Once again, the TED-Ed channel shares the Big Bang riddle, which takes us to the first moments of the Universe: a tiny particle tries to escape the chaotic fury surrounding it and avoid any contact with antimatter. Fortunately, it finds a ring of particles that propose a very special game: If the particle manages to land in the correct position and be the sole survivor after annihilation with antiparticles, it will become the seed of a new galaxy. Easier said than done…
The ring contains the same number of particles and antiparticles, and if it weren't for the intervention of our adventurous particle, the game would be impossible to carry out: the ring would annihilate itself. As the guest of honor, the particle can choose the exact place to be the last one standing and escape destruction. However, there are other rules that must be obeyed:
- All particles are facing the center of the ring to distinguish left from right.
- Each round, if a particle has an antiparticle to its right without other particles protecting it, will be annihilated.
- The cycle will continue without pause until only one particle remains... and the goal is that it's ours.
- The game doesn't accept tricks like placing yourself in the center or changing places. The particle must join the rest on the ring, be part of it, and stay in the chosen position until the end.
(Note from the editors: Unfortunately, there are no Spanish subtitles this time.)
How to Solve the Big Bang Riddle
The video explains that a general strategy cannot depend on the ring's appearance, but it can depend on its end, that is, with our particle as the sole survivor. A valid method for relatively small rings is to simulate annihilations by identifying particle-antiparticle pairs. The positions that remain outside the pair links are safe for our particle, always with an antiparticle to its left and another normal particle to its right.
Based on the video examples, the first ring has a single solution, the second has five, and the third largest ring returns to a single solution. Here it's worth noting that “five in the afternoon” is a good reference for finding an ideal position. With our particle safe and transformed into the fundamental block for a new galaxy, the game seems to be over. However…
What Happens If the Ring Is Larger?
With a cycle of one hundred million years, the alien inhabitants of the galaxy pay tribute to our tiny particle by repeating the game. The difference is that each representative of the 27,182 species places a particle and an antiparticle on the ring, making it gigantic. The only advantage our tiny particle has to find the ideal spot in a circle with more than 54,000 particles and antiparticles is a device that can detect the complete sequence of the ring, count particles and antiparticles, perform calculations, and execute logical commands.
Obviously, this second part of the riddle is an invitation to programmers in different languages, but at a general level, the idea is to focus on all particles to the right and add or subtract depending on the type (+1 for matter, -1 for antimatter), starting with the +1 of our particle. If the final result is 1, the position is safe.
