- Why did scientists before 1912 assume that atmospheric ionizing radiation came from the ground rather than from space?
- What did Victor Hess measure during his balloon ascent to nearly 5,000 metres that overturned the terrestrial-source theory?
- How do cosmic-ray-produced muons reaching sea level serve as experimental proof of time dilation?
- Why did it take twenty-four years for Victor Hess to receive his Nobel Prize for the discovery of cosmic rays?
Cosmic Rays
High-energy particles arriving from space.
- How did the curvature of a cloud chamber track reveal that Anderson had found a positively charged, lightweight particle?
- Why did Victor Hess expect ionising radiation to fade with altitude, and what did he find instead?
- How did the curvature of the mystery particle's track in a magnetic field rule out both a proton and an electron?
- How long does a muon exist before it decays, and where do muons come from?
- What new kinds of events did Blackett's coincidence-triggered chamber let him track?
- How long did it take experimentalists to confirm Yukawa's 1935 prediction, and how did they find the particle?
- Why did detecting Yukawa's predicted meson require going to high altitudes?
- How did the pion's track differ from the muon tracks that had misled earlier researchers?
- Why does a charged particle moving through water faster than light travels in that medium produce a glow?
- What is the optical equivalent of a sonic boom, and how does the Cherenkov effect resemble it?
- Why did the Nobel Committee wait twenty-one years after Cherenkov's observation to award the prize?
- How do modern neutrino observatories like Super-Kamiokande use the Cherenkov effect to detect particles?