Mars May Become A Ringed Planet Someday

Megalith

Megalith

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Looks like the Red Planet may be joining Jupiter, Saturn, Uranus, and Neptune in the esteemed ring club.

In a few tens of millions of years, the Red Planet may completely crush its innermost moon, Phobos, and form a ring of rocky debris, according to the new work. Phobos is moving closer to Mars every year, meaning the planet's gravitational pull on the satellite is increasing. Some scientists have theorized that Phobos will eventually collide with Mars, but the new research suggests that the small moon may not last that long.
 
Why can't they do this on earth? I'd trade the moon for a ring any day.
 
01%2Bmonolith_on_martian_moon_phobos.jpg
 
oh wow phd guy thinks something is going to happen that everyone already knows is going to happen.
 
Blown Cap said:
Not at all. Our moon moves farther away from Earth every year.
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That is an interesting point. Looking it up, it sounds like the Moon is being pushed away due to rotational speed of the Earth. But just like the Earth created a tidal lock on the Moon (why we never see the other side), the Moon will do the same to Earth eventually. I wonder what the net balance of this is? Will the rotation of Earth be slowed fast enough to keep the Moon in its grasp?
 
westrock2000 said:
That is an interesting point. Looking it up, it sounds like the Moon is being pushed away due to rotational speed of the Earth. But just like the Earth created a tidal lock on the Moon (why we never see the other side), the Moon will do the same to Earth eventually. I wonder what the net balance of this is? Will the rotation of Earth be slowed fast enough to keep the Moon in its grasp?
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The moon is being pulled away due to the way the tides work, the tidal bulges of Earth are a bit ahead of the Moon's position due to the rotation of the Earth, and this pulls the Moon towards the bulge when gives it more energy which it trades off for orbital energy, i.e. gets further away from Earth.

As to the slowing of the Earth keeping the Moon from fling off, not sure what time frame that is over, i.e. is it within the Sun's life time?
 
sfsuphysics said:
As to the slowing of the Earth keeping the Moon from fling off, not sure what time frame that is over, i.e. is it within the Sun's life time?
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I've seen estimates of 40+ billion years for Earth to become tidally locked to the Moon. It took 4.5 billion years to go from 8 hour to 24 hour days, and the tidal forces involved are decreasing exponentially with distance. Unless something keeps the Earth spinning faster than it should there won't be enough energy to push the Moon away.

Drag from gas escaping the sun during it's red giant phase will bring the moon crashing back down to Earth in another 4.5 billion years if the Sun doesn't just swallow them up altogether.
 
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