April 20, 2009 - Three of a Kind

2009 Week 17 c

Three of a Kind Although the nebulae in deep space do resemble clouds, their composition is quite different from their terrestrial namesakes, which are composed primarily of condensed water vapor. This image by amateur astronomer R. Jay GaBany depicts three different types of nebulae that lie about five thousand light-years away in the constellation Sagittarius. Barnard 91 is the prominent dark nebula, a molecular cloud (usually composed primarily of hydrogen) that contains enough dust grains to become opaque. IC 1274 is the blue reflection nebula, a cloud of gas and dust that simply reflects or scatters the light of nearby stars. The red regions are emission nebulae, clouds of ionized gas emitting light of various colors (as neon lights do), usually activated by radiation emitted from a nearby hot star.

Image Credit:  R. Jay GaBany / www.cosmotography.com

Weekly Calendar

April 20-26, 2009

Holidays - Sky Events - Space History

Monday 20

1972: Apollo 16 lands on Moon

Tuesday 21

Lyrid meteor shower

1997: Cremated remains of 24 people launched into orbit aboard Pegasus rocket in first space funeral

Wednesday 22

Uranus  5° S of Moon
Venus 1.1° S of Moon
Lyrid meteor shower

Thursday 23

1858: Max Planck born
1962: Ranger 4 launched
1963: M2-F1 lifting body first free flight
1996: Priroda module launched to Mir space station

Friday 24

New Moon 11:23 pm

1970: China becomes fifth nation to launch its own satellite
1990: STS-31 Discovery launched

Saturday 25

1962: Second Block I Saturn C-1 (SA-2) launched
1990: Hubble Space Telescope deployed
2003: ISS Expedition Seven crew launched on Soyuz TMA-2

Sunday 26

Mercury at greatest elongation (20° E)
Merucry 1.9° south of Moon

1920: Shapley-Curtis debate on the nature and distance of spiral nebulae
: STS-55 Columbia launched

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