Suprisingly, building bigger rockets is not the answer. Spacecraft with engines powerful enugh to reach nearby Alpha Centauri in just 10 years would require an enormous quantity of fuel, and would burn more proppellant than exist in the known Universe. If we are ever to journey to the stars, we need new technologies.
Nuclar-driven spaceships could be one way to bring the stars within reach. In the 1940,. American atomic physicts Stanislaw Ulam suggested a craft powered by a series of small nuclear bombs exploding behind it. According to Ulam's calculations, a series of detonations would accelerate a spaceship to a tenth the speed of light, or 30,000 km per second. At that speed, the one way trip of 4.35 light years to Alpha Centauri (our nearest star) would take less than haf a century.
Of course, there would be a few technical challenges, not the least being how to protect the austronouts from the deadly radioactive flash from each nuclear blast.
Anothet possibilty to power a spacecraft by the same sources of energy the Sun uses: nuclear fusion. When two hydrogens atom are fuses together to form a helium atom, not only is a great amount of energy releases, the heliums atom gets kick and shoot away. The multitude of helium prjectiles from a fusion reactions could be fired out a back of the rocket, accelerating the craft perhaps 20 per cent of the speed light. At this rate, a trek to Alpha Centauri takes about 20 years.
The ultimate propulsion system has long been the stuff of science fiction: an antimatter drive. When antimatter and ordinary matter come into contact, the two annihilate each other as their masses are converted into gamma radiation energy. If a stream of this radiation are fired out the back of a spaceship, the craft could be accelerated to near light-speed.
An antimatter drive is sciencetifically feasible, the difficult part will be finding , enough antimatter to fuel it. As the name suggests, antimatter is the opposite of ordinary matter: its atoms have negatively charged nuclie orbited by positive electrons (the opposite of ordinary matter). Tiny amounts of it have already been created in the lab, so it is possible we might one day work out how to manufucture usable quantities.
A technical hurdle will be discovering some way of storing the fuel, it would react instantly with an ordinary matter fuel tank. One possibility is to confine it inside a tank wih a magnetic field that keeps it isolated and out of contact with ordinary matter.
Perhaps we won't even have to manufacture antimatter, we might one day find the natural source of it. Some physicts have suggested that antimatter may be more common in some part of the universe, just as ordinary matter rules in our corner of the cosmos. By finding and exploiting such sources, we could really start exploring our Galaxy.
By Graham Phillips