re: 3 Body Problem - Netflix

The sophons are protons which have been unfolded from three dimensions into two dimensions. This large flat proton is then encoded with an artifical intellegence. The two dimensional proton is then folded back up into three dimensions.

The sophons are created in pairs. The pairs share a quantum entaglement where a state change in one instantly changes the state of it's twin. One twin is launched to Earth while the other remains with the Trisolarans (San-Ti). This is how the Trisolarans can affect things despite being light years away.

Because a proton has so little mass it can travel close to light speed. It reaches Earth in about 4 years. The Trisolaran fleet is traveling at 1% light speed and is expected to reach Earth in 400 years.

Anyway, something like that. It's been a while since I read the books.