Stargate Atlantis/Recap/S02 E06 Trinity

"Harry K Daghlian. He was a scientist -- worked on the Manhattan Project at Los Alamos. He was only twenty-six years old. Accidentally irradiated himself while performing a critical mass experiment on two half-spheres of plutonium. Took him a month to die. While his body was slowly shutting down from radiation poisoning, you know what he did with his last thirty days, hmm? He worked. He tried until his last breath to understand what had happened to him so that others could learn from the tragedy, so that his work, his death, wouldn't be rendered meaningless."

- McKay

Exploring the dead world of the Durandanes, the team finds a surprisingly intact Ancient outpost, housing a superweapon responsible for the desrtuction of an entire fleet of Wraith Hive Ships. McKay and Zelenka get the lights on and are delighted to discover that the outpost was in the process of developing an energy source that would make ZPMs obsolete. They used it to destroy the Wraith, but sadly all died somehow before it could be perfected.

Meanwhile, Teyla takes Ronon along on a trading mission to the planet Belkan. Ronon is no better at negotiating than Sheppard is, but they discover quite by accident that there are other Satedan survivors scattered across the galaxy - Ronon is not actually the Last of His Kind. Ronon is understandably overjoyed to learn that 300 of his people have survived, and immediately starts looking for his former commanding officer, a man named Kell. Using Teyla's contacts and general negotiating skills, they are able to get an audience to see him, and Ronon unceremoniously shoots him in the face. He later explains to an enraged Teyla that Kell's shoddy leadership was responsible for thousands of Satedan deaths, and the man had it coming. Teyla reluctanly agrees, but warns him that the rest of the Atlantis expedition will not.

The work at the Ancient outpost initially seems to be coming along very well, although not everybody is as confident as McKay that he will be able to solve a problem the Ancients couldn't. The first real test, however, suffers an unexpected overload, almost preventing McKay from shutting it down and killing one of the scientists. The death shocks everyone, particularly McKay, and they evacuate back to Atlantis to figure out what went wrong. McKay becomes more and more obsessed with getting the project to work, and begs Sheppard to take him back to the outpost. Weir and Caldwell eventually give permission for continued testing, persuaded by Sheppard and McKay's enthusiasm and by the vast rewards if the project is successful.

While McKay is setting up for the test, Zelenka calls in. He has just finished analyzing the data from the first test and discovered that the project cannot in principle succeed. Because of , the device will always overload unpredictably at any power level. This is what killed the planet after the Wraith had been defeated - the Ancients operating it had only been able to shut it down at the cost of their own lives. McKay brushes him off, insisting that he has solved the problem, and proceeds with the test. The gun successfully targets and destroys the Wraith debris in orbit - and then begins to overload as Zelenka predicted. McKay continues to work, convinced he can correct the problem, until Sheppard manages to finally talk him down. By that point, however, it's been going too long and nothing can prevent catastrophic overload - which is to say, the whole planet going up.

Sheppard and McKay flee in the jumper, but the gun is still targetting debris around the planet, preventing them from reaching the gate. They are rescued at the last moment by Caldwell and the Daedalus, which then retreats into hyperspace as the planet explodes, taking most of the solar system with it.

Tropes:

 * Apocalypse How: Initially somewhere beween a class 3a and a class 5; McKay manages to upgrade it to a class X-2.
 * Badass Longcoat: Ronon and Teyla wear them on their trading mission.
 * Earthshattering Kaboom: that takes out two thirds of the solar system.
 * Possibly even five sixths. It's not an exact science.
 * Going Critical
 * Outrun the Fireball: averted. McKay states outright that it would be impossible.
 * Science Is Bad
 * Values Dissonance: invoked. Teyla warns Ronon not to tell the Atlantis mission about Kell's murder, basically for this reason.
 * Within Parameters