Smoking Supernovae: Astronomers Claim Solution To A Mystery Of The Universe

Science Daily ^ | 7/24/03

[LibWhacker]

Astronomers from Cardiff University, in Wales, and the Royal Observatory, Edinburgh, Scotland, believe they have solved one of the long-standing mysteries of the Universe - the origins of cosmic dust.

In the latest issue of the science journal Nature, they explain how they have found that some supernovae, or exploding stars, belch out huge quantities of this dust - a discovery which suggests that supernovae were responsible for producing the first solid particles in the Universe.

Originally astronomers thought that dust was mostly made in the winds from cool, giant stars in the late stages of their lives.

Cosmic dust consists of tiny particles of solid material floating around in the space between the stars. It is not the same as house dust but more akin to cigarette smoke. It is responsible for blocking half of all the optical light given off by stars and galaxies. The presence of dust grains around young stars helps them to form and they are also the building blocks of planets.

Project leader Dr Loretta Dunne from Cardiff University said: "The origin of cosmic dust is, in fact, the basic question of the origin of our planet and others. Effectively, we live on a very large collection of cosmic dust grains and yet, until now, we have not been sure where cosmic dust is made."

This 'dusty' cloud has a silver lining, however. The dust converts the stolen starlight it absorbs into light at longer wavelengths. Astronomers can 'see' the dust 'shining' using special instruments which can detect light-waves in the far-infrared and sub-millimetre part of the electromagnetic spectrum (0.1-1mm).

One such camera is SCUBA, a UK-built instrument based at the James Clerk Maxwell Telescope in Hawaii. In recent years SCUBA has been revolutionising our understanding of galaxy formation, finding huge dusty galaxies and quasars at a time when the Universe was only 1/10 of its present age, long before the Earth formed.

"Dust has been swept under the cosmic carpet--for years astronomers have treated it as a nuisance because of the way it hides the light from the stars. Now studies have shown that there is dust right at the edge of the Universe in the earliest stars and galaxies, we realise that we are ignorant of even its basic origin," explained Dr Dunne.

The team of five astronomers from Cardiff University and the Royal Observatory Edinburgh used SCUBA to look for dust in the remains of a recent supernova called Cassiopeia A, which is some 11,000 light years from the Earth. This is the remnant of the explosion of a star some 30 times bigger than the Sun, which took place around 320 years ago.

The remnant consists of a cloud of gas travelling out from the site of the explosion at very high speeds (10,000 kilometres per second). Although astronomers had been searching for dust in supernova remnants for decades, they had used instruments that could only detect dust that was quite warm.

"With SCUBA we can see dust which is very cold," said Dr Steve Eales, Reader in Astrophysics at Cardiff University. "This is because it operates at longer sub-millimetre wavelengths than the infra-red instruments used previously. In the same way that you can only see an iron poker glowing when it has been in the fire, you can only see dust with infra-red cameras when it is warmer than around 25 Kelvin, but SCUBA can see it when it is colder too."

[bedolido]

great find. Thanks. Am saving for a Mead Telescope (donations welcome...lol)

[Barry Goldwater]

"The dust converts the stolen starlight it absorbs into light at longer wavelengths."

Interesting. I wonder if the dust is responsible for converting starlight into the much longer wavelength microwave background radiation.

[thegreatbeast]

Again?
http://www.freerepublic.com/focus/f-news/952079/posts

[LibWhacker]

Hey, I've been thinking of popping for a good telescope, too! Still trying to decide exactly what I need. I think I need an easily transportable one since the skies around here are pretty lousy. People over on sci.astro.amateur have a lot of good things to say about Starmaster Telescopes. Still mulling it over, though. :-)

[Prof Engineer]

ping

[Notforprophet]

The team of five astronomers from Cardiff University and the Royal Observatory Edinburgh used SCUBA to look for dust in the remains of a recent supernova called Cassiopeia A, which is some 11,000 light years from the Earth. This is the remnant of the explosion of a star some 30 times bigger than the Sun, which took place around 320 years ago.

If this supernova is 11,000 light years away, and it only exploded 320 years ago... then how can we even see the explosion or be aware of it yet?

NFP

[rudypoot]

They mean that you could first see it from earth 320 years ago.

[hopespringseternal]

Looks good. Glad you aren't headed down to Walmart.

[bedolido]

I've been looking at Mead. I'm a real amateur... and not smart enough locate the Messire (about 110 objects) or Hershal (about 2500 objects) lists (not sure of the spelling) without the help of a computer. Mead has a computer with both lists plus many, many more. You can download more.

You just punch in the number of the object you want in a hand-held palm-type device and the computer will take the scope to the object... of course it has to be in your viewing area.

Meade Telescopes

[FreeTheHostages]

for amateur viewing, meade is a good value

[LibWhacker]

Oh, no, not a chance! I had a rinky-dinky Monkey Ward scope when I was a kid. TOTALLY worthless.

[ex-snook]

"a discovery which suggests that supernovae were responsible for producing the first solid particles in the Universe. "

Duh? And the first supernovae came from?

[LibWhacker]

The first stars were made up of pure hydrogen atoms, which were in turn thrown out during the Big Bang. At least that's the theory.

[farmfriend]

If this supernova is 11,000 light years away, and it only exploded 320 years ago... then how can we even see the explosion or be aware of it yet?

These people who insist on clouding the issue with facts. Sheesh.

[Notforprophet]

I knew that. It's just an example of bad reporting.

NFP

[LibWhacker]

What we really need is a $200,000 Takahasi with an observatory to match. I read an article not too long ago about a 17-yr-old boy whose mother actually bought him one of these and the observatory and all the accessories:

[PUGACHEV]

After going to a local star party and having the opportunity to try lots of different scopes, I decided to get a large Dobsonian. I bought a 10" SkyQuest from Orion for ~$600, and I'm very happy with it. I bought a padded case for it too, but if I wanted something more portable, I think I'd get a set of giant binoculars.

[RadioAstronomer]

If this supernova is 11,000 light years away, and it only exploded 320 years ago... then how can we even see the explosion or be aware of it yet?

What is being said (and badly IMHO), is the light from the explosion reached the Earth 320 or so years ago. So from the Earth's standpoint, the supernova appears only 320 years old.

Does this help?

[longshadow]

for amateur viewing, meade is a good value

One word: "Stellafane."