For astronomers. Please make a estimate or guess?

Question

If a supernova were to take place in our galaxy, what is the maximum distance in light-years it could be from our solar system and still have the radiation from it turn our planet to plasma or slag (or both). Would we have any warning or was to detect it before the radiation front hit us. If you predict we could know it was coming before it destroyed us, how long would we have to wait? Notice I am looking for a maximum. Obviously a nova in closer proximity would do the same damage but the time from event to destruction would be a bit shorter.

Alex thank you for your answer. I had forgotten that a super nova does indeed put out a coherent beam of gamma radiation (or so I seem to remember from somewhere). I an not asking about probability I know that is very low I am only asking for an estimate of maximum distance. As I know that you can edit your answers just as I can add more details I hope you will return and do just that.

Ngc7331 Is the maximum star mass in our galaxy 10 solar masses. Seems to me there are many much more massive stars.

For everyone do not novae and supernovae also throw out more than radiation and would the material be destructive to life on our planet and perhaps to the planet itself. Please remember I am not asking about probability.

Ideaquest your answer is interesting but I do not feel it is aimed at my question.

Perhaps I should add this explanation to my question. Suppose a supernova of maximum known intensity (observed by astronomers) has happened in our galaxy some 4000 years ago. The radiation has not reached us yet. (1) Would it have any real effect on life on this planet? And/or (2) what is the maximum distance this supernova could be from us to have a totally catastrophic effect? Thank you all for your answers and I hope you will return to edit them.

Answer 1

Have you checked out the Wikipedia article on supernovae? It has a section on potential impacts on the Earth.

I think turning the Earth into slag is rather far-fetched, it would take too much energy. The Wikipedia article mentions mechanisms involving erosion of the atmosphere as a result of gamma rays from a supernova. The article mentions a figure of 100 light years for a noticeable affect. This however is for a Type II supernova (collapse of a large star) and we should be able to identify such candidates easily (though at present we don't really know enough to predict the timing of a supernova to any useful accuracy). A larger distance of around 3000 light years is mentioned for Type Ia supernovae, not sure I know why this might be, in any event the progenitors are smaller, dimmer stars and much more likely to go unnoticed.

Not sure what you are getting at with NGC 7331. This is a galaxy some 43 million light years distant from our own. Perhaps you meant to refer to some other object?

If gamma rays from a supernova that exploded 4000 years ago were still heading towards us then it must be further than 4000 light years away. Seems like that would already be far enough away for it not to do us any harm.

Answer 2

GAMMA RAY BURSTS MAY BE EXHIBITING TIME DILATION owing to the expansion of the universe.

The powerful gamma ray bursts studied over the past few years by the Gamma Ray Observatory (GRO) are sprinkled uniformly across the sky, suggesting that they come not from our galaxy but from beyond, perhaps in some cases from the distant edge of the universe.

At the recent meeting of the American Astronomical Society in Virginia, Jay Norris of NASA Goddard announced that from among the more than 700 bursts seen so far dim bursts are typically twice as long as brighter bursts and, furthermore, that the dim bursts lie more toward the "red" end of the gamma-ray range.

The cosmological explanation of this pattern would proceed as follows: the theory of relativity holds that a time interval measured in one frame of reference will be different for an observer in another frame of reference. The difference (or time dilation) will increase as the relative velocity of the two frames increases.

Thus gamma sources near the edge of the universe would be receding from Earth at a greater velocity than closer sources, and consequently the length of a far-out burst would appear to be longer than for near-in bursts. Radiation from the cosmic microwave background (which is presumably even more redshifted) streams in on us unabated and therefore, unlike the gamma bursts, has no beginning, middle, or end. Norris admits that the cosmological hypothesis is still tentative because the relation between burst energy and duration is not yet calibrated.

http://www.aip.org/pnu/1994/split/pnu161-1.htm

Answer 3

Well, of course, since the radiation front is in all essence moving at the same speed as light, as soon as it were detected we'd be toast. As for maximum distance, that would depend upon the mass of the star. A small mass star (perhaps one solar mass) my guess would be about 5-7 light years. For a really large mass star (perhaps excess of 10 solar masses) my guess would be in the neighborhood of 35-40 light years. Hope this helps.

Answer 4

a gamma radiation burst could remain coherent for a long time and thus take thousands of year to hit us, but gamma radiation on light travel the same speed...no warning, just crispiness. but odds are low that the narrow beam would hit us, so odds are we will all be dead from more frequnt catasphoes.....THc had a sho on this.

Answer 5

Hi. If one occured within 10 light years then life on Earth would ot be possible for certain. Maximum? Can't answer that.

Answer 6

the two, and extra. there is not any consensuse between the communnity. some even think of that a "massive crunch" will take place because of the universe slowing down its improve and compressing.