The star Betelgeuse is about 600 light years away. If it explodes tonight:

Question

Accepted Answer

We won’t know about it until about 600 years from now.

Answer

We won’t know because Betelgeuse will immediately stop shining and we won’t be able to see it anymore.

Answer

We’ll know because it will be immediately brighter than the full Moon in the sky.

Answer

We’ll know because Earth will be immediately struck by the remnants of the explosion.

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