A study published by the prepress server arXiv and already accepted for publication by The Astrophysical Journal brings a NASA report based on 30 years of Hubble data, which astronomers refer to as ” masterpiece(the largest work) of the space telescope. These data provide the most accurate measure of the rate of expansion of the universe.
We have collected 30 years of data from the Hubble Telescope to arrive at the most accurate measure of the rate of expansion of the universe. Photo: Whitelion61 /
The astronomical scientific community has known for more than a century that the universe is expanding, thanks to observations of the increasing distance between galaxies. The speed at which they move relative to their distance from Earth is called the “Hubble constant”, and measuring this value was one of the main tasks of the Space Observatory.
To measure the Hubble constant, astronomers study distances to objects whose brightness is well known – so the dimmer it looks, the farther away it is. For objects relatively close to the Milky Way or nearby galaxies, this role is filled by the Cepheids, a class of stars pulsing in a predictable pattern. For greater distances, scientists use so-called Type Ia supernovae – cosmic explosions with a well-defined brightness.
Over the last few decades, measurements of these objects have calculated the Hubble constant to be about 70 km per second. second per megaparsec (/ s / Mpc). Basically, a galaxy a megaparsec (about 3.3 million light-years) from Earth will move away at 70 km per second, and that speed increases by 70 km / s for every megaparsec away.
The Hubble Telescope provides the most complete catalog of cepheids and supernovae
For the new study, a team of scientists analyzed the most comprehensive catalog of these objects to date to make the most accurate measurement of the Hubble constant yet. This was done by studying 42 galaxies containing both Cepheid and Type Ia supernovae.