May 16, 2011 - Elementary Discovery

Elementary Discovery Astronomers have developed ingenious ways to wring information out of the light they observe from distant objects. Using a spectroscope, for example, they dissected sunlight into its component spectrum and compared it to the unique spectra of known elements. But during the solar eclipse of 1868, both Joseph Lockyer and Pierre Janssen independently detected an element in the Sun’s spectrum that was as yet unknown on Earth. Lockyer, who was born 175 years ago this week, proposed the name helium, after the Greek helios, meaning Sun. Not discovered on Earth until 1895, helium is the second most abundant element in the Universe, after hydrogen. In this narrow-band SOHO image of the Sun, light from doubly-ionized helium reveals the delicate structure of enormous erupting prominences.

Image credit: SOHO (ESA & NASA)

Weekly Calendar

May 16-22, 2011

Holidays - Sky Events - Space History

Monday 16

2011: STS-134 Endeavour launched, final shuttle mission

Tuesday 17

Full Moon 7:09 AM ET

1836: Norman Lockyer born

Wednesday 18

1969: Apollo 10 launched
1984: Viking 1 lander given to National Air & Space Museum
1996: First test flight of DC-XA rocket
: 23rd and final spacewalk to service the Hubble Space Telescope

Thursday 19

Mercury 2° south of Mars

1965: Apollo A-003 launched
1996: STS-77 Endeavour launched
2000: STS-101 Atlantis launched

Friday 20

1978: Pioneer-Venus 1 launched
1995: Spektr module launched to Mir space station

Saturday 21

2010: IKAROS spacecraft launched; first successful solar-sail propulsion

Sunday 22

Venus 1.1° south of Mars

1969: Apollo 10 lunar module descends to within 50,000 feet of the lunar surface

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