Omegoda

Omegoda arrives as a single cosmic ray carrying the punch of a thrown baseball.

The Physics

On 15 Oct 1991 the Fly's Eye detector in Utah recorded a cosmic ray with an energy of (3.2 ± 0.9) × 10²⁰ eV, about 51 J in one subatomic particle. At such energies particles lose energy on the cosmic microwave background (the GZK cutoff), so if it was a proton or neutron it very likely travelled less than about 50 Mpc from its source (Elbert & Sommers 1995).

E = (3.2 ± 0.9) × 10²⁰ eV ≈ 51 J

• E: particle energy
• eV: electronvolt, 1.602 176 634 × 10⁻¹⁹ J
• J: joule

Fly's Eye, Utah, 15 Oct 1991; the Telescope Array's "Amaterasu" particle of 27 May 2021 reached 2.44 × 10²⁰ eV.

Honest caveat: Nobody knows what kind of particle it was.

On the shirt

Front: Omegoda, the pixel-art character, with the title. Back: the energy in eV and joules, the GZK horizon, the Amaterasu comparison and the Fly's Eye source. Printed on a unisex tee.