In 1742, Swedish astronomer Anders Celsius proposed a temperature scale of one hundred degrees between melting ice and boiling water. But in his version, water boiled at 0 and froze at 100, so the hotter it got, the lower the number. Celsius died in 1744 and the scale was flipped soon after, giving the one the world uses today.
Cooled below −183 °C, oxygen turns into a pale blue liquid. Pour it between the poles of a strong magnet and, instead of flowing away, it hangs suspended between them. The reason lies in its unpaired electrons, which respond to the magnetic field. Liquid nitrogen, by contrast, is colourless and pours straight through.
In 2012, Felix Baumgartner jumped from a capsule hanging beneath a balloon, about 39 kilometres up. In that extremely thin air almost nothing slowed him down, and he reached around 1,358 km/h in free fall, or Mach 1.25. He became the first person to exceed the speed of sound with nothing but his own body.