View Full Version : Supernova 7000 ly away


Ronhrin
05-09-07, 04:38 PM
I've read in several news and science sites that a star roughly 7000 ly away from the sun is going to become a supernova in a very short time.

Most science websites say that due to the distance of the star and earth's protective atmosphere this supernova will not pose any risk to life on earth.

but now comes my question that I can't find no answer for, even though life on earth is perfectly safe when the radiation of this supernova arrives here, what will happen to the light. I mean everyone knows that when a supernova goes off, it shines more than it's entire host galaxy for a period between 30 to 80 days, if in a faraway galaxy the light of a supernova becomes more bright than an entire galaxy, what will we see when this nova goes off, I mean, 7000 ly is damn close from the sun, if this supernova is visible during the night time will it's light shine stronger than our sun and during those 30 to 80 days of supernova will the night become day?

Ophiolite
05-09-07, 05:03 PM
I believe you are talking about Eta Carinae. Remember that when astronomers (or geologists) say 'soon', they generally mean 'in the next few tens of thousands of years'. So, don't expect headlines this century.

The supernova that produced the Crab Nebula was observed by the Chinese almost 1,000 years ago. It is a little closer (6,300 light years) than Eta Carinae and although bright, it was not that bright.

The supernova was noted on July 4, 1054 A.D. by Chinese astronomers as a new or "guest star," and was about four times brighter than Venus, or about mag -6. According to the records, it was visible in daylight for 23 days, and 653 days to the naked eye in the night sky.

Source: http://seds.lpl.arizona.edu/Messier/m/m001.html

pinkiss
05-09-07, 05:24 PM
correct me if im wrong but 7000Ly means that if suprenova would occur it would take it 7000light years to reach earth and in that time there would be none radiation left.If it would become suprenova thousands of years still had to pass.

Oli
05-09-07, 05:45 PM
correct me if im wrong but 7000Ly means that if suprenova would occur it would take it 7000light years to reach earth
Correct, but what they mean is that it probably went supernova a long while ago and we'll get to see the explosion "soon". Don't forget we're seeing it as it WAS 7000 years ago, NOW.

bsemak
05-10-07, 02:14 AM
correct me if im wrong but 7000Ly means that if suprenova would occur it would take it 7000light years to reach earth and in that time there would be none radiation left.If it would become suprenova thousands of years still had to pass.

No, the radiation will mainly be as neutrinos, X-rays and visible light. That will travel all the way to us. I think the danger zone is something like 50 light years.

But your right, if it blew up now, ot would take 7000 years before anyone would notice here.

Positron
05-10-07, 09:08 AM
Isn't that the supernova that is supposed to destroy the Pillars of Creation?

orcot
05-10-07, 10:28 AM
http://www.newscientist.com/article.ns?id=dn2311

Between now and 50 000 years at only a 150LY I wonder what this one will give. I'm sure youl be able to read a newspaper at midnight.

pinkiss
05-10-07, 06:03 PM
http://www.newscientist.com/article.ns?id=dn2311

Between now and 50 000 years at only a 150LY I wonder what this one will give. I'm sure youl be able to read a newspaper at midnight.
Never trust such sources from the web :crazy: .Even nasa doesnt have that good equipment to observe objects which are 150Ly away from earth and images by telescope would only would look like bleached color.And any way there is 1% of truth in that source because there are more suprenova remnants which arent so far and didnt made or had threats on earth for example crab nebula :)

eburacum45
05-10-07, 10:26 PM
Note that there is no timescale for the explosion of HR 8210; that kind of binary pair might not explode for millions, or even hundreds of millions of years, by which time the star will probably be thousands of light years away.

orcot
05-11-07, 09:08 AM
some say it already happend (http://heritage.stsci.edu/2000/15/supplemental.html) in recent history. And quit a few have happend in recent history (http://en.wikipedia.org/wiki/Nova) altough none bright enough to be viseble during day.

I agree that there are no timetables for nova's but HR 8210 is most proberly going to blow up and with such a short distance there is a good change that it will be viseble during daytime, altough that may only happen between now and a couple of 10's of thousands years not a 100 thousand and defenitly not a million.

Starthane Xyzth
05-16-07, 04:23 PM
There was a more recent daylight supernova than the Crab Nebula: http://seds.lpl.arizona.edu/~spider/spider/Vars/sn1572.html
It was as bright as Venus, seen from 10,000 light years away.