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Author Topic: Where in the universe did the big bang occur?  (Read 1533 times)

Steve Asher

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Where in the universe did the big bang occur?
« on: 05/07/2008 13:13:52 »
Steve Asher asked the Naked Scientists:

Thanks for putting on a great show. My family and myself listen to it regularly while driving around Australia on our many holidays.

My Questions relate to Astronomy. I find the following most perplexing and would be very grateful of an explanation of the following

a) Do we know where in the universe the big bang occurred?
b) How fast are galaxies receding from the big bang?
c) If we can with high powered telescopes see galaxies 13.23 Billion light years away, and the universe is only 13.6 billion years old would that not
indicate that our galaxy is traveling at 97% of the speed of light?

(Assuming the most distant visible galaxy is the closest to the origin of the big bang).

Would that not also indicate that galaxies that are more than .47 billion light years away in the opposite direction are actually travelling at or faster than the speed of light?

d) As the earth rotates around the sun would the Doppler shift of our sun
 as visible from earth give us an indication our galaxies (or our the suns) speed away from the big bang? (Assuming the orbital plane passes through 0/180o the direction travelled)

What do you think?


Offline Soul Surfer

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Where in the universe did the big bang occur?
« Reply #1 on: 05/07/2008 17:45:26 »
Answers as follows 

a)  everywhere.  The big bang did not happen at a specific location it was the start of space and time for our universe.

b) Galaxies are not receding from the big bang like bits of shrapnel from an explosion they are moving about quite normally under gravity and forming clusters and stringy groups.  It is the space in between the galaxies that is expanding very slowly so that when galaxies are at great distances they appear to be moving very quickly.  There is no limit to the speed that galaxies may be receding but we can only see those that are receding at less than the velocity of light.

C) no! the previous answer should explain this it is space that is expanding.

d) This is not very clearly or unambiguously worded to give a clear answer but the answer is probably no because the wording appears to indicate several serious misunderstandings of what is really going on.

Firstly the earth the sun and our galaxy do not occupy any special position in the universe  everywhere else is much the same.

When observing distant objects in the universe astronomers need to take into account the local effects of our motion through space.  I will list them.

Firstly there is the velocity of the telescope as the earth rotates  this is up to 1,000 miles (1,600 km) an hour for something on the eastern or western horizon on the equator.  (This is only critical for very precise measurements)

The orbital velocity of the earth around the sun of approximately 30km/second

The orbital velocity of the sun around the galaxy of approximately 200 km/second

The velocity of our own galaxy in the local group (which I don't know off hand but its's probably around 300km/second in the vague direction of the andromeda galaxy)

« Last Edit: 05/07/2008 17:48:31 by Soul Surfer »

Offline Alan McDougall

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Where in the universe did the big bang occur?
« Reply #2 on: 07/07/2008 23:57:35 »
The big Bang was the whole universe,matter, energy, time and space These were all created in the Big Bang creation event. The universe did no exist until this moment. The universe did not explode into a primordial void, it brought the void we call space with it.

So Soul Surfers he answer everywhere is correct. I just added my peace for what it is worth



The Naked Scientists Forum

Where in the universe did the big bang occur?
« Reply #2 on: 07/07/2008 23:57:35 »


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