Catastrophic (To Earth) Supernova Event Is 'A Certainty' (?)

[punychicken]

BBC news story on the theory that dying stars will wipe us out(not our Sun but others nearby).

"Sooner or later, a catastrophe from space will wipe out almost all life on Earth.

Dr Arnon Dar.
According to Dr Arnon Dar, of the Technion Space Research Institute, Israel, a particular type of exploding star going off anywhere in our region of the Universe would devastate our planet.

Using the latest statistics and calculations, he argues that a supermassive star collapsing at the end of its lifetime would form a black hole and send out a beam of destructive radiation and particles that would sterilise any planet in its path.

The odds are that any planet in our galaxy would be affected about once every one hundred million years. "It is a certainty; the timescales are comparable to mass extinctions seen in Earth's geological record," Dr Dar told BBC News Online. "

We're doomed. Doomed doomed doomed DOOMED! Again. *sighs*

 

[Anonymous]

I think this has been know for at least a decade in astronomical circles.

 

[punychicken]

it takes a decade for them to report it to the masses! Mind you, if you think about it all manner of extra-planetary phenomena can, will and shall affect us. To what degree though. Is there anything else we should know about before its too late?

 

[Anonymous]

The odds are that any planet in our galaxy would be affected about once every one hundred million years.

Who are we trying to kid? Humanity will be long gone by then...

 

[Anonymous]

I just think it is more a case of nobody really being interested in astronomical disasters untill they found out they can make great disaster movies about it.

How should they get it out to the public anyway? If they told a journalist, they would just be told that Julia Roberts had taken her dog for a walk in the park and that was bigger news.

 

[Anonymous]

Selecting Data

This guy is using the geological eveidence of episodic mass extintions as support for his theory, huh?

The odds are that any planet in our galaxy would be affected about once every one hundred million years. "It is a certainty; the timescales are comparable to mass extinctions seen in Earth's geological record," Dr Dar told BBC News Online. "

The only problem is that the geological record is not a flippin' calendar, it's a set of estimates, based on fossil evidence that is again a set of best-guesses, based on when scientists think different animals and insects lived, and when they became extinct. And their extinction is estimated by the disappearance of fossil evidence. Hmmm, what's that old saw about negative proofs?

Another fly in this guy's ointment: depending on what yardstick you use (crater ages, fossil disappearances, layers of iridium in the soil) the periodicy is variously 26 million years (Raup and Sepkoski), 34 million years (Mueller/Alvarez) and others have gotten other measurements as long as 65 million years or as short as 11 million.

An interesting site: http://muller.lbl.gov/pages/lbl-nem.htm

And this site says Nemesis does not exist at all which blows this guy rather out of the water....
http://www.seds.org/nineplanets/nineplanets/hypo.html#nemesis

 

[rynner2]

Your criticism misses the target, F.A.

The time scales for the searing blasts of radiation and cosmic rays come from statistical analysis of stellar processes. The extinction events timings (whatever figures happen to be correct) are the same order of magnitude, which perhaps offers support to the astrophysics, but is hardly offered as proof. (Different periods for extinction events would be expected statistically - these things hardly come around like clockwork.)

And bringing in Nemesis is simply setting up a straw man - the theory under discussion has NOTHING to do with Nemesis. (Supposed to be a companion star to the sun, on an eccentric orbit, which some people thought caused recurring problems when it came close.)

I'm familiar with these supernovae theories, because I know a professional astronomer who works in this field - his speciality is investigating the'bubble' of space that was blasted out by the last supernova explosion in our corner of the galaxy. We lie inside sevaral previous bubbles, in fact.

There is also good evidence for asteroid impacts, which further complicates the extinction time-scales. Just as living is inevitably fatal, perhaps life on planets is inevitably doomed! When's the next rocket to a nice safe O'Neill habitat?

 

[punychicken]

When's the next rocket to a nice safe O'Neill habitat?

I saw in the board(and also in FT) info about starting your own country... NEVER MIND THAT! Why not start a space program?

Get off this rock, I'm sure the accumulated knowledge of 'alternative' resources and methods could -if unhindered- get a small percentage of humanity off to uncharted climes...

 

[rynner2]

HELP!

Potential Supernova next door!

The star is a large white dwarf (!) 150 ly away. Part of the article reads:

"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' i 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.

But do not panic yet. "Very soon" could mean hundreds of millions of years in the future."

 

[EnolaGaia]

Newly published research suggests earth may have endured the side effects of supernova events as many as 4 times during the past 40,000 years.

Massive Explosions of Energy Far From Earth May Have Left Traces in Our Planet’s Biology and Geology

Massive explosions of energy happening thousands of light-years from Earth may have left traces in our planet’s biology and geology, according to new research by University of Colorado at Boulder geoscientist Robert Brakenridge.

The study, published this month in the International Journal of Astrobiology, probes the impacts of supernovas, some of the most violent events in the known universe. In the span of just a few months, a single one of these eruptions can release as much energy as the sun will during its entire lifetime. They’re also bright—really bright.

“We see supernovas in other galaxies all the time,” said Brakenridge, a senior research associate at the Institute of Arctic and Alpine Research (INSTAAR) at CU Boulder. “Through a telescope, a galaxy is a little misty spot. Then, all of a sudden, a star appears and may be as bright as the rest of the galaxy.”

A very nearby supernova could be capable of wiping human civilization off the face of the Earth. But even from farther away, these explosions may still take a toll, Brakenridge said, bathing our planet in dangerous radiation and damaging its protective ozone layer. ...

To study those possible impacts, Brakenridge searched through the planet’s tree ring records for the fingerprints of these distant, cosmic explosions. His findings suggest that relatively close supernovas could theoretically have triggered at least four disruptions to Earth’s climate over the last 40,000 years. ...

FULL STORY: https://scitechdaily.com/massive-ex...ft-traces-in-our-planets-biology-and-geology/

 

[eburacum]

These explosions may have been violent and relatively close by, but they left only minor traces in the fossil record. Even Betelgeuse exploding would have only caused minor disturbance to our ecosystem (although the crew of the ISS and any other craft in space may have been at risk). You have to look back hundreds of millions of years to see good evidence of a mass-extinction caused by a supernova.

 

[Moth Twiceborn]

I'm pretty sure we're going to be ok...
Wikipedia on Gamma Ray Bursts