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Supernova poised to go off near Earth
New Scientist ^ | Eugenie Samuel

Posted on 05/28/2002 4:52:08 PM PDT by vannrox

NewScientist.com

 
 

Supernova poised to go off near Earth

 
10:30 23 May 02

Eugenie Samuel

 

A student at Harvard University has stumbled across the terrifying spectacle of a star in our galactic backyard that is on the brink of exploding in a supernova. It is so close that if it were to blow up before moving away from us, it could wipe out life on Earth.

 (Photo: SPL)
(Photo: SPL)

Most supernovae occur when large stars run out of fuel and then collapse under their own weight. As atoms in the star are squeezed together, they rebound outwards, blowing off energy in a dazzling and dangerous display lasting several weeks.

But this one is different. Called HR 8210, it is a humble white dwarf, a star that has run out of fuel and should be too small to produce a supernova. But it may not stay that way. First, it is not alone, but is orbiting a companion star in a typical binary system. And it is 1.15 times the mass of our Sun, which for a white dwarf is a whopper.

The system was first logged in 1993 but little attention was paid to it. Then when Harvard student Karin Sandstrom investigated HR 8210 for a college paper this year, she discovered that it is only just shy of the Chandrasekar limit - the mass at which it would be big enough to go supernova. That makes it the best and by far the closest supernova candidate discovered so far.

The crunch will come when HR 8210's companion begins to run out of fuel. As it expands to form a red giant star, its outer layers will be dumped onto HR 8210, pushing it over the Chandrasekar limit. "Our initial idea was that this might happen very soon," says Sandstrom's supervisor Dave Latham.


Too close for comfort

But do not panic yet. "Very soon" could mean hundreds of millions of years in the future. And that is just as well, because we are only 150 light years away from HR 8210 at present - well short of the 160 to 200 light years thought to be the minimum safe distance from a supernova. If it did let fly, the high-energy electromagnetic radiation and cosmic rays it released would destroy Earth's ozone layer within minutes, giving life little chance of survival.

This would not be the first time a supernova has changed the course of life on Earth. In 2001, Jesus Maiz-Apellaniz and colleagues from the Space Telescope Science Institute in Baltimore, Maryland, found a "smoking gun" supernova remnant, in the group of stars known as the Scorpius- Centaurus association.

The timing of the supernova corresponds to an otherwise mysterious deposit of heavy isotopes in deep Earth cores and to a mass marine extinction two million years ago. At the time, Scorpius-Centaurus was around twice as far away from Earth as HR 8210 is now.

Fortunately, it will take time for HR 8210 to accumulate the mass it needs. Preliminary calculations by Rosanne di Stefano at the Harvard-Smithsonian Center suggest this may take hundreds of millions of years. By that time it will be much further away, she says, though she still needs to confirm exactly how far. "I want to be sure I'm right."

But will similar stars threaten us before then? "The fact that there's such a system so close to us suggests maybe these objects are not so rare," says Latham.

 
10:30 23 May 02
 


TOPICS: Front Page News; Miscellaneous
KEYWORDS: catastrophism; davelatham; doom; end; explosion; goliath; hr8210; nasa; nova; planet; space; star; supernova; whitedwarf; world
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To: vannrox
DUMP DAVI$



GO SIMON



SEMPER FI


GraYout's BraiN on November 6th

41 posted on 05/28/2002 7:48:58 PM PDT by NormsRevenge
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To: montag813
Let's hope so. Mankind has outlived its usefulness.

Are you included in that assessment, or is there some special reason you should be spared?

42 posted on 05/28/2002 7:53:13 PM PDT by Denver Ditdat
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To: AtticusX
Interesting indeed. I did like it. And your thoughts on reply 9, the refutation?
43 posted on 05/28/2002 11:22:40 PM PDT by philman_36
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To: montag813
Mankind has outlived its usefulness.

Speak for yourself.

44 posted on 05/28/2002 11:32:52 PM PDT by Interesting Times
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To: Ragtime Cowgirl
Good catch!
45 posted on 05/29/2002 8:42:31 AM PDT by callisto
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To: montag813
Mankind isn't about "usefulness".
46 posted on 05/29/2002 8:46:55 AM PDT by Romulus
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To: montag813
Let's hope so. Mankind has outlived its usefulness.

Not quite: Individual men have outlived their usefulness.

47 posted on 05/29/2002 8:50:15 AM PDT by Lazamataz
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To: vannrox
If it did let fly, the high-energy electromagnetic radiation and cosmic rays it released would destroy Earth's ozone layer within minutes, giving life little chance of survival.

The article also said it was 150 light years away. Somehow I don't think "within minutes" is very accurate.

48 posted on 05/29/2002 8:53:48 AM PDT by ShadowAce
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To: vannrox
Most supernovae occur when large stars run out of fuel and then collapse under their own weight. As atoms in the star are squeezed together, they rebound outwards, blowing off energy in a dazzling and dangerous display lasting several weeks.

If that's all the guy is worried about, we've got no problems at all; it turns out, that's not the way stars work:

Plasma physics and electric sun


49 posted on 05/29/2002 9:53:14 AM PDT by medved
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To: avg_freeper
Oh, I see! Billions, not millions. Whew! You had me worried for a moment there.

Millions, billions ... whatever. Just to be safe, let's keep Strom Thurmond in office so that we'll have the "experienced leadership" we need when this deadly event does unfold.

50 posted on 05/29/2002 11:01:05 AM PDT by ArneFufkin
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To: vannrox
That explains why the Bo Peep Cult hopped on the comet when it was passing by.
51 posted on 05/29/2002 11:05:09 AM PDT by putupon
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To: Poohbah
I'm sure Osama bin Laden is behind this somehow

Congratulations! Yours is the first "Science" thread posting
to earn the prestigious "Elvis Bin Laden" award.


52 posted on 05/29/2002 11:09:33 AM PDT by ASA Vet
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To: all
Right here is where it would be nice if somebody could post a link to "The Galaxy Song" by Monty Pyton...;-D
53 posted on 05/29/2002 11:12:26 AM PDT by Judith Anne
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To: Judith Anne
Note to self: That's Monthy Pyton, dufus!
54 posted on 05/29/2002 11:13:12 AM PDT by Judith Anne
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To: Poohbah
Wrong. It has to be Reagan's fault.
55 posted on 05/29/2002 11:14:34 AM PDT by wny
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To: Judith Anne
(spoken)
Whenever life gets you down, Mrs. Brown,
And things seem hard or tough,
And people are stupid, obnoxious or daft,
(sung)
And you feel that you've had quite eno-o-o-o-o-ough,

Just remember that you're standing on a planet that's evolving
And revolving at 900 miles an hour.
It's orbiting at 19 miles a second, so it's reckoned,
The sun that is the source of all our power.
Now the sun, and you and me, and all the stars that we can see,
Are moving at a million miles a day,
In the outer spiral arm, at 40,000 miles an hour,
Of a galaxy we call the Milky Way.

Our galaxy itself contains a hundred billion stars;
It's a hundred thousand light-years side to side;
It bulges in the middle sixteen thousand light-years thick,
But out by us it's just three thousand light-years wide.
We're thirty thousand light-years from Galactic Central Point,
We go 'round every two hundred million years;
And our galaxy itself is one of millions of billions
In this amazing and expanding universe.

(waltz)

Our universe itself keeps on expanding and expanding,
In all of the directions it can whiz;
As fast as it can go, at the speed of light, you know,
Twelve million miles a minute and that's the fastest speed there is.
So remember, when you're feeling very small and insecure,
How amazingly unlikely is your birth;
And pray that there's intelligent life somewhere out in space,
'Cause there's bugger all down here on Earth!

56 posted on 05/29/2002 11:17:28 AM PDT by Liberal Classic
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To: callisto
Re: Karin's letter. You are too trusting. Karin is evidently part of the coverup. I wonder who got to her. Now I am really worried.
57 posted on 05/29/2002 11:22:18 AM PDT by sphinx
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To: vannrox
Does anyone know the proper depth for a super-nova bunker? Can you just dig your nuclear bunker deeper?? I'm buying a shovel on the way home just to be safe.

Pray for GW and the Truth

58 posted on 05/29/2002 11:23:40 AM PDT by bray
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To: tophat9000
If its 150 light years away it could have gone Supernova during the Civil War and we wouldn’t know it yet

interesting

59 posted on 05/29/2002 11:24:22 AM PDT by waterstraat
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To: lexington minuteman 1775
SPF 45,000,000,000,000 may suffice.
60 posted on 05/29/2002 11:25:50 AM PDT by Doctor Stochastic
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