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I love Ned Wright's cosmology tutorial and I highly recommend it, but that statement by him is at the least very misleading. Superluminal recession speeds plainly can't be related to spacetime curvature because they don't vanish in the limit of zero curvature (zero energy density or zero $G$). The real reason that distances can be larger than $c$ times the ...

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In a very real and fundamental way "This can't happen" Not only practically (you can't make the sun disappear) But in a fundamental way, you can't make mass disappear. Even if you suddenly converted all the mass of the sun into energy, that energy would still have a gravitational effect. And removing the mass of the sun, at speeds greater than ...

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I found my answer here : it seems my question was already has been answered by Albert Einstein.it's called cosmic catastrophe. according to that page In Einstein's spacetime model, the disappearance of the sun would create gravitational waves in the spacetime. The gravitational waves travel at the speed of light, and an orbiting planet would not react to the ...

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As we know by General Relativity, gravity propagates by the speed of light c = 299,792,458 m/s in a vacuuum (like space). The average distance between the earth and sun is about 149.6 million kilometers, so it takes light about 8.3 minutes from the sun to earth. This means, if the sun were to disappear right now, we would have to wait 8 minutes and 20 ...

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