by Victor Davis, Program Chair

The Universe in a Computer
The December, 2025 meeting of the AAAP will take place in Peyton Hall on the campus of Princeton University on Tuesday, December 9^th at 7:30 PM. As usual, the meeting is open to AAAP members and the public. Participants can join the meeting in-person at Peyton Hall or log in to the Zoom session as early as 7:00 pm to chat informally before the meeting begins.

The evening’s guest speaker, Jiaxuan Li, is a fourth-year graduate student pursuing a PhD in astrophysics at Princeton University. Recently, along with Sihao Cheng at the Institute for Advanced Study and fellow Princeton graduate student Eritas Yang, Li and his team discovered a trans-Neptunian object in an unusually wide orbit that challenges the Planet 9 hypothesis.

Options for Attending the Meeting
You may choose to attend the meeting in person or participate via Zoom or YouTube as we’ve been doing for the past few years. (See How to Participate below for details). Due to security concerns, if you log in before the host has set up internet connectivity in Peyton Hall, you may need to wait in the Waiting Room for a few minutes until the host is prepared to admit you into the meeting. You’ll need to unmute yourself to make comments or ask questions. It’s polite, though not required, for you to enable your camera so other participants can see you. The meeting will be recorded and edited for posting to our club’s YouTube channel.

Join us for our “meet the speaker” dinner
Mr. Li will be joining us for our traditional “meet the speaker” dinner at Winberie’s before the meeting. Our reservation is for 5:45 pm Tuesday, December 9th. Please contact the Program Chair if you plan to attend.

Here’s the anticipated agenda for November 11th, 2025’s monthly meeting of the AAAP:

Getting to Peyton Hall
The parking lots across the street (Ivy Lane) from Peyton Hall are now construction sites, unavailable for parking. We’ve been advised by the administration of the astrophysics department that we should park in the new enclosed parking garage off Fitzrandolph street and walk around the stadium and athletic fields. Here’s a map of the campus and walking routes from the parking garage to Peyton Hall. The map shows the recently completed East Garage. Not shown is an access road Sweet Gum that connects from Faculty Road to an entrance at the lower left corner of the garage. Stadium Road connects from Fitzrandolph Road to another entrance at the opposite corner (and higher level) of the garage. It’s about a 10-15 minute walk from the parking garage to Peyton Hall.

A Newly-discovered Distant World: The Dwarf Planet Candidate 2017 OF201
Astronomers Jiaxuan Li and Eritas Yang (graduate students at Princeton University’s Department of Astrophysics) and Sihao Chang (Institute for Advanced Study) identified a remarkable new world in the far outer Solar System: a dwarf-planet candidate named 2017 OF201, currently more than 90 times farther from the Sun than Earth. By combining observations spanning the past two decades, the team showed that it follows an enormous, elongated orbit that reaches deep into the inner Oort Cloud. With an estimated diameter of roughly 700 km, it ranks among the largest known objects on such distant orbits and is very likely a dwarf planet. Its extreme trajectory hints at a far larger, still-hidden population of similar bodies that may collectively contain about 1% of Earth’s mass. Intriguingly, its orbit does not share the clustering seen in some other remote objects—a pattern often cited as evidence for a possible “Planet Nine.” Continued searches for distant Solar System bodies will help unveil the true structure and diversity of this unexplored frontier.

Jiaxuan Li
Jiaxuan Li grew up in Dingxi, Gansu Province, a small town in northwestern China. An amateur astronomer since elementary school, Li participated in several international competitions, including the Chinese National Astronomy Olympiad. He earned his undergraduate degree in Astrophysics at Peking University, then came to Princeton to pursue his PhD. He’s interested in a variety of topics in astronomy and astrophysics, mainly on galaxy formation and evolution, low surface brightness astrophysics, sky surveys, machine learning, and instrumentation. His current research examines the formation and evolution of dwarf galaxies through both careful observation and numerical simulations.

How to Participate (Links)
Zoom & YouTube Live
Amateur Astronomers Association of Princeton is inviting you to a scheduled Zoom meeting.
Time: December 9, 2025 07:00 PM Eastern Time (US and Canada)

Join Zoom Meeting
Topic: December 9,2025 AAAP Meeting-Prof. Cheng, Jiaxuan Li, Eritas Yang, Dwarf Planet Candidate
Time: December 9, 2025 07:00 PM Eastern Time (US and Canada)
Meeting ID: 824 8572 5475
Passcode: 136481
Join instructions


….
Click the above icons for Zoom and YouTube

AAAP’s library of monthly meetings is available on the club’s YouTube channel. November’s edited meeting featuring a presentation “The Universe in a Computer” by Princeton University astrophysicist Dr. Romain Teyssier can be viewed at https://youtu.be/lqs7znI1nEg

A look ahead at future guest speakers:

Date	Featured Speaker	Topic
Jan. 13, 2026	Jamie Rankin Research Scholar Princeton University jsrankin@princeton.edu	Dr. Rankin will talk about her work as Project Manager for the Voyagers’ last gasp; observing the interaction between the solar and interstellar media as these spacecraft (still transmitting data since their launch in 1977!) leave the Sun’s influence. She’ll also speak more broadly about exciting things about how the Sun interacts with the interstellar medium and about the Princeton-led Interstellar Mapping and Acceleration Probe (IMAP) mission launched this past September.   Dr. Rankin’s role is described in a recent book “The Clock in the Sun” by Pierre Sokolsky.
Feb. 12, 2026	John Bochanski Associate Professor and Chair, Department of Computer Science and Physics Rider University	Dr. Bochanski has been connected to the Legacy Survey of Space and Time Discovery Alliance since his graduate studies more than 15 years ago. Rider University is part of the global effort using the Vera C. Rubin Observatory to map the optical sky. The Rubin observatory (formerly the Large Synoptic Survey Telescope, LSST) will capture more information about our Universe than all other optical telescopes throughout history combined. The observatory released its first images this past June. Prof. Bochanski will discuss the project’s history and discoveries.   Thanks to Nick Mellis for suggesting this speaker.
Mar. 10, 2026	Robert Vanderbei Emeritus Professor in the Department of Operations Research and Financial Engineering Princeton University   AAAP Assistant Director rvdb@princeton.edu	Prof.  Bob Vanderbei will talk about stellar dynamics.
Apr. 14, 2026	Astronomer Berkeley SETI Research Center astrobrianlacki@gmail.com	September’s guest speaker Edwin Turner voiced his less-than-optimistic view of the prospect for discovering extraterrestrial life. Dr. Lacki, affiliated with Breakthrough Listen, a SETI initiative, recently submitted for publication a catalog of objects he and his team consider to be realistic and valuable observation targets. Dr. Lacki will talk about the catalog, “One of Everything: The Breakthrough Listen Exotica Catalog” and opine on the prospects of finding technosignatures and extraterrestrial intelligence. Thanks to Ira Polans for suggesting this speaker.
May 12, 2026	John Horgan Science Writer horganism3@gmail.com	Mr. Horgan will discuss his controversial 1996 book The End of Science, in which he argues that pure science, defined as “the primordial human quest to understand the universe and our place in it,” may be coming to an end. Horgan claims that science will not achieve insights into nature as profound as evolution by natural selection, the double helix, the Big Bang, relativity theory or quantum mechanics. In the future, he suggests, scientists will refine, extend and apply this pre-existing knowledge but will not achieve any more great “revolutions or revelations.” Shades of Auguste Comte, perhaps?   We expect to have copies of his book(s) for sale for the author to sign at the conclusion of his presentation.   Thanks to Rex Parker for engaging this speaker.
Jun 9, 2026	Jacob Hamer Assistant Curator NJ State Museum Planetarium Jacob.Hamer@sos.nj.gov	As usual, the June meeting will take place in the planetarium at the NJ State Museum in Trenton. There will be no streaming of this live-only sky show and PowerPoint presentation. Topic to be announced.
Sep. 8, 2026	Michael DiMario Chair of AAAP’s Astro-imaging SIG K2mjd@outlook.com	Dr. DiMario will present a primer on astro-imaging.
Oct. 13, 2026	Becka Phillipson Assistant Professor in Physics Villanova University	Prof. Phillipson, originally scheduled to be October 2025’s guest speaker, is an unconfirmed prospect to try again in 2026.

As always, members’ comments and suggestions are gratefully accepted and much appreciated. Thanks to Ira Polans and Dave Skitt for setting up the online links and connecting the meeting to the world outside Peyton Hall.

victor.davis@verizon.net
program@princetonastronomers.org
(908) 581-1780 cell