All Activities

Giant planets

The atmospheres of the giant planets exhibit some of the most striking dynamical phenomena in the Solar System such as multiple vibrant jet-streams, Earth-sized vortices and strong equatorial superrotation.  As part of NASA's Juno science team, we are exploring fundamental questions regarding the dynamics of Jupiter's atmosphere and interior, such as the depth of the zonal jets, the structure of the polar vortices, the 3D structure of the Great Red Spot, the origin of the equatorial supper rotation, and the interaction of the deep flow with the magnetic field. In addition, we study the mechanisms driving and maintaining the multiple jets on Jupiter and Saturn, and the structure and depth of the flows on Uranus and Neptune. We are also part of the JUICE mission to Jupiter and its Icy moons, to be launched in 2022, where we are leading the radio occulations and atmospheric science experiment.

Leading researcher: Yohai Kaspi

Planet Formation and Evolution

Spacecraft exploration of the solar system unveils a diversity of planetary objects with surprising properties.  We seek to understand the stages of evolution of planetary bodies, from their formation, shaping by giant impacts, origin of their magnetic fields to the processes that sculpt their appearance today.  Using recent orbiter and rover observations, we decipher the history of climate interactions recorded in the geology (on Mars), characterize the distribution of water in its various forms near the surface (on Mars and the Moon), and probe the depths of other surprising phenomena (such as the methane lakes on Titan).

Leading researcher: Oded Aharonson

Evolution of planetary climate and chemistry

Over its lifetime, Earth has transitioned from a planet shrouded by a thick primordial hydrogen-rich atmosphere, with lifeless early oceans of uncertain chemical composition, to a planet surrounded by a N2-O2 atmosphere, with a generally mild climate and a diverse biosphere. Earth’s two nearest neighbors, Venus and Mars, experienced very different histories. On Venus, a runaway greenhouse effect resulted in the loss of all liquid water, and volcanic CO2 accumulated to form an atmosphere about 100 times thicker than Earth’s, which sustains surface temperatures of almost 500°C. On Mars, waning volcanic activity and the absence of a magnetic field led to the loss of the atmospheric CO2 greenhouse. Consequently, all of Mars’ water is locked up in ice on the surface and in the subsurface, the atmospheric thickness is less than 1% Earth’s, and the global average surface temperature is about –60°C.

Understanding these fundamental differences in atmospheric and climatic evolution of Earth and its nearest neighbors forms the basis of a general framework to understand the co-evolution of planetary atmospheres and climate, relevant to other solar-system bodies and to the growing number of detected rocky extrasolar planets. As we cannot directly observe planetary history, we rely on information encoded in the chemical and isotopic composition of sedimentary rocks, as well as their morphology and texture. To extract this information, we develop an understanding of the processes responsible for generating chemical and isotopic signals, the processes that lead to their preservation in the rock record, and those that alter the original signals to yield the observed chemical and isotopic composition of sedimentary rocks. We decode these signals by combining geochemical and geological observations, laboratory experiments, and models of variable sophistication.

Leading researcher: Itay Halevi


The discovery of exoplanets represents a fundamental intellectual leap humanity has made in recent decades. From speculation and imagination, we have entered an era of detection and characterization of planets orbiting other stars.   We develop advanced algorithms and use data from space-borne telescopes to sensitively detect and measure the physical properties of exoplanets, which in turn shed light on their possible nature and composition. Innovative dynamical tools reveal rich gravitational interactions within exotic planetary systems.

Leading researcher: Oded Aharonson


The recent discoveries of terrestrial exoplanets and super-Earths extending over a broad range of orbital and physical parameters suggest that these planets will span a wide range of climatic regimes. Characterization of the atmospheres of warm super-Earths has already begun and will be extended to smaller and more distant planets over the coming decade. The habitability of these worlds may be strongly affected by their three-dimensional atmospheric circulation regimes, since the global climate feedbacks that control the inner and outer edges of the habitable zone—including transitions to Snowball-like states and runaway-greenhouse feedbacks—depend on the equator-to-pole temperature differences, patterns of relative humidity, and other aspects of the dynamics. We use general circulation models in order to study the range of possible climates and how the climate depends on parameters such as rotation rate, orbital period, distance to parent star, obliquity, atmospheric mass, gravitational acceleration, radius, opacity etc.

Leading researcher: Yohai Kaspi


Verification of exoplanet candidates detected with the LAST array: a major goal of the new LAST telescope array being deployed in the Negev is to discover planets around white dwarf stars using the transit method; this is feasible since the size of planets is similar to the size of white dwarfs, so the expected eclipse depth is ~0.5, feasible with standard photometric accuracy. Using a new data archive, potential planets detected with LAST could be verified using 6 years of all-sky data.

Leading researcher: Avishay Gal-Yam

Solar system small bodies

Small bodies in the Solar System are primordial relics from the formation of our planetary system, and they allow us to study the formation and evolution of our own Solar System and planetary systems in general. My group conducts several studies including the characterization of small bodies in the Kuiper belt, searching for the yet unseen Oort cloud, and the study of binary asteroids. Among the tools we are using is the Weizmann Fast Astronomical Survey Telescope (W-FAST), and the under construction Large Array Survey Telescope (LAST).

Leading researcher: Eran Ofek

An extensive search for rotating asteroids: we use the all-sky, multi-visit observing strategy to study rotating asteroids in the solar system. Rotation manifests as periodic photometric variation (due to the non-spherical shape of these bodies as well as albedo variations). Measuring the rotation periods and understanding the rotation velocity distribution within the population is important in order to constrain the material strength of asteroids.

Leading researcher: Avishay Gal-Yam

Terrestrial atmospheres

Weather on Earth, and other terrestrial planets, is driven by processes interacting over a range of scales, from planetary-wide down to regional and to the micro-scale. Understanding these interactions and representing them accurately in numerical weather prediction models are key for skillful weather forecasts. We focus on process understanding of extratropical weather systems, their interaction with planetary-scale waves on the one hand, and with synoptic and meso-scale phenomena on the other. By using the wealth of observations and model simulations we aim to understand the interactions giving rise to extreme weather phenomena, their impact and predictability.

Leading researcher: Shira Raveh-Rubin


By transferring energy across longitudes and latitudes large-scale climate phenomena play a central role in the distribution of the climate zones on terrestrial planets. Motivated by the climate impacts of large-scale processes, we investigate Earth's past and future large-scale climate responses to both anthropogenic and natural forcings. Our goal is to elucidate the mechanisms underlying the changes in the large-scale climate, by investigating climate model simulations, using our theoretical understanding on the thermodynamic and dynamic states of the climate system. Given the adverse climate impacts of anthropogenic emissions, we hope that improving our physical understanding on human-caused climate change signals will allow policymakers better mitigation and adaptation options in coming decades.

Leading researcher: Rei Chemke


A key difference between classic 3D turbulence and atmospheric (geostrophic) turbulence is that energy cascades to large scales rather than to the small scales, and as a consequence coherent features such as vortices and jets form. These play a key role in shaping terrestrial planet climates. The rotation rate of a planet affect several fundamental scales that emerge such as the Rossby and Rhines scales. How these relate to the scales where energy enters from baroclinic or barotropic processes and the scales emerging from the planetary properties shape the resulting dynamics. Our focus is on how the turbulence shapes the large scale dynamics observed on different planets. Specifically we focus on eddy-driven jets which are shaped by the eddy-eddy and eddy-mean interaction, and depend on the relative relations between these different length scales.

Leading researcher: Yohai Kaspi