Interstellar travel is difficult with traditional fuel-powered rockets. Today’s paper explores how we could instead use sailing space ships, propelled by photons and particles from astrophysical sources. Spoiler alert: Sailing ships could almost reach the speed of light!
The Hubble constant describes the rate at which the universe expands. But different measurements of it yield different results – a problem for the cosmic standard model. Today’s paper discusses new Cepheid observations, which increase the problem – so, are we on the brink of new physics?