Best-Yet ‘Baby Pictures’ of the Universe Unveiled

The Atacama Cosmology Telescope (ACT) has provided the clearest images of the cosmic microwave background (CMB), offering a more refined understanding of the universe’s infancy. Located on Chile's Cerro Toco, the telescope has measured the Big Bang's afterglow from 2007 to 2022, providing insights into the early universe’s structure and dynamics. The ACT’s findings reinforce the Lambda Cold Dark Matter model, yet highlight the persistent mystery regarding the universe's expansion rate. The observed Hubble constant discrepancy, between measurements from the CMB and those from closer astronomical phenomena, remains unresolved. Efforts to identify deviations from the standard model have not yielded new physics, despite ACT’s enhanced sensitivity. However, these findings do reconfirm vital cosmological parameters, like the universe being approximately 13.8 billion years old and composed predominantly of dark matter and dark energy. This research collaborates with the European Space Agency's Planck satellite results, yet advances understanding with higher resolution and greater sensitivity. Simons Observatory, ACT's successor, is anticipated to provide further insights, potentially uncovering deviations or new physics that could redefine cosmological models. The ACT collaboration hopes these new tools will further illuminate the mysteries still surrounding cosmology.