Newton's gravitational constant may not be constant
This story is one that we present with severe reservations. The claims made
by Mikhail Gershteyn, a visiting scientist at the MIT plasma Science and
Fusion center do not accord with usual theory, but more importantly, some
physicists say that if his claims are correct, then something that looks
very like perpetual motion may be possible. The key point is that Gershteyn
says he has detected away in which the universe's uneven, an effect called
anisotropy. According to his results, the effects of gravitation vary, depending
on which way you measure them.
The story goes back to
Isaac Newton, who worked out in 1687 that the force of gravity between
two bodies is proportional to the product of their mass, divided by the square
of the distance between their centers of mass. fly introducing a constant
(G, the universal gravitational constant), we can write a mathematical
F = G M1M2/r2
The value of C was first calculated by Henry Cavendish, using an ingenious
apparatus designed by John Michell, but while we call it the universal
gravitational constant, Gershteyn claims that the value of G can vary by
as much as 0.054%, depending on the direction in which it is measured. He
announced this in early May, and it has since been published in the June
issue of the journal Gravitation and Cosmology.
This is a peer-reviewed journal, and while the peer review process can fail,
that is unusual, so for the moment, it would be wise to assume that there
is something in what Gershteyn says, though it would also be wise to watch
and wait for the moment. He says that he and his colleagues and I have
successfully experimentally demonstrated that the force of gravitation between
two test bodies varies with their orientation in space,relative to a system
of distant stars, according to press reports.
He claims his finding that G varies depending on orientation of the two
gravitating bodies relative to a system of fixed stars is a direct challenge
to Newton's views. This is either a sign of genius, or a sign of delusion:
many people delude themselves that they have contradicted one of the 'greats'
like Newton or Einstein, but only the truly great will ever do just that
- and it remains possible that Gershteyn fits that category. Only time will
reveal his true status.
The 'perpetual motion' argument is an interesting one. Given a gravitational
anisotropy, say skeptical physicists, an arrangement of two pendula at right
angles could be used to extract 'free' energy, which means that the claim
must be false, since it appears to be a totally unchangeable law that perpetual
motion is impossible. Others argue that the device would not demonstrate
true perpetual motion, but would simply milk the acquired energy from somewhere
outside the pendulum system.
It seems that there will need to be more evidence and more testing before
there will be any real consensus on Gershteyn's claims. If he is wrong, he
may well disappear without trace, but if he is right, we will be hearing
a great deal more about him.
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