# If the moon was twice as far away from the earth as it actually is, how would tides b

1. Feb 18, 2008

### kay89

"If the moon was twice as far away from the earth as it actually is, how would tides be effected?"

Thanks!

2. Feb 18, 2008

### vincentm

Tides would reduce, i'm thinking.

3. Feb 18, 2008

### cristo

Staff Emeritus
I think you're correct.

Kay, what sort of answer are you looking for? Will "they will reduce" suffice, or are you looking for more of an quantitative explanation?

4. Feb 18, 2008

### kay89

Cristo, I am definately looking for an answer that provides some meaning. This is part of a homework assignment and I am stumped!

5. Feb 18, 2008

### Kurdt

Staff Emeritus
If its homework related we kindly request that you show your attempt at this question before receiving any help.

6. Feb 18, 2008

### ray b

2 squared is = to 4

7. Feb 18, 2008

### Staff: Mentor

That's fine, but the tides do not vary with the square (or even the inverse square) of distance.

8. Feb 18, 2008

### Staff: Mentor

To help answer both the OP and explain my response to ray b, consider the Sun. The Sun is 27 million times more massive than is the Moon and is about 389 further times distant from the Earth than is the Moon. Yet the tidal forces caused by the Sun are slightly less than half those caused by the Moon.

9. Feb 19, 2008

### ray b

along with alot of other stuff works on inverse square
which is what the hint was aimed at
true thats for a point
and tides are complex with many factors
but that should be close to the correct answer

10. Feb 19, 2008

### kamerling

No. Try it for the sun.

11. Feb 19, 2008

### Staff: Mentor

Not anywhere close to the correct answer. Look at the numbers from my previous post: The Sun is 27 million times more massive than is the Moon and is about 389 further times distant from the Earth than is the Moon. If tidal effects were indeed an inverse square relationship, solar tides would be 178 times larger than lunar tides. This is not the case. Solar tides are less than half the size of lunar tides. Tidal effects are not an inverse square relationship.

12. Oct 18, 2010

### nickthrop101

Re: If the moon was twice as far away from the earth as it actually is, how would tid

the tide would reduce by half, as it is twice the difference away :D