Hubble constant tagged posts

What happened shortly after the universe was born in the Big Bang and began to expand? Bubbles occurred and a previously unknown phase transition happened, according to particle physicists.

Think of bringing a pot of water to the boil: As the temperature reaches the boiling point, bubbles form in the water, burst and evaporate as the water boils. This continues until there is no more water changing phase from liquid to steam.

This is roughly the idea of what happened in the very early universe, right after the Big Bang, 13.7 billion years ago.

The idea comes from particle physicists Martin S...

Completing a nearly 30-year marathon, NASA’s Hubble Space Telescope has calibrated more than 40 “milepost markers” of space and time to help scientists precisely measure the expansion rate of the universe — a quest with a plot twist.

Pursuit of the universe’s expansion rate began in the 1920s with measurements by astronomers Edwin P. Hubble and Georges Lemaître...

Researchers have discovered an unusual pulsar – one of deep space’s magnetized spinning neutron-star ‘lighthouses’ that emits highly focused radio waves from its magnetic poles. It is unusual because the masses of its two neutron stars are quite different — with one far larger than the other. The breakthrough provides clues about unsolved mysteries in astrophysics — including the expansion rate of the Universe (the Hubble constant).

The newly discovered pulsar (known as PSR J1913+1102) is part of a binary system — which means that it is locked in a fiercely tight orbit with another neutron star.

Neutron stars are the dead stellar remnants of a supernova...

Astrophysicists are closing in on the Hubble constant. The collision of two neutron stars (GW170817) flung out an extraordinary fireball of material and energy that is allowing a a team of astrophysicists to calculate a more precise value for the Hubble constant, the speed of the universe’s expansion. Previous estimates put the value between 66 and 90 km/s/Mpc, which this team refined to between 65.3 and 75.6 km/s/Mpc.

Exactly how fast is the universe e...