Add Yahoo as a preferred source to see more of our stories on Google. Cepheid variable star RS Puppis pulses with a regular period. (NASA, ESA, Hubble Heritage Team; Howard Bond/STScI & Penn State U.) ...

Perhaps the greatest and most frustrating mystery in cosmology is the Hubble tension problem. Put simply, all the observational evidence we have points to a universe that began in a hot, dense state, ...

The most precise measurement yet of how fast the Universe is expanding shows we have a real and serious problem on our hands. The international H0DN Collaboration – a community consensus report on the ...