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1) As far as I know, in the dinosaurs' days, it took 20 hours for one day and night to pass, which means that the Earth is slowing down!!!
2) As the sun burns and releases its potential energy, does it’s gravitational force weaken??

2006-11-06 04:35:03 · 2 answers · asked by Chris 1 in Science & Mathematics Astronomy & Space

2 answers

Yup, Earth's rotation rate is slowing down. You've always wished for more hours in the day, right? Well, it's happening! Of course, we won't notice a difference in our lifetimes. It should be noted, that our speed around the Sun isn't changing, just our spin rate - as our day becomes longer, there will be fewer days in one year.

This is actually tied in to your previous question - the same thing that slows down Earth's rotation also causes the Moon to get farther and farther away from us. The tidal force from the Moon on Earth creates tidal bulges on Earth. Earth essentially rotates underneath the tidal bulges. There's friction there, so there's a loss in energy. This is manifested by a slower rotation rate for Earth (the same thing happened to the Moon long ago, which is why it always keeps one side facing Earth).

The Sun fuses hydrogen into helium in its core to produce energy via E = mc^2, so the Sun is converting some of its mass into energy. Also the Sun loses some of its mass to the solar wind. So technically the Sun is becoming less massive as time goes on, so its gravitational force must weaken. However, the fraction of mass the Sun loses is so small that we can ignore it. When the Sun dies and sheds its outer layers, then there will be a significant mass loss, but not until then.

2006-11-06 04:45:49 · answer #1 · answered by kris 6 · 0 0

1) Yes the earth's spin is slowing down ever so slowly due to tidal forces the moon puts on earth.

2) Yes the sun loses mass as it gives off energy. In fact each second the sun converts 4 million tons of mass into energy. This would weaken it's gravitational force, although we don't notice it because over the sun's lifetime it will only lose an extremely tiny fraction of it's mass.

2006-11-06 12:49:51 · answer #2 · answered by Roman Soldier 5 · 0 0

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