Starship Asterisk*

DavidLeodis wrote:The image seemed familiar and I wanted to know when it was acquired, but on doing a search of the APOD archive it did not seem to have been used before so I found some Exif data through the APOD image properties (if the Exif data was available through the image in the NOAO website I could not obtain any). In the APOD image Exif data it stated "Create Date 2012:02:02 16:41:11-09:00...Modify Date 2013:07:17 10:12:14-07:00...Temporal Start Time 2009:11:11 02:07". Could someone please let me know what "Temporal Start Time" is, which here is about 2 years 3 months before the Exif "Create Date"! Thanks in anticipation.

Nitpicker wrote:

geckzilla wrote:
Well, if we run out of new things to learn about space, we can switch it over to Arthropod Picture of the Day. There are probably still a few million unknown species of them running around.

That is already part of the arthropods' secret plan for total world domination.

MarkBour wrote:
Can anyone give me a ride up to Hubble tonight, where I can view [the lunar eclipse] from above the clouds? I'd accept the ride from almost anyone, just not George Clooney.

http://www.nasa.gov/vision/universe/solarsystem/hubble_moon.html wrote:
<<The moon is a difficult target for Hubble because it moves across the sky faster than Hubble can track it and is very dim in ultraviolet light. The observations required steady, precise, as well as long exposures to search for resources. In spite of these challenges, Hubble was able to image all of its targets, and early results show that Hubble can detect ilmenite at the Apollo 17 site from 400,000 km away.>>

• The Hubble lunar conspiracy

Chris Peterson wrote:I predict that in another year or two we will have seen everything there is to see, discovered everything there is to discover, know everything there is to know. Then the APOD editors can retire. There are only a handful of thesis topics still remaining, so choose quickly!

MarkBour wrote:Hmmmm ... I wasn't aware that Chris had a sarcastic side.

Ron-Astro Pharmacist wrote:Chris – I think you know a lot more than I'll ever contemplate knowing about much of physics and astronomy but that statement sounds a lot like the Munich physics professor Philipp von Jolly when he advised Max Planck against going into physics - saying, "In this field, almost everything is already discovered, and all that remains is to fill a few holes."

Chris Peterson wrote:

Psnarf wrote:APOD Job Security: Discovery of such wonders will never cease. How do you choose a thesis topic when there is so much 'there' there?

I predict that in another year or two we will have seen everything there is to see, discovered everything there is to discover, know everything there is to know. Then the APOD editors can retire. There are only a handful of thesis topics still remaining, so choose quickly!

Psnarf wrote:APOD Job Security: Discovery of such wonders will never cease. How do you choose a thesis topic when there is so much 'there' there?

starsurfer wrote:
This is the first time I have seen it described as a cometary globule.
This is incorrect and it is one example of a bright rimmed globule.

http://en.wikipedia.org/wiki/Comet wrote:
<<The word comet derives from the Old English cometa from the Latin comēta or comētēs. That, in turn, is a latinisation of the Greek κομήτης ("wearing long hair"), and the Oxford English Dictionary notes that the term (ἀστὴρ) κομήτης already meant "long-haired star, comet" in Greek. Κομήτης was derived from κομᾶν ("to wear the hair long"), which was itself derived from κόμη ("the hair of the head") and was used to mean "the tail of a comet".>>

http://en.wikipedia.org/wiki/Coma_%28cometary%29 wrote:
<<Coma is the nebulous envelope around the nucleus of a comet. It is formed when the comet passes close to the Sun on its highly elliptical orbit; as the comet warms, parts of it sublimate. This gives a comet a "fuzzy" appearance when viewed in telescopes and distinguishes it from stars. The word coma comes from the Greek "kome", in Greek written as κόμη, and can be translated as "hair".>>

zbvhs wrote:
"Eating away the dust" What does that mean? Consuming somehow or merely pushing aside?

• Ionizing and pushing aside:

http://apod.nasa.gov/apod/ap131012.html wrote:
Energetic ultraviolet light from nearby hot stars has molded the globules and ionized their bright rims.

http://en.wikipedia.org/wiki/Pillars_of_Creation wrote:
<<The "Pillars of Creation" are composed of cool molecular hydrogen and dust that are being eroded by photoevaporation from the ultraviolet light of relatively close and hot stars. The finger-like protrusions at the top of the clouds are made visible by the shadows of Evaporating Gaseous Globules (EGGs), which shields the gas behind them from intense UV flux. EGGs are themselves incubators of new stars. An evaporating gas globule or EGG is a region of hydrogen gas approximately 100 astronomical units in size, such that gases shaded by it are shielded from ionizing UV rays. Dense areas of gas shielded by an evaporating gas globule can be conducive to the birth of stars.

[b][color=#0000FF]Photoevaporation occurring to a protoplanetary disk due to the presence of a nearby O-type star[/color][/b]

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Photoevaporation denotes the process when a planet is stripped of its atmosphere (or parts of the atmosphere) due to high energy photons and other electromagnetic radiation. If a photon interacts with an atmospheric molecule, the molecule is accelerated and its temperature increased. If sufficient energy is provided, the molecule or atom may reach the escape velocity of the planet and "evaporate" into space. The lower the mass number of the gas, the higher the velocity obtained by interaction with a photon. Thus hydrogen is the gas which is most prone to photoevaporation.>>