Traveling at high altitude can be hazardous. The information provided here is designed for educational use only and is not a substitute for specific training or experience. Princeton University and ...

If you are using a ruler and compass to draw something - for example, a perpendicular bisector of a line or bisecting an angle - make sure you clearly show the compass arcs in your construction.

That translates to better than 2,000 miles per hour—at altitudes between 75,000 and 85,000 feet, too high and too fast to be shot down by an enemy fighter or a surface-to-air missile.

There have previously been hints that planets on perpendicular, or polar, orbits around binary stars could exist: in theory, these orbits are stable, and planet-forming discs on polar orbits around ...