In recent months we have seen important discoveries of distant galaxies, from a time when the universe was a small fraction of the age it is now, and much smaller, too. The James Webb Telescope (JWST) has a lot to do with this, but it’s not our only weapon.
From the ends of the universe to the Chilean desert. A few weeks ago, a team of astronomers announced the discovery of an “invisible galaxy”, a galaxy so distant and dim that it had gone undetected in previous searches. It was detected thanks to the ALMA network of telescopes (Atacama Large Millimeter/submillimeter Array) located in the Chilean desert.
The team responsible for the finding communicated the details of it in an article in The Astrophysical Journal. In it, the authors explain that the image that reaches us is a snapshot of a galaxy from a young universe, when only 2,000 million years had passed since the Big Bang, that is, about 11,700 million years ago.
As described by the astronomers who discovered the new galaxy, it is compact and contains a large amount of interstellar dust. It is, as might be expected, a young galaxy that is very active in the formation of new stars, at a rate 1,000 times greater than that with which our galaxy, the Milky Way, creates new suns.
A relativistic “magnifying glass”. The new discoveries of galaxies and other very distant objects are possible thanks to a circumstance related to the work of the well-known Albert Einstein. Just as the physicist predicted, gravity is capable of affecting the path of light beams that pass close to a very massive object.
Thus, galaxies and stars located halfway between us and those distant objects that we want to observe, work as a lens that adds to the capacity of our own telescopes. This tool has enabled some of the most distant and ancient galaxies discoveries in the universe, as well as other interesting astronomical objects.
Image of the newly discovered galaxy. Giulietti et al.
The early Universe. The interest of astrophysicists to see further into space and time is not accidental. The more objects from this time we know and understand, the greater our ability to understand what happened in the first million years of our cosmos.
And it is that there are still many eggs to fill in our knowledge of cosmogenesis and the entire process that has brought us here. The latest discovery carried out by ALMA transports us to a time when the universe was still one sixth of its present size, as the researchers explain. The rate of expansion of space is also one of these enigmas that we want to solve.
“Very distant galaxies are authentic mines of information about the past and the future evolution of our universe,” explains Marika Giulietti, who heads the publication of the work, in a press release. “Even so, studying them is a great challenge. [estas galaxias son] very compact and therefore difficult to observe.”
Wavelengths. ALMA, like the JWST, takes advantage of wavelengths longer than the characteristics of the visible spectrum. This has two advantages when detecting very distant objects. The first is the redshift that light experiences as it travels great distances through stretching space, stretching its wavelength with it.
The second advantage is that these wavelengths manage to penetrate the interstellar dust that obscures the most distant galaxies. As Giulietti explains, “the cause of this dimming is the massive presence of interstellar dust, which intercepts the visible light of young stars, making it difficult to detect with optical instruments, and re-emits it in longer waves where it can only be observed with interferometers. powerful in (sub)millimeter and radio bands.”
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Images | European Southern Observatory (ESO), CC BY
