APOD: Sh2-155: The Cave Nebula (2014 Nov 06)

[APOD Robot]

Sh2-155: The Cave Nebula

Explanation: This colorful skyscape features the dusty Sharpless catalog emission region Sh2-155, the Cave Nebula. In the composite image, data taken through narrowband filters tracks the glow of ionized sulfur, hydrogen, and oxygen atoms in red, green, and blue hues. About 2,400 light-years away, the scene lies along the plane of our Milky Way Galaxy toward the royal northern constellation of Cepheus. Astronomical explorations of the region reveal that it has formed at the boundary of the massive Cepheus B molecular cloud and the hot, young stars of the Cepheus OB 3 association. The bright rim of ionized interstellar gas is energized by radiation from the hot stars, dominated by the bright star just above picture center. Radiation driven ionization fronts are likely triggering collapsing cores and new star formation within. Appropriately sized for a stellar nursery, the cosmic cave is over 10 light-years across.

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[userloser]

Cave? Looks like a hungry pidgeon to me.

[Boomer12k]

I was going for "a Robin like Bat", myself. I half expect to see the Photographer in the Picture...as it is a "CAVE"....

Awesome image!! Well done.

:---[===] *

[Ron-Astro Pharmacist]

http://en.wikipedia.org/wiki/Allegory_of_the_Cave

Maybe we are supposed to view the Cave Nebula as an attempt to ascertain the mechanism of star formation. At first we only see the shadow cast by the nebula's dust and gas; not knowing what's going on behind the clouds. If we were able to see the starlight alone we'd be blinded - wishing to return to our naïve status until we could actually conceive of how stars form. Somehow accomplished we'd return to tell those, still in the shadow, how the sun and planets form. Although shunned we'd still be but driven to get our point across lest we be untrue to ourselves. In the end, all know the truth of forming stars.

Bet you didn't know Plato was actually the first astronomer to suggest that we must ultimately uncover how stars form or we will be forever be banished to the "Cave Nebula".

But didn't Glaucon then ask Socrates, "Why don't you take a peek at the stars forming with ALMA?"

http://www.hngn.com/articles/48517/2014 ... detail.htm

[bystander]

But didn't Glaucon then ask Socrates, "Why don't you take a peek at the stars forming with ALMA?"

the-image-is-the-sharpest-image-ever-taken-by-alma.jpg

http://www.hngn.com/articles/48517/2014 ... detail.htm

http://asterisk.apod.com/viewtopic.php?t=34073

[starsurfer]

This region also includes some Herbig Haro objects, they are the small red patches south of the main nebula.

Also it's been a while since a vdB nebula has been included on APOD. Interestingly, if the field of view of this image was wider, it would also have included the reflection nebula vdB155.