Quote:
Originally Posted by xelasnave
If the Sun is moving thru space, which on all accounts it does, and if the message of gravity travels at a finite speed, I think that be the speed of light, one would think the planets each orbit a point where the Sun was such that you would expect the orbits mark out a cone shape.
I don't know if the observations would show that but seems reasonable to me.
I think the solar system should move thru space in a "pie in the face" orientation but I think observations show the orbits are inclined.
Does anyone understand the point I am trying to make?
Alex
|
I believe that gravity does indeed propagate at the speed of light, so that at this precise instant, the Earth is being pulled towards the Sun where we see it, which is where it was about 8 minutes ago. (Or more correctly, it's probably that distortion and curvature in the fabric of Space-Time propagate at the speed of light?
)
The Earth is orbiting around the Sun at about 30 km/s. The Sun is orbiting around the centre of the Milky Way at about 200 km/s, which is much faster than the Earth's orbital speed, so by the time the Earth has completed one orbit of the Sun in one year (about one billion km), the Sun has moved about 6.3 billion km.
If the Solar System was travelling "edge on" around the Milky Way, the Earth's trajectory would be a relatively small side-to-side wobble about the Sun's trajectory. If the Solar System was travelling "face on", the Earth's path would be a long slender helix, where the pitch is much longer than the diameter.
In fact, the plane of the Solar System is tilted about 63 degrees relative to the galactic plane - and it makes my brain hurt trying to work out what the Earth's trajectory looks like!
And then we need to think about the movement of the Milky Way through Space-Time ..... the Milky Way orbits around the centre of mass of the Local Group, and the Local Group is moving at about 600 kilometres per second in the direction of the constellation Hydra. (And since we're about 25,000 light years from the centre of the Milky Way, I guess that the Sun is really orbiting around the point where the heart of the Milky Way was 25,000 years ago?)
I think I'm sticking with the Earth-centric Universe - it's a lot easier to get your head around!
