"Baby Universe": Most precise map of the microwave background created to date
A telescope in Chile has spent years working on by far the most precise map of the earliest visible universe. It now reveals a lot about the cosmos.
The new map of the cosmic microwave background
(Image: ACT Collaboration, ESA/Planck Collaboration)
An international research group has created the most detailed and accurate image of the earliest epoch of the universe that we can see to date. The data on the cosmic microwave background collected with the Atacama Cosmology Telescope (ACT) shows the state of the cosmos approximately 380,000 years after the Big Bang. Assuming that the universe has now reached middle age, the image corresponds to a photo of a child just a few hours old, writes Princeton University. For the first time, the polarization of the signals can now be made out, which tells us even more about this important phase in the development of the cosmos.
The oldest detectable signals
Before the epoch in which the radiation of the cosmic microwave background was created, the universe consisted of opaque plasma. This is why the CMB (Cosmic Microwave Background) is by far the oldest signal that we can detect in the universe. Until now, the radiation has mainly been measured by the ESA Planck space telescope. However, the data now collected has five times the resolution and is much more accurate. In addition, the information on the polarization of the signals reveals how hydrogen and helium moved in this universe – long before the first stars were formed following the so-called Dark Ages.
Based on the much more precise map of the microwave background, the team has now also been able to determine much more precisely how large the observable universe is. It extends almost 50 billion light years in all directions and contains the mass of 1900 × 1021 suns – that is 1900 zeta-solar masses or the mass of almost 2 quadrillion suns. Only about 100 × 1021 solar masses are accounted for by conventional matter. A further 500 × 1021 solar masses are accounted for by so-called dark matter and the remaining 1300 × 1021 solar masses are contributed by dark energy.
Hubble tension not resolved
Overall, the new CMB map would once again confirm the standard model of cosmology, according to the team. According to this, the universe is 13.8 billion years old, with an uncertainty of just 0.1 percent. In addition, the precise measurements have confirmed earlier data on the speed at which the cosmos propagates, which was also determined based on the cosmic microwave background. This further deepens the so-called Hubble tension – there is no evidence to explain the deviation from the measurement data based on the nearby universe.
The data had also been tested in relation to possible new physics, without any evidence of anything new being discovered. The comparatively simple model of the cosmos has thus been confirmed once again, and most competing models have been ruled out based on the data. The data was collected over a period of five years, and the measurements that have now been evaluated were completed in 2022. The follow-up work is now to be carried out by a new instrument. The study itself has not been reviewed, but will be presented today, Wednesday, at the annual conference of the American Physical Society. It can be viewed online.
(mho)