Des chercheurs proposent une nouvelle estimation de la constante de Hubble la plus précise jamais obtenue par les observations. © allexxandarx, Adobe Stock

Hubble takes another step in determining the rate at which our universe is expanding

Ever since the discovery of the expansion of the universe, or nearly so, the question has plagued astrophysicists. How fast is this expansion going today? Because observation and theory don’t give the same answer. Today, the Hubble Space Telescope provides additional precision.

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[EN VIDÉO] Interview: Why is the universe expanding?
With the discovery of the expansion of the universe, other questions arose: How fast is this expansion happening? is there acceleration? or slow down? Futura-Sciences interviewed Aurélien Barrau, astrophysicist specializing in cosmology and author of Des univers multiples.

Our history of the universe begins about 13.7 billion years ago in an extremely dense and hot soup. The laws of physics as we…” data-image=”https://cdn.futura-sciences.com/buildsv6/images/midioriginal/1/5/5/1557798396_80921_universe.jpg” data-url=”https : //news.google.com/sciences/definitions/astronomy-universe-15239/” data-more=”Read more”>universe expands. there is no doubt. What is being discussed is velocity, which has a direction and an intensity represented by a vector, the velocity vector. Relative velocity is the velocity of one body relative to another or relative to a frame.” data-image=”https://cdn.futura-sciences.com/buildsv6/images/midioriginal/3/1/9/319daf63f4_77541_leibniz-dp . jpg” data-url=”https://news.google.com/sciences/definitions/physics-velocity-324/” data-more=”Read definition”>speed that continues today Movement. Its current expansion rate – which is translated by what the physicist christened it the Hubble constant. It was a tribute to the American He entered the Yerkes Observatory, where he wrote a remarkable dissertation on nebulae, which earned him a place at…” data-image=”https://cdn.futura-sciences.com/ buildsv6/images /midioriginal/7/a/5/7a55fb5c4d_50142198_hubble-700.jpg” data-url=”https://news.google.com/sciences/personalities/astronomy-edwin-hubble-715/” data-more =”Read more”>Edwin Hubble who discovered the phenomenon of the expansion of the universe and carried out the first measurements on it in the 1920s. And the homage continues to grow today as researchers unveil new things new results more precise than ever. Obtained from data collected by the for more than 30 years Hubble Space Telescope.

It is worth remembering that measurement was precisely one of the main reasons for the existence of this instrument. Efforts made as early as the 1970s aimed at developing a tool to resolve Cepheids. For the Cepheid variable starshave long served as cosmic markers, a sort of standard meter for Measure distances in the universe. Exactly since 1912. They can be seen both in our Milky Way and in us galaxies away, thanks to the Hubble Space Telescope, up to about 80 millionlight years.

When Hubble was launched in the 1990s, the first series of Cepheid observations were made. With the main goal of refining the measurement of the distances of galaxies close to us. In the early 2000s, the efforts of astronomers were rewarded. They were thus able to derive a value from the Hubble constant with an accuracy of 10%. A value of 72 plus or minus 8 kilometers per second per megaparsec (km/s/Mpc).

Which value is correct?

To refine this value, the researchers then added new cameras to the space telescope. With the idea of ​​achieving 1% accuracy. One idea in particular led to the collaboration Supernova, H0, for the dark energy equation of state (SH0ES).

The new results published today by the researchers are therefore based on a more than doubled sample of cosmic markers. They also include an updated analysis of past data. And a total of 42 supernovae – knowing that Hubble witnessed one Supernova Explosion per year, approximately… – also useful for determining distances in the Universe. Therefore, given the size of their sample, astronomers estimate the possibility to be only one in a million “from an unfortunate lot”. Give the Hubble constant a value of about 73 km/s/Mpc. Very accurate 73.04 +/- 1.04 km/s/Mpc.

The problem is that from the measurements of the Planck mission (European Space Agency, ESA) on our primitive universe and according to the Standard Cosmological Model, theorists predict a value of the Hubble constant that should be 67.5 plus or minus 0.5 km/s/Mpc. So where does this discrepancy come from? Astronomers still don’t know. But it is possible that they will have to look for the answer somewhere in new laws of science. The theories established by physics apply within a well-defined framework.
Physics…” data-image=”https://cdn.futura-sciences.com/buildsv6/images/midioriginal/8/9/6/896f032c90_91933_physics-def.jpg” data-url=”https:// news .google.com/science/definitions/physics-physics-15839/” data-more=”Read more”>physically. A brand new study tries, for example, to explain the discrepancy with a ” World mirror» invisible particles that would only interact with our world about that heaviness.

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