how can the universe be only 13 billion years old if the observable radius is at least 78 billion years??

simple, the expansion of the universe was faster than light-speed. space-time can expand faster than light-speed because it has no mass. we can observe the cosmic microwave background even tho it is receding at more than light-speed.

the 78 000 000 000 light-year estimate is uncertain. it depends on the mathematical model used in interpreting the data, but the data from nasa's microwave anisotropy probe suggest that the cosmic microwave background is at least 78 000 000 000 light-years away.

read this:

http://www.sciam.com/print_version.cfm?articleID=0...

after inflation, the expansion began to slow down, but it began to speed up about 5 000 000 000 years ago. the expansion is now speeding up not slowing down.

WOW! Is this true? If so then this is a great question... some discrepancy... both numbers can't be right.. my guess will find it some where in between the twp numbers: I think that if you're right that the 78 billion is the RADIUS and NOT the perceived diameter, then that's even more "problematic." Measuring spacetime expansion is "problematic" in and of itself, as velocity after the big bang is supposed to be ever-slowing... perhaps their calculations on initial velocity are open to revision and are discrepant; then there is the problem of "dark matter" and it's cumulative gavitational pull on that velocity or "speed of expansion."

You many want to consult the latest journals concerning this dicrepancy in measurement, and I seem to remember that the science channel had a special recently that addressed this question... I wonder what Hawking has to say about all this?

If people like Hawking have no more to add - nothing more than the offerings of "hotsoapywater," then he/she probably "nailed it!

I don't know where you got that "78 billions" stuff, but all I know is that the current observable radius is about 13 billions of light-years, according to scientific data.

Who told you the observable radius is 78 billion light years?

First, the universe did not start up at one element. even as the total observable universe might want to have fit into an fantastically small area at first, there changed into more effective to the universe, even early on, than only that. those component to the universe that are literally ninety 3 billion gentle years away have continually been outdoors of our gentle cone. 2d, the universe has stronger swifter than the speed of light very early on. The mandatory aspect right here's to keep in mind that it truly is area itself that expands even as the speed of light *by ability of area* is restricted. it truly is attainable for area to enhance swifter than gentle.

The speed of universe expansion is not at a constant rate. It's much much faster in its early satge than right now and in the future. It expands slower and slower.

warmsoapywater... that's a great article at the link you posted... thank you!!

does it matter?