Thursday, February 28, 2013


Whether a major asteroid impact or simply the Sun’s ever-warming radiation or demise, eventually Earth will become uninhabitable. The human species, if it is to survive, must learn to travel to other worlds. Such a voyage, over billions even trillions of miles and kilometers, seems impossible, an idea notable only in science fiction or of the unimaginable future. Or is it?

If the nearest star system to our Earth, Alpha Centauri, does harbor rocky planets similar to Earth as new evidence suggests, there may be a host of ways to get us there, at least in theory.

Sending a person from Earth to Alpha Centauri within an average human lifetime wouldn't be easy. Alpha Centauri is 4.37 light-years away, more than 25.6 trillion miles away. That’s more than 276,000 times the distance from the Earth to the Sun. Recognizing that interstellar travel would, at very best, take decades, some experts are now considering transporting the DNA and other resources necessary to recreate humans on an unmanned spacecraft.

Beginning with the development of a rocket engine that can reach high velocity, we are not short of initiative, but even with engines based on photon-powered sails or nuclear fusion, we are still a long way from reaching the speed of light. At a maximum speed of about 17,600 mph (about 28,300 kph), it would take a modern rocket ship about 165,000 years to reach Alpha Centauri. Other propulsion methods considered include antimatter engines, giant electromagnetic fields to suck in hydrogen to fuel a nuclear rocket and light sails that would run off not just light generated by the Sun but could also ride laser beams fired carefully at those ships to give an extra boost, especially when sails were too far away to catch much light from our sun.

With the discovery of numerous exoplanets our hopes need not depend solely upon Alpha Centari as the lone oasis in the quest for interstellar travel. But if the science to get us there advances the pursuit of prolonged human space travel at warp speeds, then on to Alpha Centari.

Image Credit: Artist rendition of part of the Centauri Star system

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