Seminar and Journal Club

Derek Fox, Penn State
1/28/21
Zoom Recording

Abstract:
I will review the Anthropic Principle of Brandon Carter (FRS), Steven Weinberg, and others, as an argument originating in astrophysics that has recently risen to new heights of popularity among philosophers thanks to Nick Bostrom. I will then discuss Carter’s Doomsday Argument as a significant extension of this idea of “anthropic selection,” with potentially enormous import, which ultimately can be judged a red herring. Finally, I will discuss Carter’s “Hard Steps” argument regarding the origins and evolution of life on Earth, and its recent application to the question of whether M-dwarf stars are likely to host habitable planets and technologically accomplished civilizations.

Evan Sneed
December 3, 2020
Zoom recording

Evan Sneed presented their final project for the Astro 576 SETI class. While many SETI searches look for omnidirectional signals, this search is motivated by the Deep Space Network and seeks to eavesdrop on similar star-system level communication networks beyond our own. If a signal is sent from one planet to another in the same system, we may be able to pick them up when at the proper alignment. Using planetplanet to predict occultation timings in the TRAPPIST-1 system, they’re working toward planning a radio observation program.

Sofia Sheikh
November 12, 2020
Zoom Recording

Sofia Sheikh presented an update on the data analysis from the 2018 PSU SETI course project. The group used the Green Bank Telescope to search for radio signals from transitting planets, proposing transits as an exoplanetary Schelling Point. They use turboSETI to search for signals in the data in a wide range of drift rates, getting ~400,000 event hits. To sort through this very large data set and get rid of the radio-frequency interference events, they use both people power and machine power. The PSU undergraduate Pulsar Search Collaboratory makes up the community-based science component, and they are sorting through the events for potential candidates by eye. Sofia et al. are also developing a machine learning method to sort the events with unsupervised clustering.

Drew Miles
October 22, 2020
Zoom Recording

Abstract:
Though the history of SETI has been dominated by searches at wavelengths from visible to radio, recent advancements in UV and X-ray technology and concepts proposed for future missions could help extend SETI’s coverage into shorter wavelengths. In this talk I will discuss UV and X-ray diffraction grating development at Penn State University and how instruments based on these gratings could be applied to SETI projects. I will also discuss several hypothetical high-energy sources of ETI signals, including X-ray photons as information carriers, the manipulation of naturally occurring X-ray emission, and artificial spectral signatures at UV wavelengths. Lastly, I will allow time for open discussion on the feasibility of the presented concepts and other potential high(er)-energy SETI applications.

Vishal Gajjar
October 15, 2020
Zoom Recording

Abstract:
The discovery of the ubiquity of habitable extrasolar planets, combined with revolutionary advances in instrumentation and observational capabilities, have ushered in a renaissance in the millennia-old quest to answer our most profound question about the Universe and our place within it – Are we alone? The recent discovery of phosphine gas in the clouds of Venus has further suggested that life on Earth might not be unique. The Breakthrough Listen Initiative announced in July 2015 as a 10-year 100M USD program is the most comprehensive effort in history to quantify the distribution of advanced, technologically capable life in the universe. Our goal is to survey 1 million nearby stars, 100 nearby galaxies, the entire Galactic plane, and the Galactic center. To achieve this, we have deployed a 64-node GPU-equipped compute cluster at the Green Bank Telescope in West Virginia and a 26-node compute cluster at the Parkes telescope in Australia. We are in the process of deploying a 128-node GPU-equipped and NVME SSD enabled compute cluster for real-time signal detection for commensal observations with the MeerKAT telescope in South Africa. In this talk, I outline the status of the on-going observing campaign with these primary observing facilities, as well as planned activities with these instruments over the next few years. I will highlight some of the novel analysis techniques we are bringing to bear on multi-petabyte data sets, including machine learning tools we are deploying to search for a broader range of technosignatures than was previously possible.

Jason Wright
October 8, 2020
Zoom recording

Abstract:
In SETI, when searching for “beacons”—transmissions intended for us and meant to get our attention—one must guess the appropriate frequency to search by considering what frequencies would be universally obvious to other species. This is a well known concept in game theory, where such solutions to a non-communicative cooperative game (such as a mutual search) are called “Schelling points.” It is noteworthy, therefore, that when developing his eponymous units, Planck called them “natural” because they “remain meaningful for all times and also for extraterrestrial and non-human cultures.”
I discuss how one might apply Planck’s suggestion in the context of Schelling points in SETI with a “Planck Frequency Comb,” constructed by multiplying the Planck energy by integer powers of the fine structure constant. This comb includes a small number of frequencies in regions of the electromagnetic spectrum where laser and radio SETI typically operates.
I will discuss the search implications of this line of reasoning, including the possibility of multi-modal communication, the anthropocentrism and arbitrariness of the comb, and the utility of “magic frequencies” in an era of broadband high resolution radio spectroscopy.

Relevant pubication: Planck Frequencies as Schelling Points in SETI – Jason Wright

Shubham Kanodia
October 1, 2020
Zoom recording

Abstract:
Originally proposed in the 1980s by Jill Tarter, the 9 dimensional cosmic haystack attempts to parameterize the various dimensions in the searches for technosignatures. By doing so, one can quantify the fraction of this high dimensional volume that has been searched; where we can rule out the presence of technosignatures. I’ll discuss our development of one such haystack to quantify the search for radio technosignatures. Finally, I’ll place the Fermi paradox in context of the amount of searching that has been done in the radio.

Relevant publication: How Much SETI Has Been Done? Finding Needles in the n-dimensional Cosmic Haystack – Jason Wright, Shubham Kanodia, Emily Lubar

Jill Tarter
September 24, 2020
Zoom recording

Meeting Summary:

This seminar doubled as a day of class for the Astro 576: The Search for Extraterrestrial Intelligence class. Dr. Jill Tarter described the motivation for the search for technosignatures in context with the search for biosignatures. She described the many approaches that have been and are currently taken to detect technology beyond our own. The vastness of possibilities evokes the metaphor of a needle in the cosmic haystack. She explained current observational SETI work and plans to further develop these in the future. Lastly, Jill provided some interesting project ideas for Astro 576 students. We are grateful for her appearance as our first external speaker and her contribution to our class.

Jason Wright
September 17, 2020
Zoom recording

Abstract:
In 2014 we launched the Ĝ search for extraterrestrial intelligence with funds from the Templeton Foundation to search for Dyson spheres within and beyond the Galaxy.  I will review the science behind Dyson spheres and how they can be detected, and describe the Ĝ search for them in 100,000 galaxies using data from WISE.  I will conclude by outlining a plan for the next phase of the Ĝ search using spatially resolved multi-band imagery of galaxies to distinguish waste heat from Dyson spheres from other sources of infrared emission in galaxies.