That depends on your mass. A human ovum can escape Earth's - and even the Sun's - gravity well on solar pressure alone. At this very movement Earth-dust is mak

That depends on your mass. A human ovum can escape Earth's - and even the Sun's - gravity well on solar pressure alone. At this very movement Earth-dust is making its way into space and even leaving our solar system without fuel. There's a group working on very low mass spacecraft to take advantage of this - http://www.spacecraftresearch.com/MII/MII_overview.html http://www.spacecraftresearch.com/MII/MII_overview.html