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Betelgeuse's nebula ..

Posted: Tue Jun 28, 2011 8:45 am
by brian livesey

Betelgeuse ready to blow?

Posted: Sun Jul 31, 2011 5:59 pm
by cigarshaped
What's with the frenzy for explosions and collisions? :?: Too much Hollywood astronomy thinking.

..the bright reddish star in the constellation Orion, has steadily shrunk over the past 15 years, according to researchers at the University of California, Berkeley.
“We do not know why the star is shrinking, considering all that we know about galaxies and the distant universe, there are still lots of things we don't know about stars, including what happens as red giants near the ends of their lives.” —Edward Wishnow, UC Berkeley's Space Sciences Laboratory.

Is there a fundamental problem with our understanding of how stars work?

The idea that stars are fuelled from the inside did NOT come from some scientific discovery. It is an idea as old as the discovery of fire. It was introduced as a belief, as an ideological perversion of science by the pioneer of the thermonuclear model of stars Sir Arthur Stanley Eddington (1882-1944). Eddington’s ideas should be regarded as a historical aberration of his candle & gaslight era where light and heat were produced from hot gases.

The forming, by gravitational collapse, of a star with a superhot core composed of the lightest gas, hydrogen, is a remarkable ‘Heath-Robinson’ construction based on the choice of an improbable model with consequent unlikely assumptions. It fails the observational test because nothing we observe on the Sun and above the Sun is predictable from the nuclear fusion model. And surprising new discoveries have required ad hoc additions to the model, while many basic observations remain unexplained—like the superhot corona above a “cold” photosphere.

So until a vital re-think is instigated, we haven't got a cat's chance in hell of predicting anything stars do. What's worrying is that our Sun is obviously becoming unpredictable and science hasn't a clue why!

Posted: Sun Jul 31, 2011 7:04 pm
by mike a feist
It is no use worrying about it however in my opinion......to quote Dad's Army......Cpl Jones "Don't Panic!" and Private Frasier "We're all doomed!".
and when a star nearby does supernovate, you can bet that the sky will be cloudy.........maf

Posted: Sun Jul 31, 2011 8:07 pm
by stella
It's Private Frazer - Frasier comes from an entirely different programme.

Posted: Mon Aug 01, 2011 9:13 am
by brian livesey
Betelgeuse is a red supergiant and is bound to implode/explode at some point, as gravity overcomes outward convective pressure.
Exploding supergiants have been monitored and analysed, so there's the proof.

Posted: Mon Aug 01, 2011 7:10 pm
by mike a feist
Hi Stella....I knew it was probably wrong.........tried replacing "s" and "z", did not thing of dropping the "i"....maf

Posted: Mon Aug 01, 2011 8:18 pm
by Cliff
Dear Brian, Cigarshaped, Mike and Stella
Brian:-
I'm more concerned that Orion won't look the same this coming winter if it blows up now.
Cigarshaped :-
I thought I was one not keen to accept everything astrophisicists\cosmologists always tell us but even I think they have a few good ideas about the stars and some stars do seem to go bang from time to time.
Mike and Stella:-
I too like "Dad's Army" but Colonel Mainwaring is my favourite.
Best wishes from Cliff

Posted: Tue Aug 02, 2011 8:20 am
by mike a feist
Cliff...I think he was a Capt not a Col! maf

Posted: Fri Aug 26, 2011 8:09 am
by nas76
The only worrying thing is that when it does explode, anywhere between today and the next couple of million years, the amount of cosmic radiation that will head our way could be quite devastating is considering its relative closeness to us. Whether it be a threat to the biology of Earth is one thing, our reliance on microchips is another.

Why anyone is worrying about the unpredictability of our sun is beyond me, it will continue in its fairly stable state for at least another 4-5 billion years.

Posted: Sat Aug 27, 2011 8:47 am
by brian livesey
There was an earlier thread on the Forum discussing whether or not Earth would be bathed in lethal radiation from an exploding Betegeuse; apparently not.
The danger is thought to be from GRBs ( Gamma Ray Bursters ). Even in this instance, there doesn't seem to be any evidence to show that, in our planet's long history, mass extinctions were caused by GRBs.

Posted: Mon Aug 29, 2011 6:24 pm
by mike_wilson73
Hi all, this is my first post. Been interested in astronomy for a long time, so thought it is a good time to join the forum :)

So, Betelgeuse as mentioned by others on the thread is a red supergiant nearing the end of its life. The apparent shrinkage observed could be part of the processes involved as its core gets fused to heavier and heavier elements. I personally think that as the core gets hotter and hotter with each new layer of elements fusing its give off a burst of heat which causes a "brief" expansion then subsequent contraction. As the core gets converted to heavier elements - ultimately iron - the period between each burst and contraction gets shorter. When the core reaches the iron end-state, the contraction keeps on going as fusion cannot provide any further outward pressure...and boom, supernova!

It may have already happened and we may get a amazing light show at any time. I don't think the Betelgeuse supernova will endanger Earth from a GRB - we are not in line of sight of the poles of the star - but we would see a few weeks of increased particle flux which could affect satellites. We will see Betelgeuse brighten dramatically; it will become by far the brightest star in the sky, visible in the daytime and casting shadows at night for a few weeks! Can't wait!

8)

Posted: Sat Sep 03, 2011 10:07 am
by brian livesey
Let's suppose that a Gamma Ray Burster had caused a mass extinction in the remote past. What sort of evidence would it leave in the rocks?
Would we, for example, see numerous microscopic gamma ray tracks in rock-slice specimens?