On 22/06/2015 13:12, Lawrence Jenkins wrote:
On Monday, 22 June 2015 13:07:17 UTC+1, Col wrote:
Lawrence Jenkins wrote:
On Monday, 22 June 2015 09:44:02 UTC+1, Col wrote:

Yes.
We can throw spacecraft around planets and they always go where we
want them to, they don't crash into the planet or go flying off into
space in the wrong direction because somebdy got the equations wrong.

we know what the equations are. We can
'slingshot' spaceprobes around planets in order to accelerate them.
And lo and behold the probes end up where we want them.

Yes you can use the equations of Newtonian gravity and calculate
these trajectories with sufficient accuracy in the solar system,
but not in a strong gravitational field where you have to use the
more accurate theory of general relativity, where gravity is
modelled not as a force but as the curvature of spacetime.

I am well aware of the limitations of Newtonian physics.


How could we do that if the theory wasn't 'proven'?
Newtonian gravity was proven to be wrong ~100 years ago.

But only *wrong* where relativistic principles become significant.
Newtonian gravity works for us in most instances, and where it
doesn't we know how to calculate it.

Einstein didn't replace Newton's theories, he merely built upon them.
--
Col

Bolton, Lancashire
160m asl
Snow videos:
http://www.youtube.com/channel/UC3QvmL4UWBmHFMKWiwYm_gg

We know its there and always has been and we (not me) know how to
calculate its effects but that is a a far cry from understanding how
it works. If we (not me) knew how it worked then there is every
conceivable chance it could be negated making leaving this planet
with heavy pay loads and travel on earth in general, a darn sight
easier than it now. Anti gravity like fusion is another one of those
mysterious holy grails

When I said we know how it works I meant we have made observations
and devised theories to explain those observations.
And those theories *work*. We can accurately predict the future motion
of planets, spacecraft, apples etc based upon them.

I didn't mean that we know how it works on a much more fundamental
level, to the extent that we could build anti-gravity drives or whatever.
Perhaps saying we know how it 'behaves' rather than 'works' would have
been a better choice of word?

Nuclear fusion, eh?
Always 30 years away. Funny, it's been 30 years away for at least the last
60 years........
--
Col

Bolton, Lancashire
160m asl
Snow videos:
http://www.youtube.com/channel/UC3QvmL4UWBmHFMKWiwYm_gg

Yeah true about Nuclear fusion, buts its still a lot closer than my love life improving.


You may be in luck Larry.

Reports are emerging in several parts of the world regarding the new
disease afflicting humanity called SAWS - Sperm Addiction in Women
Syndrome.

The first reported cases of SAWS were discovered in Dublin in January
2015, when a wealthy middle class woman was observed offering a bottle
of whiskey to a homeless drunk sitting on a bench in St Stephen's Green
and then kneeling down and performing fellatio on the drunk. She was
arrested on the charge of outraging public decency, and referred to St
Mary's Hospital, Merrion Street. After a period of observation, the
doctors learned that this woman was a fellatio addict. More precisely,
she was addicted to sperm, and suffered severe withdrawal symptoms if
she could not ingest a copious volume of male human sperm about every
four hours. Because she was unmarried, she had resorted to buying
bottles of whiskey and offering them to homeless drunks in return for
their sperm.

At first the doctors in Dublin dismissed this as an isolated case of
mental illness and placed the woman in institutional care. But then as
the weeks passed, reports came in of Irishmen frantically phoning their
doctors saying that their wives had gone crazy and were demanding
fellatio every few hours and kept shouting at their husbands:

"SPERM! SPERM! SPERM! Give me your sperm. I can't live without sperm!
I'll go insane if I don't get sperm!"

As the weeks passed in early 2015, the Irish Medical Association (IMA)
was forced to recognise that a new disease had emerged, and they named
it SAWS - Sperm Addiction in Women Syndrome.

As more time passed, reports came in of outbreaks of SAWS in many other
parts of the globe, including Sao Paulo, Manila, Canberra and elsewhere.

Now medical experts are fearing a worldwide epidemic of SAWS is looming,
with women throughout the world literally screaming for sperm and
demanding fellatio from every man who walks close to them.