Posted on 06/01/2009 6:59:33 PM PDT by SunkenCiv
Skywatchers have been trying to gauge the sun-Earth distance for thousands of years. In the third century BC, Aristarchus of Samos, notable as the first to argue for a heliocentric solar system, estimated the sun to be 20 times farther away than the moon. It wasn't his best work, as the real factor is more like 400. By the late 20th century, astronomers had a much better grip on this fundamental cosmic metric -- what came to be called the astronomical unit. In fact, thanks to radar beams pinging off various solar-system bodies and to tracking of interplanetary spacecraft, the sun-Earth distance has been pegged with remarkable accuracy. The current value stands at 149,597,870.696 kilometres. Having such a precise yardstick allowed Russian dynamicists Gregoriy A. Krasinsky and Victor A. Brumberg to calculate, in 2004, that the sun and Earth are gradually moving apart. It's not much -- just 15 cm per year -- but since that's 100 times greater than the measurement error, something must really be pushing Earth outward... Takaho Miura of Hirosaki University in Japan and three colleagues... argue that the sun and Earth are literally pushing each other away due to their tidal interaction. It's the same process that's gradually driving the moon's orbit outward: Tides raised by the moon in our oceans are gradually transferring Earth's rotational energy to lunar motion. As a consequence, each year the moon's orbit expands by about 4 cm and Earth's rotation slows by 0.000017 second... the distance between the Earth and sun is growing because the sun is losing its angular momentum.
(Excerpt) Read more at newscientist.com ...
Inside of geosync orbit, the orbit decays, outside and the object moves farther away.
This is Obama’s fault.
The earth is getting bigger.
Anybody that uses “prograde” in a sentence ought to be pants’d.
That explains *my* day.
I guess I can open the windows then. ;’)
Quite right, poindexter. Thanks.
Inside geosync, only if there’s atmosphere to slow it down.
Interesting, thanks!
As an example of the Lense-Thirring effect consider the following:Think of a satellite rotating around the earth. According to Newtonian Mechanics, if there are no external forces applied to the satellite but the gravitation force exerted by the earth, it will keep rotating in the same plane forever. This will be the case whether the earth rotates around its axis or not. But with General Relativity, we find that the rotation of the earth exerts a force to the satellite, so that the rotation plane of the satellite rotates, by a very small amount, in the same direction as the rotation of the earth.
The Earth’s angular momentum is increasing by a tad, apparently continuously, meaning that some force is being applied to make it so.
http://hyperphysics.phy-astr.gsu.edu/Hbase/amom.html
Glad someone found my shopping list.
In 1000 years that's 150 meters! There's only one solution. We have to stop the metric system NOW!
Good idea!!!
Before the 1000 years are up, the measurements will be shown to be bogus. ;’) See, I like to make my own fun.
look the moon causes a little bulge on the earth, since the earth turns faster than the moon rotates, the little bulge is always a little ahead of the moon and pulls the moon to speed up giving the moon more energy.
at geosync, the satellite and the bulge it creates stay in line with each other.
at less than geosync, the satellite goes faster than the earth is turning and the satellite is ahead of the bulge. the bulge pulls on the satellite slowing it down until it crashes.
look the moon causes a little bulge on the earth, since the earth turns faster than the moon rotates, the little bulge is always a little ahead of the moon and pulls the moon to speed up giving the moon more energy. at geosync, the satellite and the bulge it creates stay in line with each other.Geostationary doesn't have anything to do with anything except that the satellite appears to hover over the same spot on the Earth's surface. That's all.
It is not easy to estimate how far away from the Earth the Moon was when it formed, but simulations suggest is was about 3-5 times the radius of the Earth, or about 19-30 thousand km. (The Moon is currently about 384,000 km away from Earth or 3-4 thousand times further away than this.) The Moon probably couldn't have formed closer than 3 Earth radii because tidal forces from the Earth would just pull it apart again, and it is unlikely that the impact could have ejected material further than 5 Earth radii. [#699"]Geosynchronous orbit is approximately 35,786 km.
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