There’s always a touch of melancholy when a chapter that has absorbed years of work comes to an end. In the case of the Atacama Cosmology Telescope (ACT), those years amount to nearly twenty — and now the telescope has completed its mission. Yet some endings are also important beginnings, opening new paths for the entire scientific community.

The three papers just published in the Journal of Cosmology and Astroparticle Physics (JCAP) by the ACT Collaboration describe and contextualize in detail the sixth and final major ACT data release — perhaps the most important one — marking significant advances in our understanding of the Universe’s evolution and its current state.

ACT’s data clarify several key points: the measurement of the Hubble constant (the number that indicates the current rate of cosmic expansion — the Universe’s “speedometer”) obtained from observations at very large cosmological distances is confirmed, and it remains markedly different from the value derived from the nearby Universe. This is both a problem and a remarkable discovery: it confirms the so-called “Hubble tension,” which challenges the model we use to describe the cosmos.

ACT’s observations also rule out many of the so-called extended models — theoretical alternatives to the standard cosmological model. That’s another “problem,” since it narrows the range of possibilities, but it also represents a new, cleaner starting point: time to stop pursuing these models and look elsewhere.

Last but not least, ACT provides new polarization maps of the cosmic microwave background — the Universe’s “fossil light” — which complement Planck’s temperature maps, but with much higher resolution. “When we compare them, it’s a bit like cleaning your glasses,” says Erminia Calabrese, cosmologist at Cardiff University, ACT collaboration member and coordinator of one of the three papers.

After surpassing the 600-scholarship milestone last year, this year the remarkable generosity of private individuals, companies, and institutions enabled Goethe University to set a new participant record. A total of 280 private individuals, 45 companies, and 52 nonprofit organizations donated a €1,116,000 to Goethe University in 2025, which according to the matching principle was doubled by the Federal Ministry of Research, Technology and Space (BMFTR). This translates into a total of €2,232,000 raised for scholarship recipients.

A study led by Professor Nicolas DAUPHAS of the Department of Earth and Planetary Sciences at The University of Hong Kong (HKU) and Dr Timo HOPP of the Max Planck Institute for Solar System Research in Göttingen, Germany, together with their collaborators reveals that Theia—the planet-sized body that collided with the early Earth to form the Moon—was not an icy wanderer from the outer Solar System, but a rocky neighbour born close to the Sun. 

The SETI Institute is pleased to open the call for applications for the 2026 Mino Postdoctoral Fellowship. This research program offers an exceptional opportunity for talented early-career scientists worldwide to contribute significant advances in the following fields:

- Origins of life and prebiotic chemistry

- Biophysics and the nature of life

- Planetary habitability and environmental limits on life

- Coevolution of life and planetary environments across spatiotemporal scales

- Modeling and theory of life-environment systems

- Comparative studies of Earth, solar system worlds, and exoplanets

- AI/ML applied to origins, nature of life, and habitability research