Dhe astrophysicist Pieter van Dokkum from Yale University explained on American television over the weekend the surprise that awaited him and his colleagues when they analyzed their early data from the James Webb Space Telescope (JWST). He used his 14-year-old son as an example, because his age compares well with the 14-billion-year-old universe: “So basically what we did was take photos from when my son was 6 months old was. When you first look at a photo like this, you expect to see a baby. But what we see is a toddler.”
In other words, the international group of astrophysicists had used the special capabilities of the James Webb Space Telescope to look for the first galaxies. They found them too, at an early stage around 600 million years after the Big Bang, but contrary to all expectations, these galaxies were not small, but already very massive. The researchers calculated a value of 100 billion solar masses as the mass of the largest of the 13 observed galaxies, almost ten percent of that of our Milky Way.
fundamental consequences
The finding was published in the journal “Nature” in an accelerated process. If the result stands up to further scrutiny, it could have some consequences for our cosmological worldview. The model that is currently best able to describe our universe and its development is the Lamda-CDM model. It is based on Einstein’s general theory of relativity and assumes that in addition to the matter we know, the universe contains a significant proportion of dark matter and is being accelerated apart by dark energy. This model can also be used to describe how the material structures that we observe today came about. Accordingly, small galaxies initially formed in halos of dark matter, which over time merged into ever larger ones as a result of collisions.
These predictions can be checked by observing galaxies in the early days of the Universe. Given the finite nature of the speed of light, looking far into the cosmic past requires catching electromagnetic radiation from as far away as possible. You need very sensitive telescopes for this. At the same time, the radiation on its way to us is constantly being shifted to longer wavelengths due to the expansion of the universe, it is becoming redder. Light that originally resided in the ultraviolet part of the spectrum arrives with us as light in the optical or infrared part. Telescopes that look far into the past must therefore be able to observe infrared radiation – such as the James Webb Space Telescope, which also has the necessary sensitivity.