Horsehead history, fusion, orientation, repeat (06 Apr 2008)

[neufer]

http://apod.nasa.gov/apod/ap080406.html

[stargazer_7000]

...in 2006:
http://antwrp.gsfc.nasa.gov/apod/ap060221.html

exactly the same words and the same image.

I wonder why?

[henk21cm]

...in 2006:

exactly the same words and the same image.
I wonder why?

Repetition is the art of teaching. During the recent month the subject of star formation, star evolution has been discussed in some extent. That might be the reason for bringing up this image again. Such repetition of images isn't the first time, nor will it be the last time, afaik.

Is it bothering you?

Regards,
Henk

[henk21cm]

The image of 20080406 has been rotated over 90°. I had some trouble finding the two stars of the belt. The leftmost star of the belt is about 10% of the width of the image, translated to the left of the horsehead nebula, slightly upwards. The middle star of the belt is 135° upwards from the horsehead nebula, about 30% from the top of the image. It is much brighter than the leftmost beltstar.

The fact that the image was produced by earth bound amateurs is amazing. Chapeau! When i look at the sky, Orion is difficult to find, due to light polution. At the rare evenings when there is no cloudcover, when i open the shutter of my camera, after 15 seconds i get an image which beares a strong resemblence with those precious sunny summer days.

Regards,
Henk

[stargazer_7000]

hi Henk,

I was not aware NASA APOD is intending to teach ...
I just thought there must be lots of gorgeous images submitted to APOD people, that are sure worth being posted.

it does not bother me at all, since this specific APOD of today is such a wonderful rendition of that very sky-area. it just looks, like there were no new unpresented images in stock,...so they had to take the same image again...
however, a new text with new links for "teaching" would have been appreciated

never mind - it is A.O.K. since it was Jerry's and Robert's idea to create NASA APOD in the first place. (I think)

[drbuck917]

A question for the professionals. The picture of the day today showing all the hydrogen around the horsehead nebula lead me to wonder.

Do the professional astronomers feel that perhaps their studies may in some way lead to our being able to obtain energy from nuclear fusion, or perhaps a fission, fusion, fission, fusion reaction which might use up all the material and leave little or no radioactive waste?

Pardon my ignorance if this seems like a naive question but I profess ignorance in these areas.
David

[tekic545]

I fully agree with Dietmar. What's the point of repeating an APOD, especialy of a familiar object, when there's so much else to be seen, and such a variety of great new images to draw on?

"Teaching by repetition" is no excuse. If you want repetition, go to the archive.

Bob

[Case]

Here's an image showing the location of the APOD in Orion, for the visual minded.

[DavidLeodis]

I have been looking at the APOD for many years now and have no problem with images being shown again. There will also be viewers that have never seen them. I think good images are worth repeating.

[RJN]

http://antwrp.gsfc.nasa.gov/apod/ap_faq.html
Please see Q4. - RJN

[Dr. Skeptic]

The fusion of deuterium atoms is a very "clean" technique to harvest energy - with waste product of He+ and about as much residual radiation as coal burning - its the fuel confinement that makes commercial viability difficult.

[bystander]

For all the detractors of APOD for the occassional repeat of material, perhaps you would like to donate your time to research images, subjects, and relevant links in order to provide the rest of us with completely new material everyday, 365 days a year. All for free, of course.

Hey, neufer, what are you doing? You seem to have the time and resources. (just joking, though you might be a good pick)

My compliments and thanks to Jerry, Robert, and all the folks at APOD for the wonderful job they do. (u2 art)

[bystander]

The fusion of deuterium atoms is a very "clean" technique to harvest energy - with waste product of He+ and about as much residual radiation as coal burning - its the fuel confinement that makes commercial viability difficult.

Providing the fuel wouldn't exactly be simple and inexpensive.

[neufer]

For all the detractors of APOD for the occassional repeat of material, perhaps you would like to donate your time to research images, subjects, and relevant links in order to provide the rest of us with completely new material everyday, 365 days a year. All for free, of course.

Hey, neufer, what are you doing? You seem to have the time and resources. (just joking, though you might be a good pick)

My compliments and thanks to Jerry, Robert, and all the folks at APOD for the wonderful job they do. (u2 art)

Thanks, bystander, and my compliments and thanks, as well, "to Jerry, Robert, and all the folks at APOD for the wonderful job they do."

I think the solution for me and others who are hooked on APOD and can't get enough is to browse other excellent (and active) astronomy sites.
Today's link to http://www.planetary.org/blog/ is a good start and after perusing it I definitely plan to both participate & join The Planetary Society.

[iamlucky13]

http://antwrp.gsfc.nasa.gov/apod/ap_faq.html
Please see Q4. - RJN

Exactly! The FAQ is well put.

One related comment though, is that the Horsehead Nebula does seem to come up quite often. A search shows two (different) APOD's with this nebula already in 2008, plus several more last year. The search brought 45 hits total, although not all of them are explicitly about the Horsehead Nebula.

[bystander]

A couple of astronomy sites I view regularly are:

High Energy Astrophysics Picture Of the Week http://heasarc.gsfc.nasa.gov/docs/objects/heapow/

Canada France Hawaii Telescope (CFHT) Hawaiian Starlight
CFHT Astronomy Image of the Month http://www.cfht.hawaii.edu/HawaiianStarlight/

[iamlucky13]

I'm not an astronomer, but I am as avidly interested in energy, including fusion as I am in astronomy.

A lot of early fusion research involved understanding the sun, and separately, developing nuclear weapons. Probably back in the 1960's or so, most of the common details had been worked out, and fusion energy and weapons research became mostly independent of astronomy.

As far as identifying fuel for fusion in space, if that's what you were curious about, it's not necessary. We have abundant hydrogen on earth. Currently, fusion research is being done using deuterium and tritium as fuels. Deuterium makes up 0.015% of all hydrogen on earth, which might not sound like much, but there is a lot of hydrogen on earth. Both deuterium and tritium can also be produced in laboratories or as a byproduct in nuclear reactors.

The process isn't quite clean, but it is a lot cleaner than fission with uranium, etc. The reaction product is ordinary helium, hydrogen fusion releases a lot of high energy neutrons. These neutrons are absorbed by metals in the reactor wall, causing them to become low-level radioactive. These metals are much, much less dangerous and easy to dispose of than spent uranium, but still somewhat of a concern.

There is some hope, once hydrogen fusion is perfected, for switching to helium-3 fusion. This requires much higher temperatures and is therefore harder to achieve, but it releases no neutrons. Some space enthusiasts view this as a reason to push hard at manned space exploration as there are higher levels of He-3 on the moon than on earth. However, we are first of all a long, long ways away from being able to use He-3 fusion, and secondly even on the moon you would have to mine millions of tons of dirt for a few pounds of He-3. It can be made artificially on earth much, much easier, in my opinion.

Another benefit of most potential fusion reactor designs is that the total amount of fuel in the reactor at one time is much to low for a major accident to occur. Of course, nuclear fission reactors are increasingly safe, most of them outstandingly so, but fusion is even better in that regards. A complete failure of a Tokamak reactor would only release about as much energy as a small artillery shell, easily contained and trivial compared to the huge steam explosion that destoyed the core of the Chernobyl reactor. In the fusion case, the reaction would stop immediately, where as at Chernobyl it continued for a long time, in addition to a graphite fire which helped spread the radioactive fuel.

[iamlucky13]

Here's an image showing the location of the APOD in Orion, for the visual minded.

Excellent! Thanks.

Of course, the orientation is entirely arbitrary, but for probably most of us based on our experience here in the northern hemisphere.

I can't imagine how hard it must be to get a 7 hour exposure. These amatuers did an outstanding job.

[neufer]

http://home.earthlink.net/~astro-app/ho ... /B33_1.htm

http://antwrp.gsfc.nasa.gov/apod/ap060221.html
http://antwrp.gsfc.nasa.gov/apod/ap070527.html
http://antwrp.gsfc.nasa.gov/apod/ap080221.html
http://antwrp.gsfc.nasa.gov/apod/ap080406.html
http://antwrp.gsfc.nasa.gov/apod/ap080408.html

[bystander]

http://antwrp.gsfc.nasa.gov/cgi-bin/apo ... ?Horsehead