Redshift Time and the Start of the Solar System

John15

Einstein tells us time and space are linked, could redshift be caused by a change in time rather than space?
Including uncertainties how close is the start of this period of universal expansion to the start of the solar system? Could the 2 coincide?

mathman

The Solar System formed from the gravitational collapse of a giant molecular cloud 4.568 billion years ago.[112] This initial cloud was likely several light-years across and probably birthed several stars.[113]
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Above from Wikipedia. Big bang was about 13.7 billion years ago.

I can't comment on your first question.

John15

Not talking about BB expansion. Apparently expansion of universe was slowing down from BB then started accelerating again it is this point I was asking about.
How can we be so accurate about beginning of solar system.
Can anyone help with time and redshift, slowing of time I think should have same effect as expansion of space.

marcus

That's an interesting question! The 4568.2 million year figure comes from here:
http://www.nature.com/ngeo/journal/v...l/ngeo941.html

It is NOT presented as "the age of the solar system".

To be precise, it is presented as the lead isotope age of the oldest material we have found in the solar system so far.

Two points are to be made about this.
1. Because the material was found in a primitive type of meteorite that is thought to be among the very earliest solid stuff that would have collected out of a star-forming cloud of gas and dust, it's reasonable to THINK of the solar system starting to gather about the same time that meteoritic material formed. So call the solar system ROUGHLY 4.6 BILLION years old. (But no reason to put all those decimal places on the number, 4.6 is fine.)

2. They've used "lead-lead dating" since the 40s or 50s---for over 50 years, and checked it various ways. And the estimates for oldest known material have barely changed for a long time. This particular 4.568 billion is only around 1/3 of a million years older than what they had before. It is ahead "by a nose" in the competition to find the oldest material in the solar system. When estimates over many years tend to CONVERGE like that it's reasonable to guess that we needn't expect any big surprises. They aren't likely to ever find a meteorite with material much older than that in it.

Anyway it is very interesting how they date this material using two isotopes of lead
Pb-207 and Pb-206. Definitely something to find out about. If you ever want to date a really mature meteorite.

http://en.wikipedia.org/wiki/Lead-lead_dating