a couple questions about stars

[brandoncotten]

i have very little knowledge of these things so i wanted to ask the community a couple of questions that have been bothering me lately.

 

first question.

 

If there are billions upon billions of stars, why when i look up at the sky, I do not see a star exploding by the second or minute? Billions of stars would mean that thousands of stars are exploding per day every day right? Why do we never see this happening? Why in my 29 years of life, have we not had a star that has blown up remotely close to and just extinguish our lives? To me this would make sense given the fact there are countless stars. Given all the stars, there HAS to be a star close to us about to explode even before im done writing this.

 

Some of these stars are Gigantic, so big its hard to fathom.. Wouldnt even 1 of these big momma's exploding be messing with us?

[ACG52]

Since the lifetime of stars typically runs into the billions of years, supernovas are fairly rare events. Most stars do not explode when they reach the end of their lifetimes, only the largest do.

[brandoncotten]

if a stars life is a billion years or 10 years, it matters not.. after the first initial life span of a star happens, there after stars should explode per second.. thats going to be part of the billions of billions of stars, that needs to be explained. They in no way CAN be rare. matter of principle

Edited December 5, 2012 by brandoncotten

[ACG52]

But most stars don't explode.

 

Take the sun for example. In another 5 billion years or so, the sun will expand out past the orbit of mars, becoming a red giant. It will remain a red giant for a relatively short time, and then contract and settle down for the rest of time as a gradually dimmer dwarf star.

 

Only the most massive of stars explode.

[StringJunky]

ACG52 is correct: about the rarity which is once every fifty years in our galaxy...and that's 100KLYrs across. The furthest visible star, in absolutely perfect seeing conditions, is about 1200 LYrs away so the frequency is even lower for the chance of seeing one with the naked eye.

 

"Because astrophysicists had inferred that the likely sources are mainly massive stars, which end their lives as supernovae, they could estimate the rate of such supernova events. They obtained a rate of one supernova every 50 years - consistent with what had been indirectly found from observations of other galaxies and their comparison to the Milky Way." http://www.esa.int/SPECIALS/Integral/SEMACK0VRHE_0.html

Edited December 5, 2012 by StringJunky

[brandoncotten]

im lost to these explanations. I feel like your minimalising the cosmos. Billions upon billions of stars. That is EASILY enough stars to have a star wink out of existence per second for as long as the universe exists. My reasoning.. in THIS world, a person dies every second or few seconds or 8 seconds.. the point, is that with the pool of our human race, 7billion? we have a death per second or so. BILLIONS upon BILLIONS of stars.. EVEN if .05% of stars supernova'ed, that should be enough to have one wink out of existence per second for the rest of existence..

[Klaynos]

People are not the same as stars. The universe is nor obliged to follow what your nor I feel. Having said that when you take into account the stars we can directly observe then the number drops greatly, on top of that the fraction of stars that will explode is truely tiny, so tiny that even at the rate of star death there is only one per 50 year's. Now even if we observed this the chance of it destroying earth is vanishingly small because space is big, far far to big for us to comprehend.

[brandoncotten]

do you not find the irony in telling me space is far far to big for us to comprehend and at the same time giving me a 1 death per 50 year spiel?

 

also i wasnt comparing stars life and deaths to humans. I used humans as a statistical example. Given that there are vastly more stars than humans, and we extinguish at a fast rate, that with BILLIONS of stars, its only logical to assume they wink out of existence as a STATISTICALLY SIMILAR rate.

Edited December 5, 2012 by brandoncotten

[Klaynos]

No because the space taken up by stars is also vanishingly small.

 

Look up some of the numbers of visible stars and their mass distribution and the mass needed to create a black hole and the rate of star death. The numbers will give you about 1 every 50 years which is also what is observed.

 

The universe doesn't care what you think us logical, work out the numbers yourself.

[dripto biswas]

listen my friend. do you know that our universe is expand at a huge rate? if you do then please try to understand this that even the nearest star is only too far away to cause any harm. any light from its explosion will take at least 4 years to get here, thereby causing no harm. you may see a tiny flash now and then, if the light from the respective star reaches you then. and you also need a very clear sky to see most of the tiny flashes of light. also most stars of this

stellar generation is juvenile and moreover most of them do not die in an explosion.

[Ophiolite]

in THIS world, a person dies every second or few seconds or 8 seconds.. the point, is that with the pool of our human race, 7billion? we have a death per second or so.

 

 

This is very true. Now tell me, how many people have you seen die? I mean, I can't believe you aren't seeing people dying at least every minute or so. You must be surrounded by dead people, since - as you say - there are so many of them dying all the time.

 

 

I'm not being sarcastic brandon, I'm trying to help you see the error in your thinking.

[Moontanman]

im lost to these explanations. I feel like your minimalising the cosmos. Billions upon billions of stars. That is EASILY enough stars to have a star wink out of existence per second for as long as the universe exists. My reasoning.. in THIS world, a person dies every second or few seconds or 8 seconds.. the point, is that with the pool of our human race, 7billion? we have a death per second or so. BILLIONS upon BILLIONS of stars.. EVEN if .05% of stars supernova'ed, that should be enough to have one wink out of existence per second for the rest of existence..

 

 

You seem to be thinking that all stars are visible to the naked eye. There are not billions and billions of stars in the range of the human eye. Some are in front of gas clouds. If a star went super nova on the other side of the galaxy not only would it be too far away top be seen by the naked eye it would be hidden by the galactic nucleus. I'm not sure how many stars are individually visible to the naked eye but it's not all stars or even billions of stars... Then as AGC52 pointed out very few stars explode...

[Phi for All]

im lost to these explanations. I feel like your minimalising the cosmos. Billions upon billions of stars. That is EASILY enough stars to have a star wink out of existence per second for as long as the universe exists. My reasoning.. in THIS world, a person dies every second or few seconds or 8 seconds.. the point, is that with the pool of our human race, 7billion? we have a death per second or so. BILLIONS upon BILLIONS of stars.. EVEN if .05% of stars supernova'ed, that should be enough to have one wink out of existence per second for the rest of existence..

Analogies often fail, and sometimes make things worse.

 

This is more of a math problem, and your equation is unequal. On one side of the equation you're including ALL the stars in the universe, and on the other side you're using a set that is limited to only visible stars, and only immense stars that will explode. Further, you're limiting that set to your lifetime of 29 years, which is really just the few years you've been watching stars and pondering this question. I think this is what leads to your incredulity.

[Airbrush]

85% of stars are red dwarfs. Even stars that are much larger than red dwarfs, such as our sun, cannot explode. So I will go out on a limb and stay probably over 95% of stars you see in our galaxy will never explode. Also, not all stars you see in the sky are as old as you think.

 

In other galaxies we detect gamma ray bursts almost every day. But that is because there are so many galaxies.

Edited December 5, 2012 by Airbrush

[mathematic]

I believe the orignal question misses the point that there are billions of galaxies, so that, although stars are exploding frequently, they are scattered through the galaxies in the universe, most of which are not visible to the naked eye. Astronomers with powerful telescopes see them all the time.