

12. No. nt

[ipaint]

14. 'A Universe From Nothing' by Lawrence Krauss

'A Universe From Nothing' by Lawrence Krauss

Lawrence Krauss gives a talk on our current picture of the universe, how it will end, and how it could have come from nothing.
http://www.youtube.com/watch?v=7ImvlS8PLIo

Excellent lecture.

[RagAss]

23. "From the begining not a thing is." - Hui Neng 700 AD

You don't need science for everything.

[ipaint]

55. I wouldn't miss the science behind the theory for anything.

It's fascinating, mind opening and humbling. For me much more interesting and wondrous than faith alone.

[RKP5637]

16. I think Bill O'Reilly's head is larger! n/t

[derby378]

17. Not larger, but definitely stuffed with more fatty tissue (n/t)

[RKP5637]

20. LOL !!! n/t

[icnorth]

80. Purely my opinion but...

I see O'Reilly's head as finite; his ego as infinite and his intelligence as infinitesimal.

[denem]

18. We can see only 0.5% of the universe.

Perhaps a bit more with nebulas and the like:

[leeroysphitz]

19. All we are is dust in the wind...

[Duer 157099]

22. It's all about distribution

All that space, man, you'd think we could all separate into clusters of like-minded people and live happily ever after! I mean, there certainly is enough room.

But noooooooooooooooo, we insist on all crowding here together and fighting over resources.

[derby378]

24. But first, someone must invent the hyperdrive

Before anyone hatches a grand scheme for colonizing Gliese 581 or whatever that star system is called, first we have to figure out a way to get there.

[Duer 157099]

27. Perhaps that's where we go when we die?

Death, the ultimate hyperdrive!

[razorman]

30. I just wonder what it is expanding into?

[derby378]

34. That's an excellent question

Have you heard of the concept known as M-theory? In a way, M-theorists have proposed some fascinating ideas for what our space is expanding "into" - if it is proper to speak of "a space beyond space."

A very simplified way of explaining one of these ideas in M-theory is that there are various multi-dimensional realities known as "branes" that coexist with each other. Each brane is potentially larger than our universe, and they are separated from each other by some indeterminate boundary. Every once in a while, however, two branes can "touch," or interact with each other.

The theory is that the Big Bang, as we perceive it, is actually the point at which two of these branes collided with each other, forming a new entity with at least three spatial dimensions and one time dimension that started expanding with an energy and life all its own.

Resident astrophysicists, feel free to jump in any time and set me straight... :hi:

[Iggo]

31. All the big.

[unkachuck]

32. I think you're wrong....n/t

[DavidDvorkin]

35. Really big, as Douglas Adams explained to us.

"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 chemist's, but that's just peanuts to space."

[jberryhill]

36. So small that there is only one universe in it

[Warren DeMontague]

37. Compared to us, it's really, really, really, big.

However, objectively, "size" becomes meaningless unless there's something else to compare it to. How big is the universe? What's it inside?

[Richard Steele]

38. Everything is relative. Compared to Admiral Nelson, the universe is quite large indeed.

But hey: it's not the size of your universe that matters, it's how you use it.

[dimbear]

45. He may have had trouble comparing sizes, lacking that old

stereo vision thing that comes with two good eyes.

[Zanzobar]

39. The universe is a sphere about 5'11" through the center

Unless I'm swinging a dead cat. Then it's a little bigger.

[dimbear]

46. Be careful in high winds on flat surfaces.......n/t

[lightningandsnow]

40. I can't believe nobody posted this yet:

http://www.youtube.com/watch?v=buqtdpuZxvk

[lumberjack_jeff]

41. ... cuz there's bugger-all down here on earth.

Amen.

[Arugula Latte]

42. That sort of stuff is why religion is completely laughable to me.

The focus, for example, on one guy from 2,000 years ago who lived on one little planet in the midst of a galaxy in the midst of billions of galaxies ... utterly laughable.

[Kurt_and_Hunter]

65. I didn't want to get into that in the OP because

they have an itchy trigger finger when it comes to moving posts from GD to the Religion/Theology forum.

But the inflationary model of the universe is, to me, a last straw for all homo-centric religion.

The fact that there are vast areas of the universe that are effectively outside our universe makes the God/man special relationship really funny.

(That is, information transfer is impossible between us and a lot of the universe.)

[AnArmyVeteran]

72. And why would god send a son to a backward era with no technologies, no video, no printing press?

Not a very intelligent god, that's for sure!

[BzaDem]

43. It basically means the chances of extrasolar life are extremely high.

It would be extremely improbable that life didn't exist elsewhere. In fact, it would be extremely improbable that there weren't at least billions of distinct self-replicating life forms throughout the observable universe.

[scheming daemons]

48. It also means the chances of us ever interacting with extrasolar life are extremely low

Even if they figured out a way to travel at the speed of light.... mankind will have gone through our completely rise and fall before they ever got here.


We've been on this planet for a split second in celestial time. A blink of an eye.


And we'll be gone in another blink of an eye.


Even if extra-solar life ever gets here... the time window for finding us here when it gets here is extremely small.



And you can forget about us ever getting to them. Nearest planets are dozens of light years away.

[BzaDem]

49. Indeed. :( Though wormholes and/or some other manipulation of spacetime itself could conceivably

allow us to go FTL. In the sense that they haven't been conclusively ruled out yet by physics.

We can only hope. :) :tinfoilhat:

[Kurt_and_Hunter]

67. And when discussing such probabilities in other contexts we call them certainties

Given the 100+ Billion Galaxies just in our neck of the woods it is impossible that there is not extra-solar life... and even extra-solar intelligent life.

Since we have proof that life can exist in this universe (us, for starters) its isolation on one planet is, I think it is fair to say, impossible.

Earth does have some special features that favor life so life might be exceedingly rare. There may only be 500 Billion life bearing worlds out there.

[BzaDem]

70. Well to be fair, I think it is at least possible (though extremely improbable) that life is unique

We still do not know how life came from non-life (in that we don't know the exact chemistry). It could have been that abiogenesis required one specific configuration of molecules, where the number of molecules is high. If that is the case, the probability of life could be approximately 1/2^x, where x is very high. That would still be almost zero when multiplied by the number of planets in the universe where this type of chemistry were possible.

Then again, I'm not a physicist or a biologist or a chemist, so I really have no idea what I'm talking about. Just guessing.

[jimlup]

44. This was explained to me a few years back

I still can't totally wrap my head around it... I've been educated as a physicist and hold my Ph.D. in the field from a major university. My gut feeling was always that space itself was sort of illusion of particle motion. Apparently that is false, space is a real entity that has shape and is influenced by matter but not subsidiary to it. I guess if I really think about that conclusion is inevitable from General Relativity (GR) (which I do have some formal background in) but still it is hard to imagine space itself "expanding". Some part of me finds the idea absurd despite my intellectual understanding of the equations of GR.

[deacon]

47. Thats about as old as GOP economic policies. n/t

[opihimoimoi]

50. It also means them Aliens have the Same God/Goddess as we have...has to be.

[DeadEyeDyck]

51. bigger than a bread box

smaller than the grand canyon

[JCMach1]

52. 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 chemist's, but that's just peanuts to space.

Douglas Adams, The Hitchhiker's Guide to the Galaxy

[dkf]

53. I guess it means we could be squashed like a bug since we are but one little speck.

[WinkyDink]

56. If the Universe IS the Universe, into what is it expanding?

:-)

[meow mix]

57. membranes

giant ones!

&cap=ANIMATION%3A+See+how++branes++would+exist+in+a+fifth+dimension+and+create+an+Ekpyrotic+Universe.

[meow mix]

58. delete

oops

[Kltpzyxm]

59. sorry hippy

the universe is only 5000 years old.

:crazy:

[B Calm]

60. and to think it all started from a peanut shaped asteroid.

[Taitertots]

61. Short Answer: Freaking Huge

Long Answer: Much bigger than we ever thought

People started believing the universe was the solar system
Then they believe our galaxy was the universe
Then they realized there are more galaxies
Then they realized the galaxies were in galaxy clusters
Then they realized the clusters were in clusters

Possible idea?
The universe is more than infinite. There are regions so far away that light from them will never reach us.

[Motown_Johnny]

63. unprovable speculation

we won't ever be able to prove that there is anything beyond our light horizon so for all practical purposes it doesn't exist


you may as well say that is where heaven and hell are


all fantasy (in a real world sense)

[Kurt_and_Hunter]

68. au contraire

wouldn't we be able to observe effects of some invisible-to-us mass and energy on things within our light horizon being affected by things within their light horizon (but outside our horizon)?

Hypothetically.

[Toots]

64. Isn't there some way we can blow it up?

Imagine the boom that would make.......

[KittyWampus]

66. Space and Time are artificial intellectual constructs. So questions like those are similar to

"how many angels dance on the head of a pin?".

[derby378]

69. Time is what enables you to exist as KittyWampus instead of inert Planck-scale goo

Without time, motion as we know it is impossible. Electrons whirl and dance around atomic nuclei at the speed of light or darned near close enough. The orbit of electrons around nuclei make atoms possible, and therefore molecules, DNA, cells, and you.

Without the ability to actually move as provided by the dimension of time, everything would just sit at a state of absolute zero temperature as a cold, lifeless, inert mass of subquantum goo.

Time has some incidental negative effects, such as the possibility that your electric bill might not be paid on time, but time makes matter, not to mention life, possible.

[AnArmyVeteran]

73. So what time is it then? :)

Actually, your post was excellently written. Have you ever read Time Wars?

[derby378]

74. Not familiar with that, actually

Details, please? :hi:

[AnArmyVeteran]

71. The entire universe is probably just one cell of a hair on a massive creature in another dimension.

If there is god, who made god? And who made that 'god'? As advanced as we think we are we are no more than a minuscule part of a bacteria in another dimension, which is infinitely bigger than the 'known' universe.

[immoderate]

76. Bacteria all the way down; universes all the way up.

Look, I'm cosmological. :)

--imm

[JackRiddler]

75. No, and neither does anyone else.

Based on incomplete evidence, there are a few theories.

To explain the contradiction between the size of what's observable and the age posited by Big Bang theory, the latter's adherents have devised a speculative period of hyperinflation during the first few hundred thousand years. This is probably the postmodern equivalent of Ptolemy's epicycles.

Current cosmology is based on insufficient relevant observations, argues Cardiff University astrophysicist Michael Disney:

http://arxiv.org/pdf/astro-ph/0009020v1.pdf

The number of independent observations in cosmology is much smaller than the number of independent free parameters in current cosmological theories, thus "modern cosmology has at best very flimsy observational support."

[montanto]

77. So, can we have your liver?

[A HERETIC I AM]

78. And we live on "a mote of dust, suspended in a sunbeam". Carl Sagan.

[Tierra_y_Libertad]

79. Big enough to have a minor species on a speck of dust think they're the center of it.