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February 13, 2012 - Auroras Gone Wild

Auroras Gone Wild The displays of slowly-shimmering lights visible at night in far northern and southern latitudes are known as the aurora borealis and aurora australis. These glowing ribbons of light occur when highly charged particles from the Sun collide with atoms high in Earth’s atmosphere. This ionization process releases photons which we see as green, brown, red, or bluish lights. Five years ago this week, NASA launched the Time History of Events and Macroscale Interactions during Substorms (THEMIS) mission, a fleet of five spacecraft, to understand what causes substorms—sudden and frequent intensifications in the auroras. THEMIS discovered that substorms are triggered by magnetic reconnection, a sort of whiplash action in Earth’s magnetic field that releases trapped solar energy.

Image credit: NASA / Goddard Space Flight Center Conceptual Image Lab

Weekly Calendar

February 13-19, 2012

Holidays - Sky Events - Space History

Moon phase Monday 13

1852: Johan Dreyer born
1937Sigmund Jähn born, first German to fly in space

Moon phase Tuesday 14

Valentine’s Day

Last Quarter Moon 12:04 PM ET

1972: Luna 20 launched
1980: Solar Max launched
1990: Voyager 1 takes solar system "family portrait"
2000: NEAR-Shoemaker orbits asteroid Eros

Moon phase Wednesday 15

1564: Galileo Galilei born
1973: Pioneer 10 becomes first spacecraft to pass through the asteroid belt

Moon phase Thursday 16

1948: Gerard Kuiper discovers Miranda, moon of Uranus
1965: Saturn SA-9 launched

Moon phase Friday 17

1959: Vanguard 2 launched
1965: Ranger 8 launched
1996: NEAR-Shoemaker spacecraft launched
2007: THEMIS spacecraft launched
2009Dawn spacecraft flies by Mars

Moon phase Saturday 18

1930: Pluto discovered by Clyde Tombaugh
1970: HL-10 sets lifting body speed record
1977: First captive flight of space shuttle Enterprise

Moon phase Sunday 19

Neptune in conjunction with Sun

1473: Nicholas Copernicus born
1986: Mir space station launched

Suggestions for new history dates or better links? Corrections for errors on this page? Please e-mail me.