From the Program Director

by Victor Davis

The April 2021 meeting of the AAAP will take place (virtually) on Tuesday, April 13th at 7:30 PM. (See How to Join the April Meeting below for details). This meeting is open to AAAP members and the general public. Due to the number of possible attendees, we will use the Waiting Room. This means when you login into Zoom you will not be taken directly to the meeting. The waiting room will be opened at 7:00 PM. Prior to the meeting start time (7:30 PM) you may socialize with others in the waiting room. The meeting room has a capacity of 100 people.

For the Q&A session, you may ask your question using chat or may unmute yourself and ask your question directly to the speaker. To address background noise issues, we are going to follow the rules in the table below regarding audio. If you are not speaking, please remember to mute yourself. You are encouraged, but not required to turn your video on.

Meeting EventParticipant Can Speak?Participant Can Self-Unmute?
Director Rex’s General RemarksYesYes
Program Chair Victor’s  Speaker IntroductionYesYes
Speaker PresentationNoNo
Q&A SessionStart All on MuteYes                                    
5-minute bio break YesYes
Journal Club presentationStart All on MuteNo
Business MeetingStart All on MuteYes
Director’s closing remarksNoNo
Only the Business part of the meeting will be locked.

Featured Speaker: Dr. Alexandra Krull Davatzes is an Associate Professor in the Department of Earth and Environmental Science at Temple University. Her presentation is entitled,  “Precambrian Meteor Impacts and Implications for Early Earth.

About 65 million years ago, at the end of the Cretaceous period, an asteroid impact initiated a mass extinction that, among other things, is famously thought to have ended the reign of the dinosaurs. Less well known are even larger impact events that took place between 3.5 to 2.3 billion years ago. Prof. Davatzes will talk about 18 spherule beds identified in rocks in western Australia and South Africa that represent 13 separate impact events that would have local, regional, and global effects lasting seconds to decades after the impacts. Particularly large impacts, such as those in the Precambrian, may have resulted in: (1) earthquakes, large-scale tsunamis, thermal effects, and distal ejecta reentry; (2) ejection of rock vapor, dust, soot, carbon dioxide, water vapor, methane, and sulfur oxides into the atmosphere, resulting in atmospheric heating and acid rain formation; (3) evaporation in the oceans, leading to destruction of shallow water ecosystems and to hot salty surface waters; and (4) delivery of elements essential to life or transient high oxygen concentration that might have led to biodiversification. In addition, discovery and confirmation of these impact layers is critical for our understanding of the rate of impacts to the early Earth and solar system. This is gaining importance as researchers revisit and redefine the concept of a Late Heavy Bombardment.

Prof. Davatzes’ interests are planetary geology, sedimentology, early Earth processes, and geoscience education. She earned her BA from Pomona College and her PhD from Stanford University. Before coming to Temple, Dr. Davatzes was a postdoctoral fellow at the NASA Ames Research Center, working with the Mars Reconnaissance Orbiter team. She received an NSF CAREER award to study meteor impacts and their effects on the early Earth and the evolution of life. Her field work takes her to the deserts of South Africa, western Australia, and southern California.

Dr. Davatzes collaborates with cognitive scientists to study spacial reasoning in the geosciences and machine learning in aerial drones. Her scholarly work has been published in a variety of journals, including Geology, Science, and Astrobiology. Dr. Davatzes is an associate editor for the Journal of Geoscience Education. In 2020, she received the Lindback Award for Distinguished Teaching at Temple University.

AAAP webcast:  This month’s AAAP meeting, beginning with Rex’s opening remarks and ending at the break before the business meeting, will be webcast live on YouTube and recorded for subsequent public access on AAAP’s YouTube channel. Be aware that your interactions during this segment, including questions to our guest speaker, may be recorded for posterity. Here is YouTube live link

Using Zoom: While we are, social distancing the AAAP Board has chosen to use Zoom for our meetings, based our belief that many members have already have used Zoom and its ease of learning. One of its great features is you can choose whether you want to install the software on your computer or use it within your browser.

How to Join the April Meeting: For the meeting, we are going to follow a simple two-step process:

  1. Please make sure you have Zoom installed on your computer. You do not need a Zoom account or need to create one to join the meeting. Nor are you required to use a webcam.
  2. Please visit our website for the link to the meeting
  3. This session will be recorded and saved on YouTube. Send me an email at if you have any concerns.

NOTE: We plan to open the meeting site 30 minutes to the 7:30 start time. This way you won’t have to rush to join the meeting. A maximum of 100 attendees can join the meeting.

More Information: The Zoom site has many training videos most are for people who are hosting a meeting. If you’re unsure how Zoom works you might want to view the videos on how to join a meeting or how to check your computer’s audio and video before the meeting.

We hope to make these short presentations a regular feature of our monthly meetings. If you are interested in presenting a topic of interest, please contact either or We’d like to keep our momentum going!

Upcoming Programs: Here’s a look ahead at upcoming guest speakers. We’re expecting to conduct virtual meetings for the remainder of this academic year. In an effort to turn necessity into a virtue, we’re casting our recruiting net a bit wider than usual, inviting speakers for whom a visit to Princeton would be impractical or inconvenient. Suggestions for guest speakers for September, 2021 and beyond are welcome.

May 11 – Alex Hayes: Prof. Hayes is an Associate Professor of Astronomy at Cornell University and Director of its Spacecraft Planetary Image Facility. He will speak on Ocean Worlds of the Outer Solar System, plus he will give a brief report on the Mars 2020 mission.

June 8 – Anna Schauer: Dr. Schauer, a new mother, is the NASA Hubble Fellow at the University of Texas at Austin. She leads the team researching what she’s nicknamed the Ultimately Large Telescope, a lunar liquid-mirror telescope that will aim at investigating First Star Formation.

WANTED: Members with interesting stories to tell.  As of this writing, no member has volunteered to offer up a brief story or presentation for Journal Club this month. During the past months, we’ve enjoyed interesting and informative talks from AAAP members, and we’d like to keep the momentum going! We hope to make these short presentations a regular feature of our monthly meetings. We’d like to know what members are doing or what members are thinking about in the broad range of topics encompassed by astronomy. A brief ten-minute (or so) presentation is a good way to introduce yourself and the topics you care about to the club membership. If you are interested in presenting a topic of interest, please contact either or

Looking forward to you joining us on Zoom or YouTube Live webcast at the April meeting!

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