- #1
stany
- 24
- 0
much difference?
(Wikipedia)[...] this causes the Moon to slowly recede from Earth at the rate of approximately 38 millimetres per year.
dacruick said:how far is the moon away from the earth?
384,403 kilometers is the number i got for an average. 4.7 miles is about 7 kilometers.
would you notice a change of 7 kilometers if you were almost 400 000 kilometers away?
The effect of the impacts is miniscule becaues they make up a tiny fraction of the mass of the moon. 200,000 years is a pretty short time, so it is unlikely that it has changed much in that time.Stanwyck66 said:Is there any way to prove it has been moving away at this exact speed for that long? 38 millimeters a year is barely anything, so wouldn't some of the millions of impacts along the surface influence its direction?
Interesting question, even though, I think, it's based on a misconception. The recession is not an inertial but a friction effect, namely the result of a constant conversion of lunar orbital momentum into tidal effects on Earth. So, counteracting this effect by bombarding the moon with impactors would be not like changing the direction of a rolling car by throwing balls at it, which is tedious but easily doable given enough balls, but like trying to keep the car from eventually stopping due to energy loss, which is much harder in the long run.Stanwyck66 said:Is there any way to prove it has been moving away at this exact speed for that long? 38 millimeters a year is barely anything, so wouldn't some of the millions of impacts along the surface influence its direction?
Scientists use various methods to determine the distance between the Moon and Earth in the past. One method is by studying the geological records and analyzing the impact craters formed by meteorites on the Moon's surface. Another method is by using lunar laser ranging, which measures the current distance between the Moon and Earth and then calculates the average rate at which the Moon has been moving away from Earth.
Yes, the Moon was significantly closer to Earth 200,000 years ago. Based on scientific evidence, it is estimated that the Moon was around 22,000 km closer to Earth than it is today. This distance may not seem like much, but it had a significant impact on Earth's tides and the length of a day.
The Moon's orbit around Earth is not a perfect circle, but rather an elliptical shape. This means that the Moon's distance from Earth varies throughout its orbit. 200,000 years ago, the Moon was at a point in its orbit known as perigee, where it is closest to Earth. Over time, the Moon's orbit has expanded due to the gravitational pull of the Sun, causing it to move further away from Earth.
The closer distance of the Moon had a significant impact on Earth's tides. With the Moon being closer, its gravitational pull on Earth was stronger, causing higher and more frequent tides. This also affected the rotation of Earth, as the Moon's gravity slowed down the planet's rotation, making a day last longer than it does now.
Yes, the Moon will continue to move further away from Earth at a rate of about 3.8 cm per year. This is because of the tidal forces between Earth and the Moon, causing the Moon's orbit to expand. However, the rate at which the Moon moves away from Earth is gradually slowing down, and it is estimated that it will continue to do so for the next few billion years.