[kasperl]

we'been talking about his on the freespace watch forum,but i'd like your opninion to:

cappella supernova
i've just tought of a little problem with the supernova of capella.
first a question: how many light years is the nearest system from capella?

now the problem. when a star goes supernova, a pulse goes away from it at near light speed. i read this in a dutch science magasine "kijk". any inhabited planet within 50lightyears as a pretty big problem. once the wave its the planet, the people on that planet would have to ware blackout gear for a century! the exact reasons on wy and how are a bit difficult to translate, but the basics are this:

the wave of cosmic radiation from the suprnova would create a large surplus of nitrogen oxides, wich would eat theyre way true the ozon layer. it would take the ozon layer about a century to regenerate.

now this is based on a earth like planet, nut it would it every planet/station/ship pretty hard. this might give a lot of problems for the GTVA, because they would have to evac every single person within a fifty light year radius from cappela!

perhaps is this a good base for a campaign story line?


anyway, the thread is located at:
http://www.hard-light.net/vwbb/showthread.php?threadid=7776

[Kazashi]

It is a good premise to point out. I do believe that it has been discussed on these forums before, about what impact a supernova would have on GTVA space, here. It's a little old, so the topic could surely use some rehashing.

[karajorma]

Basically you describe part of the plotline for The Mercury Affair (my own campaign). However as far as I could figure out the closest major system is over 36 light years from Capella so since TMA is set 6 years after capella none of the major systems are affected.

However if you want to write camapign where Vega, say is the closest to Capella I wouldn`t complain about the science being wrong as long as the story was good enough.
If [V] can get away with missing 3 stars out of the capella system I think we can forgive you for moving a few light years

[vyper]

Originally posted by karajorma

If [V] can get away with missing 3 stars out of the capella system I think we can forgive you for moving a few light years

[Vertigo1]

One question:  Wouldn't the wave dissipate quite a bit before it even gets near us?

[karajorma]

It would. But there is so much explosive force that it's like the difference from sitting on top of a bomb or being 200m away from it.
 At this distance the explosive force has disappated but there is still enough force to do you some serious damage.

Although a supernova might be far away it puts out an enormous amount of energy. The supernova that left behind the crab nebula was so bright that it was visible for 23 days in daylight even though it occured 6300LY away.

[Black_Dragon]

What i can tell it can destroy any life of the planet if its in its way,   maybee 40 to 70 years,  to reach the nearest planet,  or more years,  depending speed, distance and space disturbance that could change the movement of the wave.  

Hey,  there are many sites that are astronomical,  so maybee it can tell you something about supernovas,   I have this magazine of Discover that explains some things about a star exploded,  the December Edition of this year, i didnt read it yet,  go find something,  in the magazines or in the internet,  is a good start,  ¿no?

[karajorma]

I posted a load of stuff on the VWBB version of this thread. Hmmm. Might as well copy it over here.

Originally posted by karajorma
The Capella supernova's effects on other systems is a minor theme in my own campaign (The Mercury Affair) so I did a little thinking about the matter a while back.

Since I don`t have any major systems under threat in my campaign and I would love to play a campaign based on that premise here's all the ideas I came up with in the hope I can spark some interest.

1) I found a document about supernova risks online which kasperi might be interested in. I`ve uploaded it to my site and you can find it here. It's quite technical so be warned.

2) Capella is 42.2 light years from Earth. This puts Earth within the danger zone but means that the GTVA has no way to warn them.

3) There are no good star maps with distances on between the stars that I could find but as far as I could figure out using the starmap from the game Frontier (which is fairly accurate close to Sol) Capella is about 36 years away from the nearest FS2 Era GTVA system (IIRC it was Sirius but don`t quote me on that). There is certainly no GTVA system within 9 LY of Capella.

4) Since the shivans made Capella go nova despite it being nowhere near that point in it's life the supernova may be much less destructive than a normal supernova, of course ANY supernova is bad new when you are in that system but the effects on outside systems may be less. So basically you can make the nova do as little damage to the GTVA systems as you want. You could even have it do more damage if you want since it is after all a non-standard supernova.

5) If the capellan supernova was not what the shivans were trying to achive (remember they did lose a couple of sathanses when the star went nova as well as all the forces battling the GTVA) they may have put there own systems at risk.

6) It might be possible to repair the atmosphere of a supernova damaged world by placing a giant electrical sparker in the upper atmosphere and feeding it lots of oxygen. What effect this would have on the planet though I don`t know

7) Since the wavefront of the explosion travels at lightspeed it would actually take several hours to travel from one side of the system to the other. I`ve based a few missions on this but I`m sure other people have ideas.

[mikhael]

It is doubtful, in my opinion, that the Capella supernova puts any GTVA system at risk.

The wavefront of a a supernova is an ellipsoid with its longest diameter in the same plane as the stars rotational equator. The wavefront is a finite amount of matter and energy projected at very high speeds.

The more massive the particles the more quickly they become effected by other sources of mass. The lower mass particles continue on with a lower percieved energy loss.  Anything within the ecliptic of Capella would be shielded from the more massive particles  the supernova by Capella's Oort cloud. A signifigant amount of highly charged particles would be absorbed here too.

As the wavefront travels it becomes more attenuated, due to simple geometry: as radius of wavefront doubles, front squares. Thus the farther away, the fewer highly charged particles per square meter are involved. Over lightyears, this mass/energy density drops to zero. If you knew the original mass of Capella, you could calculate, very easily, the distance at which the dropoff reaches zero+epsilon (ie, when the effect becomes indistinguishable from cosmic background radiation). That distance will be signifigantly less than 30 lightyears, however.

[karajorma]

Capella has 2.7 times the mass of Sol.

Whether that is enough to cause a supernova big enough to cause serious damage to a GTVA system is beyond my limited astrophysics but there are plenty of scientists who believe that supernovae may have caused extinctions on Earth

The other thing is that since the capellan supernova was artificially induced it could actually output more radiation than a normal supernova would.

Lastly as I said before who cares if you move sirius 20 or 30 light years closer to capella to make a nice story. We`ve forgiven [V] for missing out 3 stars already

EDIT : Just noticed you`re mostly talking about cosmic rays from capella. I never considered them really. I was more worried about the damage from gamma and x-rays since they would get there first. Couldn`t you expect damage from them?

[kasperl]

i jsut found the article form the science mag, already on the web. look at this link:

http://www.kijk.nl/artikel.jsp?art=3146

it's in dutch, but some people requested the original article.

i hope you can translate it.

[an0n]

.........Correct me if I'm wrong, but the ships in the final cutscene seemed to take a while to explode in the nova's blast-wave, so I'm guessing if a Rakshasa (?) can take the blast for a few seconds at only a few AU's, then a planet 5ly away would get little more than a small heat-wave.

[diamondgeezer]

Yah, either that or the ole' artistic liscence playing silly buggers again...

[karajorma]

Originally posted by an0n
.........Correct me if I'm wrong, but the ships in the final cutscene seemed to take a while to explode in the nova's blast-wave, so I'm guessing if a Rakshasa (?) can take the blast for a few seconds at only a few AU's, then a planet 5ly away would get little more than a small heat-wave.

Of course. We aren`t talking about the supernova blowing up planets light years away

Ecosystems are delicate things. A small change can result in a huge disaster further down the line.

An example of this is the hole in the ozone layer, caused by (relatively) small amounts of CFC's breaking down the ozone. It's thought that gamma and x-rays might have a similar effect. Enough of the ozone layer goes and the planet would get wiped down to simple UV resistant bacteria.

The problem is that AFAIK no one is certain how much radiation you need to wipe out the ozone layer but it's possible that a supernova could do it.

[kasperl]

the problem isn't the radiation itself, but the nitrogen oxides created by it. don't aks me how, but the radiation creates nitrogen oxides wich attack the ozone layer. after that, it will the ozone layer about a century to regenerate. (at leasrt, thats what the article says)

[beatspete]

The actuall intensity of the radiation from the nova can be calculated... Intesity=power/area, if i remember right. As the wave, assuming it is just one wave, spreads out from the supernova, it should (in theory) expand as a sphere. Therefor the power a point on the sphere will be total nova power divided by surface area of sphere from shockwave... my maths aint great but that should be roughly right.

r(radius) = 5ly = 3*10^8 X 60X60X24X365.25 X 5 =4.733*10^16m

Surface area of sphere = 4*pie*radius^2
Surface area of shockwave = 4*pie*(4.733*10^16)^2
=2.8157*10^34 square meters.

Therefor, the power of radiation upon one square meter is 1/2.81*10^34 times the total radiation.

Now, ultra violet radiation is made of photons, which travel at the speed of light... here's where my physics knowledge stops... so i'll use the equation E=MC^2 to calculate the energy produced by the star.

...the mass of the sun is 2*10^30 KG. A star three times the mass of our sun is required to start a supernova, or atleast a black hole.... or maybee that was density... so cappella should have weighed roughly 6*10^30KG.
Therefor the energy of the radiation produced, assuming all of the star was converted to energy, which wouldnt happen cause there would still be mass for a small neutron star left behind (i think), E=6.0*10^30 X (3*10^8)^2
=5.4*10^49 J

And so the energy of the radiation falling upon one square meter at 5lys distance is... 5.4*10^49 J X 1/2.81*10^34
=1.9217*10^15 J

Hmmm. Thats a ****-load of energy.  That cant ve right. The main source of error would be in the E=MC^2 equation, particularly the mass used.  Lets say only 1/100000000000 of the mass is converted to radiation energy, and the rest buggers off to form a black hole or something.
Then the mass used is 6*10^19KG, which is roughly 1/10000th the mass of the earth.  
New energy = 5.4*10^36J
...over one square meter at 5ly away : 192J ...which seems a better figure

So the intesity of radiation on a planet 5ly away would be 192W/M^2 (watts per square meter)

This is roughly as much radiation as standing near a powerful light bulb, though most of that wouldn't be deadly gamma rays...


yes, i know, a monkey picking numbers out of a hat could probably get a more accurate answer, but if someone who knows there stuff would like to improve on that feel free ...try using the inverse square law for light intensity, i don't know.


My brain hurts

[LtNarol]

Originally posted by karajorma
The other thing is that since the capellan supernova was artificially induced it could actually output more radiation than a normal supernova would.

Well, yes, it could.  Radiation as we all know is a form of energy/matter and since energy can not be created nor destroyed, we rule out the possibility of the FS2 Capella supernova's artificial origin generating any more energy than simply what is put in by the Sathani.  This means that yes, while the amount of radiation could go up, it would at most be equal to that of the normal capella supernova plus whatever is put into it by the Sathani.  That would still spread itself thin well within 36 lightyears.

[Sesquipedalian]

***Warning! Warning!  Sensors indicate a complete lack of knowledge being exhibited in this thread.  Recommend removal from area.  Sheer effects of black hole of knowledge may have destructive consequences.***

[kasperl]

originaly posted by Sesquipedalian:

 ***Warning! Warning! Sensors indicate a complete lack of knowledge being exhibited in this thread. Recommend removal from area. Sheer effects of black hole of knowledge may have destructive consequences.***

if you have a better ideae, come on and explain!

anyway, there isn't a black hole, cause IIRC somewhere someone says that in the place of capella there is a nuetron star. and there wouldn't be a nebula if there was a black hole, since the black hole would suck al the gasses in. i'm no good at maths, but i'll see if i can get my physics teacher to look in to this.

[Executor]

Originally posted by kasperl


if you have a better ideae, come on and explain!

anyway, there isn't a black hole, cause IIRC somewhere someone says that in the place of capella there is a nuetron star. and there wouldn't be a nebula if there was a black hole, since the black hole would suck al the gasses in. i'm no good at maths, but i'll see if i can get my physics teacher to look in to this.

I'm not sure about the size of the Capella star which goes supernova, but I think I heard it was 3 times the mass of the Sun. If I remember correctly, the lower limit for a star to undergo a supernova is around 8 Solar masses. The Capella supernova was also artificially created, so it could change how much mass is ejected in the initial explosion. A star loses quite a lot of its original matter during the supernova, so Capella probably wouldn't have the necessary mass to create a neutron star or black hole, both of which require different degeneracy pressures to be overcome that are directly related to the remaining mass. The most likely outcome is that it still forms a white dwarf, as it naturally would have.

Just because a black hole forms doesn't mean that a nebula can't be created as well. Over time, some of the ejected material will disappear as the gravitational pull of the black hole sucks it in, but that would likely take millions of years.