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Last Word is Â鶹´«Ã½â€™s long-running series in which readers give scientific answers to each other’s questions, ranging from the minutiae of everyday life to absurd astronomical hypotheticals. To answer a question or ask a new one, email lastword@newscientist.com
How long would it take to accelerate a spacecraft to 99 per cent light speed without major injury to the astronauts inside?
Ron Dippold
San Diego, California, US
It wouldn’t be long if you had infinite energy! Let’s lock down our units – 99 per cent of the speed of light, or 0.99c, is 1068 billion kilometres per hour. Normal Earth gravity acceleration, 1…
