Post by: Missynmax83 on 06/12/2013 04:53:25
Post by: RD on 06/12/2013 05:50:32
has there ever been tests in space to test general relativity at it most basic raw form at free orbit and try to orbit a small ball mass around a bigger heavyer ball mass (say like LAGEOS) ...
or like GPS ...
Quote from: wikipedia.org/Global_Positioning_System
In 1956, the German-American physicist Friedwardt Winterberg proposed a test of general relativity (for time slowing in a strong gravitational field) using accurate atomic clocks placed in orbit inside artificial satellites. (Later, calculations using general relativity determined that the clocks on GPS satellites would be seen by Earth's observers to run 38 microseconds faster per day, and this was corrected for in the design of GPS.)https://en.wikipedia.org/wiki/Global_Positioning_System#History
Post by: Missynmax83 on 06/12/2013 06:31:51
Post by: CliffordK on 06/12/2013 07:24:18
Of course, being in space is not without gravity (https://en.wikipedia.org/wiki/Micro-g_environment), which can actually be quite significant depending how close one is to various celestial objects. For example, the international space station is subjected to nearly the same gravity as one would have at the surface of the earth. Just the orbit is a perfect balance between gravity and centrifugal force, giving the sensation of weightlessness.
You might have difficulties getting two objects sent up from Earth to orbit each other as most satellites weigh less than a few tons.
So, say we had two 1000kg masses, spaced 1m apart.
We get:
Anyway, for the two, one-ton objects, with a 1m space (between the centers), the acceleration towards each other is awfully small.
They may still orbit each other, but it would take a couple of years per orbit.
Also, keep in mind that the volume/mass of an object increases with the cube of the radius. So, the gravity is essentially greater for the same distance from the surface for larger objects.
Anyway, for any practical experiments, one needs much bigger masses, thus using the sun, earth, moon, or perhaps some asteroids.
Post by: Missynmax83 on 06/12/2013 12:05:37
Post by: RD on 06/12/2013 13:03:47
... why is it that after billions of years the energy that a sun would use hasnt made suns mass smaller ...
It has lost mass via radiation, but only a tiny fraction ...
Quote from: astronomycafe.net
... over the entire life of the Sun to date [loss of mass] is about 3.1 x 10^29 grams.http://www.astronomycafe.net/qadir/q1491.html
The mass of the Sun is 4 x 10^33 grams so this loss equals 0.008 percent of its current mass.
Post by: Missynmax83 on 06/12/2013 13:24:06
Post by: RD on 06/12/2013 13:37:03
Quote from: wikipedia.org/Main_sequence
...The behavior of a star now depends on its mass, with stars below 0.23 solar masses becoming white dwarfs directly, while stars with up to ten solar masses pass through a red giant stage. More massive stars can explode as a supernova, or collapse directly into a black hole.https://en.wikipedia.org/wiki/Main_sequence
Post by: Missynmax83 on 06/12/2013 13:57:33
Post by: RD on 06/12/2013 14:18:00
Ok .with what we do know about physics here on earth how much fuel should ow sun used in its life time
see the link in post #5 (http://www.thenakedscientists.com/forum/index.php?topic=49707.msg425851#msg425851) in this thread.
Post by: Missynmax83 on 06/12/2013 14:38:36
Post by: Missynmax83 on 06/12/2013 16:06:48
Post by: Missynmax83 on 07/12/2013 02:57:22
4 million tonnes of mass every second for 5 billion years adds up to about 6.32*10^26 kg That adds up to a grand total of 0.0316% of its present mass. So yes, it does get smaller, but by a tiny imperceptible fraction.
As it happens, there are two main ways this is lost- one is mass lost to nuclear fusion in the core, as you thought. The other is mass ejected out the surface through solar wind. .................................... ,.i also saw that ow sun has explanded 10% over its life coz of helium ash, wouldnt that apply to all sun and black hole to make it gravity weaken ,to dont allow a size to weight ratio that would allow a mass to colaps on it self ,because the curving of spacetime would never bend anuf for compresion of matter be stronger that the energy matter realises...i know ow sun wont turn in to a black hole ...but the finding of ULX-1 show mistake with general relativity and what happpening around the event horizon
Post by: Missynmax83 on 07/12/2013 03:33:29