APOD: Cluster and Starforming Region 2... (2015 Apr 25)

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Expand view Topic review: APOD: Cluster and Starforming Region 2... (2015 Apr 25)

Re: APOD: Cluster and Starforming Region 2... (2015 Apr 25)

by Chris Peterson » Mon Apr 27, 2015 7:00 pm

tomatoherd wrote:So Chris, if only a small fraction ended up in stars, the larger fraction DID NOT, and so did not achieve fusion and remains invisible (save for the even tinier fraction in illuminated nebulae). So why then cannot this interstellar/intergalactic hydrogen, atomic or molecular, account for the alleged dark matter??
Because hydrogen isn't "dark". In sufficient quantities to create the gravitational influence observed for dark matter, it would be very luminous in multiple wavelengths.

In any case, much of the non-luminous hydrogen is detectable with radio telescopes, or recently with x-ray measurements, found in intergalactic space.

Re: APOD: Cluster and Starforming Region 2... (2015 Apr 25)

by bystander » Mon Apr 27, 2015 5:56 pm

starsurfer wrote:
bystander wrote:
Surprise Cloud Around Vast Star - Credit: ESO/VPHAS+ Survey/N. Wright

Thanks, I remember seeing that before. It is basically the same image in the paper I linked to.

Yes, it is the image from the ESO Picture of the Week that featured that paper.

Re: APOD: Cluster and Starforming Region 2... (2015 Apr 25)

by tomatoherd » Mon Apr 27, 2015 5:40 pm

Chris Peterson wrote:
tomatoherd wrote:Say, how is there still so much unused hydrogen in the universe, at an alleged age of ~14 billion years, to have fresh star formation continuing?
Because there was a lot of hydrogen created. And only a small fraction of it ever ended up in stars.
So Chris, if only a small fraction ended up in stars, the larger fraction DID NOT, and so did not achieve fusion and remains invisible (save for the even tinier fraction in illuminated nebulae). So why then cannot this interstellar/intergalactic hydrogen, atomic or molecular, account for the alleged dark matter??

Re: APOD: Cluster and Starforming Region 2... (2015 Apr 25)

by starsurfer » Sun Apr 26, 2015 11:24 am

bystander wrote:
starsurfer wrote:...
Something that receives even less attention (from amateurs anyway) is Westerlund 1 in the constellation of Ara. ...
Thanks, I remember seeing that before. It is basically the same image in the paper I linked to. Amazing how many other surprises there are waiting to be found. Another cluster that also has small nebulae associated with some of its member stars is NGC 3603, the star Sher 25 is surrounded by a gorgeous hourglass nebula.

Re: APOD: Cluster and Starforming Region 2... (2015 Apr 25)

by Ann » Sun Apr 26, 2015 4:30 am

hoohaw wrote:
Chris Peterson wrote:
tomatoherd wrote:Say, how is there still so much unused hydrogen in the universe, at an alleged age of ~14 billion years, to have fresh star formation continuing?
Because there was a lot of hydrogen created. And only a small fraction of it ever ended up in stars.
In fact, if we did not exist, we would be certain that we could not conceivably exist in this empty, seemingly purposeless, frankly stupid, universe. And yet we DO exist. Hmmmm.......
Hoohaw, the next time you're having an ice cold one, or a golden pizza, or watch a favorite movie or a glorious sunset, or do or see anything else that you like - be thankful to the Big Bang for creating all this hydrogen, so that the tiniest fraction of it could go into creating the Sun, but only after previous generations of stars had recycled the hydrogen and cooked up the rubble that later went into creating your ice cold one and other nice things, including yourself. Be thankful to this "empty" (not!), purposeless (yes, I think so), frankly stupid (c'mon!) universe. It has given you all the pleasure you've ever had in your life!

And in any case... for almost fourteen billion years none of us existed in this universe, and in the blink of an eye and for as long as the universe will exist after that, none of us will exist. And maybe, probably, some time in the utterly inconceivably far future, the universe itself may cease to exist. That's life - and death. You don't blame your mama for giving birth to you, do you?

Ann

Re: APOD: Cluster and Starforming Region 2... (2015 Apr 25)

by bystander » Sat Apr 25, 2015 11:05 pm

Guest wrote:It is time to start planning for Hubble II... Hubble, The Next Generation???
Hubble's replacement, if you want to call it that, is the James Webb Space Telescope (JWST).

Re: APOD: Cluster and Starforming Region 2... (2015 Apr 25)

by hoohaw » Sat Apr 25, 2015 10:05 pm

Chris Peterson wrote:
tomatoherd wrote:Say, how is there still so much unused hydrogen in the universe, at an alleged age of ~14 billion years, to have fresh star formation continuing?
Because there was a lot of hydrogen created. And only a small fraction of it ever ended up in stars.
In fact, if we did not exist, we would be certain that we could not conceivably exist in this empty, seemingly purposeless, frankly stupid, universe. And yet we DO exist. Hmmmm.......

Re: APOD: Cluster and Starforming Region 2... (2015 Apr 25)

by Guest » Sat Apr 25, 2015 9:58 pm

It is time to start planning for Hubble II... Hubble, The Next Generation???

Re: APOD: Cluster and Starforming Region 2... (2015 Apr 25)

by Ann » Sat Apr 25, 2015 3:46 pm

starsurfer wrote: RCW 49/Westerlund 2 is a fantastic counterpart to the much more well known nebula/cluster NGC 3603, which is also in the same constellation of Carina. You can see a wider view here by Don Goldman.
I thought so too when I saw it. Thanks for pointing it out here!

Ann

Re: APOD: Cluster and Starforming Region 2... (2015 Apr 25)

by Ann » Sat Apr 25, 2015 3:43 pm

bystander wrote:
starsurfer wrote:...
Something that receives even less attention (from amateurs anyway) is Westerlund 1 in the constellation of Ara. ...
Thanks, bystander, very interesting.

Ann

Re: APOD: Cluster and Starforming Region 2... (2015 Apr 25)

by bystander » Sat Apr 25, 2015 3:04 pm

Boomer12k wrote:
Happy Anniversary HUBBLE!!!!!

http://asterisk.apod.com/viewtopic.php?t=34695

Re: APOD: Cluster and Starforming Region 2... (2015 Apr 25)

by bystander » Sat Apr 25, 2015 3:03 pm

starsurfer wrote:...
Something that receives even less attention (from amateurs anyway) is Westerlund 1 in the constellation of Ara. ...

Re: APOD: Cluster and Starforming Region 2... (2015 Apr 25)

by Chris Peterson » Sat Apr 25, 2015 2:56 pm

tomatoherd wrote:Say, how is there still so much unused hydrogen in the universe, at an alleged age of ~14 billion years, to have fresh star formation continuing?
Because there was a lot of hydrogen created. And only a small fraction of it ever ended up in stars.

Re: APOD: Cluster and Starforming Region 2... (2015 Apr 25)

by tomatoherd » Sat Apr 25, 2015 12:42 pm

Say, how is there still so much unused hydrogen in the universe, at an alleged age of ~14 billion years, to have fresh star formation continuing?

Re: APOD: Cluster and Starforming Region 2... (2015 Apr 25)

by starsurfer » Sat Apr 25, 2015 12:38 pm

Happy birthday Hubble Space Telescope! I'd hug you if it was possible to!* I'm amazed at how the HST has revolutionised both astrophotography of the cosmos as well as science. Although there have been many amazing new discoveries made with the HST, one of my favourites is the discovery of rings in the outer haloes of planetary nebulae, still an ongoing mystery.

RCW 49/Westerlund 2 is a fantastic counterpart to the much more well known nebula/cluster NGC 3603, which is also in the same constellation of Carina. You can see a wider view here by Don Goldman. This widefield image by Marco Lorenzi also includes the Wolf Rayet Nebula NGC 3199.
Ann wrote:This is a fantastic star cluster that has been very rarely photographed.
Something that receives even less attention (from amateurs anyway) is Westerlund 1 in the constellation of Ara. The region around it includes the dark nebula Sandqvist 191, the emission nebula vBe 1 and a glorious Milky Way field!

*I would love to hug Sandgirl!!!

Re: APOD: Cluster and Starforming Region 2... (2015 Apr 25)

by kennychaffin » Sat Apr 25, 2015 11:14 am

.....Strong winds.....


If only I'd known there were winds in space!
I would have sailed beyond the stars!

:wink:

Re: APOD: Cluster and Starforming Region 2... (2015 Apr 25)

by hoohaw » Sat Apr 25, 2015 11:06 am

All day Thursday there was a 25th year celebration in Baltimore, which I was so happy to be invited to attend ... which I did. A highlight was a video from Nobel Laureate Riccardo Giacconi, former Space Telescope Science Institute director, in retirement, marking the event. We are so fortunate that Bob Brown and Holland Ford and Jim Crocker et al. were able to repair Hubble after the spherical aberration nightmare. Hubble has been, and miraculously still is, the best space science mission ever. Many years more, too, everyone hopes....

Re: APOD: Cluster and Starforming Region 2... (2015 Apr 25)

by Boomer12k » Sat Apr 25, 2015 9:25 am

Happy Anniversary HUBBLE!!!!!

Happy Birthday STARS!!!!!

:---[===] *

Re: APOD: Cluster and Starforming Region 2... (2015 Apr 25)

by Ann » Sat Apr 25, 2015 5:13 am

This is a fantastic star cluster that has been very rarely photographed. For both these reasons, today's sharp and well-resolved APOD is a splendid image and a fitting tribute to the quarter-century-old Hubble Space Telescope.

Ann

APOD: Cluster and Starforming Region 2... (2015 Apr 25)

by APOD Robot » Sat Apr 25, 2015 4:08 am

Image Cluster and Starforming Region Westerlund 2

Explanation: Located 20,000 light-years away in the constellation Carina, the young cluster and starforming region Westerlund 2 fills this cosmic scene. Captured with Hubble's cameras in near-infrared and visible light, the stunning image is a celebration of the 25th anniversary of the launch of the Hubble Space Telescope on April 24, 1990. The cluster's dense concentration of luminous, massive stars is about 10 light-years across. Strong winds and radiation from those massive young stars have sculpted and shaped the region's gas and dust, into starforming pillars that point back to the central cluster. Red dots surrounding the bright stars are the cluster's faint newborn stars, still within their natal gas and dust cocoons. But brighter blue stars scattered around are likely not in the Westerlund 2 cluster and instead lie in the foreground of the Hubble anniversary field of view.

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