Starship Asterisk*

Posted: **Thu Apr 03, 2014 4:11 am**

At the Edge of NGC 2174

Explanation: This fantastic skyscape lies near the edge of NGC 2174 a star forming region about 6,400 light-years away in the nebula-rich constellation of Orion. It follows mountainous clouds of gas and dust carved by winds and radiation from the region's newborn stars, now found scattered in open star clusters embedded around the center of NGC 2174, off the top of the frame. Though star formation continues within these dusty cosmic clouds they will likely be dispersed by the energetic newborn stars within a few million years. Recorded at infrared wavelengths by the Hubble Space Telescope, the interstellar scene spans about 6 light-years. The image celebrates the upcoming 24th anniversary of Hubble's launch onboard the space shuttle orbiter Discovery on April 24, 1990.

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Posted: **Thu Apr 03, 2014 5:09 am**

It's fun to blink this image between the visible light and invisible infrared to see all the extra things we missed with visible light. Hidden stars, galaxies, and some likely polar jets in one of the dust pillars which don't have designations yet because they were just revealed by Hubble.

: Click to view full size image 1 or image 2

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Posted: **Thu Apr 03, 2014 10:58 am**

Always awesome, and inspiring, the "built up" look of layers of clouds...

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Posted: **Thu Apr 03, 2014 12:22 pm**

That must have been some good ****. I'm seeing human forms all over that shot, reminiscent of a game of king of the mountain in Hades. I'd better get some rest.

Posted: **Thu Apr 03, 2014 12:24 pm**

The clouds gave birth to HD 42088, an O5 or O6 type star, which is now destroying its birth cloud and, in the process, creating the fantastic cloud shapes.

I found a picture of HD 42088 which I can't open, but I can give you a link to the side where I found it, which is here. HD 42088 is the second picture in the second row from the top. It looks like this star just might be the magnificent luminary of a small cluster, or else we are just seeing some sort of photographic scatter or flaw.

Ann

Posted: **Thu Apr 03, 2014 1:17 pm**

Today’s APOD really is a fantastic image. It really does give a dramatic impression of depth, even though it’s a 2D image. Wow. From foreground “nearby” stars many light-years away to huge galaxies made tiny by their tremendous distances, with an eroding (melting?) multi-layered “mountain” of star forming dust in between.

I don’t know why, but I find the orientation of the APOD with the open areas on the top more appealing than other images like those geckzilla provided with the clearer space to the right. Perhaps it’s because it looks more like a landscape…

Bruce

Posted: **Thu Apr 03, 2014 3:16 pm**

How close together are the stars in this image generally? In the interstellar scene link, the Orientation/Scale makes some of the stars appear to be much less than a light year apart?

Posted: **Thu Apr 03, 2014 3:43 pm**

Ron-Astro Pharmacist wrote:How close together are the stars in this image generally? In the interstellar scene link, the Orientation/Scale makes some of the stars appear to be much less than a light year apart? :?:

Practically none of the stars in this image are near the nebula. And of course, you can't use the scale at all to estimate (non-angular) separations for objects that aren't at the same radial distance- especially for those that aren't at the distance of the nebula itself, which is the only distance the scale is valid for.

Most of the stars we see are separated from others by tens to thousands of light years. The few stars that are part of the nebula might be as close as a light year or two in some cases.

Posted: **Thu Apr 03, 2014 4:45 pm**

Hubble keeps on amazing - what a team effort. Beautiful image.

And thank you geckzilla for the "blink" image, that was also very informative.

Posted: **Thu Apr 03, 2014 5:11 pm**

I wonder if we can detect the movement of the clouds over short periods of time. If we pointed Hubbel at the same coordinates in a year or two, would the two images be identical? I suspect they would be, considering the enormous distances involved, where a millimeter on the printed image is a bazzilion kilometers.

Posted: **Thu Apr 03, 2014 5:31 pm**

geckzilla wrote:It's fun to blink this image between the visible light and invisible infrared to see all the extra things we missed with visible light. Hidden stars, galaxies, and some likely polar jets in one of the dust pillars which don't have designations yet because they were just revealed by Hubble.

Click to view full size image 1 or image 2

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That's very cool, thanks! I'm taking a moment to be grateful for the ability of infrared and radio waves to penetrate stuff that is opaque to optical light. When I turn on my heater, I can feel the warmth even through my clothing (okay, most of that is convection rather than radiation, but still). And my radio and television receive a signal even though the antennas are completely inside the building! Pretty neat.

P.S. So April 24, 2015 will be Hubble's 25 anniversary? We should plan a party. Can a space telescope eat cake?

Posted: **Thu Apr 03, 2014 6:04 pm**

Oh, and while we're at it, let's be grateful that our atmosphere is transparent to visible light, but largely opaque to ultraviolet, x-rays, and gamma rays! Wouldn't want to get a gamma ray sunburn.

Posted: **Thu Apr 03, 2014 6:21 pm**

Anthony Barreiro wrote:Oh, and while we're at it, let's be grateful that our atmosphere is transparent to visible light, but largely opaque to ultraviolet, x-rays, and gamma rays! Wouldn't want to get a gamma ray sunburn.

Were it different, we might have evolved different senses entirely. And you'd be happy for that optically opaque atmosphere preventing you from getting a visible ray sunburn.

Posted: **Thu Apr 03, 2014 6:53 pm**

Chris Peterson wrote:
Anthony Barreiro wrote:Oh, and while we're at it, let's be grateful that our atmosphere is transparent to visible light, but largely opaque to ultraviolet, x-rays, and gamma rays! Wouldn't want to get a gamma ray sunburn.
Were it different, we might have evolved different senses entirely. And you'd be happy for that optically opaque atmosphere preventing you from getting a visible ray sunburn.

If we were able to tolerate exposure to gamma rays, how could we get a sunburn from much lower energy optical light? We don't get sunburns from the Sun's radio waves (although I think most people are much too blase about carrying a microwave transmitter, aka cell phone, next to their body 24/7 -- the inverse square law is your friend!).

Posted: **Thu Apr 03, 2014 7:03 pm**

I think you went the wrong way, Anthony. The opaque atmosphere wouldn't let anything but infrared and longer through. These creatures would have no tolerance for red light, much less UV and gamma rays.

Posted: **Thu Apr 03, 2014 7:07 pm**

geckzilla wrote:I think you went the wrong way, Anthony. The opaque atmosphere wouldn't let anything but infrared and longer through. These creatures would have no tolerance for red light, much less UV and gamma rays.

There are materials that are opaque to visible light and will let shorter wavelength radiation pass. (But I agree, typical gaseous atmospheres occurring naturally are likely to be as you describe.)

Posted: **Thu Apr 03, 2014 7:09 pm**

I forgot all about the aluminum foil atmosphere planet. Those guys have it rough.

Posted: **Thu Apr 03, 2014 7:24 pm**

geckzilla wrote:
I forgot all about the aluminum foil atmosphere planet. Those guys have it rough.

http://en.wikipedia.org/wiki/Tin_foil_hat wrote:
<<The concept of a tin foil hat for protection against interference of the mind was mentioned in a science fiction short story by Julian Huxley, "The Tissue-Culture King", first published in 1927, in which the protagonist discovers that "caps of metal foil" can block the effects of telepathy. Over time the term has been associated with paranoia and conspiracy theories. They are worn by believers to prevent mind control by governments, spies, or paranormal beings, employing ESP or technologies such as microwave radiation.

The notion that a tin foil hat can significantly reduce the intensity of incident radio frequency radiation on the wearer's brain has some scientific validity, as the effect of strong radio waves has been documented for quite some time. A well-constructed tin foil enclosure would approximate a Faraday cage, reducing the amount of (typically harmless) radiofrequency electromagnetic radiation passing through to the interior of the structure. A study by graduate students at MIT determined that a tin foil hat could attenuate incoming radiation depending on frequency. At WIFI frequencies - 2.4 GHz is attenuated by up to 90 dB; the effect was observed to be roughly independent of the relative placement of the wearer and radiation source. At some microwave wavelengths, the skin depth is less than the thickness of even the thinnest foil.>>

Posted: **Thu Apr 03, 2014 7:34 pm**

geckzilla wrote:I think you went the wrong way, Anthony. The opaque atmosphere wouldn't let anything but infrared and longer through. These creatures would have no tolerance for red light, much less UV and gamma rays.

I was following Chris' hypothetical scenario of an atmosphere transparent to gamma rays and opaque to optical light, or at least I thought I was.

Posted: **Thu Apr 03, 2014 8:03 pm**

Well, he didn't say it was transparent to gamma rays. Then again, he didn't say it was opaque to them, either.

Posted: **Thu Apr 03, 2014 8:52 pm**

While comparing the images that geckzilla kindly shared, one of the stars (upper right corner, about 1 o'clock) appears to be in a different position!

Is this a known phenomena or an optical illusion of some kind?

Posted: **Thu Apr 03, 2014 9:34 pm**

geckzilla wrote:Well, he didn't say it was transparent to gamma rays. Then again, he didn't say it was opaque to them, either.

He also didn't say that pigs could fly, but he didn't say they couldn't, either. Once you start wandering around in counterfactual hypothetical land, it's easy to lose your bearings.

Posted: **Thu Apr 03, 2014 10:53 pm**

Astro Quake wrote:While comparing the images that geckzilla kindly shared, one of the stars (upper right corner, about 1 o'clock) appears to be in a different position!

Is this a known phenomena or an optical illusion of some kind?

A little of both. I'd guess at least one is a cosmic ray hit which just happens to be sort of near a real star or another cosmic ray hit in the other image. I don't see any real stars moving, though it does happen quite a lot when you have two images of the same thing a few years apart. Parallax can cause nearby stars to look as if they are moving even over short periods of time, say while the telescope is on one side of the earth and then moving to the opposite side. Other than that, stars do move. Neither of those are happening noticeably in the blink image, though.

It's funny, because the specks of cosmic rays which are completely and utterly mundane, boring things, but when you don't know what they are they seem mysterious and exciting. They're just a confusing nuisance. The vast majority of them are cleaned off the images but sometimes they sneak in if they are small or look enough like a star.

Posted: **Thu Apr 03, 2014 11:55 pm**

Unbelieveable!
24 years old and it still keeps working

Starship Asterisk*

APOD: At the Edge of NGC 2174 (2014 Apr 03)

APOD: At the Edge of NGC 2174 (2014 Apr 03)

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