What would happen if the moon disappeared?

[wacki]

I was reading an article about the asteroid that at one point was thought might hit in 2029 (and now they say won't) and it also said that they ruled out a moon impact.

Which got me wondering. What would happen if an asteroid smashed into the moon and let's say it hits in a Deathstar-like manner and completely shatters the moon into tiny pieces, none of which have any significant earth impact. So, the only effect to consider is the fact that there is no longer a moon.

What happens then?

 

[sao123]

none of which have any significant earth impact.

I dont think this is a reasonable constraint. If something large enough collided with the moon to completely shatter it, a significant portion of that debris would definately rain down on earth in some form.

 

[Ice Czar]

well for starters the ocean tides
and the moon exerts a powerful influnece on terrestrial life
possibly on plate tectonics as well
the lack of a moon would to a certain extent mean that on average we would get more solar wind as well

it maybe that the moon has an effect on the Electromagnetic motor that is the earth core
it might cool faster with it gone

 

[wacki]

Originally posted by: sao123

none of which have any significant earth impact.

I dont think this is a reasonable constraint. If something large enough collided with the moon to completely shatter it, a significant portion of that debris would definately rain down on earth in some form.

If the moon was on the far side and was struck on the side facing us and in a direction away from the planet, I think it may be possible. Not very likely, but possible. A friend asked me this question, so I'm just curious because I don't know.

 

[Zebo]

we would die in short order due to atmospheric pressure... see venus.

 

[wacki]

What does the moon have to do with atmospheric pressure?

 

[wacki]

http://lasp.colorado.edu/~colw...-s99/Mar16lecture.html

# Earth's atmospheric pressure of 1 bar is due to an atmosphere composed mostly of N2 (nitrogen) and O2 (oxygen) molecules.
# Venus's atmospheric surface pressure is 90 bar, and its atmosphere is mostly CO2.

I think you might be wrong

 

[rgwalt]

Originally posted by: Zebo
we would die in short order due to atmospheric pressure... see venus.

The moon doesn't skim off too much atmosphere any more. In the early days of the earth, it was important. I doubt we would miss it much, with the exception of the problems caused by not having tides.

R

 

[IEC]

Originally posted by: Ice Czar
well for starters the ocean tides
and the moon exerts a powerful influnece on terrestrial life
possibly on plate tectonics as well
the lack of a moon would to a certain extent mean that on average we would get more solar wind as well

it maybe that the moon has an effect on the Electromagnetic motor that is the earth core
it might cool faster with it gone

No moon = heckuva lot more difficult to survive here on earth...

 

[DrPizza]

Originally posted by: wacki

Originally posted by: sao123

none of which have any significant earth impact.

I dont think this is a reasonable constraint. If something large enough collided with the moon to completely shatter it, a significant portion of that debris would definately rain down on earth in some form.

If the moon was on the far side and was struck on the side facing us and in a direction away from the planet, I think it may be possible. Not very likely, but possible. A friend asked me this question, so I'm just curious because I don't know.

What on earth (no pun intended) do you mean by "the moon was on the far side"??

 

[Tab]

Originally posted by: ariafrost

Originally posted by: Ice Czar
well for starters the ocean tides
and the moon exerts a powerful influnece on terrestrial life
possibly on plate tectonics as well
the lack of a moon would to a certain extent mean that on average we would get more solar wind as well

it maybe that the moon has an effect on the Electromagnetic motor that is the earth core
it might cool faster with it gone

No moon = heckuva lot more difficult to survive here on earth...

Why?

It'd be pitch dark at night, what else?

 

[Gibsons]

Lack of tides would wreck a few ecosystems, but life would continue. Some nocturnal animals might go extinct from lack of moonlight. Tidal dams would be useless.

But there's no way the moon gets shattered without enormous amounts of debris hitting the earth. Better to invoke aliens with tractor beams dragging it away.

 

[BW86]

We would have very dark nights

 

[jagec]

well, it would solve the werewolf problem for one...

 

[wacki]

What on earth (no pun intended) do you mean by "the moon was on the far side"??

From the asteroids point of view.

 

[wacki]

Originally posted by: rgwalt

The moon doesn't skim off too much atmosphere any more. In the early days of the earth, it was important.
R

I tried googling, but I couldn't find any links about this.

 

[Vee]

The moon stabilizes the Earths rotation axis.

Sufficient moons are now considered a requirement for development and sustainment of life on a planet.
Without the moon, Earth would wobble now and then. This would expose some of its surface to the sun for like half a year, continuosly. Then it would have night for half a year.

Temperatures would be what you can imagine, or worse, killing us all. Even if they weren't, all plant life would still die.

 

[Gibsons]

The moon stabilizes the Earths rotation axis.

You sure about that? Afaik, Mercury and Venus have stable rotations without a moon.

Sufficient moons are now considered a requirement for development and sustainment of life on a planet.

cite for this?

Without the moon, Earth would wobble now and then. This would expose some of its surface to the sun for like half a year, continuosly. Then it would have night for half a year.

Where does the energy come from to make it wobble?

 

[sao123]

Where does the energy come from to make it wobble?

The center of rotation (center of mass) between the earth and moon does not lie at the central point of the earth, and indeed it may lie not even inside the earth itself. With the removal of the moons mass, and the rotational point being where it currently is, would definately cause a wobble in the earths motion.

 

[artikk]

Originally posted by: jagec
well, it would solve the werewolf problem for one...

Hey I wanted to say that.:|

 

[silverpig]

Originally posted by: sao123

Where does the energy come from to make it wobble?

The center of rotation (center of mass) between the earth and moon does not lie at the central point of the earth, and indeed it may lie not even inside the earth itself. With the removal of the moons mass, and the rotational point being where it currently is, would definately cause a wobble in the earths motion.

Without the moon the centre of mass of the earth/moon system would be the centre of the earth...

There will still be a precession of the earth's rotation, but we have that already anyways.

 

[JustAnAverageGuy]

Originally posted by: DrPizza

Originally posted by: wacki
If the moon was on the far side and was struck on the side facing us and in a direction away from the planet, I think it may be possible. Not very likely, but possible. A friend asked me this question, so I'm just curious because I don't know.

What on earth (no pun intended) do you mean by "the moon was on the far side"??

Perhaps something similar to this?

Drawing not to scale. Line does not take into account gravitational effects. Diagram for illustrative purposes only.

 

[sao123]

Without the moon the centre of mass of the earth/moon system would be the centre of the earth...

The change in centre of mass would not change instantenously. The forces would begin to act in a manner according to the speed of light, but it will take time for the new balance to occur completely (days, maybe weeks).
If the earth and moon just suddenly let go of each other (as if a string holding them together was cut) they would fly apart in a straight line as they continue. This same phenomenon would occur if the moon just disappeared and could cause the solar orbit of earth to change its radius by some small vector (+ or -) depending on the moons position relative to the earth and sun when this disappearance occurred.
.

 

[Safeway]

No effect except visual light.

Since you people like making things up, what would happen if you replaced the sun with a 1 solar mass blackhole? (I know the answer)

 

[Safeway]

Originally posted by: sao123

Without the moon the centre of mass of the earth/moon system would be the centre of the earth...

The change in centre of mass would not change instantenously. The forces would begin to act in a manner according to the speed of light, but it will take time for the new balance to occur completely (days, maybe weeks).
If the earth and moon just suddenly let go of each other (as if a string holding them together was cut) they would fly apart in a straight line as they continue. This same phenomenon would occur if the moon just disappeared and could cause the solar orbit of earth to change its radius by some small vector (+ or -) depending on the moons position relative to the earth and sun when this disappearance occurred.
.

"Speed of light" in reference to moon-Earth distance is irrelevant. For all practical purposes, it's instantenous. The earth and moon flying away from each other bit? In order for that to happen, the gravitational attract between all matter would have to cease. If it acted as you describe, the moon + earth would "fly away" proportional to their respective masses. The moon would get caught by the suns gravity and either orbit or hit the sun.