Cosmology

Blog about cosmology

An artistic illustration of the test of the postquantum theory of classical gravity

An article published in the journal “Physical Review X (PRX)” proposes what is called a postquantum theory of classical gravity. Professor Jonathan Oppenheim of University College London (UCL) offers a different approach to that adopted by most of his colleagues by proposing to modify quantum theory to unify it with relativistic gravity. An article published in the journal “Nature Communications” offers some reflections from Professor Oppenheim’s former Ph.D. students on the consequences of his theory and proposes an experiment to verify it.

The Perseus galaxy cluster (Image ESA/Euclid/Euclid Consortium/NASA, image processing by J.-C. Cuillandre (CEA Paris-Saclay), G. Anselmi, CC BY-SA 3.0 IGO)

ESA has presented the first official images captured by its Euclid space telescope. After some delays due to problems with the fine guidance sensor, it was possible to calibrate Euclid’s instruments and obtain the extraordinary precision of observations necessary for its mission. The result is a resolution that allows a quantity of detail never seen before to be included in the images, be it galaxies, stars, or other objects, often discovered by Euclid. The presentation showed the results both with distant objects such as the Perseus galaxy cluster and with others close in astronomical terms such as the Horsehead Nebula.

A diagram illustrating the combined power of the James Webb and Hubble space telescopes in studying Cepheids present in the galaxy NGC 5584 with the NIRCam (Near-Infrared Camera) and WFC3 (Wide Field Camera 3) instruments, respectively

An article accepted for publication in “The Astrophysical Journal” reports the results of calculating the universe’s expansion rate based on the observation of Cepheids with the James Webb Space Telescope. In particular, a team of researchers led by Adam Riess used the NIRCam instrument to observe over 330 cepheids in the galaxies NGC 4258 and NGC 5584. The results are more precise than those obtained in the past with the Hubble Space Telescope but confirm the accuracy of the previous calculation of the universe’s expansion rate. This leaves open the question of the difference in results obtained with different methods.

JADES-GS-z13-0, JADES-GS-z12-0, and JADES-GS-z11-0

An article published in the journal “Proceedings of the National Academy of Sciences” reports the discovery of candidate supermassive dark stars observed by the James Webb Space Telescope. Cosmin Ilie, Jillian Paulin, and Katherine Freese argue that three of what were considered primordial galaxies have characteristics of a type of object that so far was only hypothesized. According to the model proposed in 2007, supermassive dark stars have a large dark matter component that powers them instead of nuclear fusion. These strange objects could reach masses up to ten million times the Sun’s and a brightness up to ten billion times the Sun’s, which could lead to mistaking them for primordial galaxies.

The Euclid Space Telescope blasting off atop a Falcon 9 rocket (Image courtesy SpaceX)

A little while ago, ESA’s Euclid Space Telescope was launched atop a SpaceX Falcon 9 rocket from Cape Canaveral. After just over 40 minutes, it successfully separated from the rocket’s last stage and entered its course that will take it towards the so-called L2 point, about 1.5 million kilometers from Earth, where its scientific mission will begin with an investigation of the dark universe.

The Euclid Space Telescope mission is focused on the cosmological mysteries connected to dark matter and dark energy. Cosmological research in recent decades indicates that the universe we see with the ordinary matter that forms galaxies constitutes only a small part of the cosmos. Astronomers and physicists are having difficulty investigating parts of the cosmos that we can neither see nor directly detect. It’s a problem that makes it difficult to test models that try to explain the effects that led to hypothesize the existence of dark matter and dark energy. For this reason, ESA developed a scientific mission focused on these cosmological problems.