Tuesday, April 22, 2008

"Gravity" on History Channel shows how mankind can save itself from a Red Giant Sun

The History Channel ran a program “Gravity” in its Universe series, and it’s a significant addition to the “mega-disaster preparation” concept with one discussion toward the end of the one hour show.

The show points out that gradually the Sun will expand, starting in some hundreds of millions of years. In five billion years it will be a red giant reaching almost to Earth, and long before that Earth will have become another Venus.

A future civilization could, however, use the “simple” Newtonian mathematics of gravity to save itself. It could capture a large asteroid (100 km) or comet and position the body in such a way as to sling the earth into a longer orbit. If it did this every 10000 years, in theory the civilization could go on for billions of years longer. However, remember that eventually the Sun will become a white dwarf star.

Any such maneuver would have to be calculated very carefully, lest the captured asteroid crash into Earth and create an extinction event.

The show also discussed gravity waves through the Universe, which in theory could change someone’s body shape.

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