Launch Window Time: 6:05 p.m. - 6:23 p.m. EST
More info at the NASA website
The THEMIS satellite's task is to measure details of the Earth's magnetic field, which is responsible for the phenomenon of the Aurora. If you've never seen it, have a look at this stunning time lapse movie, filmed in British Columbia, Canada.
While the basic physics of Auroras is more or less understood - electrons trapped in the magnetic field of our planet hit and ionise the gas of the upper atmosphere around the magnetic poles - these great phenomena still pose some riddles. For example, how come about all the different appearances of Auroras, and why can they change dramatically from gentle waves of light to wildly shifting streaks of colour?
Answers to these question are supposed to be found in a better understanding of the detailed dynamics of the magnetosphere. This dynamics will be explored by five satellites in an experiment called THEMIS, short for "Time History of Events and Macroscale Interactions during Substorms". Substorms here relates to strong, turbulent fluctuations in the Earth's magnetic field. Such substorms kick around the electrons, which then ionise oxygen or nitrogen in the atmosphere, which again, when recombining, emit the beautiful green and red lights.
If you think it's quite an idle project to work on improvements of Auroral Activity Forecasts, keep in mind that such predictions are extremely useful for those of us living at comfortable distance from the poles not to sleep on the rare occasions when we can witness these fantastic lights at low latitudes.
- The NASA THEMIS website has more information about auroras and the magnetosphere including instructive multimedia
- See also this video for the THEMIS Launch Preview
- Spacedaily: THEMIS Launch Now Set for Feb 16
TAGS: GEOPHYSICS, AURORA, NASA