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View Full Version : Eagle Nebula's Pillars Were Wiped Out Thousands of Years Ago



Fraser
2007-Jan-12, 01:51 AM
One of the most famous space photographs ever taken is the "Pillars of Creation" by Hubble, an amazing image of the Eagle nebula. But a new image from the Spitzer Space Telescope provides evidence that those towers of gas and dust might have already been wiped away. ...

Read the full blog entry (http://www.universetoday.com/2007/01/11/eagle-nebulas-pillars-were-wiped-out-thousands-of-years-ago/)

baselle
2007-Jan-12, 06:23 AM
I'm missing something here. If no information can travel faster than light, what evidence of an explosion is being used? Wouldn't that evidence have to travel at the speed of light?

ChrisColes
2007-Jan-12, 11:52 AM
With the greatest of respects someone has lost their way. If the region is 7,000 light years away, it takes all light of whatever spectrum, 7,000 light years to get here. What you may say is that some light will travel more slowly and thus some effects may not be visible for longer than 7,000 years.

If someone has come forward to say this is caused by some time effect caused by the likes of String Theory, they need to wrap a cold towel around their head and go sit in a darkened room for a few days while they catch up with reality.

This must be the worst headline yet..... Pure Bunkham, utter rubbish.

AstroDuck
2007-Jan-12, 03:01 PM
I don't think it is that hard to follow. Light takes 7,000 years to reach us from the Eagle Nebula so we see it today as it was 7,000 years ago. If a supernova exploded in the Eagle Nebula about 1 to 2 thousand years ago, then I assume that it is talking about 1 to 2 thousand years from our perspective which would mean since light takes 7,000 years to reach us it actually exploded 8,000 to 9,000 years ago. Astronomers calculate that the blast wave of that supernova will reach the pillars in about another 1,000 years from our perspective. At 7,000 light years away, that means that today from the Eagle Nebula's perspective, the pillars disappeared 6,000 years ago if the prediction is correct that the blast wave is sufficient to destroy the pillars.

Amber Robot
2007-Jan-12, 05:15 PM
I'm missing something here. If no information can travel faster than light, what evidence of an explosion is being used? Wouldn't that evidence have to travel at the speed of light?

Reading the Spitzer Press Release it states that the evidence they have is that there is dust near the pillars that looks like a supernova shock wave has passed by it. This shockwave is capable of destroying the pillars.

Because of the lookback time this means that the destruction has already happened, even though we won't see it for a while.

GBendt
2007-Jan-12, 10:58 PM
Hi,

Spitzer is insensitive to visible light, it is an infrared telescope. It can only detect infrared light, that is its purpose.
Fine dust particles, which make up the magnificent clouds the shape of which inspired the name "pillars of creation" for them are transparent to infrared light, as the size of the dust particles is much smaller than the wavelength of infrared light. This is the reason Spitzer cannot display the "pillars of creation": Spitzer is simply blind for them.

If Hubble would look at the site again today and take a picture, and if you put the same people on the job to process that Hubble picture just like that famous "pillars of creation" one, we would get the same picture again: The pillars are still there. But Spitzer cannot see them.

This shows very clearly that Spitzer cannot provide the information that the Hubble telescope can do: Spitzer´s is intended to look through the dust (to reveal what lies behind...), but not to look at it.

This press release is a shame. It reveals a deep ignorance of the nature of the telescope, the nature of the object, of natural science in general, and of the astronomical research and observations that were carried out during the last decades.
A supernova the shockwave of which is able to tossle and blow the "pillars of creation" within a few years would not have evaded our perception: It would have shone in the sky at least as bright as the moon, for more than a year. The world wold still be ringing from that news.
One should consider the size of the pillars, which is some 3,2 lightyears. It would even take a supernova shockwave many many years to cross them. Further, the mass of the pillars is some decillion tons. A supernova is a banger, but if it is to work on decillions of tons, it is only a supernova.

The "pillars of creation" will be eroded by the radiation and the stellar winds coming from the hot young stars that shine on them. This, however, is a process that will take millions of years, and one that will goe on very very gradually.

Regards,

Günther

Amber Robot
2007-Jan-12, 11:11 PM
Hi,

Spitzer is insensitive to visible light, it is an infrared telescope. It can only detect infrared light, that is its purpose.
Fine dust particles, which make up the magnificent clouds the shape of which inspired the name "pillars of creation" for them are transparent to infrared light, as the size of the dust particles is much smaller than the wavelength of infrared light. This is the reason Spitzer cannot display the "pillars of creation": Spitzer is simply blind for them.

Actually, if you look at the Spitzer image that accompanies the press release you can see the pillars. And I'm not talking about the HST view in the inset.



If Hubble would look at the site again today and take a picture, and if you put the same people on the job to process that Hubble picture just like that famous "pillars of creation" one, we would get the same picture again: The pillars are still there.

Yes, they would still appear to be there. The Press Release suggested it would be another thousand years before we would see them gone.


This shows very clearly that Spitzer cannot provide the information that the Hubble telescope can do: Spitzer´s is intended to look through the dust (to reveal what lies behind...), but not to look at it.

Actually, Spitzer is sensitive to some dust emission. The dust itself emits at infrared wavelengths. More likely it is a sub-component of dust called poly-cyclic aromatic hydrocarbons that they are seeing in emission. I'd have to read through the source material to know for sure.


A supernova the shockwave of which is able to tossle and blow the "pillars of creation" within a few years would not have evaded our perception: It would have shone in the sky at least as bright as the moon, for more than a year. The world wold still be ringing from that news.

And it may well have. The Press Release states that the event took place about 6000 years ago. It would be interesting to see if there is any achaeological evidence that humans saw this event and recorded it in any way.

GBendt
2007-Jan-16, 11:06 PM
The site we are looking at is 7000 lightyears distant. Thus we see the site now as it looked like 7000 years ago. If you want to see how that site looked like 6000 years ago, you will have to wait until 3007. To say that these structures of dust will have been already gone and blown apart today is based on nothing reasonable, and I cannot take someone serious who does so. No information can travel faster than light, and the information that cannot have reached us yet is no information, but fiction. Replacing science by fiction, no matter how impressive, has nothing to do with astronomy. It’s Bad Astronomy at its worst.

The site is the heart of an open star cluster that was called M16 by Charles Messier in 1764. The cluster has since been carefully observed and measured by generations of astronomers, with telescopes of all kinds, types and sizes, up to the 100 metre Green Bank radio telescope.
No trace of a supernova remnant has ever been detected in it, and is most unlikely to be found in it, as the stars of that open star cluster are one a few million years old, far too young to be old enough that any of them may have ended its life already in a supernova explosion, neither a type II, nor a type I supernova.

If hot gas collides with dust particles in space, the dust particles are heated up and radiate in infrared light. That way the dust cools the gas with time and slows the speed of the gas atoms down to a rate that gravity can gradually take effect on them and force the gas to form new stars. Spitzer can detect that infrared radiation from heated dust, as the radiation can easily escape from the dust, due to its long wavelength.

Regards

Günther

Amber Robot
2007-Jan-16, 11:20 PM
All the press release says to support their statement is the following:


Flagey and his team say evidence for this scenario comes from similarities observed between this hot dust and dust around known supernova remnants. The dust also appears to have a shell-like shape, implying that a supernova blast wave is traveling outward and sculpting it.

Until they have a paper available, we won't really know the reasoning behind their argument.

YankeeJeff
2007-Jan-17, 01:08 AM
I think it's important that folks read the original article carefully before criticizing it...

http://www.spitzer.caltech.edu/Media/releases/ssc2007-01/release.shtml

Here's just one quote from the article:


Astronomers have long predicted that a supernova blast wave would mean the end for the popular pillars. The region is littered with 20 or so stars ripe for exploding, so it was only a matter of time, they reasoned, before one would blow up. The new Spitzer observations suggest one of these stellar time bombs has in fact already detonated, an event humans most likely witnessed 1,000 to 2,000 years ago as an unusually bright star in the sky.

GBendt
2007-Jan-18, 08:43 AM
I started with astronomy 45 years ago. Since, I read hundreds of books on astronomy, hundreds of papers, have attended various meetings and congresses on astronomy. I subscribed two different monthly journals on astronomy.
In all these years, I never came across the opinion that any author, writer or lecturer expected a supernova to explode or have exploded inside M16.
From that, I cannot back that statement:

Astronomers have long predicted that a supernova blast wave would mean the end for the popular pillars. The region is littered with 20 or so stars ripe for exploding, so it was only a matter of time, they reasoned, before one would blow up.

The M16 star cluster is a very young cluster, and though its hottest stars each have several solar masses, none of these is massive enough to blow up in a supernova within the several million years to come, if ever. There is no one star "ripe for exploding" in M16. And of course not 20.
Only one in a hundred thousand stars is massive enough to end in a supernova, and it takes such a star many million years until it reaches the final state in which it can explode. Therefore, a supernova is a rare event. Of what I know of the stars in M16, none of them is "ripe" ore even able for a supernova.
A supernova is something that kindles imagination, and imagination can have mighty wings. Some authors simply love to play with the imagination of their listeners or readers.

Regards,

Günther