Re: Two questions

In message <427ce7d3$0$10302$afc38c87@xxxxxxxxxxxxxxxxxxxx>, Peter Webb <webbfamily-diespamdie@xxxxxxxxxxxxxxx> writes 

"Zdenek Jizba" <jizba@xxxxxxxxxxx> wrote in message
news:wz4fe.740$w81.359@xxxxxxxxxxx

   These questions are strictly hypothetical.

   Question 1.
      If the earth expanded at the same rate as the
universe, how much would the radius increase in 1
million years?


The Earth is expanding at the same rate as the Universe, because it is part
of it. The tip of your nose and all the atoms in it are also expandin g at
the same rate.

Not according to current theory. Look at <http://www.physics.adelaide.edu.au/~dkoks/Faq/Relativity/GR/expanding_un
iverse.html>, for instance. But AFAIK, it's not (yet ?) possible to measure such expansion if it was occurring, either on Earth or between the Earth and Moon.

The Universe is probably about 30 billion light years across, and the edge
recedes at the speed of light.


No. The _observable_ universe is expanding at the speed of light, but the current rate of expansion of the local universe is given by the Hubble constant (70 km/s/Mpc, or whatever the current figure is) So you have to turn that last bit (megaparsecs, 3.26 million light years) back into kilometres to get the expansion rate of the Earth.




   Question 2.
       Were all planets at the same distance from the
sun 100 million years ago as they are today?

Yes.

There's no way of knowing, but some theories say not. Look at <http://www.space.com/scienceastronomy/mystery_monday_031201.html>, for instance.
It's known that there were more days in an Earth year several hundred million years ago, but that's usually ascribed to the tidal action of the Moon slowing the Earth. If the Earth had actually moved away from the Sun (due to mass loss from the sun, for instance) I can't think of any way to find out.
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