NASA has released a blockbuster report that astronomers call the Hubble Space Telescope masterpiece . New research analyzes 30 years of data from the famous space telescope to provide the most precise measurement yet of how fast the universe is expanding. For more than half a century, astronomers have known that the universe is expanding, thanks to observations of galaxies that are moving away from us—the farther away they are, the faster they are moving. The speed at which they move relative to their distance from Earth is a number known as the Hubble constant, and measuring this value is one of the Hubble Space Telescope’s primary missions. To measure the Hubble constant, astronomers study the distance of an object whose brightness is sufficiently known—in this way, the dimmer it appears, the further away it is. For relatively close objects within the Milky Way or nearby galaxies, this role is assumed by Cepheids, a class of stars with predictable pulsing patterns. For further distances, astronomers use so-called Type Ia supernovae — cosmic explosions with well-defined peaks in brightness. In the new study, the team of scientists collected and analyzed the most comprehensive catalog yet of these objects to make the most precise measurement of the Hubble constant. This was done by studying 42 galaxies, including Cepheids and Type Ia supernovae, in images taken by Hubble over the past 30 years. “That’s what the Hubble Space Telescope was built for, and doing it with the best technology we know,” said Adam Riess, lead scientist on the research team. “This is likely to be a Hubble masterpiece, because Hubble needs to go through It takes 30 years to double this sample size.”
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