Sailing along

Scientists have known for quite awhile about a method of propulsion that requires no fuel at all. The solar sail is a giant solar panel consisting of heat-resistant carbon, which would be unfurled in Astronomy.lifetips.com/cat/57774/interstellar-travel/index.html">space to a width of nearly half a kilometer. The constant pressure of sunlight (composed of photons) will accelerate a ship to speeds five times more than is currently possible with fuel-propelled systems. At that speed, a probe launched in 2010 would overtake the Voyager 1 spacecraft (the most distant spacecraft from Earth) in 2018.