# Big and fast rogue planet

There is a big, very big planet that is travelling fast, very fast. It’s a rogue planet (not attached to a star system). It’s going to pass close, very close to the earth.

The earth is probably going to be destroyed by the gravitational forces and sent spinning as a rogue planet itself or toward the sun, I don’t really care. What is of interest, is that some humans that were on the earth were sucked by the nomad planet’s gravity (Edit for Raditz comment: if you prefer, you can make them sucked by something else, but please not laser beams, only natural-ish forces).

Assuming:

• The fate of earth afterward to be irrelevant
• Long and medium-term survival on the rogue planet to be irrelevant
• People should however land alive on the new planet

Would such a transfer be possible?

• If the planet gets close enough for Earth for humans to be pulled by the planet's gravity away form Earth (assuming that made sense), the light released in the collision of the atmospheres will evaporate all life basically instantly. However, this might lead to creative answers if you could leave the door open for other options than the planet's gravity sucking people towards it. Oct 12, 2018 at 9:51
• @Raditz_35 What else could suck them? Winds? Ok, I'll edit and see what comes. Oct 12, 2018 at 9:53
• Such questions are better left to other users. Winds would be the same issue, if you get planets close enough, everyone dies instantly. You need a solution where the planets stay far away from each other and then a reason why the people are not simply recovered afterwards. Perhaps specify if you want this to be a natural phenomenon. Also note that a high relative velocity = this could be like a rocket flying into a solid wall. Oct 12, 2018 at 9:56
• It's kinda been done before, multiple times. scifi.stackexchange.com/questions/182698/… en.wikipedia.org/wiki/When_Worlds_Collide en.wikipedia.org/wiki/When_Worlds_Collide_(1951_film) Oct 12, 2018 at 10:13
• The passing planet will also be damaged by tides. While material, particularly atmosphere, might be transferred to the more massive planet during a pass, far more will be ripped up and lost to space. Apr 8, 2023 at 16:18

Unfortunately no it can't happen.

TLDR

Let's say the gravity is high enough to pull people off Earth and into the Rogue Planet, they would then be falling at terminal velocity to the surface of the RP, the problem with trying to land on your feet at terminal velocity is that it tends to be somewhat terminal...

Atmospheric Issues

Ok so let's somehow take the terminal velocity splatting as handwaving-ly survivable. And let's also assume that the RP is going somewhere in the region of 525km/s then the atmosphere would have so much friction between the two that it would turn into plasma that somehow your people need to survive traveling through...

Along with some of the Earth's atmosphere being ripped off with you, make just a small amount of catastrophic turbulence that no aircraft could survive let alone a person out for a morning run.

Gravitational Issues

Even if we assume that the RP is roughly 5x the diameter of the earth (assuming this based on a rough estimate from your pictures) then the gravity would be crushingly strong once the people land there and would be immediately crushed by their own weight.

AND then there is the fact that even with how small Earth is by comparison it would cause huge earthquakes and general doomsday situations on the RP to make habitability quite unlikely once landed

EDIT: Only potential chance of survival

The one chance of people surviving would be if there were anyone on the International Space Station (ISS), and it was in the perfect place, it might... I stress might be possible that it could get dragged out of Earth's orbit into the RPs orbit, however, the velocity change would rip it apart, but perhaps maybe just maybe if a couple of the crew were in the Return capsule with a heat shield, then they have a chance of survival until they reach lower altitudes and are crushed at least

• what if you stand on the other side of the planet?
– user55267
Oct 12, 2018 at 12:25
• @Jannis chances are that you wouldn't die outright, but you also wouldn't be dragged off the planet, but you would die either from the effects of gravity, the atmospheric changes or from the planet either boiling or freeze do to orbital changes... basically death one way or another Oct 12, 2018 at 12:56
• Well Legisey was just concerned about the landing, I'm absolutely on your side that this is impossible to survive for long term
– user55267
Oct 12, 2018 at 12:59
• @Jannis. Indeed, I've edited in a part about the only thing i can think of for a survivable transfer. its very very unlikely but its the only way i see it as being even remotely possible Oct 12, 2018 at 13:04

No, it’s completely impossible. If the rogue planet passes close enough that the Earth is inside its Roche limit then things including people could indeed get pulled off the surface of the Earth by the tidal force, but there’s no way that humans could land alive on the surface of the rogue.

• Mind developing a bit? Why is there no way they could land alive? Oct 12, 2018 at 9:55
• @Legisey this "big, very big planet" has a lot higher gravity than Earth, meaning... it's going to pull you a lot harder than Earth will. Oct 12, 2018 at 10:15
• @Legisey and the gravity on this giant planet won't be too pleasant for humans. In fact, it'll be downright bad. Oct 12, 2018 at 10:17
• @RonJohn "bad" is such a cute word for falling hundreds of meters with an acceleration way greater than 1g and then abruptly stopping when you finally impact on the surface. Oct 12, 2018 at 10:28
• Space is big, really big. A rogue planet, in order to stay rogue, need to be moving much faster than the Earth has it pass close ... On the order of 10's of thousands of miles per hour. ... Splat. If people are pulled across, so will anything lose in their vicinity that is held in place by gravity. Cars, . The first 100 feet of clay and topsoil, buildings ... Splat. Oct 12, 2018 at 10:29

I'm not sure about the physics ... ask on 'what if' for that, but
IF your're in a plane, while the lighter Atmosphere is pulled towards the planet, you could survive
(prove required, maybe with a test series. Do you have a giant planet somewhere hidden in your garage you can borrow me?)
But watch out for the inhuman pressures if the air is sucked in the next planet and pressed on the surface there. And don't land quick if water is coming after you

EDIT:
What you want to do is standing (flying in a plane ... you never know) on the other side of the earth. Then you get pulled down with the hole earth. AND thats the part I'm not sure of. Just make sure you have enough fuel to fly one time around the world and to stay another in the air. Actually the higher pressures of the atmosphere on the bigger planet makes it easíer to fly. If you have luck the other Planet is so cold you don't get the feeling from 65 million years ago.

Concluding I would say:
It's a montrous balancing act. If of all planes only one can survive I'd be surprised.
Either way, on the other planet the humanity is likely to die out, because of:
-Gravity
-Inferno
-Human Behavior
-did I mention the apocalypse yet?

• I like the idea of a plane. Oct 12, 2018 at 11:50
• I'm really sure i didn't mention all the debris in the air which you have to dodge in the plane.
– user55267
Oct 12, 2018 at 11:56
• "Human Behavior"? Please explain how human behavior contributes to cause its own extinction. We are currently at 7.6 billion humans, which is a very strong empirical and Darwinian counter-argument. I fail to see what part of human behavior (but not, let's say, that of other mammals) would contribute to its extinction in that scenario - on a similar level as extreme gravity, "Inferno" and the "Apocalypse." Oct 15, 2018 at 13:49
• @Battle We are ruining this planet. We'll probably if we'd survive ruin that planet. Or just kill ourselves instantly.
– user55267
Oct 15, 2018 at 14:40
• @Jannis - But that's just plain doom sayer hysteria. It's neither the first, nor the last time we had that, and it's fundamentally rooted in irrationality. In the past those people were radical theocrats, today it's environmentalists as ideologues. "The wrath of god/nature will hit you if you don't change your ways immediately all together!" - Also they cheer when natural disaster occur and humans die for "told you so!" Oct 16, 2018 at 5:44

If the planet is close enough that someone from the surface of the earth is going to "fall" onto the larger planet- so will the rest of the earth- right on "top" of them. And even then, during this "fall" they will continue to be held to the surface of the earth by its gravity.

(The rogue planet would need to be incredibly dense for there to be a significant enough tidal-force gradient between a person's center of gravity, and the surface of Earth to lift someone from the surface. And even if one does "float" off the surface for a short period of time due to this tidal-force gradient, the earth, or at least some of it, is still going to land on "top" of them. Certainly, as others have mentioned, having such a density would render the rogue planet uninhabitable by humans.)