These nanodiamonds observed by James Webb fascinate the beginnings of the

These nanodiamonds observed by James-Webb fascinate the beginnings of the universe – Futura

It is known that in the depths of the earth, high pressures and temperatures lead to the formation of diamonds from carbon. The same is probably true for the carbonaceous dust that stars produce at the end of their lives in the red giant phase, as well as for the explosions of supernovae. In fact, nanodiamonds have been discovered for decades in presolar grains older than the Solar System and found in the oldest carbonaceous meteorites.

These are objects containing a few thousand carbon atoms that form a characteristic crystalline structure and are concentrated in a volume of a few nanometers, i.e. a billionth of a meter in diameter. They can be obtained as a milky residue of a fragment of a carbonaceous meteorite dissolved in acid.

As an article published in Nature explains, it is now believed that the infrared signature of these nanodiamonds is likely to be observed in galaxies like those discovered by the James Webb Space Telescope no later than about a billion years after the Big Bang.

Galaxies Growing Faster Than Theory Predicts?

Joris Witstok of the University of Cambridge, one of the main astrophysicists behind this discovery, explains: “Carbon-rich dust grains are particularly good at absorbing ultraviolet light with a wavelength of around 217.5 nanometers, which we observed for the first time directly in the spectra of very old galaxies.” Let’s recall in passing that the James-Webb (JWST) sees, for example, lines in the ultraviolet at the origin in the infrared spectra, whose light has been red-shifted by the expansion of the universe .

Also in the same ESA press release, his colleague Renske Smit, a member of the team at John Moores University in Liverpool, UK, added: “This discovery implies that young galaxies in the early Universe grew much faster than we expected.” Webb shows us a complexity in the early birthplaces of stars (and planets) that models have yet to explain.”

Once again, Hubble’s successor gives us evidence that galaxies have been evolving faster than we have assumed for several decades, possibly suggesting that the standard cosmological model needs to be revised, for example by replacing the presence of dark matter with a modification of the gravitational laws within the framework of lunar theory, although it is too early to conclude that this model is in fact incapable of predicting the observations made with James-Webb.

Incidentally, despite the recent and very exaggerated rumors that have angered the cosmological community, we have no serious reason to believe that the observable universe is older than 13.8 billion years, and specifically 26.7 billion years old, as suggested by the physicist Rajendra Gupta by multiplying the epicycles. In particular, we’ve known for decades that the “tired” light theory – which proposed explaining spectral redshifts without accounting for the expansion of the observable cosmos – leads to at least three predictions that are contradicted by observations at around 10 sigma, to use physicist jargon (see what cosmologist Ned Wright has been saying for a long time). A refuted result at 5 sigma already means that the probability that the refutation is wrong is only one in a million, even at 10 sigma the probability is significantly lower.

This gives a glimpse of the unlikely, if logically possible, acrobatics that must be multiplied to arrive at an age of 26.7 billion years. In particular, when these possible variations are already severely constrained, certain fundamental constants of physics must be assumed to change over time, as well as the chronometer dating of star clusters and the abundance of certain nuclei in the Milky Way, all of which are, to a first approximation, inconsistent with a universe actually older than 13.8 billion years.

Nanodiamonds or Polycyclic Aromatic Hydrocarbons?

But back to the detection of nanodiamonds. In fact, the signature discovered by James-Webb could very well be interpreted in the case of galaxies observed as recently as a few billion years ago, by the abundant presence of carbon-containing molecules called polycyclic aromatic hydrocarbons, cousins ​​of benzene (polycyclic aromatic hydrocarbons, or PAH) molecules. But in galaxies around 600 million years old after the Big Bang, as observed by the JWST Advanced Deep Extragalactic Survey (Jades), the astrochemists do not believe this hypothesis to be credible and therefore conclude that nanodiamonds are likely to be observed.

If so, “this discovery was made possible by Webb’s unprecedented improvement in the sensitivity of near-infrared spectroscopy, and in particular his near-infrared spectrograph (NIRSpec).” The sensitivity increase provided by Webb corresponds in the visible to the immediate improvement of Galileo’s 37-millimeter telescope by ESO’s 8-metre Very Large Telescope,” explains Roberto Maiolino, a member of the Cambridge University and University College London team behind the discovery of nanodiamonds.

“We plan to work more with theorists who model the production and growth of dust in galaxies. This will shed light on the origin of dust and heavy elements in the early Universe,” adds Irene Shivaei, team member from the University of Arizona, Centro de Astrobiología (CAB).

nanodiamonds and meteorites. For a reasonably accurate French translation, click the white rectangle at the bottom right. The English subtitles should then appear. Then click on the nut to the right of the rectangle, then on “Subtitles” and finally on “Translate automatically”. Choose French. © thebrainscoop