• Question: what would happen if the moon crashed into the sun

    Asked by rache to Ben, Jony, Katharine, Mark, Peter on 16 Nov 2011.
    • Photo: Ben Still

      Ben Still answered on 15 Nov 2011:

      I could not say for certain – I’d have to write a simulation which had all of the correct physics represented. For sure though it would alter the orbit of the Earth quite a bit as the Moon is a fair sized chunk of rock. We would lose all tides on the Earth, as these are governed by the gravitational force of the Moon. The Sun would also not be too happy I would imagine, but it should not have too dramatic an effect on something as big as that.

      The honest answer is I don’t really know.

    • Photo: Jony Hudson

      Jony Hudson answered on 15 Nov 2011:

      That’s a good question!

      I don’t know for sure, but we can try and make a rough guess by looking at some numbers.

      The sun weighs 100,000,000 times more than the moon. So it would be a bit like a fly crashing in to a 300 ton ship. The ship wouldn’t notice it at all. So I don’t think the sun would care if the moon crashed in to it.

      The earth only weighs 100 times more than the moon. So like Ben says it would probably make a difference to our orbit if the moon were to get pushed into the sun, maybe a 1% change. I’d guess, but I don’t know, that this would make a big difference to our weather, maybe even enough to start an ice age or heat-wave or something. But that last bit is a guess!

    • Photo: Katharine Schofield

      Katharine Schofield answered on 15 Nov 2011:

      Hi rache,
      I don’t know either, but if the moon did crash into the sun then something pretty crazy would need to happen to cause the moon to be knocked right out of it’s orbit and into the sun, which is about 93 million miles away. I’m struggling to think that even a collision with a massive asteroid could do that. But if it did happen, I don’t think we’d be worrying too much about what happens if moon and the sun collide because things here on earth would have gone pretty extreme already. I guess what I’m saying is that it would have to be something so massive it would take out the earth too.

    • Photo: Mark Basham

      Mark Basham answered on 16 Nov 2011:

      One thing about planets and moons is that orbiting bigger things is what they do best, so as Katherine says it would take a pretty big impact to make that happen. Now I’m not 100% sure but there was a really big colision with something early on when earth was very young which created the moon from the bit that was broken off. Now even after that impact were still orbiting the sun quite happily.

      I guess the best thing would be to hope we never find out 🙂

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