Where does the Earth’s atmosphere stop and space begin? It is tempting to take the approach Justice Potter Stewart did for pornography when judging a 1964 obscenity case and say “I know it when I see it.” That’s not good enough for scientists, though. The Kármán line is what the World Air Sports Federation (FAI) […]
OK, so this isn’t really a rocket. In the strictest definition, rockets are vehicles or projectiles that propel themselves through jettisoning mass, usually through the combustion of fuel. But with electric motors getting stronger and stronger, folks are building craft that look a lot more like rockets than airplanes. [Tom Stanton] is one such person […]
If you are a certain age, you probably remember the promise of supersonic transports. The Concorde took less than 4 hours to go across the Atlantic, but it stopped flying in 2003 and ended commercial supersonic passenger flights But back in the 1970s, we thought the Concorde would give way not to older technology, but […]
The popular press was recently abuzz with sad news from the planet Mars: Opportunity, the little rover that could, could do no more. It took an astonishing 15 years for it to give up the ghost, and it took a planet-wide dust storm that blotted out the sun and plunged the rover into apocalyptically dark […]
Water is a stable chemical, but with the addition of a little electricity, it can be split into its component parts. The result is just the right mix of H2 and O2 to convert back into water with a bang. [Peter Sripol] has built a charming desktop cannon in just such a way. The build […]