Earth without its moon

[Ronnie67]

What would happen if earths moon started to move away and is the earth dependant on the moon, just a question as I watched a program this morning, which stated that the earth would not exist without the moons protection and life as we know it would perish.

[DirkSteele]

The moon already is moving away from the Earth at a rate of approximately 3.8cm per year. Barely noticeable on human timescales but over millennia, it starts to add up.

If the moon moved away from us more rapidly so we could witness the impact over our lifetimes, the tides will be weaker because of the Moon's weaker gravitational pull. The release of tidal energy in Earth's oceans and crust will continue to slow down the Earth’s spin and thus increase the length of the day. Currently it is increasing at a rate of one second every 50,000 years.

And the biggest disappointment.....No more total solar eclipses! Only annular which are nice, but not as good as total.

As for why all life would perish?? I am curious as to the reasoning. My guess is the implication that the moon is acting as some kind of shield to large meteor impacts, though I find that hard to give much credit to. Jupiter sweeps up more impactors (such as schumacher levy 9) though also helps to fling some into the inner solar system.

Clear skies,

[sologuitarist61]

What would happen if earths moon started to move away and is the earth dependant on the moon, just a question as I watched a program this morning, which stated that the earth would not exist without the moons protection and life as we know it would perish.

I can think of no reason that life would perish if the moon were to move away from us. As Dirk has said, there is the possibility that it might shield us any major meteor impact that may be coming in from the direction, but that is only a possibility.

[Qualia]

If the moon gradually disappeared, then I imagine the Earth would spin faster. If that happened perhaps there would be bigger winds and storms, and as the day and night sped up, animal hunting and sleeping cycles and plants' photosynthesis would have to adapt or perish. Dividing the months up into 12 units would become a matter of curious tradition. I imagine Earth's precession would slow down and that perhaps its angled tilt would change significantly. If that were to be the case, we could end up with completely different seasons, or in some places there might not even be differing seasons to count and I guess herein, Milankovitvh's theory of Earth's movement and cycles would help inform us on the effect that could have. No doubt life in itself would adapt to such changes, life would continue but perhaps not always in the form we know it today.

[JamesF]

I have a feeling that one of the reasons stated is that the Moon helps stabilise the natural "wobble" of the Earth's axis. Without that effect and the moderation of the seasons that results life might be considerably more difficult. It's also the case that the Moon is heavily linked into our ecosystem. It works as a trigger for reproduction for all sorts of creatures that could have knock-on effects way up the food chain if they failed to adapt to its disappearance.

I *think* there is a view that we have evolved the way we have because the moon exists. The tides create all sorts of evolutionary niches that may not have developed otherwise, and those led to further new mutations. It's possible therefore that if the moon had never been present that we would not have evolved in our present form, or perhaps would not have evolved at all.

James

[sologuitarist61]

You are quite right James, I had forgotten about that.

[Rihard]

What would happen if earths moon started to move away and is the earth dependant on the moon, just a question as I watched a program this morning, which stated that the earth would not exist without the moons protection and life as we know it would perish.

Good question

It seems that the lack of tidal forces would cause a rise in the sea level everywhere, it should also impact the rotational axis of earth,

stopping the seasonal routines and causing severe temperatures changes and disasters.

It would become a colder place with less marked seasonal changes.

The earth's spin will also slow down, so that one side of the earth would be exposed for much longer to the solar radiation,

and the other side would be exposed to the night much longer, causing much more extreme weather conditions, with big

amounts of water steam being released from the sea, this would cause at first a greenhouse effect, more powerful streams,

mixing up with the cold in the night side.

Skies would darken and less heat would pass through the thick water clouds, eventually cooling down the whole planet's environment.

I imagine that our planet's weather would become both as violent as on Venus and as cold as on Mars, eventually settling on a

new endless ice age.

As suggested in other replies (especially by James) , life might have evolved this way thanks to the conditions we live in, so this would affect the whole

chain for several reasons, with a lot animals unable to find their way, other ones might be unable to reproduce themselves and others could not survive at all (like reptiles who need an external heat source to heat up their body).

Some other species might find a way to adapt to the new conditions, but many others will be just get caught and perish.

The planet might also be subject to an higher amount of meteorites strikes and different things might happen depending on which

way would the moon escape from Earth's orbit. If the moon was to be torn out of Earth's orbit quickly, like by a giant meteorite or

something like that, that would cause a huge mess, a slower departure would be less painful and drastic.

When the Moon will be far away from Earth (as it is already slowly moving away) things will be very different for sure.

The most terrible thing is that the world would be a less romantic place without the Moon

[Ronnie67]

Well put James and TziuRiky, two well put answers , the program was well worth watching

[Rihard]

Well put James and TziuRiky, two well put answers , the program was well worth watching

Did you have any doubt?

"They said it on TV, so it Must be true!"

[Ronnie67]

Yeh, I did have my doubt, that is why I made a post on here to clear my punie mind

[TheNorthernMonkey]

Why would the earths speed of rotation slow down with no moon? The angular momentum of system is always preserved, so if the moon could be magically removed from the earth moon system, the earths rotation would remain constant from that point

[Rihard]

Why would the earths speed of rotation slow down with no moon? The angular momentum of system is always preserved, so if the moon could be magically removed from the earth moon system, the earths rotation would remain constant from that point

I thought that without Moon the tilt of Earth's axis might easily change due to the Sun's gravitational pull, so that the planet would be more subject to the Sun's tidal forces, slowing down its rotation and eventually getting tidal locked to the Sun, like Venus and Mercury.

[Naemeth]

I thought that without Moon the tilt of Earth's axis might easily change due to the Sun's gravitational pull, so that the planet would be more subject to the Sun's tidal forces, slowing down its rotation and eventually getting tidal locked to the Sun, like Venus and Mercury.

Mercury isn't tidally locked to the Sun though, it is in a 3:2 orbital resonance with it. I don't think it's been proved that Venus is tidally locked with the Sun, but there is a lot we don't know about Venus .

[TheNorthernMonkey]

I thought that without Moon the tilt of Earth's axis might easily change due to the Sun's gravitational pull, so that the planet would be more subject to the Sun's tidal forces, slowing down its rotation and eventually getting tidal locked to the Sun, like Venus and Mercury.

Angular momentum of a system is always preserved. In order to remove rotational angular momentum from the earth, the total angular momentum of the earth sun system would have to increase somewhere else to maintan equilibrium,. If the earth's rotation speed were to reduce, then the orbital velocity would increase, with a consequental increase in orbital radius, terefore maintaining angular momentum. It is likely that something similar happened when the moon became tidally locked.

[symesie04]

Surely the moon stabilises the earths wobble. Without the moon seasons would become both unpredictable and extreme, such extremes are not good for life.

The moon obviously is responsible for tidal generation, tides are a major part of current and temperature distribution throughout or oceans. Without currents our oceans would be far less populated with life than its current level. There is actually a whole list of reasons why no moon would be bad for life on earth, and as already pointed out its certainly questionable if life would have ever evolved without it.

[Rihard]

Mercury isn't tidally locked to the Sun though, it is in a 3:2 orbital resonance with it. I don't think it's been proved that Venus is tidally locked with the Sun, but there is a lot we don't know about Venus .

Angular momentum of a system is always preserved. In order to remove rotational angular momentum from the earth, the total angular momentum of the earth sun system would have to increase somewhere else to maintan equilibrium,. If the earth's rotation speed were to reduce, then the orbital velocity would increase, with a consequental increase in orbital radius, terefore maintaining angular momentum. It is likely that something similar happened when the moon became tidally locked.

Thanks both to pointing that out, especially about Venus and Mercury not being actually tidally locked as I always thought