When people think about space travel, they usually think of a giant spacecraft with rockets and fuel—lots of fuel. However, there's a way to sail across the solar system without fuel. In fact, it's done with a sail, but instead of being pushed by the wind, the sail is pushed by the Sun's solar energy.
Scientists discovered at the turn of the century that sunlight pushes against objects. The force is called radiation pressure, and it's too weak to feel while you're on Earth. However, in space, the radiation pressure is enough to push against light objects like dust.
While the solar sail has yet to be tested, there is hope that the pressure of light can steady space exploration the same way winds steadied ships and schooners hundreds of years ago.
3
Based on the central idea, which would be the best title for the passage?
A.
Solar Sail Offers New Option for Space Travel
B.
Sunlight Pushes Against Objects in Space
C.
New Craft Makes Space Travel More Affordable
D.
Solar Sail to be Used During Next NASA Mission