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ZylonBane t1_iy6gi1a wrote

We would have been forced to come up with actual names for them.

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blazingknight144 t1_iy6grgo wrote

Youtube channel "What if.." had a scenario like this I think? I recall that there could be stronger tides, and also the possibility that the gravitational pull of the bigger moon will destroy the lesser moon and absorb it.

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StayYou61 t1_iy6hbtt wrote

Pink Floyd would have had to specify the dark side of which moon.

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O5-20 t1_iy6jvyd wrote

I’m guessing the effects would depend upon the size, mass, and orbital distance of the new moon.

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NewPlanetarium t1_iy6l0ij wrote

This is a pretty interesting scenario! Here's an interesting article that explains what would happen if Earth captured a second moon today.

This scenario though is obviously unrealistic today, and if a second moon was captured it would have occurred billions of years ago more realistically if it would ever happen. In this case, if the second moon was the same size as our moon, then the three body system would cause the two moons to collide and form a larger moon than our Moon. This would wreak havoc on the tides, seasons, and length of days. Life as we know it wouldn't exist, though life would adapt to the different conditions if they are suitable for complex organisms.

In another scenario where the second moon is rather small, more like the captured asteroid moons of Mars, not much would change, though it would be neat to have a second moon.

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_verixsans t1_iy6lvf5 wrote

Which moon would we build a civilization on?

And which moon would we visit first for the Apollo missions?

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Bipogram t1_iy6njgk wrote

It depends on what type of moon it is.

Phobos-esque? A little scrap of rock that offers little more than the IAU to argue over names of features on it.

Vesta-like? More hydrated minerals! Woohoo!

As moon's go, Luna's rather nice. Small enough to not have a ludicrous escape speed and large enough to have had some interesting times with volatile-delivering comets.

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m4nu3lf t1_iy6o19w wrote

There would be one more moon than we have today.

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AzarthIV t1_iy6o6z3 wrote

Mythology.

Oh, theres a goddess/god of the moon? Well, theres two moons now, so either a deity of two moons or one for each. Anyways, some mythological stories would probably change a lot.

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Jogaila2 t1_iy6p7ys wrote

Tides would be quite different. So weather too.

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noseboy1 t1_iy6q9se wrote

Replying to blazingknight144 (#751,959)

On the topic of moon collision, I don't imagine that being necessarily true... or, at least, not on a timeline even remotely significant to human existence. But, like, several planets have multiple moons that seem to be fine. I do think it might screw with tidal locking though, but again idk

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PoppersOfCorn t1_iy6ql60 wrote

Replying to Any_Palpitation_3110 (#753,347)

The moon caused a lot of drag on our rotation and massively slowed us. It is reckoned the Earth used to have a ln 8/10 hour that gradually slowed.

So if we had another moon and depending on what type of resonance it had as well as its mass, yes, it could have changed our day either nearly nullifying the drag from the other moon, or even causing more "drag" and slowing our day even futher.

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noseboy1 t1_iy6w5bv wrote

Replying to Any_Palpitation_3110 (#754,927)

My astrophysics is not nearly as well informed as I'm sure many are here, but the nice thing about space is that it's infinite. With infinite space and stars and planets and moons I'm sure it exists.

... but generally speaking, because of how fast everything moves and the fact that gravity would dictate the two also pull on each other, so they should collide, that possibility is probably stupid low.

But hey, it was once thought binary stars were impossible, turns out they're actually pretty common, the rule book gets thrown out on stuff like this every time we make a better telescope.

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Pure_black_void t1_iy6xih1 wrote

Fucked up tides?????? Idk man I think it’d be mad cool but who knows the gravitational madness that might ensue😂

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zer05tar t1_iy70t1p wrote

We could definitely see that one was fraudulent and one was real.

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I-am-I-said t1_iy714wi wrote

Magnetic field could be more challenging or sporadic?

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Radiant_Nothing_9940 t1_iy77u64 wrote

Replying to noseboy1 (#755,012)

Space sadly isn’t infinite. It’s just very big. Also they wouldn’t be pulled together if they were binary, same way our moon isn’t pulled towards earth. If you want an example of a planetary binary, we actually have one in our solar system; Pluto and Charon are 2 bodies orbiting a barycenter which I believe (I might be wrong) is outside of Pluto’s surface. Charon and Pluto are pretty damn close together, and could likely be much closer. If 2 objects are too close, they will begin to pull each other apart. The issue then is not whether or not 2 objects could sustain distance from each other without colliding, as they just orbit each other, but more an issue of the 2 objects not ripping each other apart through tidal forces.

Sorry if this is illegible or sounds like thinking out loud, I’m pretty fucking tired so forgive me at least a little bit.

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FINALCOUNTDOWN99 t1_iy77wo9 wrote

"We choose to go to Moon 2 in this decade, and not the other moon, not because it is easy, but because its easier than Moon 1."

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JustMotorcycles t1_iy77yuw wrote

Necklace Nebula. A binary star system where the hot smaller star orbits ... INSIDE the bigger, cooler partner. fucks with my head.

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PoppersOfCorn t1_iy79h20 wrote

Replying to Radiant_Nothing_9940 (#757,168)

So basically, from the gravitational interaction between earth and the moon. The moon creates a bulge on the earth surface(tides) but this bulge isn't directly underneath the moon, so it causes torque, and the difference slows the earths rotation and also results in the moon continually moving away from earth

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Grifcannon26 t1_iy7b505 wrote

That depends - would this second moon also be hallow Giorgio tsoukalos approves 👍

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The_elk00 t1_iy7d37j wrote

Replying to Radiant_Nothing_9940 (#757,142)

Space is such a crazy concept to think about. If it's not infinite, what's the end or edge like? Does time move at an insurmountably slow speed at the edge? Is space infinite but there's just nothing there? Is it a wall? Does all matter become more tightly packed that it acts like a wall but can expand?

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imapassenger1 t1_iy7gmhh wrote

If they orbited each other while orbiting Earth it would be interesting, if that's possible.

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Aekiel t1_iy7hyfh wrote

Replying to The_elk00 (#757,987)

There's a lot of debate about this.

The prevailing theories at the moment are that the universe is either infinite or finite. If it is infinite then there is no question of whether it is bounded or not (it is unbounded as you can't name two points within the universe and have the distance between them encompass everything within it).

If it is finite then the question is whether it has an edge or not. If it has an edge it is referred to as a bounded universe and we have little idea what could be at or beyond the edge of such a universe.

If it is a finite but unbounded universe then there's a definable volume to the universe (that is growing all the time due to expansion), but it doesn't have an edge. This is where the common balloon analogy comes in (a balloon doesn't have an edge, but as it expands the surface area of the balloon and distance between two points expansions).

Current thought rules out a finite bounded universe as it violates homogeneity, but there's no settled consensus on whether we live in an unbounded infinite universe or an unbounded finite one.

EDIT: If we do live in a bounded finite universe there's also debate as to the geometry of it (is it like a sphere? a torus? something weirder?).

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XNormal t1_iy7ksti wrote

A related question is what would be different if Venus had a moon the size of ours. It would have been visible to the naked eye and everyone could see that not everything revolves around the Earth. Could have had an interesting effect on the history of science and religion.

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TwoUglyFeet t1_iy7lii5 wrote

Replying to Ripper209 (#758,433)

Gravity. The moon pulls on the earth like two people holding a rope. This force is called tidal force and causes to water (and the earth) to move to side closest to the moon. These are what tides are.

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piero_deckard t1_iy7m7ra wrote

Astrophotographers interested in deep space objects would have an even harder time finding suitable conditions...

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Fosferus t1_iy7piuw wrote

Love songs would be very different. Older cultures would have applied different traits to each moon. I imagine the larger one would be seen as 'male' and the smaller 'female.' These assigned traits would have leaked into our figures of speech and cultural touchstones.

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FeatherLightDK t1_iy7sra6 wrote

So we already have a moon called moon... would a second moon then be called moon moon?

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codikane t1_iy87qsz wrote

We would have more Lagrange points in the earth-moons system. This would mean more spots for potential telescopes and/or space stations. We would have less stable tides. Greater third-body perturbations on high-Earth satellite orbits could cause them to be less stable. Something about women's cycles may be different...not sure what. We'd have a scientific theory about how the two moons formed. Undoubtedly a story in all ancient texts about how the two moons got there. And we'd have a pretty sweet night sky, though it would have more light pollution and the stars and our galaxy would be more difficult to see with the naked eye.

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strange--alien t1_iy88lp4 wrote

Replying to Ripper209 (#760,348)

If you imagine this scenario, having a tennis ball on a string and holding it above your head spinning it like a helicopter rotor. Generally speaking, the tennis hall represents a moon, rope is the gravitational tether between the two, and (with a bit of imagination) your hand are represents the earth. So, when spinning the tennis ball around, the mass of the tennis ball sets a limit on the speed of spinning. One rotation is an earth day. If you had a heavier ball like a basket ball (larger moon) the speed of rotation would be slower because the earth has to sling a heavier moon. Spinning a lighter ball like a ping pong ball (tiny moon) would be so easy that the tiny moon wouldn't have any affect on spinning speed basically. Smaller you get and the moon wouldn't be able to hold itself in the earth's gravity and would fling off in to space. To summarise, larger moon puts a brake on our earth's rotation, Smaller moon would ease pull back on our earth. Two moon's would be wack! Double the werewolves, double the astrology readings. Spooky

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Radiant_Nothing_9940 t1_iy8c0ym wrote

Replying to Aekiel (#758,704)

There’s also the theory that it’s a 4d hypersphere, meaning reaching one “edge” will just be the same as making it to the opposite side and nothing else. I love this theory as it adds both an explanation for the expansion of space (the sphere itself is expanding, so all the 3d things are getting further apart) as well as possibly leaving a scientific space for a god. I am an atheist, but if we live in a 4 dimensional (or more) universe, a god could easily exist outside the 3d bounds of it, and would therefore be able to see and interact with any part of it.

Too bad this universal theory is likely untrue and these days not considered a prevailing theory. It just explains so much for me, and could even let string theory exist, but I think the math just doesn’t work out.

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Macktologist t1_iy8j1xv wrote

Replying to ZylonBane (#751,922)

Our moon was named by the same type of people that have a boy and girl and refer to them as brother and sister to the other one.

“Go see what Brother is doing.” “Timmy, please make sure to look after Sister.”

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PandaEven3982 t1_iy8ricl wrote

Hmm. No circadian rhythm, but something more complex. Tides very high when both moons in conjunction. Increased vulcanism in tectonics from gravitic stresses. Lots of effects on biology.

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LegitimateGift1792 t1_iy8x5if wrote

Replying to O5-20 (#752,596)

And did they assume current moon would be the same? Or would we have like Mars' moons.

I remember seeing a show long ago about the Moon and why it is so unique (singular and large compared to planet size) for this system and how that might be why Earth has life.

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Ok_Neighborhood_1203 t1_iy968gk wrote

Replying to PandaEven3982 (#770,885)

True... though in the case of the moon-earth system, the barycenter is about 1000 miles inside the Earth. And all the other planets, meteors, comets, and dust in the rest of the solar system are perturbing our orbit too. Even the surrounding stars and galaxies have tiny effects on orbits if you can measure them precisely enoigh.

Neat fact, the Sun-Jupiter barycenter is outside the surface of the sun. So, the solar system actually orbits empty space :)

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strange--alien t1_iya1txe wrote

Replying to Ripper209 (#775,930)

I could hear your unspoken question very clearly. Btw I messed up one piece. One tennis ball rotation is one moon orbit (27 days), not one day. Still same physical concept though.

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SpartanJack17 t1_iya7evq wrote

Hello u/Any_Palpitation_3110, your submission "what would be different if we had two moons" has been removed from r/space because:

  • Such questions should be asked in the "All space questions" thread stickied at the top of the sub.

Please read the rules in the sidebar and check r/space for duplicate submissions before posting. If you have any questions about this removal please message the r/space moderators. Thank you.

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ronnyhugo t1_iych9dl wrote

Replying to Connect_Eye_5470 (#777,357)

All that shiny moon stuff is 99.9999% from the sun. Otherwise we'd never have any dark bits of the moon towards us, would we? :P Its not like the moon actually gets carved in half when half of it is dark, its still there, it just doesn't get sunlight! :P

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