A tachyon, or tachyonic particle, is a particle that always travels faster than light.
Tachyons mess with what is arguably Doctor Manhattan’s greatest power: his ability to experience time as non-linear, which allows him to see the future. Ozymandias neutralizes Doctor Manhattan’s powers by enveloping his own Antarctic retreat, Karnak, in a shower of tachyons, preventing Manhattan from knowing that he would one day discover Ozymandias’ plan until he actually discovered it.
- Doctor Manhattan's weakness to tachyons is akin to Superman's weakness to kryptonite.
- In the real world, tachyons are hypothetical particles that most physicists believe cannot exist because they are not consistent with the known laws of physics. If such particles did exist, they could be used to build a tachyonic antitelephone and send signals faster than light, which (according to special relativity) would lead to violations of causality. No experimental evidence for the existence of such particles has been found.
- Albert Einstein's theory of special relativity states that nothing can accelerate faster than the speed of light, while tachyons are theorized to be constantly traveling faster than the speed of light.