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Profile Chris SProject donor
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Message 1365088 - Posted: 6 May 2013, 10:50:05 UTC

Hubble constant which was most recently established at 69.32 ± 0.80 (km/s)/Mpc (or 21.25 ± 0.25 (km/s)/Mega-lightyear).


As of 20 December 2012 the Hubble constant, as measured by NASA's Wilkinson Microwave Anisotropy Probe (WMAP) and reported in arxiv (http://arxiv.org/pdf/1212.5225.pdf), is 69.32 ± 0.80 (km/s)/Mpc (or 21.25 ± 0.25 (km/s)/Mega-lightyear)

156,064mph

As of 21 March 2013, the Hubble constant, as measured by the Planck Mission, is 67.80 ± 0.77 (km/s)/Mpc.

151,664mph

All somewhat less than 186,000mph the speed of light. Well if galaxies are moving away from us, under Einsteins theories, they can't be at the speed of light, else that infinite mass would need infinite energy to move them.

Or am I not understanding things correctly?

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Message 1365089 - Posted: 6 May 2013, 11:12:23 UTC - in response to Message 1365088.

Not using miles, 67.3 km/s is 2,422,800 km/hour. The speed of light is 300,000 km/s.
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Message 1365224 - Posted: 6 May 2013, 18:30:43 UTC

Or am I not understanding things correctly?

Nope I wasn't at all! I was rushing out of the house to a meeting when I typed that and didn't have my thoughts straight. Of course the speed of light is 186,000 miles/second NOT mph. Just forget my last post it is a load of rubbish and I should have realised that at the time. Sorry folks. :-(

But then again

Not using miles, 67.3 km/s is 2,422,800 km/hour. The speed of light is 300,000 km/s.


Surely, 67.3 km/s = 242,280 km/hour? I think you also had an extra nought there!

Shall we both start again ? :-)


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Message 1365232 - Posted: 6 May 2013, 18:55:12 UTC - in response to Message 1365224.

Or am I not understanding things correctly?

Nope I wasn't at all! I was rushing out of the house to a meeting when I typed that and didn't have my thoughts straight. Of course the speed of light is 186,000 miles/second NOT mph. Just forget my last post it is a load of rubbish and I should have realised that at the time. Sorry folks. :-(

But then again

Not using miles, 67.3 km/s is 2,422,800 km/hour. The speed of light is 300,000 km/s.


Surely, 67.3 km/s = 242,280 km/hour? I think you also had an extra nought there!

Shall we both start again ? :-)



You are right.
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Message 1365268 - Posted: 6 May 2013, 21:03:38 UTC - in response to Message 1365088.

The speed of light is 186,000 miles per SECOND. This is roughly 3 x 10^10 cm per second. Parts of the Universe are moving away from us at faster than the speed of light due to the expansion of space. This is part of the confusing things about cosmology.

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Message 1365288 - Posted: 6 May 2013, 22:29:04 UTC - in response to Message 1365268.

The speed of light is 186,000 miles per SECOND. This is roughly 3 x 10^10 cm per second. Parts of the Universe are moving away from us at faster than the speed of light due to the expansion of space. This is part of the confusing things about cosmology.

Quite correct. Called inflation. We know there is stuff past the edge of the observable universe.

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Message 1365324 - Posted: 7 May 2013, 1:55:43 UTC

Does anyone know how wide the universe is? The most accurate age estimate I have heard is 13.75 billion years, so that would be 27.5 billion light years in diameter. How much is space expansion, and how much is what we would expect?

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Message 1365327 - Posted: 7 May 2013, 2:34:51 UTC - in response to Message 1365324.

The Universe is 56 billion light years across. It is finite but unbounded

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Message 1365408 - Posted: 7 May 2013, 11:59:01 UTC

It is finite but unbounded

Can't have it both ways!

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Message 1365422 - Posted: 7 May 2013, 13:36:54 UTC - in response to Message 1365408.

It is finite but unbounded

Can't have it both ways!

Expand brain to accept this concept.

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Message 1365425 - Posted: 7 May 2013, 13:53:55 UTC

Gaaaahhh

Either something is finite, or it is in-finite and un-bounded.

I don't need to expand my brain, others need to expand their knowledge of the English language. If you are trying to explain a new concept then you are not doing very well so far!



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Message 1365431 - Posted: 7 May 2013, 14:04:27 UTC - in response to Message 1365425.
Last modified: 7 May 2013, 14:16:54 UTC

Try this. The surface of a balloon is finite and unbounded in two dimensions. If you head out on a geodesic (i.e. a "straight" line in two dimensions) line you come back around to where you started. Space is expanding but there is nothing outside of it. Since mass tells space how to bend (gravity for youse proles) then I surmise that space is curved back on itself perhaps in a sphere. In the future we may find this very slight curvature--Euclid my have been slightly off and that may be why our math causes confusion at the very small and by induction the very large arenas,

Blow up the balloon a little more and it is still finite and unbounded in 2 dimensions. Here the surface of the balloon represents all of the space in the Universe--it is getting larger but thats all the space that there is.

Are we expanding into another dimension ?? Can we go North of the North Pole ??

Hard to grasp perhaps; but, ask yourself what is North of the North Pole??

Another good, arrogant scientific ?? rant by Daddio

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Message 1365445 - Posted: 7 May 2013, 14:32:41 UTC
Last modified: 7 May 2013, 14:39:22 UTC

Try this. The surface of a balloon is finite and unbounded in two dimensions.


It is not!!! A balloon blown up to a certain diameter, will have a finite surface area and a finite enclosed volume. Blow it up some more and those values will increase. Are you sure that you are not getting confused with the Mobius strip?

Hard to grasp perhaps; but, ask yourself what is North of the North Pole??

On earth nothing. Go past the North pole and you go South again. The North Pole is a defined point in the Arctic sea where compasses show zero deflection, i.e. 90 degrees North.

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Message 1365572 - Posted: 8 May 2013, 0:46:25 UTC - in response to Message 1365445.
Last modified: 8 May 2013, 0:50:01 UTC

Chris,

Volume is a 3 dimensional concept. The surface of a balloon is 2 dimensional. There are only two dimensions on the surface of a sphere hence longitude and latitude. I asked you to visualize a 2-dimensional world so that you could see by analogy what I was talking about.

Perhaps you should read the book 'Flatlander" or watch some of the Flatlander -type videos on the Web.

If there were no space other than that created by the expansion of the universe then there is no space outside of the universe. By thinking about the balloon there is no surface other than that on the balloon and when it expands there is more space but still finite and unbounded in 2 dimensions.

Tough things to visualize but try to see the analogy.

The mobius strip has only one side. If the universe were shaped like it then you could tunnel thru and shorten your journey. Think of an ant crawling along the strip. If he ate a hole in the strip he could shorten his path along the surface.

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Message 1365574 - Posted: 8 May 2013, 1:05:37 UTC - in response to Message 1365572.
Last modified: 8 May 2013, 1:06:35 UTC

William you're trying to engage someone who doesn't even have a concept of what the Hubble Constant means.
Save your breath.

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Message 1365580 - Posted: 8 May 2013, 2:36:49 UTC - in response to Message 1365574.

William you're trying to engage someone who doesn't even have a concept of what the Hubble Constant means.
Save your breath.

@Chris, it can't be described in English, only in math.

Or try William's analogy in 12 dimensions and you can only go one direction in one of those dimensions, call that one time.

Maybe this is a way to think of it in English. We experience X, Y, and Z. We are fixed in T, it zips along at C for us. X, Y and Z are finite for any given T, but are of infinite extent.

Or how about thinking of this from the point of a photon. As the photon moves at C, time is still for it. So send on on a journey from here and now. Here and now the observable universe is about 14 billion old. So check back with the photon in about 15 billion years. For it time hasn't passed, so the universe has not gotten bigger, yet it now is farther away from where it started than the age of the universe. Neat trick.

It is finite and unbounded at the same time.

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Message 1365592 - Posted: 8 May 2013, 3:50:43 UTC
Last modified: 8 May 2013, 3:55:34 UTC

The radius of the Observable Universe can never be greater than the speed of light divided by the Hubble Constant.

the speed of light = 299,792.458 (km/sec)
the Hubble Constant is 67.80 ± 0.77 (km/s)/Mpc

Maximum Radius of the Observable Universe= 299,782.458/67.80 Mpc
or 4421.570 Mpc or 14423 Mly which is also the minimum radius of the Universe proper because
no matter in which direction we look all equally distant galaxies appear to be receding at the same rate.

No matter how large the Universe really is we, from our vantage point in space, can never see any part
of the Universe further than 14.4 billion light years from Earth, because the expansion of the
intervening space has the points so separated receding from each other at the speed of light or greater.

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Message 1365613 - Posted: 8 May 2013, 5:30:27 UTC

The implications of dark energy see :

Fabric of the Cosmos by professor Brain Green episode 3 Qantum Leap

The short answer is Multiverse !!!!!

10 to the power of -187 I believe is the energy of dark energy but just watch the program as I probly got it wrong
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Message 1365633 - Posted: 8 May 2013, 6:18:39 UTC

Quantum Leap

Learn how to post links Glenn.

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Message 1365654 - Posted: 8 May 2013, 7:23:23 UTC - in response to Message 1365633.

Quantum Leap

Learn how to post links Glenn.


I wasn't posting a link and if I had you would not have able able to watch it from where you are as I would have posted http://www.sbs.com.au/ondemand/
not youtube
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