On 11-07-17 03:26, Fred J. McCall wrote :
Alain wrote:


Also, the fact
is that you need to take into account both Special and General
Relativity for GPS to work. The satellites are moving fast enough and
are far enough out of the gravity well for both effects to be
significant. The relevant equations of Special Relativity were
originally from Lorentz, and Poincaré showed that they were applicable
in real life so it isn't really Einstein's Special Relativity that is
needed, it is Poincaré's Relativity. Poincaré used observations of
Mercury's orbit for his work. And Einstein used Special Relativity to
develop General Relativity and was also aware that tweaking
gravitational laws was necessary to accommodate Mercury.


Mercury was a proof, not a prerequisite.

Go read Henri Poindcaré. It isn't a prerequisite, but it was
instrumental in the development of his relativity which predates
Einstein's Special Relativity.

Of
course you don't need to know about mass-energy equivalence to make
vegetable soup but it still is important in our everyday lives.


Is it? How?

As I said, for instance GPS.


GPS isn't about mass-energy equivalence.

I wasn't talking specifically about mass-energy equivalence. GPS uses
Special and General relativity. For usage of mass-energy equivalence in
our every day lives, maybe your computer is connected to an electric
grid. Maybe there is some nuclear power plant on that grid.

You probably already knew about nuclear power plants. I think you are
trolling, you are getting close to plonk territory.

Another way that telescopes were useful for the discovery of nuclear
energy is that Einstein and other scientists at the time were well aware
of the "black energy" of that time. That is, they knew that the Sun
could not have as an energy source something like burning coal. It
wouldn't last long enough. So looking for large amounts of energy hidden
within the atom wasn't completely out of nowhere.


It also had nothing to do with telescopes.

See my reply to Quadibloc.


Alain Fournier