February 27 – Look! Up In The Sky!

Today’s factismal: 600 trillion trillion particles from the Sun hit the Earth every second!

We all know and love the Sun. Powered by fusion, it gives off light which warms the Earth and powers the photosynthesis that is the root of nearly all life on the planet. But the Sun does more than shower us with photons; it also sprays the Earth and everything else in the neighborhood with the byproducts of its fusion reaction. Those particles include neutrons, protons, helium-3 nuclei and assorted other odd bits (including the neutrino which was so odd that it powered three different Nobel prizes!).

A sounding rocket launching into the aurora to study upper atmosphere dynamics (Image courtesy NASA)

A sounding rocket launching into the aurora to study upper atmosphere dynamics
(Image courtesy NASA)

Those particles have a variety of effects on the Earth. They help create rain clouds. They distort our compass headings with potentially disastrous effects. They short out our electrical grids. And, most spectacularly, they power the aurora (aka the “Northern Lights” even though they also appear in the Southern hemisphere). Best seen from above 45°, the aurora is an amazing example of physics in action. The charged particles given off by the Sun are trapped by the Earth’s magnetic field and funneled down into the upper atmosphere where they ionize different atoms, giving the aurora its characteristic eerie glow. The color of the glow tells which element was ionized; green is mostly oxygen as a molecule (O2), blue is mostly nitrogen as a molecule (N2), and red is usually atomic oxygen (O).

The aurora as seen from the ISS (Image courtesy NASA)

The aurora as seen from the ISS
(Image courtesy NASA)

But while we know how the aurora works in general, there are still a lot of details to be worked out. And that means that there is a lot of data that is needed – which is where you come in! (Or go out, as the case may be…) You see, one of the hardest things to quantify is the extent of the aurora. But that is also one of the most important things to know. So, in order to help discover how the aurora changes size over time, scientists have launched the Aurorasuarus (get it?) site. Once you’re registered, you just go out at night and let them know if you saw the aurora or not. So you get to see an amazing cosmic spectacle and the scientists get more data – win-win! To participate, shine a light at:
http://www.aurorasaurus.org/

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