Alpha Centauri is the closest star system to us, at 4.37 light-years (about 25 trillion miles) away. In 2016, astronomers…
Every so often, engineers send a spacecraft in Earth's general direction to pick up a speed boost before heading elsewhere.…
Imagine plunking your spacecraft down on an asteroid. The gravity would be small. The surface would be uneven. The space…
[/caption] On Tuesday, January 31, asteroid 433 Eros will come closer to Earth than it has in 37 years, traveling…