When I was younger, I made a bucket list of four things I wanted to see before I turned into worm food. They were the Taj Mahal, Mount Everest, Machu Picchu, and the northern lights. I’ve now seen the first three, but not yet the last.
But I can do it vicariously: from EarthObservatory comes this stunning photograph of the aurora australis, the southern lights, taken only a few days ago (Sept. 17) from the International Space Station. It was taken between Madagascar and northern Australia, and you can see the station’s solar panels.
Be sure to click to enlarge:
If you want even more of a stunner—a video of the lights moving and flickering—be sure to watch either the high-resolution movie or the low-resolution movie appearing on the site, which compresses 23 minutes of time-lapse photos into a 35-second movie. At the end of the movie you can see a bunch of wildfires and human-set fires in Australia.
And here’s how auroras are produced (also from the site):
In this case, the space around Earth was stirred up by an explosion of hot, ionized gas from the Sun—a coronal mass ejection—that left the Sun on September 14, 2011.
The pressure and magnetic energy of the solar plasma stretches and twists the magnetic field of Earth like rubber bands, particularly in the tail on the night side. This energizes the particles trapped in our magnetic field; that energy is released suddenly as the field lines snap the particles down the field lines toward the north and south magnetic poles.
Fast-moving electrons collide with Earth’s upper atmosphere, transferring their energy to oxygen and nitrogen molecules and making them chemically “excited.” As the gases return to their normal state, they emit photons, small bursts of energy in the form of light. The color of light reflects the type of molecules releasing it; oxygen molecules and atoms tend to glow green, white or red, while nitrogen tends to be blue or purple. This ghostly light originates at altitudes of 100 to 400 kilometers (60 to 250 miles).
h/t: Diane G.