Re: Arrow of time

Dr Umesh Bilagi wrote in talk.origins

On May 4, 5:27 am, *** C <foo.dic...@xxxxxxxxxxx> wrote:
Dr Umesh Bilagi wrote in talk.origins

On May 3, 11:11 am, "Ross Langerak" <rlange...@xxxxxxxxxxxxx> wrote:
Applied to the formation of a star and planets, a cloud of dust and
gas collapses under its own gravity. Potential energy is turned
into kinetic energy and then heat. The hot star and planets radiate
heat out into the cold Universe. This represents an increase in
entropy. To reverse this - to return the system to a diffuse cloud
of dust and gas - would require an input of work. The cloud of dust
and gas is the low entropy condition; the planetary system is the
high entropy condition.

ALL the heat produced formation gets dispeated if then why core of
earth is still hot

as someone else said, nuclear decay. On an historical note, one famous
scientist,Lord Kelvin, over a hundred years ago, calculated the age of
the earth based on rate of cooling. His first estimate was about 98
million years, then revised to 20 million years. This was before the
discovery of nuclear decay.
And nuclear decay releases heat, lots of it. And that heat is why the
earth's core is so hot, and why the sun is so hot.

I may asking very useless question please tell me

Not at all. Sometimes the answers are a little hard to find, and you
never learn if you don't ask.

I learnt some where Even the heat produced while formation planets
contrubtes to core heat along with radioactive decay is it false?


No, it is not false. Heat is generated by during planetary formation,
and planets, as all things, will cool off more on the outside than
the inside. And the heat on the inside will slowly move to the outside
and away from the planet. Thus the core will remain hot for a long time
after the exterior cools.

You can see this with ordinary objects, such as a cake or rolls. Fresh out
of the oven the cake will be mostly the same in temperature inside and out.
Wait a couple of minutes and the outside will be near room temperature,
while the inside is still hot.
The same goes with heating. Take something out of the freezer, and as it
warms up the outside will be far warmer than the core. Eventually though,
a uniform temperature will be reached.
With planets, though, nuclear decay is constantly generating heat in the
interior so that it remains hot, long after the heat generated by the
formation of the planet should have cooled off.



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