So this is where Arctic Penguin vacations....

Andonyx · 21st February 2003, 07:25 AM

http://www.smh.com.au/articles/2003/...638427695.html

Quote:

Five thousand light years from Earth in the constellation of Centaurus, the nebula, a gas cloud formed from a dying star, has a temperature of minus 272 degrees.

arcticpenguin · 21st February 2003, 07:51 AM

I think I can see my igloo in this photo ...

espritch · 21st February 2003, 04:11 PM

Quote:

It appears that the ultra-cold gas is flowing from the nebula's central star so fiercely, at 140 kilometres per second, the background radiation is simply blown away.

So how can the gas be blowing that fast and not be heated by friction? And what's blowing it?

jj · 21st February 2003, 04:24 PM

I want to know what's keeping it cold, myself.

Tez?

Andonyx · 21st February 2003, 11:27 PM

Quote:

Originally posted by jj
I want to know what's keeping it cold, myself.

Tez?

Friction?

Keeping it cold?

Nothing.

Friction? What exactly do you think this is rubbing against? It's empty space? There's no friction to be had.

Cold?

Cold is the absence of heat. You can ask what's keeping something hot, in other words hotter than background radiation. Thequestion is why is it any hotter than that.

Cold, everything becomes cold. Ultimately.

Nothing "Keeps" anything cold.

Soapy Sam · 22nd February 2003, 10:44 AM

Is this just a super version of expanding-gas refrigeration? Do the thermodynamics of "normal" gas laws stand up under these conditions?

And what IS a penguin doing in the Arctic anyway?

espritch · 22nd February 2003, 12:22 PM

Quote:

Cold is the absence of heat. You can ask what's keeping something hot, in other words hotter than background radiation. Thequestion is why is it any hotter than that.

Cold, everything becomes cold. Ultimately.

Nothing "Keeps" anything cold.

My question had more to do with the fact it was moving so fast. Getting gas moving that quick require energy, and where you have energy you generally have heat. APOD had this same picture displayed recently.

http://antwrp.gsfc.nasa.gov/apod/ap030220.html

Quote:

The symmetric cloud appears to have been created by a high-speed wind of gas and dust blowing from an aging central star at speeds of nearly 600,000 kilometers per hour. This rapid expansion has cooled molecules in the nebular gas to about one degree above absolute zero - colder than even the cosmic background radiation - making it the coldest region observed in the distant Universe.

So I guess the star is providing the energy to push the gas. The gas expands so fast that the expansion cools it (the way expansion of Freon in a refrigerator coil causes it to loose heat). I agree (in hind sight) that friction probably wouldn’t apply unless the gas being expelled encountered gas previously expelled. I guess the measured temperature applies only to the expelled gas, not to the central star. The original link didn’t really make this clear to me.

Quote:

And what IS a penguin doing in the Arctic anyway?

Avoiding the skuas?

shanek · 22nd February 2003, 12:51 PM

Quote:

Originally posted by espritch
Avoiding the skuas?

Q: What's the penguin's natural defense against polar bears?

A: They live on the other side of the world from them.

Samurai Muppet · 22nd February 2003, 09:34 PM

Quote:

Originally posted by Andonyx

Nothing "Keeps" anything cold.

hOW ABOOUT A REFRIGERATOR ?

tim · 23rd February 2003, 02:32 AM

Quote:

Originally posted by Samurai Muppet

hOW ABOOUT A REFRIGERATOR ?

Nah - that just stops stuff getting warm

21st February 2003, 07:25 AM	#1
Andonyx Graduate Poster Join Date: Jul 2002 Posts: 1,834	So this is where Arctic Penguin vacations.... http://www.smh.com.au/articles/2003/...638427695.html Quote: Five thousand light years from Earth in the constellation of Centaurus, the nebula, a gas cloud formed from a dying star, has a temperature of minus 272 degrees.
Andonyx Graduate Poster Join Date: Jul 2002 Posts: 1,834	__________________ Andonyx www.andonyx.com Shy Gypsy Slyly Shyly Tryst By My Crypt.

21st February 2003, 07:51 AM	#2
arcticpenguin woo ban clan Join Date: Sep 2002 Posts: 5,717	I think I can see my igloo in this photo ...
	__________________ The power of accurate observation is frequently called cynicism by those who don't have it. - George Bernard Shaw

21st February 2003, 04:11 PM	#3
espritch Graduate Poster Join Date: Jul 2002 Posts: 1,380	Quote: It appears that the ultra-cold gas is flowing from the nebula's central star so fiercely, at 140 kilometres per second, the background radiation is simply blown away. So how can the gas be blowing that fast and not be heated by friction? And what's blowing it?
	__________________ "I'm the master of low expectations." - G. W. Bush

21st February 2003, 04:24 PM	#4
jj grumpy old skeptic Join Date: Oct 2001 Location: Deep in the rain Posts: 18,512	Hey, Tez! I want to know what's keeping it cold, myself. Tez?
	__________________ The Power to Quit

21st February 2003, 11:27 PM	#5
Andonyx Graduate Poster Join Date: Jul 2002 Posts: 1,834	Re: Hey, Tez! Quote: Originally posted by jj I want to know what's keeping it cold, myself. Tez? Friction? Keeping it cold? Nothing. Friction? What exactly do you think this is rubbing against? It's empty space? There's no friction to be had. Cold? Cold is the absence of heat. You can ask what's keeping something hot, in other words hotter than background radiation. Thequestion is why is it any hotter than that. Cold, everything becomes cold. Ultimately. Nothing "Keeps" anything cold.
Andonyx Graduate Poster Join Date: Jul 2002 Posts: 1,834	__________________ Andonyx www.andonyx.com Shy Gypsy Slyly Shyly Tryst By My Crypt.

22nd February 2003, 10:44 AM	#6
Soapy Sam NLH Join Date: Oct 2002 Posts: 25,885	Is this just a super version of expanding-gas refrigeration? Do the thermodynamics of "normal" gas laws stand up under these conditions? And what IS a penguin doing in the Arctic anyway?
Soapy Sam NLH Join Date: Oct 2002 Posts: 25,885

22nd February 2003, 12:22 PM	#7
espritch Graduate Poster Join Date: Jul 2002 Posts: 1,380	OK. I think I have it now...maybe. Quote: Cold is the absence of heat. You can ask what's keeping something hot, in other words hotter than background radiation. Thequestion is why is it any hotter than that. Cold, everything becomes cold. Ultimately. Nothing "Keeps" anything cold. My question had more to do with the fact it was moving so fast. Getting gas moving that quick require energy, and where you have energy you generally have heat. APOD had this same picture displayed recently. http://antwrp.gsfc.nasa.gov/apod/ap030220.html Quote: The symmetric cloud appears to have been created by a high-speed wind of gas and dust blowing from an aging central star at speeds of nearly 600,000 kilometers per hour. This rapid expansion has cooled molecules in the nebular gas to about one degree above absolute zero - colder than even the cosmic background radiation - making it the coldest region observed in the distant Universe. So I guess the star is providing the energy to push the gas. The gas expands so fast that the expansion cools it (the way expansion of Freon in a refrigerator coil causes it to loose heat). I agree (in hind sight) that friction probably wouldn’t apply unless the gas being expelled encountered gas previously expelled. I guess the measured temperature applies only to the expelled gas, not to the central star. The original link didn’t really make this clear to me. Quote: And what IS a penguin doing in the Arctic anyway? Avoiding the skuas?
	__________________ "I'm the master of low expectations." - G. W. Bush

22nd February 2003, 12:51 PM	#8
shanek by Charles M. Schulz Join Date: Aug 2001 Posts: 15,990	Re: OK. I think I have it now...maybe. Quote: Originally posted by espritch Avoiding the skuas? Q: What's the penguin's natural defense against polar bears? A: They live on the other side of the world from them.
	__________________ "James Randi is awesome!" —Ian Bernard, primary host of Free Talk Live "It really does take people like Penn & Teller or James Randi to be able to see through these deceptions, and so those are perhaps the people we should be paying the most attention to." —Harry Browne, 4/10/2004 I know there is a lesson to be learned here somewhere, but I don't know what it is.

22nd February 2003, 09:34 PM	#9
Samurai Muppet New Blood Join Date: Oct 2002 Posts: 11	Re: Re: Hey, Tez! Quote: Originally posted by Andonyx Nothing "Keeps" anything cold. hOW ABOOUT A REFRIGERATOR ?
Samurai Muppet New Blood Join Date: Oct 2002 Posts: 11

23rd February 2003, 02:32 AM	#10
tim Lasiorhinus latifrons Combat Division Join Date: Jan 2003 Location: Bedfordshire, UK Posts: 11,334	Re: Re: Re: Hey, Tez! Quote: Originally posted by Samurai Muppet hOW ABOOUT A REFRIGERATOR ? Nah - that just stops stuff getting warm