The Propellantless Spacecraft Technologies That Could Help Us Reach the Stars
Future spacecraft may travel farther by drawing momentum from planets, sunlight, and the solar wind instead of onboard fuel. Every conventional rocket faces the same problem: it must carry the material that propels it. Since Konstantin Tsiolkovsky described the rocket equation in 1903, spacecraft have burned fuel and expelled it backward to move forward under [...] 

A strange new hypothesis.
Could the Universe hold minds built from radically different stuff?
It might be right in front of us.
Here's how to see it.
One of the most violent events the Solar System has ever witnessed.



