Re: Gravity

On Mon, 06 Apr 2009 19:48:20 -0500, metspitzer wrote:
On Mon, 06 Apr 2009 19:04:35 -0500, metspitzer <kilowatt@xxxxxxxxxxx>
wrote:

I have been watching Live Webcast of Origins Symposium at ASU.
Lawrence Krauss just said that gravity pushes.

I saw a Universe show on the History channel and Michio Kaku said that
space was actually pushing you into your chair.

Who is right?

Lawrence Krauss said that gravity pulls


I vote for pull.

Consider the two possibilities:

1. Masses exert a gravitational attraction that pulls you toward
them in proportion to their mass and your distance to them.

This theory predicts that if you are X distance from Jupiter, you
will feel the effect of gravity more than if you are X distance
from Earth. Further, it predicts that if you travel from Earth to
the Moon, there will be a point at which you reach equilibrium and
it will be closer to the Moon than the Earth because of the Earth's
greater mass.

Those predictions are bourne out by observations.


2. Something (the vacuum of space?) pushes you away.

Under this "theory" what direction should it be pushing you? Let's
say, mass has no effect, but lack of mass, IOW vacuum, pushes. You
might argue that this then makes the same predictions as above.
But, ISTM, that it would also predict that in the vacuum of space,
you would feel pressure, since you are being pushed from all sides.
This prediction has obviously been falsified.

So, I think the pull theory wins. Of course, WRT science, I am just
a lay person.


--
Greg
http://www.spencerbooksellers.com
newsguy -at- spencersoft -dot- com

.

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