Planetary Science Directorate


Upcoming SwRI Boulder Colloquia

Colloquia are normally on Tuesdays at 11:00 am in the 4th-floor conference room, except as indicated below in bold text.
Show previous colloquia
Suggest a New Speaker

For questions or suggestions for speakers, please contact the SwRI colloquium organizers:
Raluca Rufu, 303-226-0879 or raluca(at)
Julien Salmon, 720-208-7203 or julien(at)
Kelsi Singer, 303-226-5910 or ksinger(at)
Sierra Ferguson, sierra.ferguson(at)
Rogerio Deienno, rogerio.deienno(at)
Sam Van Kooten, 303-226-5909 or svankooten(at)

To be added to the SwRI Boulder Colloquia email list, please contact Kelsi Singer, ksinger(at)

Suggest a New Speaker HERE
Tue Mar 5, 2024
In CR4+ webex
11:00 am Michael Chaffin University of Colorado Sweating the Small Stuff: Photochemical Hydrogen Loss from Venus and the Fate of an Earth-like Water Inventory
This will be a hybrid colloquium - dial in will be sent out closer to the event to the colloquium e-mail list
Abstract: Dry accretion and/or early rapid loss cannot adequately explain the extremely dry state of present-day Venus: still-active nonthermal hydrogen loss mechanisms are required. Accretion differences are inadequate because the feeding zones of the Earth and Venus were likely very similar, so that Venus must have had a similar initial hydration state as the Earth. Rapid loss via fluid outflow of hydrogen from a steam-dominated atmosphere can remove a large fraction of this initial inventory, but it cannot explain the D/H enrichment of Venus water, and leaves behind a large remnant water inventory that would still be present today if not for photochemical H loss from the upper atmosphere to space. With new photochemical modeling and reinterpretation of Pioneer Venus Orbiter data, we show that the dominant H loss process at present is HCO+ dissociative recombination, a process overlooked in previous studies. Loss via this channel is nearly equal to that provided by all other processes combined, doubling the estimated H loss rate from the present-day atmosphere. Faster escape provides more room for ocean scenarios early in Venus history if the atmospheric water inventory is still evolving, and implies a doubled flux of water to the atmosphere from volcanic outgassing and/or impact delivery in an atmospheric steady state. We will discuss the surface, atmospheric, and solar processes that drive the present water loss rate in the context of past and planned missions, and argue that future upper atmosphere measurements are essential for understanding the evolution of Venus to its present state.
Thu Mar 14, 202411:00 am Kathy Reeves Harvard CfA TBD
Tue Mar 19, 2024
In CR4+ webex
11:00 am Robert Citron University of California, Davis Effects of Large Impacts on Early Planetary Evolution
Tue Mar 26, 2024
In CR4+ webex
11:00 am Ariel Cukierman Caltech SPHEREx: An All-Sky Spectral Survey
Thu Apr 4, 202411:00 am Martin Van Kranendonk Curtin University (Australia) TBD
Tue Apr 9, 202411:00 am Rachel Slank LPI TBD
Thu Apr 11, 202411:00 am Ren Ikeya Kobe University (Japan) TBD
Tue Apr 16, 2024
In CR4+ webex
11:00 am Sean Raymond Laboratoire d'Astrophysique de Bordeaux TBD
Mon Apr 22, 2024
In CR4+ webex
11:00 am John O’Meara Keck TBD
Tue Apr 23, 2024
In CR4+ webex
11:00 am Adolfo Carvalho California Institute of Technology Planet-forming environments in protoplanetary disks
Tue Apr 30, 202411:00 am Andy López-Oquendo Northern Arizona University TBD
Thu Aug 22, 202411:00 am Barbara Thompson NASA Goddard Next generation communication challenges