Invent a second moon for Earth

[Kerbface]

Where is it? What features does it have? How did it become a moon? How does it affect Earth? How does it affect humanity?

[Apollo1391]

Well I think it will be along the lines of a captured asteroid it will probably not affect earth and you can see it as a small grey dot in the sky

[Kerbface]

You have creative freedom by the way, doesn't have to be the most likely thing.

[Omicron314]

Truth is stranger than the strangest fiction.

There is an asteroid called 3753 Cruithne that orbits the Sun in a 1 : 1 resonance with the Earth, in a bean- or horseshoe-shaped orbit. It can sometimes intersect Earth, but it never remains, and this is not qualified as a moon. But still, it's pretty neat.

Wikipedia page: http://en.m.wikipedia.org/wiki/3753_Cruithne

[Themohawkninja]

Something like Minmus may be too large to work, as it would mess up the tides. Some tiny captured asteroids would probably be the most likely candidate as far as not disturbing our current state goes.

[Kryten]

We have actually had a 'tiny captured asteroid' second moon-and there probably have been others we've missed. It lasted less than a year due to various gravitational effects, particularly from the Moon, and any others aren't likely to last much longer.

[XilentDude]

Something like Minmus may be too large to work, as it would mess up the tides. Some tiny captured asteroids would probably be the most likely candidate as far as not disturbing our current state goes.

Moon's equatorial radius is 1200 kilometers. Earth's equatorial radius is 6000 kilometers. Kerbin is 600 kilometers, Mun is 200 and Minmus is 60. If we would have a Minmus-like moon at that distance ( probably twice the Moon's orbit ), I don't really think that it would affect us. Even if it had 600 kilometers. Correct me if I'm wrong.

[Whirligig Girl]

When I was a kid, I watched over and over and over a documentary called "If We Had No Moon" (narrated by Patrick Stewart! although I didn't even care about Star Trek when I was a kid) If the Theia (Called "Orpheus" in the documentary) impact happened differently, we could have had two moons... For a few million years. a moon formed from a single Theia impact can not create two stable moons. One is either flung out, collides with earth, or collides with the other moon.

But, it's possible to imagine that two different impacts with different parameters occurred, which might create two stable moons if they are in a good resonance that doesn't flung each other out. It's possible the Apollo Missions sent spacecraft to the closest moon, then a totally different program sent missions to the other moon. Even more fascinating is if the Apollo missions visited each moon in the same mission, or perhaps there were steps, like Apollo 11 landed on Moon1 and Apollo 13 or so landed on Moon2.

The most fascinating idea were if two bodies capable of sustaining intelligent life in the same orbital system. Imagine if the Moon really did have oceans. While Galileo is pointing his telescope at the Moon, Neil Moonstrong is climbing aboard the Command Module to land on Earth with an Earth Excursion Module. You'd only really need a Saturn IB Rocket to get to Earth, as de-orbiting from the Moon would be much easier than transfering to the Moon. I am assuming for the purposes of a thought experiment that both planets have humans on them, and similar histories.

[chri]

I personally enjoy the fact that we have only one Moon...THE Moon..if we had two I think Moon 1 would still be considered the most important...but it wouldn't be the same thing..it wouldn't be that grey circle in the sky that made us dream for centuries and millennia...it wouldn't have the same..taste and mystery..if there were more than one

[Themohawkninja]

Moon's equatorial radius is 1200 kilometers. Earth's equatorial radius is 6000 kilometers. Kerbin is 600 kilometers, Mun is 200 and Minmus is 60. If we would have a Minmus-like moon at that distance ( probably twice the Moon's orbit ), I don't really think that it would affect us. Even if it had 600 kilometers. Correct me if I'm wrong.

If I knew how to do tidal force calculations, I'd find out one way or the other... but I don't .

[andrewas]

Scaling up by ten to get it into scale with the rest of the real universe, its half the radius of the moon, so its (very roughly) one-eighth the mass. Divide by the cube of the distance between the hypothetical moon and Earth, which is twice the distance between the moon and Earth, and you get a total force of 1/64th the force exerted by the moon on Earth.

[Motokid600]

I wish the Earth was the second moon of a gas giant.

[Seret]

You have creative freedom by the way, doesn't have to be the most likely thing.

Well in that case, let's have something useful.

I'd like to see a moon made up of all the discarded rocket stages, broken satellites and general orbital bric-a-brac. It could be inhabited by a friendly group of moon wombles who like to tidy up the mess we humans leave whirling around the planet.

[magnemoe]

I wish the Earth was the second moon of a gas giant.

Why, yes the sky would be interesting on the inside but the days would probably be long as it would be tidal locked, one serious downside even if it has low radiation would be that you would get far more asteroid impacts. The best part is that traveling to the other moons would be easy.

For extra fun add two moons with life.