First, a little background information.
For the purpose of my story, I'm making the Earth uninhabitable, similar to this question.
This is to cause a mass exodus from the solar system through a bit of fantasy science of artificial wormholes for interstellar travel.

From other questions like this one, I think it wouldn't too far out there to suggest that a rogue planet could pull Earth out of it's current orbit. But...
Would it even be reasonable that a civilisation capable of creating artificial wormholes couldn't stop a rogue planet?
Could there be a reason why they wouldn't be able to stop it, an excuse? Or should I just look into blowing up the sun instead?

  • 2
    $\begingroup$ Are you asking specifically, "Can they stop it with wormholes?" Otherwise, we have no idea what kind of technology they have, even if you specify that they are a Kardashev II civ. $\endgroup$
    – Kys
    Jun 28, 2016 at 19:28
  • $\begingroup$ I'm going to look into this Kardashev scale, I've never heard of it. $\endgroup$
    – Cairyn
    Jun 28, 2016 at 19:50
  • $\begingroup$ moving planets is't big problem, like so as example blowing star is more viable treat $\endgroup$
    – MolbOrg
    Jun 28, 2016 at 20:38

3 Answers 3


Would it even be reasonable that a civilisation capable of creating artificial wormholes couldn't stop a rogue planet? Oh yes, it would. Firstly, the commentators and answerers are right. If this was a Kardashev type 2 civilisation, then it should be able to fend off rogue planets. I suspect they could handle hypervelocity stars and neutron stars too. K2 civilisations will possess technology and science capable of doing things we wouldn't believe. This is background to my proposal.

I believe suggestions about K2 civilisations were made because they were aware that current models of wormholes require near stellar masses of energy to make them. However, science will march on, so let's assume that a century or two hence science discovers wormholes that can be easily created for smallish amounts of energy.

This gives a future Earth civilisation with practical interplanetary and interstellar travel via artificial wormholes. But they won't have the super-technology to save themselves from rogue planets and upwards. There's no choice other than a mass exodus.

As for the kind of rogue object destroying to destroy Earth, the Sun, or the solar system, they can be ranked as follows.

Rogue planets: Preferrably Jupiter mass. Earth doesn't have a chance. Could disrupt the Sun enough to make the solar system uninhabitable. Not easily detected. Travelling at around 30 kilometres per second (kps).

Hypervelocity stars. The solar system hasn't a chance. Easy to see coming though. Only travelling at roughly one-thousandth of lightspeed. So there's plenty of time to prepare.

Runaway neutron stars. The solar system hasn't a chance. The neutron star needs to be old, so it's cooled down, lost its high rotation and magnetic field. Otherwise it would be easy to see coming. Only travelling at around 30 kilometres per second (kps) or roughly one-ten-thousandth of lightspeed. Might be a nasty surprise.

Black holes. Really deadly especially if on collision course with the Sun. Hard to see coming. Though there might be giveaway signs of their presence. Gravitational perturbations, bursts of radiation, etc. No idea about their speed of approach. Needs further research.

Rogue planets are most sneaky, neutron stars might be but also could be easily spotted depending on its age. Hypervelocity stars will be seen for millennia before they arrive. Black holes can sneak up and really ruin the neighbourhood.

Conclusion: Assume artificial wormholes (as you said it's fantasy science) developed in the reasonably near future (say, only centuries ahead) and then choose the rogue object you prefer to wreak havoc.

  • $\begingroup$ Earth moves through space, in a sun-centric reference frame, at a velocity of about 30 km/s. Our present-day spacecraft headed for the other planets (think New Horizons, Juno, etc.) move at around 15 km/s, sun-centered. The solar system moves at about 200 km/s in a reference frame centered around the center of the Milky Way. It's all about your frame of reference. $\endgroup$
    – user
    Jul 1, 2016 at 15:47

If it's a type 2 civilization, there's probably a number of different ways to block a rogue planet (use a laser to adjust its trajectory, move it via artificial gravity, blow it up with some kind of super weapon, etc.)

What you might need for your story is to up the ante to something far more destructive. If we were to see a hyper-velocity star, a neutron star, or even a rogue black hole hurtling towards the solar system, our only chance of survival would be to leave it entirely.

This video here describes a scenario just like this.

  • $\begingroup$ I hadn't even considered any of those options! Thank you, that is exactly the kind of alternative I was looking for. $\endgroup$
    – Cairyn
    Jun 28, 2016 at 20:15
  • $\begingroup$ @Mattias. Good suggestions, K2 civilisations will fix rogue planets. However, they might easily fix hypervelocity stars & neutron stars too. Rogue black holes definitely not easy. Do you have any information on rogue black hole velocities? I have no idea. $\endgroup$
    – a4android
    Jul 1, 2016 at 7:42
  • $\begingroup$ @a4android I still think that a type 2 civilization would have quite a bit of trouble handling hypervelocity stars and neutron stars. Both of them could be hurtling though space at a pretty high percentage of the speed of light. Slowing and/or deflecting something like that would take a lot of energy to do. Plus, if you add in the immense mass and density of a neutron star, reducing or altering that much inertia would be astronomical (no pun intended). $\endgroup$
    – Mattias
    Jul 2, 2016 at 0:00
  • $\begingroup$ @Mattias. The velocities of hypervelocity stars and neutron stars are modest fractions of lightspeed. One-thousandth and one-ten-thousandth of c respectively. Slow enough for time to be on their side. Still it's a lot of momentum. Their tech should cope. K2's might have gamma-ray lasers capable of inducing supernovas in stars (suggested by Sagan & Shklovsky). H/v stars fixed. They might trigger neutronium to unbind, turning neutron stars into neutron rockets. No guarantees. This is my high-tech optimism. $\endgroup$
    – a4android
    Jul 3, 2016 at 13:26
  • $\begingroup$ @a4android There's just one slight problem with destroying a star in a violent supernova though. By destroying the hypervelocity star, the K2 civilization might have stopped the star itself from hitting the system. But as a side effect, they just caused a nearby supernova that is pretty much aimed straight at us. Its comparable to destroying a rifle bullet in the air, only for it to shatter and spread out at you like a shotgun blast. $\endgroup$
    – Mattias
    Jul 3, 2016 at 17:31

This is very difficult to answer as we have nothing to compare to. It sounds though that this will be at least a level 2 civilization on the Kardashev scale, which in turn means it's reasonable to expect such civilization to be able to construct megastructures such such as Dyson spheres and/or mine their star.

If that would be the case it's very difficult for me to imagine such civilization not being able to deal with a rogue planet. I would imagine they would be able to deal with exploding star as well.

  • $\begingroup$ Stellar husbandry is one theoretical way they could prolong their star's life and also extract as much energy as possible from it $\endgroup$
    – Kys
    Jun 28, 2016 at 20:13
  • $\begingroup$ @ventsyv I agree K2 civilisations should be able to shrug off rogue planets even survive having the Sun destroyed. My take on this would be to wind back on the tech level, making it far from and definitely not K2. Then a rogue planet becomes a real threat $\endgroup$
    – a4android
    Jul 1, 2016 at 7:47

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