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August 12, 2013 - Solar Secret Revealed

Solar Secret Revealed A solar eclipse that occurred 145 years ago this week led to an unexpected discovery about Earth. While studying the Sun using a spectroscope, French astronomer Pierre Janssen detected a line in the Sun’s spectrum that did not correspond to the chemical signature of any known element. Observations of the Sun later in 1868 by English astronomer Norman Lockyer confirmed it was caused by a new element, which he named after helios, the Greek word for the Sun. Not discovered on Earth until 1895, helium is the second most abundant element in the Universe, after hydrogen. In this image of the Sun by the Solar Dynamics Observatory, light from doubly-ionized helium reveals the delicate structure of enormous erupting prominences. The black circle is Venus, during its 2012 transit.

Image credit: NASA / Goddard Space Flight Center / SDO

Weekly Calendar

August 12-18, 2013

Holidays - Sky Events - Space History

Moon phase Monday 12

Spica 0.6° south of Moon
Perseid meteor shower

1877: Asaph Hall discovers Deimos, moon of Mars
1960: Echo 1 satellite launched on first successful Delta rocket
1962: Vostok 4 launched
1977: HEAO-1 launched
1977: Space shuttle Enterprise’s first glide test
2005: Mars Reconnaissance Orbiter launched

Moon phase Tuesday 13

Saturn 3° north of Moon
Perseid meteor shower

Moon phase Wednesday 14

First Quarter Moon 6:56 AM ET

Moon phase Thursday 15

Moon phase Friday 16

1963: M2-F1 lifting body makes first glide flight after being towed aloft by a C-47

Moon phase Saturday 17

Ceres in conjunction with Sun

1966: Pioneer 7 launched
1970: Venera 7 launched
2006: Voyager 1 is 100 AU from Earth

Moon phase Sunday 18

Moon at perigee

1868: Total solar eclipse leads to discovery of helium
1877: Asaph Hall discovers Phobos
1960: Discoverer XIV launched, first successful US photo reconnaissance satellite
1993: First DC-X flight
1999: Cassini spacecraft flies by Earth

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