PICS Seminar: Sam Birch (Cornell)

Sam Birch (Cornell)
Tuesday, April 17, 2018 - 12:30pm to 1:30pm

Sediment Transport and Landscape Evolution on Comet 67P/Churyumov-Gerasimenko

Comets are the oldest objects in our solar system and typify the remnant, unprocessed materials from which all the larger planets and moons were constructed. Consequently, they represent a window into the initial conditions that proved favorable for the formation of the Earth and life as we know it. With Rosetta’s rendezvous of 67P in the summer of 2014, we now have a dataset that permits access to the spatial scales where the processes relevant to small body evolution can be directly observed. These observations have allowed for detailed analyses of morphologies down to the meter scale across the entire nucleus, and have provided a long temporal data set with which to search for changes on the surface, important observations that have given us the opportunity to watch how a comet erodes. Numerical landscape evolution modeling offers the possibility to tie Rosetta’s many observations to the fundamental physics that drives the observed changes, and ultimately determine whether 67P evolves gradually, through its jets, or stochastically through large outburst events. In this talk, I will detail our work on 67P, including our discovery and analysis of observed surface transients, and our associated numerical simulations. Using observed transients to tune our simulation, we can constrain the rates of landscape evolution and the total erosional exhumation on 67P. This allows us to directly answer the question as to how its surface evolved despite the current apparent low levels of observed activity.

Sam is a research associate in Cornell’s Astronomy Department working with Alexander Hayes. His research focuses on understanding the evolution of the surfaces both Titan and Comet 67P, both of which are being actively eroded to form new morphologies today, and at rates quick enough to make their surfaces among the youngest we observe in the solar system. These processes, while often familiar, are also sufficiently different that they reveal a variety of new mechanisms that can modify a planetary surface. To understand these processes, Sam use a combination of qualitative and numerical techniques. Spacecraft image data acquired of these surfaces allows for description and mapping of their surface morphologies, which allows for the construction of qualitative models as to their surface evolution. He then use these models to develop numerical tests of landscape evolution of their surfaces to more thoroughly understand the rates and scales over which these processes occur, and how they govern the overall landscape evolution. 

About the Series

The MIT Planetary Lunch Colloquium Series [PlCS] is a weekly seminar series organized within the EAPS department. Colloquia topics span the range of research interests of the department's planetary sciences research program. The seminars usually take place on Tuesdays from 12-1:30 pm in 54-517 unless otherwise noted (term-time only). Speakers include members of the MIT community and visitors. Talks are intended to appeal to graduate students, postdocs, research scientists, and faculty with a background in planetary science. A light lunch is provided.