So what will happen when Betelgeuse explodes?

[Dave S]

It's not debris from a supernova that close you need to worry about. Unlike what the movies show for effect i.e big chunks of rock etc. The energy of a supernova explosion is such that it resolves any solid matter to molecular gases. It is Gamma and X-rays that are the danger. Gamma rays would cause chemical reactions in the atmoshere converting nitrogen into nitrogen oxides which would cause massive depletion of the ozone layer exposing the earths surface to extreme levels of Ultraviolet. Fortunately the estimated danger distance is calculated to be less than 100ly for a type II supernova of Betelgeuses size.

On the up side we would be subjected to some very intense and pretty Auroral displays.

Dave...

[spaceboy]

Because light has no mass, it can not carry other objects along with it, like a wave of water can. So if we have not even seen the light from a possible Supernova, there is no way that any debris from it would reach us first or even a long time after.

I think I kind of get it now. Basically the light is always going to travel quicker in relation to the object so we will always see the light first no matter how energetic an explosion.

On another note: As for the speed of light being the fastest thing I think this is incorrect. Darkness of space travels infinitely faster than anything. Just because we do not scenes movement doesn't mean it isn't. We have to bear in mind no human eye or electronic equipment can measure anything traveling faster than the speed of light so who can is say space is standing still?? Darkness is the true constant in the universe but this too has to come from some where just as everything is created by something. We all know the...what came first the chicken and egg? question. Just because our eyes and brains cannot contemplate the vastness of space it doesn't mean it isn't a tangible entity. If we were to travel to the end of the universe what would be the other side? is it what creates darkness??

My point is darkness doesn't have to travel as it IS! light has to travel through darkness...so surely darkness is quicker than light ??Just trying to think 4 dimensionally

[astroimpulse]

Same speed...just more of it...I believe.

Edit: Ok...I need to check beyond page 1 lol Terribly out of date response

[Zakalwe]

I think I kind of get it now. Basically the light is always going to travel quicker in relation to the object so we will always see the light first no matter how energetic an explosion.

On another note: As for the speed of light being the fastest thing I think this is incorrect.

Hmmm...there might be a few astrophysicists, scientists, and physicists that would disagree with you (including the ghost of one Mr. A. Einstein). To make such an extraordinary claim you would have to supply extraordinary evidence. And that evidence would have to show that Special Relativity was incorrect.......

What General and Special Relativity tells you, IIRC, is that nothing can accelerate beyond the speed of light. Objects already travelling faster than the speed of light are exempt, although they cannnot decelerate to the speed of light (tachyons). Although SR or SR does not preclude such particles, their existence has never been verified. If they existed, then they may cause all sorts of headaches with causality.

Darkness of space travels infinitely faster than anything. Just because we do not scenes movement doesn't mean it isn't. We have to bear in mind no human eye or electronic equipment can measure anything traveling faster than the speed of light so who can is say space is standing still?? Darkness is the true constant in the universe but this too has to come from some where just as everything is created by something.

"Darkness" is not a "thing" as such. It is the absence of light, or the absence of something for light to reflect off. The information about darkness (ie, if light is present, or if there is a surface to reflect light) is also constrained by the speed of light. By that, I mean that the information about darkness cannot travel faster than C. If it did, then it would violate causality and SR.

Now I have a headache. I am going to lie down in dark room with a damp towel on my fevered brow.

[spaceboy]

Same speed...just more of it...I believe.

Edit: Ok...I need to check beyond page 1 lol Terribly out of date response

It's my fault astroimpulse I guess I've somewhat hijacked the thread...........SORRY Claire!!!! I don't suppose my questions are helping your question get answered

SPACEBOY

[davy999]

I think we may have more answers should CERN ever prove dark matter and the higgs boson particle thingy.

[spaceboy]

Hmmm...there might be a few astrophysicists, scientists, and physicists that would disagree with you (including the ghost of one Mr. A. Einstein). To make such an extraordinary claim you would have to supply extraordinary evidence. And that evidence would have to show that Special Relativity was incorrect.......

What General and Special Relativity tells you, IIRC, is that nothing can accelerate beyond the speed of light. Objects already travelling faster than the speed of light are exempt, although they cannnot decelerate to the speed of light (tachyons). Although SR or SR does not preclude such particles, their existence has never been verified. If they existed, then they may cause all sorts of headaches with causality.

"Darkness" is not a "thing" as such. It is the absence of light, or the absence of something for light to reflect off. The information about darkness (ie, if light is present, or if there is a surface to reflect light) is also constrained by the speed of light. By that, I mean that the information about darkness cannot travel faster than C. If it did, then it would violate causality and SR.

Now I have a headache. I am going to lie down in dark room with a damp towel on my fevered brow.

Most of that went straight over my head Zakalwe I don't claim to be a scientist but I do understand that we often don't see beyond the horizon. We try in theory but in truth we can't be 100% certain. I read that it takes 9 minutes for light to travel from the sun to us. WHY if "Darkness" is not a "thing" is light restricted to speed. Darkness is every where but it has to come from some where so it must be getting about some how? and it would have to be pretty quick as space is huge. I feel we are often limited to what we find familiar. For example: Just say there is a star bigger than R136a1 and all the conditions were perfect and an earth like planet evolved but to the same ratio to R136a1 as we are to our sun then you would end up with some pretty big ET's. This said we still insist that there will be aliens with the same dimensions and intellect to us and send messages out in to space.

For me to supply evidence is impossible but to not consider it a viable possibility? No-one can claim to know all the answers but it's only human nature to ask the questions.

[Zakalwe]

Apologies to the OP for the thread hijack!

Most of that went straight over my head Zakalwe I don't claim to be a scientist but I do understand that we often don't see beyond the horizon. We try in theory but in truth we can't be 100% certain.

Because the Earth is a sphere. TO see over the horizon would call for light to be refracted a massive amount in air. Which would make getting about the place a real pain in the bum.

I read that it takes 9 minutes for light to travel from the sun to us. WHY if "Darkness" is not a "thing" is light restricted to speed.

Yes, because the speed of light, although very very fast, it is still finite. And the Sun is an awfully long way away.

Why is light restricted to c? I am no physicist, but it appears to be a fundamental part of the space-time continuum that makes up the Universe. In the same way that electrons, protons, neutrons always have the same mass, no matter what atom or compound they are in, or where they are residing.

I believe that faster-than-light effects can be created...but they can carry no energy, information or matter faster than c. Some examples are given in the Wiki article here

Just say there is a star bigger than R136a1 and all the conditions were perfect and an earth like planet evolved but to the same ratio to R136a1 as we are to our sun then you would end up with some pretty big ET's. This said we still insist that there will be aliens with the same dimensions and intellect to us and send messages out in to space.

Based on what makes you think this? There are limits for different body types/biomechanical limits/energy limits that are fundamental. A bad example: Insects cannot grow beyond a certain size because of the way in which they respire. They do not have lungs, rather air diffuses into their bodies, and respiration by-products diffuse outwards. This limits the size of their bodies, as a larger body would mean that oxygen cannot reach into their bodies. It also limits their ability to burn energy in their cells. That is why giant insects aren't ever going to take over the world (Hollywood notwithstanding:D)

For me to supply evidence is impossible but to not consider it a viable possibility? No-one can claim to know all the answers but it's only human nature to ask the questions.

Nothing wrong with that at all....day-dreaming is good. But the difference between day-dreaming and fact is that facts are backed up with evidence and are repeatable. To rule something out just because there is no evidence is wrong....but it would also be wrong to support something that has no evidence if it counteracted or refuted something that was supported by a mountain of tested evidence.

If I can recommend a couple of books that I found fascinating:

The Demon Haunted World by Carl Sagan

Why People Believe Weird Things by Michael Shermer.

Thread hijack over:icon_salut:

[spaceboy]

Based on what makes you think this? There are limits for different body types/biomechanical limits/energy limits that are fundamental. A bad example: Insects cannot grow beyond a certain size because of the way in which they respire. They do not have lungs, rather air diffuses into their bodies, and respiration by-products diffuse outwards. This limits the size of their bodies, as a larger body would mean that oxygen cannot reach into their bodies. It also limits their ability to burn energy in their cells. That is why giant insects aren't ever going to take over the world (Hollywood notwithstanding:D)

Again!! Whats saying they would breath at all. Restricted to what we are familiar with. We cannot explain how some creatures survive down in the depths of our oceans so how can we expect to know for certain there isn't a Gulliver ET out there

Thanks for the info Zakalwe and sorry again for the hijack Claire.

SPACEBOY

[Zakalwe]

Again!! Whats saying they would breath at all. Restricted to what we are familiar with. We cannot explain how some creatures survive down in the depths of our oceans so how can we expect to know for certain there isn't a Gulliver ET out there

Thanks for the info Zakalwe and sorry again for the hijack Claire.

SPACEBOY

Where would they get the energy to think/move/reproduce from?

[spaceboy]

Where would they get the energy to think/move/reproduce from?

Who knows? I'm bound by familiarity But there once was a man who could walk on water

[Zakalwe]

"A fanatic is someone who can't change his mind and won't change the subject."

Winston Churchill

Only joking....

[spaceboy]

:D

[WayneR]

...all the governments of the world are doing is building bunkers for seeds to re-propagate...

I've always felt like a bit of a mushroom - do you think they'd let me in??

[spaceboy]

I don't know you could try giving them a bell, you might want to take your thermals and your scope . BBC NEWS | Science/Nature | 'Doomsday' vault design unveiled

[david's dob]

They are building a vault for seeds? nice so buggar the human race save the seeds

[spaceboy]

I think the idea is all the world class Dr's, Historians, Physicists, Royal Family, etc, etc, etc go in to nuclear bunkers with their fingers crossed. The asteroid wipes the rest of us out they re-amerge 20-50 years later try to propagate the land and in doing so actually do save the human race. The less fortunate of us will get to see what wiped out the dinosaurs.

[Mr Spock]

So, if light has no mass, why does gravity in a black hole pull it down...?

[Celeste]

Wow...I now have a headache lol.....*slowly backs out of the thread

[E621Keith]

So, if light has no mass, why does gravity in a black hole pull it down...?

May be because light have momentum despite not having mass or how gravity can warp space time.

[Mr Spock]

But the theories of space-time don't agree with quantum mechanics.

If you try to imaging light as travelling in 'hyperspace' (for want of a better word), and only becoming visible when impact with a particle forces the light particle out of 'hyperspace', then the speed of light can be explained as the exit velocity. This would also explain why light is both a particle and a wave, and why it has zero mass, and why it appears to have a constant velocity

Mr Spock's theory of light © 2011...

[Zakalwe]

So, if light has no mass, why does gravity in a black hole pull it down...?

Because gravity affects the space-time continuum that light travels through. A massive object warps or distorts space-time. This can be evidenced by gravitational lensing (predicted by Einstein's GR theory).

A black hole distorts space-time so much that the path that light follows has to bend back in on itself...in other words, it cannot escape. Its not so much that gravity pulls light back (because it has no mass to work on) but rather that a massive body bends the path that light has to follow. The photons of light are following the curvature of space-time....but they are still travelling at c. This gets interesting when considering black holes. The light trying to leave the black hole is still travelling at c, however space-time is curved so much that it cannot exit.

Damn....now I have another headache....

[Zakalwe]

Here's a link explaining far more succinctly than I ever could about why gravity affects light.

[spaceboy]

Could it be a black hole is not actually a hole but darkness speeding through the universe faster than light speed and creating some kind of gravitational pull which light can be sucked along?? am I being a day dreamer again ? I understand there are passionate people out there who have devoted a great deal of time and energy in to building a substantial case for their "theories" but should we not keep an open mind about things we truly cannot explain? During a history lesson I was told our ancestors had a "theory" that the earth was square.

THE FANATIC

[Godders84]

Hi all, my first post!

An interesting discussion forming here I think, so I'd like to throw my 2 cents in!

My understanding is that we "see" things because a wave of light (or stream of photons) hits our retina. The optic nerve carries this information to the brain, which then interprets this information and tells us that we've seen something, it's colour, size, texture etc.

The light that enters our eyes will either be from a chemical reaction that emits 'visible' light (such as nuclear fusion, which is why we see the sun and stars), or by reflection of this light by light-reflecting matter (the planets and moons reflect the sun's light which is why we see them - they do not emit visible light of their own).

Empty space (i.e. space that is not made up of stars, planets etc.) is a vacuum, and so by definition is empty. As it's empty, there is nothing to emit light, and nothing to reflect light, which is why it appears dark. Darkness is not a tangible 'thing' that is moving through space, it is simply an absence of any light-reflecting matter (note it's an absence of light-reflecting matter. It may be filled with a currently misunderstood form of matter that does not reflect light, such as 'dark-matter')

With regards to the black hole Spaceboy, you are right in that it is not a hole, but a singularity. Bizarrely, you will never be able to see anything 'fall' into a black hole - gravitational time dilation means that, to an observer outside the event horizon, anything falling into the black hole will take an infinite amount of time to reach it. Imagine that!!!