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Hubble, Gaia produce most precise measure of universe's expansion rate

Hubble, Gaia produce most precise measure of universe's expansion rate

Science
July 12 (UPI) -- By combining the observations of the two most powerful space telescopes in orbit, scientists have achieved the most precise measurement of the Hubble constant, the universe's expansion rate. The new measurement confirms the tension between explosion rate in the early and late universe, researchers report. Astronomers can measure the expansion of the universe by measuring a galaxy's redshift, a change in the wavelength of the light due to a change in the velocity of the object. By measuring the redshift of galaxies using the Hubble Telescope, scientists have established the Hubble constant. But investigations of the cosmic microwave background, the oldest radiation in the universe, can also be used to predict the universe's expansion rate. Maps of the microwave signature ...
Gravitation lens yields most precise test of general relativity yet outside our Milky Way

Gravitation lens yields most precise test of general relativity yet outside our Milky Way

Science
June 21 (UPI) -- The theory of general relativity states that objects and their gravitational pull distort the spacetime around them. The phenomenon explains the gravitational lens effect, the bending of light in a lens-like shape around large galaxies and cosmic structures. Recently, astronomers successfully measured the gravitation lensing effect around the elliptical galaxy ESO 325-G004, located 450 million light-years from Earth. The test proved with record-precision the general relativity. Astronomers used the MUSE instrument on the Very Large Telescope to analyze the movement of stars within ESO 325-G004 to estimate the galaxy's mass. Astronomers than used high-definition images collected by the Hubble Space Telescope to measure the lensing ring around the galaxy. Their measurement...