Hard Light Productions Forums
Off-Topic Discussion => General Discussion => Topic started by: Hippo on June 10, 2009, 11:53:03 pm
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http://www.foxnews.com/story/0,2933,525695,00.html
Not quite Capella
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D'oh. That would invalidate the node map. :(
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A Slightly Better Source (http://edition.cnn.com/2009/TECH/space/06/10/shrinking.star/).
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D'oh. That would invalidate the node map. :(
I thought the node map stars were different to the real ones?
But still, it would be a special event if it has gone supernova for the light to reach us in the next 50 years or so.
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D'oh. That would invalidate the node map. :(
I thought the node map stars were different to the real ones?
But still, it would be a special event if it has gone supernova for the light to reach us in the next 50 years or so.
There's no evidence that they are.
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Okay, own up guys. Who said Betelgeuse three times? :p
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Okay, own up guys. Who said Betelgeuse three times? :p
/me doesn't raise his hand
Does that make me... normal? :shaking:
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...I seem to remember either this one or some other star is close enough that if it goes, we're in trouble.
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Nope. To affect us it should be less than 100ly away (http://en.wikipedia.org/wiki/Near-Earth_supernova). Beetlegeuse is safey outside that range (even mentions it in that article as an example of a safe star).
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Yay! More fuel for 2012 theorists to burn :D
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No poor Orff :(
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I hope I get to see it at night! :D
Looks like the shivans are at it again...
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Whenever I hear about interesting things happening in the sky, I always curse this stupid, rainy overcast island.
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Britain? ;)
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Hm... interesting. But even if it does go nova, we're still talking stellar timescales here, prolly won't happen in our lifetine.
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o noez!
Well, if this does happen, then there's only one thing to do.
Set the first few missions of the FSPort main campaign in a nebula.
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NOOO!!!! BEETLE JUICE!!!!!
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I wonder why the common English pronunciation is "Beetlejuice". I mean, the one I use is much closer to the original Arabian spelling.
Other than that, well... it's sad that my 2nd favorite star may be already dead. :(
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You have favorite...stars???:wtf:
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Sure. The first one is Antares, and the second is Betelgeuse. I also love Alpha Crucis.
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Well, the original Arabic is yed al-jouza, but someone misplaced a dot in the original Arabic when it was transliterated. A "y" in Arabic with only one dot is a "b". Hence the name we know it as today.
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The B at the beginning is ok, it's the rest that is constantly misspelled. Not that this is a problem, anyway, because importing words also means changing their original pronunciation.
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You have favorite...stars???:wtf:
:lol:
Well, the original Arabic is yed al-jouza, but someone misplaced a dot in the original Arabic when it was transliterated. A "y" in Arabic with only one dot is a "b". Hence the name we know it as today.
That makes sense...I read the Qur'an.
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Sure. The first one is Antares, and the second is Betelgeuse. I also love Alpha Crucis.
How can you...love a star?? What makes it so special?
I'm sorry for the off-topic-ness, but...:wtf:
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Sweet name?
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*waits for sol to nova*
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*waits for sol to nova*
December 9, 2012 :P
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December 9, 2012 :P
:shaking:
OMG!! I have to get a raincoat right now!!! or at least a thicker coat.
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And my neighbors think I'm nuts for reinforcing my dog house with steel.
they'll see.
When my dog is alive, and theirs is dead,
they'll see.
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Sure. The first one is Antares, and the second is Betelgeuse. I also love Alpha Crucis.
Rigel pwns Betelgeuse any day. :p
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Sure. The first one is Antares, and the second is Betelgeuse. I also love Alpha Crucis.
Rigel pwns Betelgeuse any day. :p
Them fighting words
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True though :p
I can see this ending with that animation appearing again...
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Thank goodness Ford Prefect's here. 8D
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You may be surprised. It could be the name of the star system or its appearance from light years away.
Why 5 000 000 012, by the way?
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Sure. The first one is Antares, and the second is Betelgeuse. I also love Alpha Crucis.
Rigel pwns Betelgeuse any day. :p
Rigel FTW
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http://qntm.org/?particles (http://qntm.org/?particles)
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What if...a gamma ray burst lasted for 2 hours. Does that mean half the Earth would be dead?
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Sure. The first one is Antares, and the second is Betelgeuse. I also love Alpha Crucis.
No love for Sol?
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Hm... interesting. But even if it does go nova, we're still talking stellar timescales here, prolly won't happen in our lifetine.
Except if it has already happened, say some 550 to 599 years ago.
Lightyears remember ? Astronomy is basically observing the distant past due to how slow light (which is what we are observing) actually moves on a cosmic scale.
The actual event of the Star collapsing and going boom/nova is measured in seconds, which is one reason why it is quite so violent.
It would be about as bright as the moon in the nightsky when the light from a potential Beetlejuice Nova finally reaches us, except all the brightness would be condensed to a very small spot, so it might not be safe to look at with the naked eye. Or thats what i read anyways ;)
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Always was a fan of Alioth.
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How can you...love a star?? What makes it so special?
I'm sorry for the off-topic-ness, but...:wtf:
Sweet name?
Names? Not necessarily...
Antares = Alpha Scorpii, and I'm Scorpio. If something is related to your date of birth, you do have some consideration of it.
Betelgeuse = Alpha Orionis (it should be Beta Orionis due to Rigel's brightness). Orion is a very good looking constellation... and the guy was a hunter. ;7 Furthermore, there's a legend about Scorpio and Orion - he has been killed by a scorpion (mythology facts, of course), and whenever Scorpio appears on the nightsky Orion disappears. I feel like I have the copyright (OrionTM) because my sign owned him. :p
Sure. The first one is Antares, and the second is Betelgeuse. I also love Alpha Crucis.
No love for Sol?
Well, yeah...
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Except if it has already happened, say some 550 to 599 years ago.
Lightyears remember ? Astronomy is basically observing the distant past due to how slow light (which is what we are observing) actually moves on a cosmic scale.
I doubt that.
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Except if it has already happened, say some 550 to 599 years ago.
Lightyears remember ? Astronomy is basically observing the distant past due to how slow light (which is what we are observing) actually moves on a cosmic scale.
I doubt that.
You doubt that what he said is true?
Are you not familiar with the concept of the lightspeed limit and the definition of a light-year?
Or are you just doubting that the star blew up at some point in the past 600 years?
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That goes without saying, Goob. We all love that star. After all, without it, we kinda wouldn't be here discussing it now would we?
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No love for Sol?
The term "Lost Generation" passed out of use with the NTF; it was pointless now, it encompassed more than a single generation. We were simply 'the Lost', born under the light of distant suns. It was our fate to wander the universe, far from home, never to return.
When we Returned, it was an almost religious experience; we who had been born and expected to die never having felt Sol's rays. Nothing could have kept us from our home.
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No love for Sol?
You obviously haven't seen my YouTube Channel. :drevil:
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Wait, I thought that the first FS1 missions were in Antares?
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Well, the one with the GTC Orff was in Betelgeuse.
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Ah. Ok.
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Except if it has already happened, say some 550 to 599 years ago.
Lightyears remember ? Astronomy is basically observing the distant past due to how slow light (which is what we are observing) actually moves on a cosmic scale.
I doubt that.
You doubt that what he said is true?
Are you not familiar with the concept of the lightspeed limit and the definition of a light-year?
Or are you just doubting that the star blew up at some point in the past 600 years?
I doubt that it already happened.
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what do you mean?
that you do know that the things we observe with stars happened hundreds, thousands, millions of years ago, you know that right?
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Lightyears doesn't measure time, it measures distance.
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No, but if something is one million light years away, we are seeing what happened one million years ago.
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Lightyears doesn't measure time, it measures distance.
In this context, it does both.
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Lightyears doesn't measure time, it measures distance.
it measures the distance it takes light to travel in a year, therefore the number of lightyears away something is is the number of years ago what you see now happened.
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I think I will take a closer look at the eye damage from the supernova later this afternoon. There could be something to learn in there, actually.
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Lightyears doesn't measure time, it measures distance.
We know speed = Light travels at 1 Lightyear per Year (doh - well its defined that way heh) and distance: 600 Lightyears.
Therefore we can measure time. Speed x Time = Distance. Therefore Time = Distance/Speed = 600 Lightyears / 1Lightyear/Year = 600 Years.
Means a photon takes 600years to travel from Beetlejuice to where your eye can observe it, therefore anything you do observe happened 600 years in the past already.
i.e., If it blew up 595 years ago, we won't find out for another 5 years, but then we WILL see it LOL ;)
I think I will take a closer look at the eye damage from the supernova later this afternoon. There could be something to learn in there, actually.
Whenever i have another eye-exam i'll make sure to ask the doctor about it, just to see the WT* look on his/her face LOL.
"Oh and btw Doc, when Beetlejuice goes Supernova; will it be safe to look at or can it damage my eye"? :lol: :nod:
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Why do you keep calling it Beetlejuice? :(
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Why do you keep calling it Beetlejuice? :(
Guess because of that "said it 3 times" comment at the start aha. Betelgeuse of course :p But Beetlejuice (i.e. the movie) was inspired by the name (and just the name) i believe lol
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Betelgeuse is a noble name. Typing "Beetlejuice" because of a movie is an insult, IMO. :(
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Betelgeuse is a noble name. Typing "Beetlejuice" because of a movie is an insult, IMO. :(
If you check some clips from the movie on youtube... it actually says "Betelgeuse" on his grave, even tho the movie is called Beetlejuice LOL. ;) So if you look at it that way, the whole movie must appear as an insult heh.
Also, the movie / star name relation has been pointed out before in this thread.
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I find the comment about eye damage little bit strange.
I calculated that the Betelgeuse has power output of 3.846e26 * 5e9 W (5e9 brighter than sun) ~ 1.923e36 W.
640 lightyears is 2.9979 m/s * 60 * 60 * 24 * 365 * 640 ~ 6.05e18 m.
The irradiance falling from Betelgeuse up to a sphere whose radius is the above number is then 1.923e36 W / pi*(6.05e18)^2 ~ 0.0167 W/m^2, and assuming the spectrum behavees similarly as the sun's, there is 25 % loss due to scattering. Earth based observer then has average irradiance of 0.0122 W/m^2 from Betelgeuse. If he is using Mark I Eyeball for viewing, the iris aperture is maximally about 8 mm with scotopic vision. This means he collects approximately 0.0122 W/m^2 * (4*10^-3)^2 *pi ~ 613 nW on the retina.
For the contrast, usually Class I or II lasers are limited below 1 mW of power. This does not pose a significant eye hazard as long as the laser is not pointed on the eye for a long time. To really damage the retina, optical powers of order milliwatts are needed. Because these lasers are also relatively well collimated and form about as small spot as the distant star, I think the comment about the potential eye damage is exaggerated.
However, there most likely is a strong difference of contrasts as the moon is relatively nice on the eye due to a larger size which provides some sort of averaging for the eye. For a distant star, it is small and black background will enhance the observed brightness. I could expect some kind of bright spot as an after image in the field of view, but I highly doubt any of those could do real damage to the eye.
Mika
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Agree with Mika, eye-damage would require a lot of time just staring at the event, possibly through magnification.
If it does go, I probably going to spend the first couple of days on the shed roof with the camera ;)
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How long would the supernova actually last? A few months?
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For some reason, I'm reminded of the old movie "Day of the Triffids." Everyone goes blind watching a meteor shower, and killer plants try to take over the world.
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How long would the supernova actually last? A few months?
If Betelgeuse was comparable to the star whose collapse generated the Crab Nebula, we would see the supernova for a while. Even during the day.
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How long would the supernova actually last? A few months?
If Betelgeuse was comparable to the star whose collapse generated the Crab Nebula, we would see the supernova for a while. Even during the day.
The actual "kaboom" is quite short from what i read, but yeah we would likely see the aftereffects for quite a while.
Again, "from what i read", the eye-damage part was also just something mentioned as a "possibility" on a webpage.
I guess when you have to point out to people that you don t put wet pets into the microwave to dry, then its just natural to point out that staring at a Supernova might not be the brightest thing one can do heh ;)
But yeah, i doubt it would be much different than staring at the sun currently, except the visible "spot" that emits light would be even smaller.
If you account for the possibility of hordes of hobby astronomers with all kinds of optical devices without proper filters... mentioning the possibility, is the least one can do i guess eh ;)
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Will we be able to hear the kaboom?
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Only in computer games and TV shows can you hear sounds in space. :p
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Only in computer games and TV shows can you hear sounds in space. :p
In fact it would be possible to "hear" (as in, aurally detect) gravitational waves of sufficient amplitude within 20-20000 Hz range.
Basically because they would make everything vibrate in the space around them. Including your eardrums. Something like two black holes orbiting each other for example could cause such phenomenon.
Also, a large mass collapsing withing an event horizon would likely cause a "crash" or shockwave-like gravitational wave, which - if powerful enough in amplitude - could very well cause some sort of sound to be detected by human ear. However, the intense radiation would be a much bigger problem and the rapid expansion, vaporization and ionization of everything around you would probably create much more noise.
:lol:
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I'm pretty sure there was a research whose objective was "hearing" sounds coming from space, like the ones caused by black holes (as explained by Herra Tohtori)...
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On a somewhat related note, I recall reading about people hearing sounds caused by meteors, simultaneous to seeing them burning up in the atmosphere. Obviously the sound can't be directly from the meteors since they occur somewhere between 40 to 100 miles from the observer and sound can't possibly cover that distance instantly, so the current theory is something along the lines of radiation from the plasma trail interacting with objects on the ground.
Edit:
Wikipedia article specific to Betelgeuse's demise:
http://en.wikipedia.org/wiki/Betelgeuse#Betelgeuse.27s_fate (http://en.wikipedia.org/wiki/Betelgeuse#Betelgeuse.27s_fate)
It is likely that Betelgeuse will become a supernova.[3][21] Considering its size and age of 8.5 million years – old for its size class – it may explode within the next thousand years—if it hasn't already.[21] Since its rotational axis is not toward the Earth, Betelgeuse's supernova would not cause a gamma ray burst in the direction of Earth large enough to damage its ecosystem even from a relatively close proximity of 520 light years.[21]
A Betelgeuse supernova could easily outshine the Moon in the night sky.[21] It will likely be the brightest supernova in recorded Human history, easily outshining SN 1006. After it explodes, it will likely linger for several months, being visible in the daytime sky and lighting up nighttime skies in the Solar System for a long time, after which the "right shoulder" of Orion will disappear forever.
Reported on June 9, 2009, the star has shrunk 15% since 1993. This means the average speed at which the radius of the star is shrinking, over the last 15 years is approximately 470-490 miles per hour. The rate that it has been decreasing in size has accelerated.[22]
Nobel Laureate Charles Townes announced evidence that fifteen straight years of stellar contraction has now observed to be occuring by UC Berkeley's Infrared Spatial Interferometer (ISI) atop Mt. Wilson in Southern California.
According to the university, Betelgeuse's radius is about five astronomical units, and the star's radius has shrunk by a distance equal to half an astronomical unit, or about the orbit of Venus. Some theorists have speculated that this is the behavior we should expect if a star begins the gravitational collapse at the end of its life. The mass of Betelgeuse puts it in range to become a neutron star or possibly a black hole. At 520 light years away it poses little threat to life on Earth, but it could cause some very bright nights when the red giant finally does go supernova.[23]
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An aurora borealis also causes sounds, if I remember well.
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Mhhh... something that is strong enough to cause a "soundwave" within our atmosphere likely WOULD pose a problem lol ;)
But nope, i don't think we'll "hear" it anymore than we "hear" the Moon or the Sun LOL.
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I can actually hear the sun burning. :p
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I can hear God. He's talking to me right now, in fact. :P
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Reported on June 9, 2009, the star has shrunk 15% since 1993. This means the average speed at which the radius of the star is shrinking, over the last 15 years is approximately 470-490 miles per hour. The rate that it has been decreasing in size has accelerated.
...this really sort of puts the size of Betelgeuze in proper context.
It's been shrinking, for 15 years, about as fast (or perhaps a tad slower than) as passenger airliners cruise speed. And it's shrinking has been accelerating. :nervous:
That's a long distance.
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I can actually hear the sun burning. :p
DZZZZZZZZZZHHHHHH...
I can hear God. He's talking to me right now, in fact. :P
:wtf:
Will we be able to hear the kaboom?
Yes, if you're within 1 mm of the explosion... :drevil:
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An aurora borealis also causes sounds, if I remember well.
So do lots of other things that aren't in space too. :p
While the aurora's causes may be due to something from space, it is an atmospheric effect.
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Reported on June 9, 2009, the star has shrunk 15% since 1993. This means the average speed at which the radius of the star is shrinking, over the last 15 years is approximately 470-490 miles per hour. The rate that it has been decreasing in size has accelerated.
...this really sort of puts the size of Betelgeuze in proper context.
It's been shrinking, for 15 years, about as fast (or perhaps a tad slower than) as passenger airliners cruise speed. And it's shrinking has been accelerating. :nervous:
That's a long distance.
But still, you can't really tell if its just a burp or a hickup yet, even tho it seems likely its the big boom LOL :)
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Betelgeuse! Betelgeuse! Betelgeuse!
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According to the university, Betelgeuse's radius is about five astronomical units
This shows how gigantically HUGE this thing is. For those who don't know, an AU (astronomical unit) is the average distance from the Earth to the sun. Call it 143,598,000 kilometers. The radius of Betelguese is five of those. 717,990,000 kilometers. That's the radius. The diatmeter would be twice that. Betelguese is 1,435,980,000 kilometers in diatmeter.
EDIT: Sorry, the wiki on astronomical units actually mentions Betelgeuse as having a diameter of 5.5 AU. Rougly 789,789,000 km.
The mean diameter of Betelgeuse is 5.5 AU (511,258,000 mi.).
I'll leave both up because I don't know which one is the actual size.
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An aurora borealis also causes sounds, if I remember well.
So do lots of other things that aren't in space too. :p
While the aurora's causes may be due to something from space, it is an atmospheric effect.
Well, those sounds haven't been explained yet. They appear to be connected to particular electromagnetic fields. They're not a product of Earth's atmosphere, only.
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From what I understand, the effect is atmospheric, even though the Aurora is magnetic, I seem to recall it's something to do with the heating of the upper atmosphere meaning that sound can travel much further than it normally would, otherwise, we shouldn't be able to hear it.
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The origin of the phenomenon is not to be connected to Earth's atmosphere, only. But we're going off topic here... :nervous:
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So? What the **** has that got to do with the sound coming from outer space? That's exactly what I said in my first post.
While the aurora's causes may be due to something from space, it is an atmospheric effect.
The sound does not come from space any more than the sound your radio makes came all the way from the radio station.
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Charged particles coming from the sun spiraling around the lines of Earth's magnetic field are focused toward the magnetic poles by the focusing magnetic lines. When the charged particles collide with the upper atmosphere, they push the atoms into a higher energy state. When the electrons around these atoms are returning to their base state light of specific wavelength is radiated. You need very low density, so the energy is not lost by collision before the electron transition occurs.
So it IS a very specific upper atmosphere phenomenon. UFF! The astrophysicist has spoken!
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From what I understand, the effect is atmospheric, even though the Aurora is magnetic, I seem to recall it's something to do with the heating of the upper atmosphere meaning that sound can travel much further than it normally would, otherwise, we shouldn't be able to hear it.
I like the "ELF induced local vibrations" (or something) hypothesis better. It'd also explain nicely some of the other stranger sounds (meteors).
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Coming from a person who is living pretty close to the Arctic circle, I know only a couple of people who have said Aurora Borealis make any kind of sound. I have never heard it, and it seems that the noise is audible only in really isolated places. I recall one of my lecturers actually tried to make the sound audible for microphones, but the results were varied. As far as I know, it is still a question whether it exists or not.
What it comes to Betelgeuse brightness, to clear one thing up, it shouldn't be even closely as bright as sun is. That doesn't mean though that it would not be a spectacular sight. I'm with Flipside on this one, count me in on photographing and sleeping on a roof, given it is on summer time and there is a low amount of mosquitos present.
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I can hear God. He's talking to me right now, in fact. :P
Ah, but are you listening to him?
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I can hear God. He's talking to me right now, in fact. :P
Ah, but are you listening to him?
Only when I'm not wearing my foil hat.
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They even say that if a roaming black hole (ones that are said to actually move through the universe) was to start coming close to Earth and sucking the atmosphere, you would hear it too.
Wouldn't the sudden change in air pressure(?) deafen/kill you, first?
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How big of a black hole are we considering here?
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Will we be able to hear the kaboom?
Only in computer games and TV shows can you hear sounds in space. :p
:(
"There's supposed to be an Earth shattering Kaboom!"
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...Kaboom!
The detergent?
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"Brad Schaefer: For all we know, Betelgeuse has just gone supernova. Betelgeuse is about a thousand light years away. So if Betelgeuse has gone supernova anytime in the last thousand years, the light of this supernova explosion could be speeding to us even as we speak – maybe it will arrive tonight – and suddenly Betelgeuse will flash into being brighter than a million full moons in the sky – all up above us. It would be a spectacular sight."
Okay...I don't doubt anymore.
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Did you miss the part where it would kill everything on the side of the planet facing it?
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Did you miss the part where it would kill everything on the side of the planet facing it?
Extremely unlikely. Supernova's have been witnessed in past history...its rare but not completely unheard of.
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You would need a very young huge star going nova and creating a super massive black hole like in the center of a galaxy to get a gamma ray burst. Think the term for that is hypernova. They only occur in star nurseries.
Has anyone thought of what having several months of near daylight would do to plant life especially crops?
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Has anyone thought of what having several months of near daylight would do to plant life especially crops?
Not much. Total daylight is only responsible for so much. Climate, soil conditions, and moisture are all big factors for plants.
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If I understand correctly, it wouldn't be entirely daylight all the time or anything. The Earth would still rotate, so sections of the planet that wouldn't be able to see Betelgeuse wouldn't be affected at that time, and the light would likely be a very bright harvest moon brightness, not another sun.
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Seems like a lot of crops only ripen in the dark though. Peppers, tomatoes, etc. Not sure about the science of it but it sure seems that way.
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Eh... maybe the person I talked to misheard the figure. It's possible he gave me the outlook for a 40-lya supernova, and not a 400.
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A supernova of Betelgeuse wouldn't be bright enough to turn night into day, though it would be plainly visible in the daytime. I'd think the effect on plantlife would be minimal at best. As for possible hypernova, the rotation axis isn't aimed at us so we're not at risk from that either. Sorry to the doomsday aficionados. ;)
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Like Eta Carinae. o.O
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"Brad Schaefer: For all we know, Betelgeuse has just gone supernova. Betelgeuse is about a thousand light years away. So if Betelgeuse has gone supernova anytime in the last thousand years, the light of this supernova explosion could be speeding to us even as we speak – maybe it will arrive tonight – and suddenly Betelgeuse will flash into being brighter than a million full moons in the sky – all up above us. It would be a spectacular sight."
I wish they would be more careful with the terms when they say something like that. There are pretty good reasons why Scientists should use words like irradiance, radiance and radiant intensity and especially NOT to use the damn "intensity" in their papers (it's almost always wrong). Brighter with respect to what? For the general audience, "brightness" is also a physical term, but with a totally different meaning: http://en.wikipedia.org/wiki/Brightness
Yes, if all the light comes from a point (distant star), the relative radiance between moon and star gone supernova is definetely high, but since it is almost a point source, it doesn't have surface area to provide high amount of power.
This all comes back to question how much EM radiation does the supernova release. SN1006 (class 1a) blew up 7200 lightyears back, and the result was that it was visible, about the size of Venus and one quarter of the brightness of the moon. Betelgeuse is 640 lightyears away, so a factor of ten less for distance equals factor of 100 for the area. So about hundred times brighter than the moon, if it has approximately the same amount of energy. I need to check the former irradiance number and how close it is to this estimation.
How much brighter is 100 times more brighter illumination than the moon?
http://en.wikipedia.org/wiki/Daylight
It is about the illumination under a storm cloud during midday. It is hard to believe one could damage eyes with that amount of power.
There are some differences between classes 1 and 2, and I think 1a would be the most dangerous. I'll let the astronomers do the classification stuff, just tell me the estimate of the released electromagnetical radiation.
Mika
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Astronomy babble time.
Betelgeuse would be a type II supernova (core collapse of a massive star). Type Ia supernovae involve the collapse of a binary white dwarf when it reaches ~1.4 solar masses (through accumulating matter from the partner star).
Type Ia's are very consistent in their brightness since it's pretty much always the same thing blowing up every time. They have a peak absolute magnitude of ~-19.5. As for Betelgeuse, it depends on what variety of SNII is goes off as (I'm not sure). There's P and L type, P meaning the intensity plateau's after the peak, while L has a linear decline. SNII-P can have a wide range of peak brightnesses, while SNII-L are usually ~2.5 magnitudes fainter than Ia's, which would be -17.
If we assume Betelgeuse goes off with peak absolute magnitude -17, and it's distance is 640LY = 196 parsec, then:
mv - Mv = -5 + 5log10(d)
mv - (-17) = -5 + 5log10(196)
mv = ~-10.5, which is slightly less than the full moon in apparent brightness. But since it will be a point source it will appear quite intense.
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Has anyone thought of what having several months of near daylight would do to plant life especially crops?
It would screw them completely. Lots of plants, including plenty of commercial crops rely on the length of the day/night cycle to tell them the season, and thus when to move between phases of growth, and they're surprisingly precise about it (i.e. to the minute accuracy). Fortunately, as has ben pointed out, this isn't what we're going to have.
Yeah, they say that the gamma ray burst that would do that to Earth is so unlikely that it has a very small chance of ever happening during the entire 10 billion year life time of the earth. Of course there is a theory that a gamma ray burst was responsible for a mass extinction that occured about a few hundred million years ago. I think it was one of the first mass extinctions and the most devastating one.
It's closer to 4 billion years of life on Earth, for starters, (The whole planet's only been here 4.5, give or take) and the event you're thinking of (Ordovician-Silurian around 450 odd mya) was only the first one if you want to think about in the old "Big Five" mentality. We don't know an awful lot abut the really early earth, but the likelihood is that mass extinction evens had been going on for almost the entire time life's been here - hell, in all likelihood life has been sent entirely extinct and re-evolved multiple times, especially if you accept the light carbon they found in the Jack Hills diamonds last year as evidence for life (That would mean we had life less than 300 million years after Earth formed, suggesting it's more or less inevitable whenever there's somewhere it'll form, making extinction and re-evolution far more likely). Even if you want to wait until we have a better idea of what's going on, then the first (and by far the most severe) confirmed mass extinction happened around 2 billion years ago when photosynthetic micro-organisms started polluting the atmosphere with oxygen and killed off almost the entire (at the time anareobic) ecosystem. Even in terms of the big five, the Permian Triassic has the O-S beat for severity.
And, at least vaguely on topic, the idea that it was a gamma ray event has no real evidence to support it - it was just a computer model that said it was possible. There're much more plausible explanations that have actual geological evidence backing them up, specifically that a continental landmass was sitting over the south pole while a massive ice age event was occuring, which sucked up a lot of water, destroyed almost all shallow marine habitats by dropping sea levels way down (possibly all the way to the continental shelf margins at times) and then flooding them again during interglacials, over and over again. It's important to note that defining an extinction event is based on marine life, and that, at the time, life on land was very restricted, so changes in the marine environment are what matter.
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Seeing that it would be a Class II supernova with two magnitudes less of optical power, I would approximately get about the same number using both the radiometric powers and historical information of supernovas.
It would most likely cause lasting after images if viewed for a long period, but not serious kind of damage. There could be some amount of iris adapting diameter to decrease the amount of light, but this is contestable since the rest of the sky is almost black.
Long time since I have last seen the apparent brightness formula, could've been 7 years ago.
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(Editted to be less confusing) I understand that with a lightsource viewed at infinity (like in the case of a star), the light entering the eye is focused to a point on the retina. But does the angular size of the source factor in at all for how damaging it is to the eye? I.e, would looking at the sun be any more or less damaging if it were instead a pointsource of the same magnitude?
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You are basically talking about things that are related to the optical energy conservation law (called optical invariant or etendue). If you are looking at a point source, the image of this point would be imaged as a perfect point if the lens was perfect. When you extend the source slightly and would consider two points, the two points will always be separated by some distance governed by magnification if the imaging would otherwise remain constant. In principle, there will always be some infinitesimal difference between these two points if the imaging was perfect. Well, that's the theoretical stuff of imaging. And everybody knows, in theory practise and theory don't differ, but in practise they do.
I'll post some more stuff here tomorrow, as there is a party I need to attend.
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Continuing the post before
Unfortunately, perfect point to pont imaging does not exist. This is because one would need to collect the whole inpinging wavefront in order to get a perfect point image, but this would require infinitely large aperture (ouch). The minimum achievable spot size is given by the Airy radius, which in turn depends on the lens F/number.
With F/8 (2 mm iris diameter), the spot size is of order 4 µm (Airy radius). So the image of the point will be spread over this area. Now, if one looks at the larger object, there will be some overlapping energy on this spot (human eye "pixel size" is about 2.5 µm). However, when one looks at the whole situation, I think that the amount of energy that the is spread over the other pixels due to diffraction is actually regained by the diffraction effects on those other pixels. So, even a point source can damage your eye (as evidenced by the lasers). So what happens when you increase the size of the source? You simply destroy larger area of the retina. Would this answer your question?
Another thing to note is that those rods and cones don't see Apparent Brightnesses or Watts, they are mainly photon counters. So to damage the retina, one has to fire enough photons in small enough area to cause damage. Only those photons that arrive on your 2mm diameter iris from the distance of 640 lightyears count.
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Did you miss the part where it would kill everything on the side of the planet facing it?
Extremely unlikely. Supernova's have been witnessed in past history...its rare but not completely unheard of.
A supernova might have caused a mass extinction at the end of the Ordovician:
Gamma ray burst hypothesis
Scientists from the University of Kansas and NASA have suggested that the initial extinctions could have been caused by a gamma ray burst originating from an exploding star within 6,000 light years of Earth (within a nearby arm of the Milky Way Galaxy). A ten-second burst would have stripped the Earth's atmosphere of half of its ozone almost immediately, causing surface-dwelling organisms, including those responsible for planetary photosynthesis, to be exposed to high levels of ultraviolet radiation. This would have killed many species and caused a drop in temperatures. While plausible, there is no unambiguous evidence that such a nearby gamma ray burst has ever actually occurred.
Adrian L. Melott et al estimated that gamma ray bursts from "dangerously close" supernova explosions occur two or more times per thousand million years, and this has been proposed as the cause of the end-Ordovician extinction.
I read more than what the Wiki reports a few months ago. Analysis of Ordovician-Silurian rocks proved how, in that period, the Earth was hit by radiation.
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EDIT: Frak it. Nevermind.
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:wtf:
Stars are constantly generated. Why would the stars of the Ordovician-Silurian be any different from the stars we see today...?
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Mika: Yep, that answers my question perfectly. Thanks. :)
I read more than what the Wiki reports a few months ago. Analysis of Ordovician-Silurian rocks proved how, in that period, the Earth was hit by radiation.
Ooh, could I get a source to that?
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:wtf:
Stars are constantly generated. Why would the stars of the Ordovician-Silurian be any different from the stars we see today...?
Metal concentration.
The first generation of stars were mostly very large and short-lived and they only consisted of hydrogen and helium and trace amounts of lithium and beryllium (which are the four elements that were originally formed in the aftermath of the Big Bang, aka nucleosynthesis) into heavier elements (or metals, as the cosmological terminology goes - anything heavier than helium is called metal), all the way to iron. Elements heavier than iron require supernovae.
Essentially the first generation of stars had zero metal concentration. Second generation already has stuff like carbon, oxygen, silicon, sulfur, and iron and various other elements in supernovae, which show up on the later stars' spectra.
So yes, stars of different age are are somewhat different. The heaviest elements also largely sink to the core of the star, and if a star has significant amount of heavy elements to begin with, it obviously forms a heavy element core faster than a mostly "pure" hydrogen-helium star, which can affect it's life span and behaviour. Not as much as the simple size of the star dictates, but still some.
The metal concentration of protostars has much more relevance to the formation of planets around the star.
You are right, though, that in the time span from Ordovician/Silurian era to Holocene era is somewhat too short for meaningful differences to occur in the general consistency of stars visible from Earth. Half a billion year as opposed to 13.7 billion years of the universe is not really enough to discern a difference. But if you were to compare the stars born now and the stars born ca. 5 billion years ago (about when the Sun was born) there would already be some difference.
The only visible difference between 500 million years ago and now would be the positions of the stars and the amount of some giant stars with life spans of only millions of years as opposed to billions of "average" stars like Sun.
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True, the average metal concentration cannot change in such a limited time span. 500 million years are not that much.
Ooh, could I get a source to that?
I'd like to make it public, but I can't. The info comes from a relatively old and dedicated magazine that could be anywhere in my house. :(
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Mika, you are so smart you make this ignorant farmboy's head hurt.
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Huh?
Firstly, my roots are not that different.
And secondly, my day job is in the field of optics. Designer, researcher, engineer, whatever necessary, it all goes.
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Mika, you are so smart you make this ignorant farmboy's head hurt.
Hey, give Herra some credit.
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I read more than what the Wiki reports a few months ago. Analysis of Ordovician-Silurian rocks proved how, in that period, the Earth was hit by radiation.
I call bull****. You may have read it, but I'd go back and recheck your source. I remember my lecture on this particular even mentioning how unlikely the gamma ray hypothesis was because of the lack of physical evidence. What you mighthave read is that there was an altered oxygen isotope ratio as a result of increased UV radiation and while yes, technically this might occur as a result of a stripped ozone layer it's used in paleoclimatology to detect climate. The general idea is that as the earth cools, more water is locked up at the poles, where UV radiation is more intense, and so the Oxygen isotope ratios change (I think O13 content increases, but I'm not 100% on that). Plus, the O-S was a bimodal extinction event, a double pulse over around 10 million years, which is far more likely attributable to two phases of glaciation than a gamma ray burst that somehow had its effects felt as an separate incident 10 million years later. now, granted, 10 million years isn't super long, geologically, but it is longer than the systems that affect the biosphere would typically take to cycle things like a gamma burst.
So, yes, while the gamma burst hypothesis has a certain interest factor to it (and fits nicely with the K-T impact as an extraterrestrial mass extinction event) it really doesn't fit the evidence we do have, and there's never been much found which supports it since the publication of the paper, at least, not as far as I know.
That said, if you do find the paper you were talking about, I'd definitely like to see it. Evidence supporting a GRB for the O-S would definitely be something I'd like to see. :)
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Behold the wrath of geologists ;)
As for the OT: The original source never mentions anything about it going supernova. But the speed at which it is contracting surely makes it worth to keep a very close eye on Betelgeuse over the next few years.
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I just hope it goes off in wintertime, when Orion is actually visible from here.
It would be so wrong if the southern hemisphere got that event as well as all the awesome constellations they already have there. :p
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I call bull****. You may have read it, but I'd go back and recheck your source. I remember my lecture on this particular even mentioning how unlikely the gamma ray hypothesis was because of the lack of physical evidence. What you mighthave read is that there was an altered oxygen isotope ratio as a result of increased UV radiation and while yes, technically this might occur as a result of a stripped ozone layer it's used in paleoclimatology to detect climate. The general idea is that as the earth cools, more water is locked up at the poles, where UV radiation is more intense, and so the Oxygen isotope ratios change (I think O13 content increases, but I'm not 100% on that). Plus, the O-S was a bimodal extinction event, a double pulse over around 10 million years, which is far more likely attributable to two phases of glaciation than a gamma ray burst that somehow had its effects felt as an separate incident 10 million years later. now, granted, 10 million years isn't super long, geologically, but it is longer than the systems that affect the biosphere would typically take to cycle things like a gamma burst.
So, yes, while the gamma burst hypothesis has a certain interest factor to it (and fits nicely with the K-T impact as an extraterrestrial mass extinction event) it really doesn't fit the evidence we do have, and there's never been much found which supports it since the publication of the paper, at least, not as far as I know.
That said, if you do find the paper you were talking about, I'd definitely like to see it. Evidence supporting a GRB for the O-S would definitely be something I'd like to see. :)
Special reply tag for you:
I did not mention any O2 isotopes. By proof of the explosion of a supernova during that period I meant the presence of much heavier elements. We all know that, due to atom degradation, we will never, ever be able to see certain isotopes here on Earth - it doesn't mean that no isotopes of that kind ever existed here, it simply means that all isotopes (again, of that kind) no longer exist due to degradation.
So, if studies prove that a particular kind of isotopes are in rocks originated at the end of the Ordovician, we need to assume that Earth was hit by a flood of elements during that period.
It's pretty much what happened with the meteor impact that might have caused the mass extinction of the Crataceous-Paleocene - research proved how traces of iridium isotopes could be found in rocks that originated during that period.
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It wouldn't be that the earth was hit by a flood of heavy elements in this case. For that to happen the event would need to be really close, within a few tens of lightyears. I'd think if a GRB/hypernova were that close then nothing at all would have survived. Nevermind the statistical implausibility of having one occur that close to begin with.
What you may have read is that the radiation from the event could have altered the isotopes in the rocks exposed to it, and perhaps this change was measurable. If so I'd be interested in knowing what exacly was detected and where.
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So, if studies prove that a particular kind of isotopes are in rocks originated at the end of the Ordovician, we need to assume that Earth was hit by a flood of elements during that period.
You what? :confused:
How the hell is a supernova going to result in a measurable difference in the concentration of heavy elements?
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So, if studies prove that a particular kind of isotopes are in rocks originated at the end of the Ordovician, we need to assume that Earth was hit by a flood of elements during that period.
You what? :confused:
How the hell is a supernova going to result in a measurable difference in the concentration of heavy elements?
It doesn't.
...Well, technically there's a thing called photoneutron process which means that if a neutron is hit by a gamma ray with energy higher than the binding energy, it can be ejected from the nucleus, causing the isotope to become lighter (which can cause it to become unstable and further decay into other isotopes). There are definitely sufficiently energetic gamma rays in gamma bursts, to achieve this, but the question is would it cause detectable changes. Which is a three-fold question; first is the rate of transmutation achieved by the gamma burst, second is the stability of the isotopes made, and the third is the rarity of the isotopes in question.
If the rate of transmutation is small enough (too small amount of nuclei go through the isotopic changes), they can't be detected.
If the half-lifes of the isotopes are small enough, there's no chance to detect the rare isotopes after hundreds of millions of years.
If the isotopes happen to be common, there is really no way to tell what caused them.
All in all, I don't think there is any way to detect if such event took place based on the isotopes, similar to how asteroid or comet impacts can be detected. To introduce alien isotopes on Earth in any detectable or meaningful volume (detectable amount) requires an actual influx of the isotope (impact of some sort, which you referred to with the indium traces), or a neutron flux of significant strength... And there's no way in heaven or hell that either the heavy elements from the supernova or the neutron flux from it would ever reach Earth through several light years of space.
Nearby gamma burst would have other effects, mainly on molecular level, which could possibly be detected. Stuff like changes in crystal structures of some minerals for example... I'm going to just quote wikipedia because I don't think there's much I can add or improve on this:
A gamma-ray burst in the Milky Way, if close enough to Earth and beamed towards it, could have significant effects on the biosphere. The absorption of radiation in the atmosphere would cause photodissociation of nitrogen, generating nitric oxide that would act as a catalyst to destroy ozone. According to a 2004 study, a GRB at a distance of about a kiloparsec could destroy up to half of Earth's ozone layer; the direct UV irradiation from the burst combined with additional solar UV radiation passing through the diminished ozone layer could then have potentially significant impacts on the food chain and potentially trigger a mass extinction. The authors estimate that one such burst is expected per billion years, and hypothesize that the Ordovician-Silurian extinction event could have been the result of such a burst.
So, yeah. I don't think isotopic concentration of soil layers from different times can be used to detect gamma bursts in any meaningful accuracy. I could be wrong though, but there just seems to be too many problems with it.
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:nervous:
[attachment has decomposed]
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:lol:
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Oh, and this...
:nervous:
[attachment has decomposed]
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:lol: But seeing the skybox stars behind the nebula seems odd...
It's also interesting (to me) to see the HUD in Italian.
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I just hope it goes off in wintertime, when Orion is actually visible from here.
It would be so wrong if the southern hemisphere got that event as well as all the awesome constellations they already have there. :p
Actually Orion is visible from pretty much anywhere on Earth (arctic circle excluded) at any time of year. It's not that it's too far south for the summer months, but Earth's orbit brings it near the sun at that time. Wouldn't matter in the case of it going supernova, though probably from May to July it'd be too close to the sun and lost in the glare.
If you wanna see it at night though (naturally), then yeah, winter would be best when it's near opposite the sun.
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I did not mention any O2 isotopes. By proof of the explosion of a supernova during that period I meant the presence of much heavier elements. We all know that, due to atom degradation, we will never, ever be able to see certain isotopes here on Earth - it doesn't mean that no isotopes of that kind ever existed here, it simply means that all isotopes (again, of that kind) no longer exist due to degradation.
So, if studies prove that a particular kind of isotopes are in rocks originated at the end of the Ordovician, we need to assume that Earth was hit by a flood of elements during that period.
It's pretty much what happened with the meteor impact that might have caused the mass extinction of the Crataceous-Paleocene - research proved how traces of iridium isotopes could be found in rocks that originated during that period.
I know you never mentioned Oxygen isotopes - I thought you might have been getting confused between real phenomena that have been measured at the O-S and something else. As for the rest of it, I think you're getting your physics confused. As has been mentioned, direct gamma interaction would cause elements to lighten, while a flood of heavy elements as direct ejecta from a supernova is extremely unlikely due to the likely distance and the inverse square law. Plus, even if you were talking about direct gamma impact, I can't see how you'd have a measurable change 500 odd million years later. As for the iridium at the K-T boundary, that was a combination (it's assumed) of the residue left after the meteor more or less vaporized on impact and ejecta from the Deccan traps (which were most likely set off by the impact, and so were coincident, stratigraphically. There's no large scale input of matter during a GRB to leave a chemical signature of that nature.
Again though, if you find the original source, please post it, or at least the author and title of the article. I'll probably be able to access it through uni.
Just for the record, I'm not trying to say that a GRB definitely did not cause the O-S extinction. I'm just saying that there's essentially no evidence that it did (only models which say it might have, and no obvious evidence ruling it out), while there's plenty of evidence for tectonic alteration of climate as a cause. As such, while an interesting aside, the GRB theory really doesn't deserve the kind of exposure it's gotten since it was published.