For a space ship, can light can be used as fuel?I mean to ask it will emit light and move forward with speed of light?
Try to think about those who type, them are at least learned elementary physics and ask smarter question.
www.okorder /.. Light has more of PUSH that a PULL effect but it does not transfer enough energy to move an object to the speed of light else you would have a tough time holding on to your flashlight
Producing light requires an energy source. Focusing the light in one direction creates thrust in the opposite direction. The thrust is incredibly small compared to the weight of the power source. Low thrust creates low acceleration. To attain a large velocity → V = a*t, so if a is small, t must be VERY large. To stop at the end of your trip, you have to reverse the thrust halfway through the journey, thereby doubling the already centuries long trip time. (Unless, of course you use dilithium crystals as the power source.....)
Designs of such are being thought, but it would be more like para-gliding, I mean light from other source pushing a huge light weighing parachute like structure. Well ofcourse this wont happen in near future. Right now small titanium disks can be thrown at small heights by lasers. But this certainly will not replace present mechanism for transport for a long time.
