Archive for SETI

Weekly Update from the Open Journal of Astrophysics – 06/12/2025

Posted in OJAp Papers, Open Access, The Universe and Stuff with tags , , , , , , , , , , , , , , , , , , , , , , , , , , , on December 6, 2025 by telescoper

Once again it’s time for the usual Saturday morning update of the week’s new papers at the Open Journal of Astrophysics. Since the last update we have published a further six papers, which brings the number in Volume 8 (2025) up to 190, and the total so far published by OJAp up to 425. I blogged about the significance of the latter figure here.

The first paper this week is “The galaxy-IGM connection in THESAN: observability and information content of the galaxy-Lyman-alpha cross-correlation at z>6” by Enrico Garaldi (U. Tokyo, Japan), Verena Bellscheidt (Tech. U. Munich, Germany), Aaron Smith (U. Texas Austin, USA) and Rahul Kannan (York U. Canada). This paper was published on Monday 1st December 2025 in the folder Cosmology and Nongalactic Astrophysics. It describes an investigation of the impact of observational limitations on the ability to retrieve the intrinsic galaxy-Lyman-alpha cross correlation from line-of-sight observations.

The overlay is here:

 

 

You can find the officially accepted version on arXiv here and the Fediverse announcement is here:

Open Journal of Astrophysics

New Publication at the Open Journal of Astrophysics: "The galaxy-IGM connection in THESAN: observability and information content of the galaxy-Lyman-alpha cross-correlation at z>6" by Enrico Garaldi (U. Tokyo, Japan), Verena Bellscheidt (Tech. U. Munich, Germany), Aaron Smith (U. Texas Austin, USA) and Rahul Kannan (York U. Canada)

doi.org/10.33232/001c.151666

December 1, 2025, 8:37 am 1 boosts 0 favorites

The second paper of the week is “A Less Terrifying Universe? Mundanity as an Explanation for the Fermi Paradox” by Robin H.D. Corbet (U. Maryland, USA). This paper was published on 1st December 2025 in the folder Instrumentation and Methods for Astrophysics. It presents a discussion of possible explanations for the lack of s evidence for the presence of technology-using extraterrestrial civilizations in the Galaxy (usually called the Fermi paradox). The overlay is here:

 

 

You can find the official version of this one on arXiv here. The federated announcement on Mastodon is here:

Open Journal of Astrophysics

New Publication at the Open Journal of Astrophysics: "A Less Terrifying Universe? Mundanity as an Explanation for the Fermi Paradox" by Robin H.D. Corbet (U. Maryland, USA)

doi.org/10.33232/001c.151454

December 1, 2025, 8:50 am 2 boosts 2 favorites

 

Next one up is “Sulphur abundances in star-forming regions from optical emission lines: A new approach based on photoionization models consistent with the direct method” by Enrique Pérez-Montero, Borja Pérez-Díaz, & José M. Vílchez ( (Instituto de Astrofísica de Andalucía, Spain), Igor A. Zinchenko (LMU, Germany), Asier Castrillo, Marta Gavilán, Sandra Zamora & Ángeles I. Díaz (Universidad Autonoma de Madrid, Spain). This was published on 1st December 2025 in the folder Astrophysics of Galaxies. This study uses the emission lines produced in the optical part of the spectrum and with photoionization models to derive sulphur chemical abundances in the gas-phase of star-forming galaxies.

The overlay is here:

 

 

You can find the official accepted version on arXiv here. The fediverse announcement is here:

Open Journal of Astrophysics

New Publication at the Open Journal of Astrophysics: "Sulphur abundances in star-forming regions from optical emission lines: A new approach based on photoionization models consistent with the direct method" by Enrique Pérez-Montero, Borja Pérez-Díaz, & José M. Vílchez ( (Instituto de Astrofísica de Andalucía, Spain), Igor A. Zinchenko (LMU, Germany), Asier Castrillo, Marta Gavilán, Sandra Zamora & Ángeles I. Díaz (Universidad Autonoma de Madrid , Spain)

doi.org/10.33232/001c.151253

December 1, 2025, 9:12 am 0 boosts 0 favorites

The fourth article of the week is “Bayesian Posteriors with Stellar Population Synthesis on GPUs” by Georgios Zacharegkas & Andrew Hearin (Argonne National Laboratory, USA) and Andrew Benson (Carnegie Observatories, USA). This is an exploration of a range of computational techniques aimed at accelerating Stellar Population Synthesis predictions of galaxy photometry using the JAX library to target GPUs (Graphics Processing Units, in case you didn’t know). This paper was published on Tuesday December 2nd 2025 in the folder Astrophysics of Galaxies.

The overlay is here:

 

You can find the official published version on arXiv here. The Fediverse announcement follows:

Open Journal of Astrophysics

New Publication at the Open Journal of Astrophysics: "Bayesian Posteriors with Stellar Population Synthesis on GPUs" by Georgios Zacharegkas & Andrew Hearin (Argonne National Laboratory, USA) and Andrew Benson (Carnegie Observatories, USA)

doi.org/10.33232/001c.151255

December 2, 2025, 7:38 am 3 boosts 1 favorites

Next one up is “IAEmu: Learning Galaxy Intrinsic Alignment Correlations” by Sneh Pandya Yuanyuan Yang, Nicholas Van Alfen, Jonathan Blazek and Robin Walters (Northeastern University, Boston, USA). This presents a neural-network-based emulator that predicts the galaxy position-position, position-orientation, and orientation-orientation, correlation functions and their uncertainties using mock catalogs based on the halo occupation distribution (HOD) framework. It was published on December 2nd 2025 in the folder Cosmology and Nongalactic Astrophysics. The overlay is here:

The official accepted version can be found on arXiv here. The Mastodon announcement is here:

Open Journal of Astrophysics

New Publication at the Open Journal of Astrophysics: "IAEmu: Learning Galaxy Intrinsic Alignment Correlations" by Sneh Pandya Yuanyuan Yang, Nicholas Van Alfen, Jonathan Blazek and Robin Walters (Northeastern University, Boston, USA)

doi.org/10.33232/001c.151749

December 2, 2025, 7:52 am 1 boosts 0 favorites

The last paper for this weel is “Unraveling the Nature of the Nuclear Transient AT2020adpi” by Paarmita Pandey (Ohio State University, USA) and a team of 15 others based in the USA, UK and Australia. This was published on Thursday December 4th 2025 in the folder High-Energy Astrophysical Phenomena. It is an investigation into a particular transient event AT2020adpi and a discussion of whether it is an extreme example of AGN variability or a Tidal Disruption Event (TDE). The overlay is here:

You can find the officially-accepted version on arXiv here, and the Mastodon announcement is here:

Open Journal of Astrophysics

New Publication at the Open Journal of Astrophysics: "Unraveling the Nature of the Nuclear Transient AT2020adpi" by Paarmita Pandey (Ohio State University, USA) and 15 others based in the USA, UK and Australia

doi.org/10.33232/001c.151453

December 4, 2025, 8:48 am 1 boosts 0 favorites

And that concludes the update for this week. I will do another next Saturday.

Do you believe there is intelligent life out there?

Posted in Astrohype, The Universe and Stuff with tags , , on February 15, 2021 by telescoper

Following on from yesterday’s post and inspired by this tweet

I thought I’d try a quick poll on what people think about the existent of intelligent life “out there”. In my experience, and in contrast to the tweet, most astronomers are actually quite open-minded about the possibility of extraterrestrial intelligence. My own view is that while it is entirely possible that there is intelligent life elsewhere in the Universe, scientific belief* should be based on evidence and we simply don’t have any evidence to support the idea. I would therefore say that I don’t “believe” but am agnostic. Sometimes “I don’t know” is the only rational answer.

You might ask me as a cosmologist whether I believe in the Big Bang theory. My answer would be “yes” because I think the evidence supports this description of the Universe. If evidence came along to change my opinion I might believe in it less or not at all. I might also change my mind if a different model came along that fits the observations better.

*In a Bayesian sense I would interpret “refusing to believe” as meaning setting a prior probability of zero, so that no amount of evidence would produce a non-zero posterior probability.

Anyway, setting aside the issue of whether there is even any evidence of intelligent life on Earth here is a poll:

How not to behave in a Zoom discussion…

Posted in The Universe and Stuff with tags , , , on February 14, 2021 by telescoper

A couple of days ago, on February 12th, there was a ‘Golden webinar in Astrophysics’ one of a series that seeks to bring forefront research in astronomy, astrophysics, and cosmology to the public in the English and Spanish languages. The speaker this time was Avi Loeb and the full title of his talk was  Extraterrestrial Life: Are We the Sharpest Cookies in the Jar? A video of the entire event can be viewed here.

Avi Loeb is a very distinguished theoretical physicist, with broad interests in the fields of astrophysics and cosmology who has done excellent rather mainstream work on the formation and evolution of black holes, the first generation of stars in the universe and the epoch of reionization, as well as high-redshift gamma-ray bursts. He has also produced a large number of much more speculative articles in areas such as extra-terrestrial life (including SETI) some of which, in my opinion, is rather flaky. Loeb was a long-serving Chair of the Department of Astronomy at Harvard University and is the current Director of the Institute for Theory and Computation there.

The following is a short excerpt from the panel discussion following his talk. I was surprised to Avi Loeb adopt such a dismissive and confrontational attitude towards Jill Tarter (who has worked in the field of SETI for over 40 years). I’m also surprised that there was no intervention by the moderator of the discussion.

Many members of the astrophysics community have worked very hard to ensure that conference talks, seminars and panel discussions (whether in person or virtual) are conducted in a collegiate and cooperative manner. I don’t think Loeb is setting a good example in this clip, especially for someone who is an experienced former Department Chair. We all have strong feelings about certain things, but there’s no need to adopt such an aggressive tone. No wonder so many people find academia a toxic environment.