Saturday, September 26, 2009

Real science: "Round trip to the edge of cosmos"

From an article of this title by Rachel Courtland in New Scientist, 26 September 2009:

"How far could an astronaut travel in a lifetime? Billions of light years, it turns out."

"The furthest that the light emitted from our sun could reach ... currently lies at about 15 billion light years away." Traveling in "a super-advanced rocket" at "a comfortable 1g", this journey would be made "in only 30 years" in "astronaut's reference frame, because time would pass slower than on Earth due to relativity", according to "a paper to appear in Publications of the Astronomical Society of Australia" authored by "Kwan & her colleagues".

"But ... returning home presents its own challenges... Beginning deceleration just a second too late could cause you to overshoot the Milky Way". "even if you did stop in the right place, you would be disappointed. Some 70 billion years would have elapsed back home, so the sun would long, long since have expired, taking Earth with it".