What if the Earth had a 2nd moon?

[Atlas2342]

What if the Earth had a second outer moon like Minmus? What effects would it have on Earth? Also, would its orbit be stable?

 

Edited February 11, 2016 by Atlas2342

[fredinno]

5 minutes ago, Atlas2342 said:

What if the Earth had a second moon like Minmus? What effects would it have on Earth? Also, would its orbit be stable?

 

Please go further. Is it a trojan moon of Luna? A inner moon? Outer Moon?

[Atlas2342]

1 hour ago, fredinno said:

Please go further. Is it a trojan moon of Luna? A inner moon? Outer Moon?

Oops, I meant outer....exactly like the order in the moon system of Kerbin

Edited February 11, 2016 by Atlas2342

[Findthepin1]

It would not be in Earth SOI. Minmus is 4 times as far away as the Mun is to Kerbin. Something 4 lunar distances from Earth wouldn't be in a stable geocentric orbit, if a geocentric orbit at all. It would end up orbiting the sun as a thousand-km-wide Apollo or Aten asteroid/dwarf planet. Basically Charon moved to be a Near Earth Object. My guess is it would be eventually get into a resonance with Earth or Venus, or Jupiter, or collide with something. 

Edited February 11, 2016 by Findthepin1

[Atlas2342]

What if we moved it closer? Disergarding the distance from kerbin to minmus

[Streetwind]

Gravitational interactions with the Moon would probably eject it out of the Earth/Moon system within a few thousand years.

Our moon is unusually large. It loves ejecting things.

 

EDIT: however, it might be possible for a second natural satellite to exist within a somewhat eccentric orbit that's in resonance with the Moon, so that the two continually miss each other. See: Neptune and Pluto.

Edited February 11, 2016 by Streetwind

[Hannu2]

As far as I know there are not other stable orbit around Earth than Moon and its trojans. Minmus would be ejected out from system or crashed to Moon in relatively short time (astronomically). It is also impossible to use artificial satellites as time capsules (except maybe trojans).

[K^2]

I wonder if a resonance along the lines of Janus-Epimetheus one would be possible between our Moon and a smaller moon sharing an orbit. Or would the Moon eject it? You might need the two objects to have similar masses for this resonance to be stable.

[Atlas2342]

If a minmus configuration is impossible a trojan one could work

 

[Spaceception]

The Apollo missions would've been longer as the two superpowers USA/Russia eyed the Earths second Moon as the grand prize

Also, we wouldn't have called the Moon 'the Moon' as we had two.

Plus, history would've been different as old civilizations probably would've eyed the two Moons as feuding gods or something.

[fredinno]

9 hours ago, K^2 said:

I wonder if a resonance along the lines of Janus-Epimetheus one would be possible between our Moon and a smaller moon sharing an orbit. Or would the Moon eject it? You might need the two objects to have similar masses for this resonance to be stable.

Resonances, I think would destabilize due to the motion of the Moon moving away from Earth- and the 2nd moon is too small to stabilize the Moon's orbit.

So the only stable location for a 2nd moon would be a trojan point.

6 hours ago, Spaceception said:

The Apollo missions would've been longer as the two superpowers USA/Russia eyed the Earths second Moon as the grand prize

Also, we wouldn't have called the Moon 'the Moon' as we had two.

Plus, history would've been different as old civilizations probably would've eyed the two Moons as feuding gods or something.

Barely would have mattered. Technically, the Russians won in terms of the importance of their accomplishments, but since the space race's "winner" was the one who landed on the moon, the US would still win, even if the Russians landed on "Minnmus".

Would be especially interesting if the 2nd moon was trojan. "Minnmus would always be "followed", or "chased" by, Luna.

[sevenperforce]

How large of a body could stably orbit the moon?

2 hours ago, fredinno said:

Technically, the Russians won in terms of the importance of their accomplishments, but since the space race's "winner" was the one who landed on the moon, the US would still win, even if the Russians landed on "Minnmus".

The Russians had showy stuff like the first satellite and first manned mission, but the US was first to get some of the really technically important stuff like first EVA, first orbital rendezvous, and other stuff that set them up for the moon shot.

[Bill Phil]

17 minutes ago, sevenperforce said:

How large of a body could stably orbit the moon?

The Russians had showy stuff like the first satellite and first manned mission, but the US was first to get some of the really technically important stuff like first EVA, first orbital rendezvous, and other stuff that set them up for the moon shot.

Well, the Russians had the first EVA. But it wasn't like later EVAs, since there was barely any of the A. The US had to learn the hard way how to effectively execute an EVA, through the suffering of Gene Cernan during one of the many Gemini missions.

[DerekL1963]

3 hours ago, fredinno said:

Technically, the Russians won in terms of the importance of their accomplishments, but since the space race's "winner" was the one who landed on the moon

o.0

The Soviets had some important and showy 'firsts', but by middle of the Gemini program (when we had mastered rendezvous and docking and were starting to get a handle on EVA and the Soviets had neither) the US had pulled ahead and remained there to the end of the Space Race era (the Lunar landing).   They wouldn't even break the "longest total time in space" as well as "longest single time in space" we established during Skylab until 1977 - and it took eleven missions and (IIRC) four or five different stations to accomplish that.

[fredinno]

6 hours ago, sevenperforce said:

How large of a body could stably orbit the moon?

The Russians had showy stuff like the first satellite and first manned mission, but the US was first to get some of the really technically important stuff like first EVA, first orbital rendezvous, and other stuff that set them up for the moon shot.

Nothing can stability orbit the moon because of tiny differences in gravity destabilizing an object. However, an object 100x smaller than the Moon can exist in a trojan point.

5 hours ago, DerekL1963 said:

o.0

The Soviets had some important and showy 'firsts', but by middle of the Gemini program (when we had mastered rendezvous and docking and were starting to get a handle on EVA and the Soviets had neither) the US had pulled ahead and remained there to the end of the Space Race era (the Lunar landing).   They wouldn't even break the "longest total time in space" as well as "longest single time in space" we established during Skylab until 1977 - and it took eleven missions and (IIRC) four or five different stations to accomplish that.

They still did the first space station- and first landing on a extraterrestrial object- first planetary probe, etc.

"Longest time in space" also eventually was taken to the Russians via Mir.

And yes, the space race's winner was determined by who landed men on the moon first, nothing else

[sevenperforce]

1 hour ago, fredinno said:

Nothing can stability orbit the moon because of tiny differences in gravity destabilizing an object. However, an object 100x smaller than the Moon can exist in a trojan point.

I thought the destabilization problem was only for low lunar orbit.

[fredinno]

40 minutes ago, sevenperforce said:

I thought the destabilization problem was only for low lunar orbit.

Yeah it is, but a high orbit is unstable due to the Earth's gravity.

[PacThePhoenix]

The Earth actually does have a second moon... kinda. It's actually a quasi-orbital satellite called 3753 Cruithne. Cruithne isn't really a moon of Earth as it orbits the sun primarily, but it's orbital period is almost exactly 1 year, resulting in the satellite entering the Earth's SOI quite frequently. The Earth also has a Trojan satellite orbiting at L₄ called 2010 TK7 that you can look into as well. Just some things I thought were interesting .

[fredinno]

25 minutes ago, PacThePhoenix said:

The Earth actually does have a second moon... kinda. It's actually a quasi-orbital satellite called 3753 Cruithne. Cruithne isn't really a moon of Earth as it orbits the sun primarily, but it's orbital period is almost exactly 1 year, resulting in the satellite entering the Earth's SOI quite frequently. The Earth also has a Trojan satellite orbiting at L₄ called 2010 TK7 that you can look into as well. Just some things I thought were interesting .

That's not a moon, so it's automatically disqualified. I'm pretty sure it's not in astable orbit either.

[KerbMav]

19 hours ago, Spaceception said:

The Apollo missions would've been longer as the two superpowers USA/Russia eyed the Earths second Moon as the grand prize

Also, we wouldn't have called the Moon 'the Moon' as we had two.

Plus, history would've been different as old civilizations probably would've eyed the two Moons as feuding gods or something.

I like your completely non-physics approach to the question.

[Darnok]

Ceres fits in here Since Moon:Earth radius ratio is about 3/11

same as Ceres:Moon ratio.

[peadar1987]

35 minutes ago, Darnok said:

Ceres fits in here Since Moon:Earth radius ratio is about 3/11

same as Ceres:Moon ratio.

So what is the significance of this?

[Darnok]

42 minutes ago, peadar1987 said:

So what is the significance of this?

Math constant is not some random number, it suggests that we don't live in chaotic environment.

[sevenperforce]

6 hours ago, fredinno said:

Yeah it is, but a high orbit is unstable due to the Earth's gravity.

Too bad.

Are there any metastable figure-eight orbits between Earth and Luna where we could build a semipermanent Earth-Moon transfer space station?

17 minutes ago, Darnok said:

Math constant is not some random number, it suggests that we don't live in chaotic environment.

So because one of the planets in one solar system has a density that makes the ratio of its diameter and the diameter of its primary satellite equal to the ratio of that satellite's diameter to another random object's diameter...suddenly the solar system must be designed by a math enthusiast? Gotta give me a bit more than that.

Now, if all the planets and moons in our solar system had exactly matching ratios of diameter, mass, and orbital periods, then we might have something to investigate.

[Darnok]

1 minute ago, sevenperforce said:

So because one of the planets in one solar system has a density that makes the ratio of its diameter and the diameter of its primary satellite equal to the ratio of that satellite's diameter to another random object's diameter...suddenly the solar system must be designed by a math enthusiast? Gotta give me a bit more than that.

Now, if all the planets and moons in our solar system had exactly matching ratios of diameter, mass, and orbital periods, then we might have something to investigate.

Earth, Moon and Ceres fits this ratio, so it is possible that same even that formed Moon also formed Ceres, but over time Ceres drifted on its current orbit.

They have different ratios because they are build from different elements... as orbital periods check Titius–Bode law.