Why is the Earth moving away from the sun?

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.

from wiki

link

http://en.wikipedia.org/wiki/Orbital_decay

[edit] By tidal effects
An orbit can also decay by tidal effects when the orbiting body is large enough to raise a significant tidal bulge on the body it is orbiting and is either in a retrograde orbit or is below the synchronous orbit. The resulting tidal interaction saps momentum from the orbiting body and transfers it to the primary’s rotation, lowering the orbit’s altitude until frictional effects come into play.

fyi “below synchronous orbit” is the same as “inside geosync orbit”

How about this link
http://www.associatedcontent.com/article/72725/the_moon_is_moving_away_from_the_earth.html

The Moon is Moving Away from the Earth

...Now, the tidal bulges that are created on the Earth, by the moon, are not exactly located directly below the moon. Instead, they are located slightly ahead of the moon, and because the Earth is spinning faster than the moon, this causes the gravitational force on the tidal bulge to pull on the moon, slightly increasing its’ orbital velocity. When the moons’ orbital velocity increases, the Earths’ rotation slows. It’s this unique relationship between these two bodies, that is causing the moon to slowly move away from the Earth...about an inch a year. Although it’s not noticeable now, the scientist say in about a million years, the effects will be very noticeable.

Thanks. Geosync is just a nice spot where some mathematical data points intersect.

An orbit can also decay by tidal effects when the orbiting body is large enough to raise a significant tidal bulge on the body it is orbiting and is either in a retrograde orbit or is below the synchronous orbit.

and

...this causes the gravitational force on the tidal bulge to pull on the moon, slightly increasing its' orbital velocity. When the moons' orbital velocity increases, the Earths' rotation slows.

and there's this:

The Moon
The moon is Earth's only natural satellite... The Moon's orbit is expanding over time as it slows down (the Earth is also slowing down as it loses energy). For example, a billion years ago, the Moon was much closer to the Earth (roughly 200,000 kilometers) and took only 20 days to orbit the Earth. Also, one Earth 'day' was about 18 hours long (instead of our 24 hour day). The tides on Earth were also much stronger since the moon was closer to the Earth.

Since the Earth is causing a bulge and accelerating the Moon, that body should be getting closer, but it's in a very slow process of escape. Those figures on spin rates etc differ from this:

When the Days Were Shorter
by Larry Gedney
Alaska Science Forum
Present-day nautilus shells almost invariably show thirty daily growth lines (give or take a couple) between the major partitions, or septa, in their shells. Paleontologists find fewer and fewer growth lines between septa in progressively older fossils. 420 million years ago, when the moon circled the earth once every nine days, the very first nautiloids show only nine growth lines between septa. The moon was closer to the earth and revolved about it faster, and the earth itself was rotating faster on its axis than it is now. The day had only twenty-one hours, and the moon loomed enormous in the sky at less than half its present distance from earth.

Since the hypothesized impact was 4 billion years ago, and by this data, the Moon has acquired more than half its altitude in one-tenth that time, there's no way the Moon originated in Earth orbit.

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