The Physical World
Young Scientists, Old Universe
Astrophysics and space researchers at the Weizmann Institute of Science aim to answer some of the biggest questions in the universe. They want to learn how stars explode, how planets form, and whether conditions on other planets could allow the emergence of life. To explore the history and environments of planets and other celestial bodies, they use observations and measurements from spacecrafts, satellites, and telescopes, as well as theoretical and numerical models and laboratory experiments. They're also taking on significant roles in national and international research teams and space missions.
Since 1987, several Institute scientists have been prominent participants in the international consortium that conducts experiments utilizing the Large Hadron Collider (LHC) at CERN (the European Laboratory for Particle Physics). They were involved in the landmark discovery of the Higgs boson, thought to be the particle that gives all the other elementary particles their mass. The LHC, which is underground near Geneva, Switzerland, is the largest, highest-energy particle accelerator ever built – and Weizmann scientists were there from the beginning.
Over the past several years, the Institute has considerably expanded its space and astrophysics research. For example, the Helen Kimmel Center for Planetary Science, launched in 2011, nurtures novel collaborations in topics such as planetary surface geology and geophysics and planetary atmospheres and climates. Currently, scientists at the Helen Kimmel Center are working with colleagues in the U.S., Israel, Canada, and India to design and build Israel's first research satellite. Known as the Ultraviolet Transient Explorer, it will carry an array of UV cameras capable of an unprecedentedly wide field-of-view survey in the ultraviolet region of the electromagnetic spectrum. Its purpose is to search for big cosmic events like supernovae and stellar disruptions caused by black holes. Whenever such a major event is detected, scientists on Earth will be alerted; they can then point more advanced spectrometers and other instruments at the location, thus capturing the lifetime of the phenomenon.
The Martin S. Kraar Observatory, which also began operation in 2011, is sited on top of the Koffler Particle Accelerator, the Institute's most famous – and recognizable, as it looks a bit like the cartoon beagle Snoopy, and indeed bears that nickname – landmark. While the Kraar Observatory was initially envisioned primarily as an educational tool, it has already been involved in several major scientific discoveries. For example, it was among the first observatories in the world to image the Type IIb supernova that occurred in nearby galaxy M51 in May 2011, also contributing data relating to the early phases of this event.
Another notable development is the recent recruitment of several talented young investigators who focus on Earth and planetary sciences:
Prof. Oded Aharonson studies the surfaces and environments of other planets. He serves as a scientific advisor, or co-investigator, on a number of space missions, including the Mars Exploration Rovers, the Lunar Orbiter Laser Altimeter and the Lunar Reconnaissance Orbiter, the Cassini Radar Science Team, and the Near Earth Asteroid Rendezvous (NEAR). Prior to joining the Department of Environmental Sciences and Energy Research in 2011, he was a professor at the California Institute of Technology (Caltech).
Dr. Itay Halevy's research focuses on the climate and geochemistry of Earth and other planets. He provided the first direct evidence that near-surface conditions on ancient Mars were wetter and warmer than the current climate. He has also provided insights about the amount of sulfur that cycled through Earth's early oceans, atmosphere, and land. Dr. Halevy completed a postdoctoral fellowship at Caltech and joined the Department of Environmental Sciences and Energy Research in 2011.
Dr. Yohai Kaspi is a member of NASA's science team for the Juno spacecraft mission to Jupiter, responsible for calculating the expected gravitational signal of the giant planet's atmospheric dynamics. On Earth, he studies regions of turbulent energy called storm tracks, which dominate atmospheric circulation in the mid-latitudes; understanding storm tracks is essential to understanding Earth's climate as a whole. Following a postdoctoral fellowship at Caltech, he joined the Department of Environmental Sciences and Energy Research in 2011.
Dr. Boaz Katz studies how planetary systems form and evolve. He investigates a class of unexplained planets called "hot Jupiters" that are as massive as Jupiter and orbit very close to their planet stars. He is also exploring the origins of cosmic rays and collaborating with research groups at the Institute that work to detect – and immediately follow up – transient planetary events such as supernovae. He joined the Department of Particle Physics and Astrophysics in 2013 after completing a postdoctoral fellowship at the Institute for Advanced Study in Princeton, New Jersey.
Another young scientist who has been at the Weizmann Institute somewhat longer, Prof. Avishay Gal-Yam conducts groundbreaking research on supernovas. In the first observation of its kind, Prof. Gal-Yam and colleagues at San Diego State University were able to directly track the process of a massive star exploding and turning into a black hole. The scientists located the star when it was on the verge of exploding using the W.M. Keck Telescope on Mauna Kea in Hawaii and the Hubble Space Telescope. At the time, astrophysicists generally maintained that very large stars do not explode. However, as Prof. Gal-Yam states, during this research he and his group "came to realize that stars of at least 200 solar masses do exist in our current universe, and that they end their lives with the most energetic explosions in the universe." They published a paper in the journal Nature on their findings in 2009, and Prof. Gal-Yam wrote extensively on the project in Scientific American in 2012.
Prof. Gal-Yam and his research team also recently discovered two new types of supernova explosions. One very faint type – that occurs when helium detonates – appears to produce significantly more calcium and titanium than was thought possible, and probably contributes a significant portion of these critical elements in the cosmos. The second new type is called pair-production supernovae. These are 10 to 100 times more powerful than any previously known type and may be the first supernova explosions to have occurred after the Big Bang.
Before joining the Department of Particle Physics and Astrophysics in 2007, Prof. Gal-Yam received NASA’s prestigious Hubble postdoctoral fellowship and spent four years conducting research at Caltech. With the aid of research satellites and giant telescopes, he is now surveying previously unexplored areas of the universe so that he can identify new supernovae and illuminate the physical processes involved in these explosions.
The challenges of space research are extraordinary – vast distances; extreme conditions; limited, sometimes rare windows of opportunity to make observations; long time scales between launching probes and reaping the first data; no room for error in the calculations made for probes, satellites, or other space-surveying equipment; and the uncertainties and difficulties inherent in exploring barely known regions far from Earth.
These challenges, however, tend to attract some of the most inventive, imaginative thinkers in science. As the Weizmann Institute continues to grow its space and astrophysics research programs, Prof. Gal-Yam and his new colleagues are poised to continue making extraordinary discoveries and revealing new information about our planet and the universe around us, perhaps even answering some of humanity's oldest questions, such as "who are we?", "why are we here?", and maybe even – who knows? – "are we alone?"
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