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Lets assume we humankind can not only wormhole the spacecraft, but planets and moons. So, what would've happened to Earth if we pulled Europa to be Mars's third moon? What if we moved Titan in between Mars and Jupiter,setting it to orbit the Sun just like a planet. What would've happened to us? I'm also interested on how many of those small moons we can make to orbit Mars, Earth and/or Titan? Such as Iapetus,Rhea,Enceladus,Tethys and Dione. Please respond, it seem like no one on internet has an even theory on that.

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    $\begingroup$ Might be better for world building or Astronomy. $\endgroup$ – userLTK Jun 17 '15 at 4:19
  • $\begingroup$ What's the actual question you want answered? How many moons we can put in orbit around Mars? $\endgroup$ – Tim B Jun 17 '15 at 8:19
  • $\begingroup$ How would such actions affect our planet? $\endgroup$ – user10476 Jun 17 '15 at 12:11
  • $\begingroup$ @UnduLationer Simply "how would it affect" is too broad a topic for us to cover - we can cover the effects on something more specific, like climate or gravity, but not the whole planet. $\endgroup$ – ArtOfCode Jun 17 '15 at 15:52
  • $\begingroup$ Climate and tides. If there are something extra bad comes with it. I'll be eager to know. $\endgroup$ – user10476 Jun 17 '15 at 15:56
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I'm interested the answers to some of the questions you didn't ask, so I'll answer your and then provide my additional information. Sorry, it's my price for admission :)

What Happens to Earth?
Nothing much.

The force of gravity wanes as the inverse square. The bodies that you mentioned (Titan, Europa, and the smaller moons of Saturn) just aren't very massive and aren't very close.

You mentioned putting Europa in orbit around Mars and this is the closest object you mentioned. Let's look at the mass and gravity of several other objects currently in our Solar System.

$$\begin{array}{|c|c|c|c|c|} \hline \text{Body} & \text{Mass (kg)} & \text{Gravity (g)} & \text{Temperature (K)}^3 & \text{Lowest mass gas it can retain}^1 \\\hline \text{Earth} & 6 \cdot 10^{24} & 1.0 & 254 & \text{Methane} \\\hline \text{Mars} & 6 \cdot 10^{23} & 0.38 & 210 & \text{Carbon Dioxide, Nitrogen}^2 \\\hline \text{Ganymede} & 1.5 \cdot 10^{23} & 0.15 & 106 & \text{None, Argon}^2 \\\hline \text{Titan} & 1.3 \cdot 10^{23} & 0.14 & 85 & \text{Nitrogen}^2 \\\hline \text{Moon} & 7 \cdot 10^{22} & 0.17 & 269 & \text{None, Iodine}^2 \\\hline \text{Europa} & 5 \cdot 10^{22} & 0.13 & 93 & \text{None, Sulfur Dioxide}^2 \\\hline \end{array} $$

  1. This uses Jean's Escape mechanism plus some fudge factor for gas longevity on the planet.
  2. Gasses with this possess a long resident half-life on the body but will leak over billions of years.
  3. This temperature is calculated using geometric albedo and the radiative heat transfer equations and can only be used to calculate surface temperature not the temperature of the upper atmosphere. It is not the known surface temperature of these bodies but is a relative comparator of their temperatures.

Since gravity scales linearly with mass but as the inverse square of distance, if you move Ganymede to Mars' orbit, you'll see a gravitational force less than $ \frac {1}{4} $ of Mars. Other bodies have less mass and would have less influence. Moving any of these bodies to a location further away from Mars' orbit would have a much smaller effect.

Tidal forces would be even smaller since those forces scale as the inverse cube of distance and can safely be ignored.

What Happens to the Moved Body
I think this is the more interesting question :)

What this chart shows is that the Moon, Ganymede, Titan, and Europa all possessing similar surface gravity; but only Titan can retain atmospheric gasses. This has to do entirely with its surface temperature.

If you warm Titan by even 10-15 K, it will begin to lose its atmosphere. If you move these bodies closer to the Sun, none of them would could retain an atmosphere. If you move them inside the "Snow Line", then they'll start losing their water ice to sublimation.

Solar System Snow / Frost Line
Solar System Snow / Frost Line

Basically, you wouldn't get any inhabitable real estate by moving these bodies around. In a SE World Builder answer, I posited that you could get more inhabitable real estate by playing Solar System billiards but the bodies you need to use are Mercury, Venus, and Mars.

Unfortunately, even in very chilly but still livable regions of the Solar System you just can't get Mars and Mercury to hold onto our atmospheric gasses for billions of years. But they will hold them for millions perhaps hundreds of millions of years and that's probably good enough for Humanity.

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  • $\begingroup$ I wasn't seeing this as inhabitable at first, but a source gathering sight. Which sized moon will be the safest to orbit our planet and how far (roughly) it must be located from the Moon? I know that our satellite keeps moving away tiny bit year by year. Just to make sure that it will be there till we gather all data on undiscovered elements, use full capacity of water, finishing of with a high tech too dangerous for Earth lab on the surface. PS: assuming that we can wormhole safe water from the moons onto Earth. $\endgroup$ – user10476 Jun 17 '15 at 16:03
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    $\begingroup$ physicsforums.com/threads/… a user said otherwise- You will end up with unpredictable chaotic orbits which depend on exactly where the objects are moved to and what initial momentum they have upon arrival. Similarly, the sudden disappearance of a moon from orbiting it's original parent planet would have unpredictable consequences for the rest moons orbiting the parent, as the orbital periods of different moons orbiting a parent planet is often phase locked.. $\endgroup$ – user10476 Jun 17 '15 at 16:11
  • $\begingroup$ I plan to add this to my answer later but @UnduLationer is correct. N-body problems don't have analytical solutions except for special cases. However, some combinations are more unstable than others and we might be able to propose plausible answers. Just take them with a grain of salt, because short of running a detailed simulation we just don't know what the answer will be. $\endgroup$ – Jim2B Jun 18 '15 at 1:11
  • $\begingroup$ Reading this I just realized that "inhabitable" means "habitable". What a country! $\endgroup$ – xDaizu Jul 21 '16 at 11:30
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Lets assume we humankind can not only wormhole the spacecraft, but planets and moons.

Well, wormholes might not even be possible, so that part isn't answerable, but the rest of it is, cause planets/moons can be moved.

So, what would've happened to Earth if we pulled Europa to be Mars's third moon?

There's no reason why Mars couldn't have a 3rd moon, especially since it's 2 moons are very small. Moons interact with each other gravitationally so a 3rd moon on Mars, depending on it's size and distance form Mars, it might affect the orbits, gradually pulling the 2 little moons into different orbits, but that would take some time.

What if we moved Titan in between Mars and Jupiter,setting it to orbit the Sun just like a planet. What would've happened to us?

in the putting Titan between Mars and Jupiter - there would be no effect on earth other than 1 more visible planet in the night sky (might be pretty dim depending on where in that orbit - there's a fair bit of difference between Mars & Jupiter).

One potential issue with Titan in an orbit there, is it might tug on some asteroids from the asteroid belt - perhaps sending a few towards earth. So, it's probably not something we'd want to do, unless we had a fool-proof asteroid defense. We'd have to do this with care if it was done.

I'm also interested on how many of those small moons we can make to orbit Mars, Earth and/or Titan? Such as Iapetus,Rhea,Enceladus,Tethys and Dione. Please respond, it seem like no one on internet has an even theory on that.

Those moons aren't exactly "small" - Iapetus & Rhea are roughly 1/2 the diameter of the moon. Tethys and Dione about 1/3rd the moon's radius - so "small" is relative, especially compared to Mars or "planet" titan. Compared to Titan, those moons would be downright huge.

There's no reason why Mars or "Planet" Titan could have a good sized moon like one of the 4 you mention. Now, when you ask "how many" that's more complicated. Look up the N-Body problem - that applies to Moons too, to an extent.

Jupiter has a lot of moons because it's so large and there's not that much close to, so it's like a Moon Magnet, same with Saturn, Uranus and Neptune.

Also, Jupiter's close and large moons are in orbital resonance with each other, which increases stability. Mars, Earth and "Planet" Titan would have a much harder time holding onto a few moons and if you're looking for long term stability - many millions of years, you might want to limit it to one fairly good sized moon for each planet. I'm not clear what would happen if the earth had 2 good sized moons - maybe they could be stable, but moons of that size, 2 might be the limit, and perhaps just 1, but it depends on how long you want them stable and the precise math is very hard.

Now if you don't care about stability - then, dozens - easy, but they would wreck havoc on each other's orbits.

Edit - to answer your comments.

Oh snap I meant Europa not Aurora, oh well... Yep I know that currently we don't own much of technology to wormhole or wrap-drive. There are many scientists state that the surface of Titan is the most advanced in terms of possible life(not including Earth). I'm interested in this cause, if we moved those filled with ice moons closer to the sun, we might use our flaming torch to melt it down. If we at first, travel them through portal like structures next to Venus. We can heat it up, so it melts faster for calculated time and then send it back towards Mars.

Moving Europa in an orbit around Mars doesn't change the answer much. It wouldn't affect Mars other than giving Mars a pretty moon and it wouldn't affect Earth at all. It could effect Mars' 2 little moons, at least pulling probobly the farther out of the 2, spiraling into Europa or perhaps out away from Mars.

But, doing this would affect Europa (I agree with Jim2B's answer). There's also a problem with melting Europa, in that, if you get the ice on it's surface hot enough to melt, the first thing it would do is evaporate and once evaporated (basically moon sized and less weight than the moon), it could lose some of it's atmosphere to space.

I don't know how much of an atmosphere Europa would generate if it was close enough to the sun to melt - it depends on how much gas is trapped in it's ice, there might be a fair amount, enough for an atmosphere, but with it's low gravity (a bit less than the moon, maybe 14% of Earth's gravity), so holding onto it's atmosphere long term becomes a problem if it's close enough to the sun to melt.

363,104 km is from the center of Earth to the center of Moon. Which sized moon will be the safest to orbit our planet and how far (roughly) it must be located from the Moon? I know that our satellite keeps moving away tiny bit year by year.

I'm not smart enough to say what would be the most stable, but I think it's safe to say that with the Earth/Moon/Sun system, there is no long term stable 2nd part.

You can look at L4 and L5 of the Moon, but neither of those are stable because the sun is too close and it's too big an influence on the Moon's orbit.

And you can't really go too far past the moon, cause anywhere too much over 500,000 KM from the earth and the orbit would be dangerously unstable. Also, an orbit that far out would be influenced by the Moon almost as much as the earth, so you'd probobly have to go for an inside the moon for a 2nd orbit - even there, the 2 moons would interact, but you'd probobly have the longest stability.

(more on Hill Sphere and it touches on L4 and L5 here) https://en.wikipedia.org/wiki/Hill_sphere

Also, I liked this article on what would happen if the Earth had 2 moons: http://www.universetoday.com/92148/what-if-the-earth-had-two-moons/

Now, you might get some stability with an orbital resonance, 2nd moon inside the first - maybe. This is where I don't have the Math to say how stable it would be. Just cause something works for Jupiter (which is HUGE) doesn't mean it would work around the earth, 1/300th the mass and some 5 times close to the sun, so 25 times more solar tidal forces. . . . but, orbital resonance on Jupiter: http://www.planetary.org/multimedia/space-images/charts/orbital-resonances-of-galilean-moons.html - so, you might get some stability with a 2:1, 3:1 or 4:1 orbital resonance with the moon - maybe. the distance ratio to a 2:1 orbital resonance is about 63% - so we're talking 63%, 48% or 40% the distance of the Moon from the earth - as possible sweet spots. (take the whole number to the power of 2/3) and as I said - I have no idea if that would actually work around the earth - Jupiter's a whole different ballgame.

Other options would be much closer, inside a geosynchronous orbit where the inner moon would actually be pulled towards the earth, not away. That would have the problem that the moon would eventually crash into the earth - so, I wouldn't want to do that, but it could provide some temporary stability, but also, of even the smallest of the moons you mentioned, a Geosynchronus orbit is some 10-11 times closer than the moon - and we wouldn't want it that close. The tides alone would be a big problem and it might crash into the earth in a few million years or so, perhaps less.

Bottom line, there's no "stable" orbit for a 2nd moon around Earth or Mars - that I can see, but if we have the ability to move a moon, we could probobly keep it in orbit using the same technology.

Just to make sure that it will be there till we gather all data on undiscovered elements, use full capacity of water, finishing of with a high tech too dangerous for Earth lab on the surface.

OK, here, you've lost me. There are no undiscovered elements on any of these moons and Europa for example has like 3 pacific oceans of water - how much water do you need? If you want to turn Mars into a world with abundant water, sure, maybe you put Europa into Orbit around it and gradually siphon off it's water onto Mars' surface, but outside of creating an entire ocean on Mars or our moon as another possible example, I'm not sure what we would use that much water for.

In either case, most anything could be researched by leaving the moons where they are, and if they're going to do dangerous research - just use a dead asteroid, or even use the moon - don't use Europa (water) or Titan (atmosphere) as those 2 might be long term useful for what already exists there.

Though I gotta admit, melting Europa does sound kind of cool, as long as there's no life there. If there is life on it, it might not be ethical, or . . . if done slowly enough, it might inspire evolution.

anyway, it's been pointed out in questions I've asked that trying to build another livable planet might not be the most effective method of creating space habitats when smaller bodies might work more efficiently and there's a lot more of them. Drill inside any asteroid belt or Kuiper Belt object and build a habitat and you'd have everything you need. The frozen ice on the outside could provide a protective barrier from radiation, heat the inside using fusion - all the water and oxygen and energy you'd need could be taken from the icy body.

(too long?)

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  • $\begingroup$ Oh snap I meant Europa not Aurora, oh well... Yep I know that currently we don't own much of technology to wormhole or wrap-drive. There are many scientists state that the surface of Titan is the most advanced in terms of possible life(not including Earth). I'm interested in this cause, if we moved those filled with ice moons closer to the sun, we might use our flaming torch to melt it down. If we at first, travel them through portal like structures next to Venus. We can heat it up, so it melts faster for calculated time and then send it back towards Mars. $\endgroup$ – user10476 Jun 17 '15 at 6:09
  • $\begingroup$ 363,104 km is from the center of Earth to the center of Moon. Which sized moon will be the safest to orbit our planet and how far (roughly) it must be located from the Moon? I know that our satellite keeps moving away tiny bit year by year. Just to make sure that it will be there till we gather all data on undiscovered elements, use full capacity of water, finishing of with a high tech too dangerous for Earth lab on the surface. $\endgroup$ – user10476 Jun 17 '15 at 6:23
  • $\begingroup$ Incredible, just incredible, such cutting edge speculation,loving it. I meant using high tech labs at the time when there is nothing left to gather from those smaller satellites of Saturn. I'm speechless... $\endgroup$ – user10476 Jun 18 '15 at 2:18
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You'd need more than a wormhole - you'd also need a way to generate speed to keep this moon from dropping directly into the sun.

Planets in the outer solar system are moving much slower than required for a stable orbit. Since nothing in a wormhole requires it to generate angular momentum, it would keep its original momentum. For a planet or body in orbit around the sun, the move would cause it to drop into the sun, or an extremely eccentric orbit that approaches the sun very closely at aphelion.

A moon already in orbit around a massive gas giant might have the reverse problem - depending how you snatched it out of orbit, it might be moving too fast and have an outbound eccentric orbit or even a cometary one.

Moving planets like spaceships needs more than a wormhole, it needs cosmic engines to steer the planets about, or at least nudge them into close approaches to other planets to produce nice stable orbits in the inner system.

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