In Star Wars Episode VII: The Force Awakens, the Starkiller Base

eliminated the sun in its own system (as well as the intended target's system).

Would that not have killed everyone on the surface of Starkiller Base and on the targeted planet almost instantly? Rey and Kylo go on to spend some time fighting on the surface of a planet

that no longer has a sun,

and the planet's shields are certainly down by then.

I have only seen the movie, so I don't know if anything is written about this issue. Also, I'm willing to understand: "it's just a movie; get over it."


If a sun is drastically reduced, gravity, heat energy and light are, too. Planets go hurtling out into space, atmosphere's freeze, etc.

  • 6
    Come to think of it, why blow up the planet anyway? Just suck out the sun and move along.
    – Mikey
    Commented Apr 5, 2016 at 18:38
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    I reopened this question, since the one Richard closed it as a dupe of was a) itself a duplicate of a third question and b) concerned with a narrower question than this one. Whether or not this is a duplicate of the third question, "How is the Starkiller Base supposed to work more than one time given how it draws its power?", I'll leave to those who know more about Star Wars than I.
    – Rand al'Thor
    Commented Apr 5, 2016 at 18:59
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    Just go with novelization. It's far better science-wise for the whole Starkiller thing than the final Jar Jar Abrams abomination Commented Apr 6, 2016 at 1:05
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    The spoiler tags in the question body here aren't that effective given the question title. Commented Apr 6, 2016 at 4:41
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    @JDoe: Absorbing a star's energy is equivalent to absorbing its mass, due to the mass-energy equivalent. Though I am not sure how this is supposed to work in practice because there is no way you could "suck up" the radiation in a meaningful manner. All you can do is absorb the radiation that the star emits anyway and which happens to hit you (it would however simply go "lost in space" otherwise, so you're not really taking away anything) and power the super cannon with that. Unless of course you have a gravity well approximately as strong as a black hole (but then you're kinda dead...).
    – Damon
    Commented Apr 6, 2016 at 11:41

4 Answers 4


It will, but the timeframe for that to occur is longer than the few days the movie is set in. Residual heat will keep the planet surface (atmosphere) warm for a few days for the same reason we on this planet don't freeze every time we hit 2am in the morning.

Keep in mind, weather systems take days to cross continents and oceans, so the cold isn't as instant as when the sun goes out.

  • 5
    Ever experienced a total eclipse? The cooling is surprisingly sudden, though of course not fatally. Otoh, the star isn't actually removed, it can heat the planet while inside it, and is then apparently returned after firing.
    – OrangeDog
    Commented Apr 5, 2016 at 17:48
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    @OrangeDog sure, but that cooling is just not being hit by light (I.e. Heat isn't continually refreshed). It doesn't actually remove heat from the air.
    – Escoce
    Commented Apr 5, 2016 at 17:57
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    At 2 am, the other side of the world is being kept warm, at 2 am, we stay warm because the ground and air are already warm from the previous day. If the sun went sudden nova, we'd be gone in 8 minutes. If the sun blinked out, I.e. Silently went dark, it would be a few days before we got cold, winter would set in globally after several weeks, the oceans would initially rise without evaporation, the land would be covered in ice as all the water fell out of the air, and we'd die of starvation after all our food supplies ran out because we can't grow more food. It would take months.
    – Escoce
    Commented Apr 5, 2016 at 18:09
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    @MichaelRichardson It's even more complicated than that. There's a whole lot of weather systems that "try" to balance temperatures (and more importantly, pressures) across the globe. As your particular place gets colder, it will suck more warm(er) air from its surroundings. The only reason the Antarctic is so cold is the circumpolar wind and water currents that prevent the cold waters and airs of the Antarctic from mixing with the rest of the world. It was much warmer (and the rest of the world colder) before those circumpolar currents came to be. The colder you are, the more warm air comes.
    – Luaan
    Commented Apr 5, 2016 at 21:50
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    @MichaelRichardson At the same time, the only way the Earth loses heat is through radiation, and that is inversely proportional to temperature. As it cools down, it will gradually lose the ability to cool down. And as we lose sunlight, Earth's own heat sources will become dominant - I can't guess what the new equilibrium temperature would be, though. Some places will hurt more than others - the global temperatures should be much more equally distributed than now, which will likely impact locations with no heaters more than people in colder climates, though it's hard to tell if that's enough.
    – Luaan
    Commented Apr 5, 2016 at 21:53
  1. Would that not have killed everyone on the surface of Starkiller Base ... almost instantly?

    No. They would not be killed instantly on the surface of Starkiller Base.

    • While Starkiller Base is now without a sun, it also now has all of its sun's heat and energy stored inside it, thus making it unlikely it was in any danger of freezing completely. In fact it's possible that the planet's overall temperature went up once it consumed the sun.

      RESISTANCE OFFICER: In order for that amount of power to be contained, that base has to have some kind of thermal oscillator.
      FINN: There is one. Precinct 47. Here.
      RESISTANCE OFFICER: If we can destroy that oscillator, it might destabilize the core and cripple the weapon. Maybe the planet.
      - Star Wars: The Force Awakens

    • Even without the sun's heat being inside the planet, the sun's absence wouldn't have too much of an immediate or drastic effect on Starkiller Base's surface. As Escoce's excellent answer states:

      Residual heat will keep the planet surface (atmosphere) warm for a few days for the same reason we on this planet don't freeze every time we hit 2am in the morning.

  2. Would that not have killed everyone on the surface of ... the targeted planet almost instantly?

    Yes. They were indeed killed instantly on the surface of the targeted planet.

    After gaining Supreme Leader Snoke's approval, General Hux ordered the base to fire on the capital of the New Republic, Hosnian Prime, and four other planets in the Hosnian system, utterly destroying the planets and a significant portion of the New Republic's fleet.
    - Wookieepedia - Starkiller Base

    Visual evidence of total destruction of the Hosnian system and all life thereon: Video and GIF

    Had the planets in the Hosnian system lost their sun (instead of being destroyed themselves), then yes, loosing their sun would indeed have eventual negative effects but not much in the way of immediate effects.

  • +1 Would they have been dead already, on Hosnian Prime, before StarKiller fired at them? That's a heck of a targeting system, since 8 or so minutes in, HP would be way off orbit (as gravity travels the same speed as light). I realize I may be asking too much from a good sci/fi story, but was wondering if this all was addressed in storywriting at all.
    – Mikey
    Commented Apr 5, 2016 at 19:49
  • @Mikey "During this process, the dark energy transformed to a state known as "phantom energy", and left the planet behind, tearing a hole through hyperspace along a perfectly linear path. The people stationed at the Base called the dimension through which the phantom energy beam traveled "sub-hyperspace", and this method of delivering the payload was near-instantaneous across vast distances." starwars.wikia.com/wiki/Starkiller_Base
    – RedCaio
    Commented Apr 5, 2016 at 20:05
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    @Mikey It's not as if it is hard to calculate where the planet would be anyway. It will just continue in the same direction it was going previously - much easier to target than a planet in an orbit :) Actually, in reality, you wouldn't even notice. The gravitational acceleration exerted by the Sun on Earth is absolutely tiny - that's why it takes us half a year to "turn the orbital velocity around". 8 minutes is peanuts.
    – Luaan
    Commented Apr 5, 2016 at 21:59
  • @Mikey Starkiller was not in the Hosnian system when it fired at the Hosnian system. The Hosnian sun is still intact. I've also read conflicting reports of the planets being destroyed vs the planets being wiped of all life/organics and left as barren, charred rocks.
    – TylerH
    Commented Apr 6, 2016 at 18:26
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    @Mikey had the planets themselves not been destroyed, then yes, loosing their sun would have eventual negative effects but not much immediate effects.
    – RedCaio
    Commented Apr 6, 2016 at 19:08

Because the sun hadn't gone out fully. As you can see from this image, there is (apparently) sufficient light to illuminate the day side of the planet even after the energy had been sucked out of it.

enter image description here

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    @ibid - The red arrow wasn't in the original film
    – Valorum
    Commented Apr 5, 2016 at 18:29
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    Yea, but that's just dramatic lighting. In the same way all movies have at least some kind of "moonlight" even though the impression is that it's completely dark. Otherwise, it would just be black and boring. Having no star in the immediate area would make everything completely dark, except for the red glow in the photo. It doesn't say if this area is in a globular cluster of some kind or how near the next star is. I also doubt that any internal heating would illuminate only one side. The other side should be emitting just as much if that were the case.
    – coblr
    Commented Apr 5, 2016 at 23:12
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    @ibid - In hindsight, it would have been funnier to correct you that the arrow wasn't the light source.
    – Valorum
    Commented Apr 6, 2016 at 7:40
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    Is the arrow from the Special Edition? Commented Apr 6, 2016 at 20:02
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    I'm tempted to -1 since that arrow is an arrow instead of a circle and isn't free hand. @fractalspawn We could also look to the fact that it was daylight in all outdoor scenes on the planet. Dim, yes, but it was still light. Is that dramatic lighting, too?
    – jpmc26
    Commented Apr 6, 2016 at 21:58

Yes, everything will go to hell in a few months' time.

As for the planets flying off into space, from what I understand, the weapon consumes energy from the star, not the mass. Obviously, removing energy would eventually remove mass, causing the orbits to widen, but it would take years, centuries, or even millenia, for this to have much effect. It all depends on how much mass is extinguished. Even if the mass was completely gone, the biggest influences over the first weeks would be lack of sun, not lack of gravitational pull. The planet would leave on a tangent, but not do anything major otherwise. "Flying off into space" for a planet means, well, nothing really, since it's already in space.

Now, taking into account the lack of sunlight, yes, that will have an immediate effect. The most immediate effect would be lack of light on the surface. Yes, that sounds obvious, but it is the most profound. The existing weather systems will keep the temperatures of the planet fairly stable for days or even weeks. As Escoce states the planet would have no more incoming radiation, but it has what is already in its weather systems and rocks and such. And, like others state, there is a huge source of energy seeping heat into the planet, keeping the interior warm. Planets don't radiate much heat to space because there is not much matter in space (it's space, a near vacuum) meaning space can't take the radiated heat. The people on the planet would be quite comfortable in the interior of the planet, since they have heat sources and light sources and no real reason to need the sun anyway.

  • 2
    The last bit of your answer is actually describing heat conduction. In space, radiative cooling is the only way to lose heat, since as you say, vacuum can't conduct or convect. However, that doesn't mean a planet can't radiate a lot of heat. Earth's net power intake is very small, but gross power intake and output is huge. That power output (mostly as infrared radiation) would still happen with no sun, so it would cool quickly (days). Commented Apr 7, 2016 at 6:39
  • Ah, I was unaware of the difference. That complicates things terribly. I'd have to do more research to verify your saying it would take mere days to cool, especially since the planet appears to have more heat in the interior than it could possibly take in through the atmosphere, given how cold the planet's surface normally is.
    – methuseus
    Commented Apr 7, 2016 at 7:21

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