Seminars for Scientists

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Review of the SORCE mission accomplishments.

What are Coronal Mass Ejections (CMEs) and why are they important? CMEs have typically been observed in white light near the Sun by coronagraphs, recently those on the SOHO LASCO and STEREO missions. I will review our current knowledge of CMEs including their coronal and heliospheric properties. I will discuss their importance for space weather,… Read more »

The analysis of different CDA subsystems data, acquired since SOI, reveals that the Saturnian system is permanently crossed by dust grains originating from the Interplanetary medium, as well as from the neighboring interstellar medium surrounding the Solar System. We observe two main types of particles: on the one hand, those with low injection velocity with… Read more »

Observations of the neutral thermosphere during the extended 2008-2009 solar minimum period found anomalously low density, implying that thermospheric temperature was also lower than usual for solar minimum.  A variety of solar measurements and proxies indicated commensurately lower levels of solar extreme-ultraviolet (EUV) irradiance, although there remains considerable uncertainty concerning the magnitude of the reduction…. Read more »

It has now been 50 years since NASA had launched its first successful planetary spacecraft. Virtually everything we knew about the solar system, up to that time, came from ground-based telescope observations or the analysis of meteorites. NASA has literally invented planetary science that has allowed us to reveal many of the wonders of the… Read more »

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no seminar

The global, long-term temperature variations curve constructed  from Antarctica ice-core project data is decomposed  into two parts: the “auto-oscillation” part and the “convective” part. These two parts represent two different but tightly interconnected processes and, correspondingly, two different types of self-organization of the Earth’s climate system. The self-organization in the “auto-oscillation” component is the non-linear reaction of the Earth’s… Read more »

The global, long-term temperature variations curve constructed  from Antarctica ice-core project data is decomposed  into two parts: the “auto-oscillation” part and the “convective” part. These two parts represent two different but tightly interconnected processes and, correspondingly, two different types of self-organization of the Earth’s climate system. The self-organization in the “auto-oscillation” component is the non-linear reaction of the Earth’s… Read more »

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Spring Break – No Seminar

The MESSENGER spacecraft has been in orbit around Mercury since March 2011. Magnetic field measurements taken by MESSENGER have yielded definitive evidence for a weak dipolar internal field, generated by dynamo action in Mercury’s core.  The weak field, together with Mercury’s proximity to the sun, mean that Mercury’s magnetosphere is small and highly dynamic, responding… Read more »

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The Acceleration, Reconnection, Turbulence, and Electrodynamics of Moon’s Interaction with the Sun (ARTEMIS) mission is a dual-probe plasma and fields mission currently in orbit around the Moon. Among its many scientific objectives is to study pick-up ions at the Moon, with the goal of understanding both pick-up ion production mechanisms, such as photo-ionization, sputtering and… Read more »

The radial motions of small moons in Saturn’s rings can provide excellent tests of satellite  migration models.  In theory, radial drifts arise from a torque exchange between these moons and ring particles.  We predict that moons of radius 2–20 km in the A ring are massive enough to clear a gap in the ring, yet… Read more »

An important part of assessing present and past habitability of Mars is to understand and characterize “life limiting factors” on the surface, such as the radiation environment. Radiation exposure is also a major concern for future human missions and characterizing the radiation environment, both on the surface of Mars and inside the spacecraft during the… Read more »

We present laboratory measurement of vapor produced by simulated micrometeoroid bombardment, with direct relevance to the study of surface-bounded exospheres around the Moon, Mercury and other solar system bodies. Exciting new in-situ observations from MESSENGER at Mercury, and the anticipation of results from LADEE at the Moon, have highlighted the uncertainty surrounding the role of… Read more »

Comet ISON (C/2012 S1) is a recently discovered sungrazing comet that will reach perihelion in November 2013 less than 2 solar radii from the Sun’s photosphere. While it is still more than 3.5 AU from the Sun and is currently relatively faint, it is predicted to become very bright near perihelion and has therefore gained… Read more »