[Mobius]

Why do you keep calling it Beetlejuice?

[Mikes]

Why do you keep calling it Beetlejuice?

Guess because of that "said it 3 times" comment at the start aha. Betelgeuse of course But Beetlejuice (i.e. the movie) was inspired by the name (and just the name) i believe lol

[Mobius]

Betelgeuse is a noble name. Typing "Beetlejuice" because of a movie is an insult, IMO.

[Mikes]

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.

[Mika]

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

[Flipside]

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

[Snail]

How long would the supernova actually last? A few months?

[Scotty]

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.

[Mobius]

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.

[Mikes]

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

[GTSVA]

Will we be able to hear the kaboom?

[karajorma]

Only in computer games and TV shows can you hear sounds in space.

[Herra Tohtori]

Only in computer games and TV shows can you hear sounds in space.

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.

 

[Mobius]

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)...

[watsisname]

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

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]

[Mobius]

An aurora borealis also causes sounds, if I remember well.

[Mikes]

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.

[Mobius]

I can actually hear the sun burning.

[watsisname]

I can hear God.  He's talking to me right now, in fact.

[Herra Tohtori]

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.

That's a long distance.