Dear Yousuf Khan:

"Yousuf Khan" wrote in message
...
N:dlzc D:aol T:com (dlzc) wrote:
Dear Yousuf Khan:

"Yousuf Khan" wrote in message
...
Sometimes you wish people would just get their
stories straight sometime. According to this theory,
Mars' magnetic field got shut down by a supergiant
asteroid hitting it, probably about the size of Texas.

Hit a magnet with a hammer, and you risk
demagnetizing it.

That'll work with a permanent magnet, but not an
electromagnet. I'd say a planet is closer to an
electromagnet than a permanent magnet.

We do have that liquid core...

So why didn't something like that shut down
Earth's magnetic field?

Liquid, differentially rotating, core.

Which apparently both Mars and Venus had at one
point too, just like the Earth.

But Mars didn't when it got hit. And Venus doesn't have our
"nuclear reactor".

Well, because you'd need an even bigger asteroid
to affect the Earth. Well, isn't the leading theory
of how the Moon formed, that a planetesimal the
size of Mars itself hit the Earth? Wouldn't that be
even bigger than a Texas sized asteroid? No
answer.

Use your head.

Elaborate.

Before we had the collision, did we have a magnetic field?
Immediately after the collision, did we have a magnetic field?
What is the duration of a pole flip, and do we have a magnetic
field during that peroid? We don't know. We've only been at
this (measuring magnetic fields for other planets) for less than
100 years.

Then the most ludicrous one is the explanation
about Venus. So why doesn't Venus have a
magnetic field? Well its mantle is too dry and stiff
to allow for a dynamo effect! So why is Venus's
mantle so stiff and dry? Is it because Venus's water
disappeared, that's why it's so dry in its mantle? If it
had a magnetic field it wouldn't have lost its water,
and if it had water, it would've had a magnetic field.

We still haven't gotten off this planet. Enjoy the
conundra while you can. Obviously, Venus does
not have Earth's history.

Even after we get off this planet, we still would have
a ways to go before we can go back in history.

I agree. I'd suggest the "red & dead" galaxies, as a place to
start. Coalescence must occur, but at what rate? Gravity is
fully conservative of momentum, only friction is not. If they
are still "red & dead", then there may be something special about
them. Not a different time rate, but something.

David A. Smith