Despite its name, a light-year is a distance, not a duration: it is how far light travels in a vacuum in one year, about 9.46 trillion kilometres. Saying something will happen light-years from now is therefore a mix-up. On the other hand, looking at a star 100 light-years away really does mean seeing light it gave off a century ago.
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.