Stephen Hawking says the Earth will be a fireball by 2600

Stephen Hawking says the Earth will be a fireball by 2600 Jan 11, 2018 22:05:14 GMT captainbryce likes this

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Post by shadrack on Jan 11, 2018 22:05:14 GMT

Jan 11, 2018 13:25:09 GMT captainbryce said:

1) No physical craft can travel at the speed of light because that would give it infinite mass and require infinite energy. It would also cause time dilation according to Einstein’s theory of special relativity.

Hawking of all people knows this. My bet is that the statement in the article is from the (scientifically illiterate) author of the article, not Hawking himself.

Edit: Yep. Here's an article about the same thing from CNBC. It describes the ship as an "ultra-fast, light-powered spacecraft". No mention of it traveling "at the speed of light".

Jan 11, 2018 13:25:09 GMT captainbryce said:

2) IF it were possible to travel at the speed of light, a trip to Alpha Centauri would take approximately 4.3 years, not 20 years.

You need to factor in acceleration and deceleration time. The propulsion mechanism mentioned in the article isn't really clear ("The idea behind this innovation is to have the nanocraft on the light beam"), but sounds a bit like a solar sail which I believe accelerates VERY slowly. You'd basically spend half the trip accelerating and the other half decelerating. There's also the time dilation effect you mention. That would make the trip seem to take longer from our perspective.