Orbital explosion

[hardsciencefanagain]

Drof,you got it right.I always blame the system,too

 

[Ray McCarthy]

Radiation damage.

 

[Droflet]

Yeah, that's it, Ray. I've spent sooo much time in front of my screen it's obvious. I am indeed suffering from radiation exposure. Yeah, that'll do nicely.

 

[Wanderlog]

Am I correct in assuming that the EM pulse would not only stuff communications but he radioactive fallout would irradiate the area?

As it was already mentioned before, there would be no fallout. It's possible on the planetary surface only when dust and debris are sucked into the blast's epicenter and then dropped back to the surface. However, there is a thing called induced radioactivity. Many materials can become radioactive after being exposed to a source of external radiation. Here is the link explaining the basics: https://en.wikipedia.org/wiki/Induced_radioactivity

Depending on the kind of used nuclear weapon, it can be a moderate problem even in space. However (it was already mentioned, too), the main problem is, energy of the blast decreases in proportion to the second power of the distance. In ten kilometers, radiation will be weak enough to induce significant secondary radioactivity.

explosion occurred part way into a stable asteroid field that surrounds the planet.

No atmospheric shock wave = no influence.

 

[Droflet]

Thanks for that, Wanderlog.

 

[Mirannan]

Regarding EMP, and I'm not at all sure about this, IIRC the effects of EMP are caused by the interaction of bomb plasma with the planetary magnetic field. Out in deep space, magnetic fields are much lower so EMP would be lower as well.

I'm inclined to think that nuclear weapons in space would be rather ineffective unless one uses really big warheads, because of the inverse square law. Bomb-pumped lasers might be the way to go.

 

[Vertigo]

I'm inclined to think that nuclear weapons in space would be rather ineffective unless one uses really big warheads, because of the inverse square law. Bomb-pumped lasers might be the way to go.

That's the approach Weber takes.

 

[Ray McCarthy]

Scrap iron on a rail gun ... More effective than laser.

 

[Wanderlog]

Scrap iron on a rail gun ... More effective than laser.

Over a short distance, yes. However, if you're far away from your target, it becomes ineffective. You can't speed it up event to the percentage of C. In addition, it's very dangerous not only for the target, but for everyone on the star system for an indefinite period of time. A projectile launched in the space will never stop and never slow down. It can hit someone a day, a year or a millennium later. I believe ballistic weapons in the space will be strictly prohibited in the future.

 

[Ray McCarthy]

I believe ballistic weapons in the space will be strictly prohibited in the future.

Or already?
Perhaps we are very late to the party and in quarantine.

 

[Wanderlog]

Perhaps we are very late to the party and in quarantine.

Who knows...?

 

[Piousflea84]

Calling out to the brains trust. Okay, a big nuclear explosion in orbit. Am I correct in assuming that the EM pulse would not only stuff communications but he radioactive fallout would irradiate the area?
Secondly, explosion occurred part way into a stable asteroid field that surrounds the planet. Hey, I know but this is science fiction so I can write anything I want, as long as no one can prove me wrong.
So, Chronauts, what do you think would be the outcome. It's a massive explosion by the way.

Thanks for that, Vertigo. Hmm, more info. The explosion is caused by a massive space platform, four million tons thank you very much. It has four massive reactors and when one blows they all blow. That combined with the debris, both large and minute, from the asteroids might cause a bit of a problem for our hero. I shall think upon your sage advice. Thanks again.

(puts on radiation science hat)

First let's talk about the nature of your nuclear explosion. An explosion caused by a nuclear bomb is completely different from an explosion caused by a nuclear reactor meltdown. Since you are talking meltdowns, let's talk about them. Only a fission-based reactor can melt down, as far as we know. Fission is a chain reaction, while fusion requires an external confinement force... a fusion reactor that overheated and damaged itself would lose confinement, so the fusion plasma would dissipate. This could cause massive thermal damage as it hit the walls of the reactor, but it would not create a runaway exothermic chain reaction. Some proposed fusion-reactor designs (inertial confinement) only react a miniscule amount of fusable material at a time, which means that there simply isn't enough fuel to create a big explosion.

Therefore, if we are talking about a nuclear reactor meltdown, we are talking about fission reactors. A meltdown is not the same as a nuclear bomb explosion. The fissile material in a reactor is much less enriched than so-called "bomb-grade" fissile material. In most cases it's not physically capable of creating a nuclear detonation. This is why plenty of countries can have nuclear reactors without having the capability to make nuclear bombs.

In every major nuclear meltdown (ie Three Mile Island, Chernobyl and Fukushima), part of the reactor exploded during some point of the disaster. However, these were regular-old-fashioned explosions and not nuclear explosions. We are either talking about a pressure-vessel explosion (overheated and overpressurized steam), a hydrogen-oxygen explosion, or a graphite fire explosion. All of which are capable of blowing the top off a 1,000 ton reactor core, but simply not powerful enough to shred a 4-million-ton space city.

The main danger of a reactor meltdown is that it generates a truly staggering amount of fission byproduct material. That's all of the iodine, strontium, cesium and other isotopes that will make Chernobyl uninhabitable for centuries to come. You certainly wouldn't want to be living on a space city when a reactor meltdown spews craploads of radioactive debris into your atmosphere. However, no meltdown could completely "kaboom" the city.

If you really want a 4-million-ton space city to completely destroy itself with a reactor malfunction - an antimatter reactor is waaaaaaay better than fission/fusion. All it takes is a little loss of confinement, and that antimatter will happily meet and annihilate everything in its surroundings! Or you could be more creative and make up a handwavium reactor - Oh Noes, our Murkowski-Sorrell Core is Hypertessagonated - Kaboom!

If you really want to limit your tech level to near-future technology, it would make much more sense for someone to smuggle in a bomb. After all, you could uranium in deep space where UN inspectors can't find it, and the radioactivity would be easily concealed among the heavily radiation-shielded bowels of a starship.

(Takes off radiation science hat)

(Puts on astronomy hat)

... explosion occurred part way into a stable asteroid field that surrounds the planet.

A stable asteroid field cannot exist near a planet because gravity would make the asteroids smash into the planet. It's part of the definition of the word "planet":
http://missionscience.nasa.gov/nasascience/what_is_a_planet.html

The IAU definition of a planet is an object that:
1) orbits a star
2) is spherical
3) has enough gravity to clear its orbit of debris

Therefore, if your fictional world is surrounded by a stable asteroid field, it is by definition too small to be a planet. The only way that a stable trans-planetary debris field makes sense is if they are not asteroids, they are ring bodies and your planet has a ring. An Earth-sized planet may not be massive enough to keep its ring; the ring bodies will eventually be destabilized by Jupiter and crash into the Earth.

Other possibilities:
- The unstable debris field. Maybe the debris came from a giant asteroid that was blown up by nuclear weapons. Maybe it came from a massive # of satellites / space cities that were destroyed in a war. The debris is unstable and will eventually re-enter the atmosphere, but it could take a few years to do so.

- The artificial debris field. People have used space tugs to drag thousands of asteroids into orbit where they are mined for minerals. They are in stable orbits because there are station-keeping thrusters keeping them there. Maybe your space city is in the middle of the highest concentration of asteroids because it is a manufacturing plant and it uses asteroid minerals?

- The magical debris field. The planet of Draenor is surrounded by asteroids for no reason, but it probably has something to do with Illidan, Gul'Dan and Kil'Jaeden.