NEUPLAY

Neutrinos come in three flavours — electron, muon and tau. Each flavour is a quantum mixture of three mass states, which travel with slightly different phases. As a neutrino flies, the mixture drifts, so a neutrino born as one flavour can be detected as another. The chance depends on distance L and energy E through sin²(1.27 Δm² L / E). The discovery earned the 2015 Nobel Prize and proved neutrinos have mass.

A telescope only sees a small patch of sky — its field of view. Faint steady sources need long exposures to build up enough signal, while transients such as gamma-ray bursts, supernovae and fast radio bursts flash for seconds to days. Survey astronomers trade off a wide field (find more) against depth (see fainter), exactly the choice you make with the field-of-view control.

• Dipole magnets (1232 of them, at 8.3 tesla) bend the protons around the 27 km ring.
• Quadrupole magnets squeeze the beam like lenses so it doesn't spread out.
• RF cavities give the protons a kick on every lap, up to 6.8 TeV per beam.
• Protons arrive pre-accelerated from a chain of smaller machines ending with the SPS at 450 GeV.
• Two beams counter-rotate and collide inside ATLAS, CMS, ALICE and LHCb.

Nothing with mass reaches the speed of light c. As speed v grows, the Lorentz factor γ = 1/√(1 − v²/c²) grows without limit. Moving objects are measured shorter along their motion by 1/γ (length contraction), moving clocks run slow by γ (time dilation), and starlight bunches up ahead and shifts blue (aberration and Doppler shift). At 99.5% of c, γ ≈ 10: a 10-light-year trip lasts only about a year on board.