@pawnpaw saidBetelgeuse is a huge star, I mean really huge, huger than Trump. I'd be more concerned about it going supernova, which could happen any day, although experts say that's not likely, but they're really not sure. If it does go supernova, we'll be in for the biggest light show in history, and when it's over, we'll have a new neighbor ... a super-groovy neutron star. Then we can open-up this neutron star to vacationing thrill-seekers so they can walk around, as long as they don't forget their anti-grav boots.
https://www.universetoday.com/144694/betelgeuse-is-continuing-to-dim-its-down-to-1-506-magnitude/
The distant star Betelgeuse has been dimming since last year, even more than its usual cycles.
Can Orion exist without its main actor?
@bunnyknight saidWhen astronomers say "...any day now." what they mean is at any point in the next couple of million years. It seems to have shed a lot of dust, so the dimming's likely to be due to occlusion rather than impending doom. It's a supergiant and it's close at 700 light years, it has an angular diameter of 44 milli-arcseconds so with the latest kit they can look at the surface.
Betelgeuse is a huge star, I mean really huge, huger than Trump. I'd be more concerned about it going supernova, which could happen any day, although experts say that's not likely, but they're really not sure. If it does go supernova, we'll be in for the biggest light show in history, and when it's over, we'll have a new neighbor ... a super-groovy neutron star. Then w ...[text shortened]... ationing thrill-seekers so they can walk around, as long as they don't forget their anti-grav boots.
27 Feb 20
@deepthought saidActually some astronomers say that it could likely blow within 100,000 years, or much sooner. No way to be sure.
When astronomers say "...any day now." what they mean is at any point in the next couple of million years. It seems to have shed a lot of dust, so the dimming's likely to be due to occlusion rather than impending doom. It's a supergiant and it's close at 700 light years, it has an angular diameter of 44 milli-arcseconds so with the latest kit they can look at the surface.
@bunnyknight saidThe biggest light show in history, at least as far as apparent magnitude is concerned, was the Soviet RDS-202, code name Ivan, NATO name Tsar Bomba. They show it go off several times, at 2:00 they show the moment the bomb goes off from inside the cockpit of the bomber that dropped it, which was hightailing it out of there as fast as it could, giving an idea of how bright it was:
Betelgeuse is a huge star, I mean really huge, huger than Trump. I'd be more concerned about it going supernova, which could happen any day, although experts say that's not likely, but they're really not sure. If it does go supernova, we'll be in for the biggest light show in history, and when it's over, we'll have a new neighbor ... a super-groovy neutron star. Then w ...[text shortened]... ationing thrill-seekers so they can walk around, as long as they don't forget their anti-grav boots.
28 Feb 20
@pawnpaw saidRigel and the belt are co-stars aren't they?
https://www.universetoday.com/144694/betelgeuse-is-continuing-to-dim-its-down-to-1-506-magnitude/
The distant star Betelgeuse has been dimming since last year, even more than its usual cycles.
Can Orion exist without its main actor?
@wolfgang59 saidWhat do you mean by co-star? Rigel is 860 light years away and has 3 companion stars called Rigel Ba, Rigel Bb and Rigel C. The belt consists of Alnitak 1,260 ly away, Alnilam 2,000 ly away, and Mintaka 1,200 ly away. Alnitak is a triple system, Alnilam is a blue supergiant and Mintaka is a binary. The stars are not gravitationally coupled to each other, so if by co-star you mean a gravitationally bound system then no.
Rigel and the belt are co-stars aren't they?
The belt stars are in a stellar association called OB1 and share a common origin, Rigel is an outlying member of this association - if this is what you mean by co-star then yes.
28 Feb 20
@deepthought saidYup, that bomb was probably the most illuminating Earth-based event in recent human history, but compared to cosmic explosions it was nothing more than a tiny spark.
The biggest light show in history, at least as far as apparent magnitude is concerned, was the Soviet RDS-202, code name Ivan, NATO name Tsar Bomba. They show it go off several times, at 2:00 they show the moment the bomb goes off from inside the cockpit of the bomber that dropped it, which was hightailing it out of there as fast as it could, giving an idea of how bright it was:
https://www.youtube.com/watch?v=BBNhYOmEgy0
@bunnyknight saidI used the words "apparent magnitude" for a reason. As seen from Earth it was brighter than the Sun. Drop one on the Sun and you'll barely notice it. I'm intrigued by the words: "... event in recent human history", do you know of an older event that was brighter? Unless they start doing atmospheric tests of ludicrously oversized buckets of sunshine then I think it actually will be the brightest event in the entire lifetime of the planet from just after the collision event that formed the moon until its likely absorption by the Sun when it becomes a red giant.
Yup, that bomb was probably the most illuminating Earth-based event in recent human history, but compared to cosmic explosions it was nothing more than a tiny spark.
28 Feb 20
1 edit
@deepthought saidI was thinking of that Krakatoa volcano explosion which was much more powerful, however in pure light output that bomb might have been brighter. Of course, a hi-power laser 1 inch from your eye would top even that, so it depends on how you decide to measure it.
I used the words "apparent magnitude" for a reason. As seen from Earth it was brighter than the Sun. Drop one on the Sun and you'll barely notice it. I'm intrigued by the words: "... event in recent human history", do you know of an older event that was brighter? Unless they start doing atmospheric tests of ludicrously oversized buckets of sunshine then I think it act ...[text shortened]... ision event that formed the moon until its likely absorption by the Sun when it becomes a red giant.
28 Feb 20
@deepthought saidCLUE: I was replying to Can Orion exist without its main actor?
What do you mean by co-star?
@bunnyknight saidIt's the energy density that matters, so although Krakatoa, or for that matter the meteorite that put paid to the dinosaurs were really energetic events the energy was spread over a lot of material so they can't really compete with a hydrogen bomb.
I was thinking of that Krakatoa volcano explosion which was much more powerful, however in pure light output that bomb might have been brighter. Of course, a hi-power laser 1 inch from your eye would top even that, so it depends on how you decide to measure it.
Synchrotron radiation is a thought, that might actually compete. The problem is that the Diamond synchrotron website [1] just gives 10 billion times brighter than the Sun. In the first millisecond an atom bomb is probably brighter than that. As the temperature just after the nuclear reactions have ceased is of the order of hundreds of millions of Kelvin (for Tsar Bomba I got a back of the envelope figure of 37 billion Kelvin) and the luminosity goes as the fourth power of temperature it should be considerably brighter, but I'd prefer an actual figure for the brightness of the synchrotron rather than how much brighter it is than the Sun where I'm not sure how they've done the calculation.
[1] https://www.diamond.ac.uk/Home/About/FAQs/About-Synchrotrons.html
28 Feb 20
@deepthought saidI was just trying to imagine the entire light output of that Tsar Bomb concentrated into a parallel beam 1cm in diameter. I bet it could burn through more than a cardboard box.
It's the energy density that matters, so although Krakatoa, or for that matter the meteorite that put paid to the dinosaurs were really energetic events the energy was spread over a lot of material so they can't really compete with a hydrogen bomb.
Synchrotron radiation is a thought, that might actually compete. The problem is that the Diamond synchrotron website [1] ...[text shortened]... ey've done the calculation.
[1] https://www.diamond.ac.uk/Home/About/FAQs/About-Synchrotrons.html
28 Feb 20
@bunnyknight saidWell the experimenters can't be in the room that the synchrotron radiation is deposited into. The closest I think one could do to focusing the output of an atom bomb is to encase it in a hollow shell of lead, or some other dense material, to a thickness of several tens of metres, but with an opening. The interior of the lead would turn to plasma which would tend to reflect the X-rays out of the hole. I think the opening would have to be wider than a couple of centimetres though. I've an idea that they were investigating that kind of idea when they started looking at SDI in the 80's.
I was just trying to imagine the entire light output of that Tsar Bomb concentrated into a parallel beam 1cm in diameter. I bet it could burn through more than a cardboard box.
06 Mar 20
@bunnyknight
Someone told me if you place Betelgeuse in the position of our sun, it would engulf Mercurius, Venus, Earth, our moon, Mars, Neptune and Saturn.
Quite big...