Picture of Light (1994)

Don Lind: Self - Representative from space

Quotes 

• Don Lind - Representative from Space : If you can imagine, a rather spectacular display of lights in the sky, you may have seen the aurora, but try to imagine that from orbit. What the aurora is actually, if you can imagine my hand as the earth, and unfortunately I'm holding my mike button with my other hand so I can't gesture very well. But if you could imagine the earth, surrounded by its magnetic field, that earth orbits in the atmosphere of the sun. Now the upper corona is a supersonic wind that expanding and blows past the earth and the earth is actually in that wind. And that sweeps the magnetic tail... magnetic field around the earth into a long tail, and the residual magnetic field is called the magnetosphere and its called the magnetic tail... and if the magnetic field were visible the earth would look like a tremendous comet with a tail that goes way out past the moon. And as the solar wind sweeps along the sides of this magnetic field, it generates energy that is dumped into the tail. And then every once in a while by some impulsive mechanism that we don't quite understand yet, that energy is dumped down the magnetic field lines into the earth and hits the earth in two circles, one around the north magnetic pole and one around the south magnetic pole and that constitutes the aurora.

• Don Lind - Representative from Space : So what is this aurora that we talked about? Let me show you what an aurora looks like when viewed from space. And what you're looking at is, first of all, the moonlit clouds below us and a bright streak of light in the sky which is just one filament of this great circle that surrounds the south geomagnetic pole and then there's the mirror image of that in the Northern Hemisphere. And you're looking at the stream of particles that's streaming in from the magnetosphere that's actually exciting the atoms in the atmosphere to glow. When you look down at that aurora you really see an impressive scene. You're looking at the electrical current surging through that aurora that on average is about the same energy as the entire network of high-tension power lines in North America, Bonneville Dam and Hoover Dam and all the rest of the power lines put together. The bottom of that curtain is about 70 miles in the air and we're about 190 miles up so we're looking down on the top of it that's sweeping past the aurora at 17,500 miles an hour... and as the magnetic tail, the magnetsophere shimmers and shakes and jiggles it changes the pattern of that aurora.

• Don Lind - Representative from Space : Now the aurora is of interest to us because if one of these great impulses of energy comes into the earth's ionosphere, it wipes out long distance radio communications and causes power surges in the high-latitutude power lines and this sort of thing. But more importantly, this magnetosphere is the environment in which we live and we simply need to understand it.