APOD: Halloween and the Ghost Head Nebula (2010 Oct 31)

[APOD Robot]

Halloween and the Ghost Head Nebula

Explanation: Halloween's origin is ancient and astronomical. Since the fifth century BC, Halloween has been celebrated as a cross-quarter day, a day halfway between an equinox (equal day / equal night) and a solstice (minimum day / maximum night in the northern hemisphere). With a modern calendar, however, the real cross-quarter day will occur next week. Another cross-quarter day is Groundhog's Day. Halloween's modern celebration retains historic roots in dressing to scare away the spirits of the dead. Perhaps a fitting tribute to this ancient holiday is this view of the Ghost Head Nebula taken with the Hubble Space Telescope. Similar to the icon of a fictional ghost, NGC 2080 is actually a star forming region in the Large Magellanic Cloud, a satellite galaxy of our own Milky Way Galaxy. The Ghost Head Nebula spans about 50 light-years and is shown in representative colors.

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[jkbonner]

That is a beautiful post.

[Ann]

NGC 2080 and friends in the Large Magellanic Cloud.

Click to view full size image

Ann

[orin stepanek]

by geckzilla » Sat Oct 30, 2010 2:36 pm

Ahhh this is a great Halloween themed APOD. I was hoping for something other than the witch head again and glad she got a much deserved break!

Looks like that witch got that break!

Click to play embedded YouTube video.

[owlice]

B O O !


Did I scare you?


Wonderful image, great text, with lots of information. I know more about Halloween and Groundhog's Day than I thought possible! And I thought Parentalia was something completely different from what I now know it is!

I like the dancing skeletons on one of the linked sites.

dancing_skeletons.gif (12.78 KiB) Viewed 4510 times

All dancing skeletons should have purple top hats!

In the thumbnail picture, the nebula looks a bit like an owl; in the large version (clicking through to a bigger image), a bit like a flower. It's a lovely nebula.

Next year's pumpkin will look like this:


Wish I'd seen that earlier, I do I do.

[León]

More information about de image http://photojournal.jpl.nasa.gov/catalog/PIA04226

Returning from a trip to the Galapagos Islands where persistently seek the ghosts of the pirates who hid in the island, and I find that in parallel Apod has dealt with the ghosts in the week.
Not found but some parishioners exhibited a knowing smile to my question
http://blogdeamigos.blogspot.com/
The ghost of a pirate, from Howard Pyle's Book of Pirates (1903).

[neufer]

Ahhh this is a great Halloween themed APOD.
I was hoping for something other than the witch head again and glad she got a much deserved break!

Aah; but Halloween is Sunday. We could get her (the Witch) yet.

But we didn't.

Surprisingly, the ubiquitous witch's head & witch's broom nebulae
have only shown up ONCE in a 'Halloween themed' APOD: in 2008.

The Ghost Head Nebula, OTOH, has returned for Halloween every three years (2001, 2004, 2007, 2010)
making it the most popular Halloween themed APOD of the 21st century.
(Although, NGC 2080, could also be called the Owl or the Cat Nebula.)

[biddie67]

Halloween or not, this is a magnificent photo!!

The info about the staggered and reluctant acceptance of the current calendar was fascinating; as was learning about cross-quarter days!! There are so many unexpected directions to the influence of the universe on humans over the eons ...

Happy Halloween, all !!!!!

[Ann]

Surprisingly, the ubiquitous witch's head & witch's broom nebulae
have only shown up ONCE in a 'Halloween themed' APOD: in 2008.

That's not enough! We need her NOW!

Click to view full size image

Here is a blue Witch Head contemplating a very BLUE Rigel! Note the Witch's stylish hat!

Ann

[Ann]

The info about the staggered and reluctant acceptance of the current calendar was fascinating

It's incredible to think about.

Today quite a few people think that their government is robbing them when they are forced to pay taxes. Imagine, then, having ten (or eleven, twelve or even thirteen) days actually stolen from you by your government!

I'd say we are not as oppressed these days as some people like to think!

Ann

[bystander]

Happy Samhain and All Hallows Even.

http://asterisk.apod.com/vie ... 29&t=21808

[neufer]

http://apod.nasa.gov/apod/ap100104.html
http://asterisk.apod.com/vie ... 25&start=0

Code: Select all

Attributes               Halley       Borrelly      Hartley 2
-----------------------------------------------------------------------
Aphelion distance:   	 35.1 AU 	   5.83 AU 	   5.87 AU
Perihelion distance: 	  0.583 AU     1.35 AU 	   1.05 AU
Semi-major axis: 	     17.8 AU 	   3.59 AU 	   3.46 AU
Eccentricity: 	         0.967 	    0.624 	     0.694
Orbital period: 	      75.3  	     6.8  	      6.46
Inclination: 	        162.3° 	    30.3° 	     13.6°
Dimensions:              15×8×8 km    8×4×4 km    2.2×0.7×0.7 km
Albedo:                   0.04         0.03          0.028
Density:                  0.6 g/cm³    0.3 g/cm³   

[robolt]

How far apart are the molecules of the gases that form the image? If we had a cubic foot of the stuff, are the individual gases in a concentration we could detect?

[neufer]

How far apart are the molecules of the gases that form the image?
If we had a cubic foot of the stuff, are the individual gases in a concentration we could detect?

It's about one atom per cubic centimeter (or 30,000 atoms in a cubic foot).

<<Bok globules or Thackeray's Globules are dark clouds of dense dust and gas in which star formation sometimes takes place. Bok globules are found within H II regions, and typically have a mass of about 2 to 50 solar masses (i.e., up to 1×10³² kg) contained within a region about a light year or so across (about 4.5 × 10⁴⁷ m³). They contain molecular hydrogen (H2), carbon oxides and helium, and around 1% (by mass) of silicate dust.>>

• Vacuum __________________ Pressure (Torr)
  ------------------------------------------------------------
  Low vacuum _______________ 760 to 25
  Medium vacuum ____________ 25 to 1×10⁻³
  High vacuum _____________ 1×10⁻³ to 1×10⁻⁹
  Ultra high vacuum _________ 1×10⁻⁹ to 1×10⁻¹²
  Extremely high vacuum _______ <1×10⁻¹²
  Bok globules _____________ 6×10⁻¹⁶ to 15×10⁻¹⁵ (at room temperature)

------------------------------------------------------------------------------------------------------------------------
# Low vacuum, also called rough vacuum or coarse vacuum, is vacuum that can be achieved or measured with rudimentary equipment such as a vacuum cleaner and a liquid column manometer.

# Medium vacuum is vacuum that can be achieved with a single pump, but the pressure is too low to measure with a liquid or mechanical manometer. It can be measured with a McLeod gauge, thermal gauge or a capacitive gauge.

# High vacuum is vacuum where the MFP of residual gases is longer than the size of the chamber or of the object under test. High vacuum usually requires multi-stage pumping and ion gauge measurement. Some texts differentiate between high vacuum and very high vacuum.

# Ultra high vacuum requires baking the chamber to remove trace gases, and other special procedures. British and German standards define ultra high vacuum as pressures below 10⁻⁶ Pa (~10⁻⁸ Torr).

Deployment of the WSF using the Space Shuttle robotic arm. Night period STS-60 photo

---

<<Wake Shield Facility is an experimental science platform that was placed in low-earth orbit by the Space Shuttle. It is a 3.7 meter (12 ft) diameter, free-flying stainless steel disk. The WSF is deployed in the wake of the Space Shuttle at an orbital altitude of over 300 kilometers (186 mi), within the thermosphere, where the atmosphere is exceedingly tenuous. The forward edge of the WSF disk redirects atmospheric and other particles around the sides, leaving an "ultra-vacuum" in its wake. The resulting vacuum is used to study epitaxial film growth. Pre-flight calculations suggested that the pressure on the wake side could be decreased by some 6 orders of magnitude over the ambient (10⁻⁸ Torr) pressure in low earth orbit. Analysis of the pressure and temperature data gathered from the two flights concluded that the decrease was some 2 orders of magnitude or 4 orders of magnitude less than expected (i.e., from 10⁻¹⁰ to 10⁻¹² Torr).

[BMAONE23]

It reminded me of this

[Ann]

http://www.telegraph.co.uk/culture/tvan ... erage.html



Ann

[neufer]

WHO is this supposed to be:

1) Ann with her cat or
2) Owlice with her owl?

http://asterisk.apod.com/vie ... 96#p131896

[owlice]

Can't be my cat; my black cat has a white bib.

Puddems

And the owl doesn't look right, either.

One-eyed Jack

Neufer, this is for you.

[DavidLeodis]

Spooky (and nice) APOD.

Even spookier is that in the information brought up through the 'Ghost Head Nebula' link it states "This "enhanced color" picture is composed of three narrow-band-filter images obtained by Hubble on March 28, 2000" yet the image is also stated to have been added to the Jet Propulsion Laboratory Photojournal website on 1999-12-03 (under PIA04226). It was thus added before it was acquired! Now that is spooky.