Asteroid impact avoidance comprises the methods by which near-Earth objects (NEO) on a potential collision course with Earth could be diverted away, preventing destructive impact events. An impact by a sufficiently large asteroid or other NEOs would cause, depending on its impact location, massive tsunamis or multiple firestorms, and an impact winter caused by the sunlight-blocking effect of large quantities of pulverized rock dust and other debris placed into the stratosphere. A collision 66 million years ago between the Earth and an object approximately 10 kilometres wide is thought to have produced the Chicxulub crater and triggered the Cretaceous–Paleogene extinction event that is understood by the scientific community to have caused the extinction of all non-avian dinosaurs.
The B612 Foundation is a private nonprofit foundation headquartered in Mill Valley, California, United States, dedicated to planetary science and planetary defense against asteroids and other near-Earth object (NEO) impacts. It is led mainly by scientists, former astronauts and engineers from the Institute for Advanced Study, Southwest Research Institute, Stanford University, NASA and the space industry.
Astrophysics is a science that employs the methods and principles of physics and chemistry in the study of astronomical objects and phenomena. As one of the founders of the discipline, James Keeler, said, Astrophysics "seeks to ascertain the nature of the heavenly bodies, rather than their positions or motions in space–what they are, rather than where they are." Among the subjects studied are the Sun, other stars, galaxies, extrasolar planets, the interstellar medium and the cosmic microwave background. Emissions from these objects are examined across all parts of the electromagnetic spectrum, and the properties examined include luminosity, density, temperature, and chemical composition. Because astrophysics is a very broad subject, astrophysicists apply concepts and methods from many disciplines of physics, including classical mechanics, electromagnetism, statistical mechanics, thermodynamics, quantum mechanics, relativity, nuclear and particle physics, and atomic and molecular physics.
Mordehai "Moti" Milgrom is an Israeli physicist and professor in the department of Particle Physics and Astrophysics at the Weizmann Institute in Rehovot, Israel.
Peter Goldreich is an American astrophysicist whose research focuses on celestial mechanics, planetary rings, helioseismology and neutron stars. He is the Lee DuBridge Professor of Astrophysics and Planetary Physics at California Institute of Technology. Since 2005 he has also been a professor at the Institute for Advanced Study in Princeton, New Jersey. Asteroid 3805 Goldreich is named after him.
Avishai Dekel is a professor of physics at the Hebrew University of Jerusalem, Israel, holding the Andre Aisenstadt Chair of Theoretical Physics. His primary research interests are in astrophysics and cosmology.
Irwin Ira Shapiro is an American astrophysicist and Timken University Professor at Harvard University. He has been a professor at Harvard since 1982. He was the director of the Center for Astrophysics | Harvard & Smithsonian from 1982 to 2004.
Scott Duncan Tremaine is a Canadian-born astrophysicist. He is a fellow of the Royal Society of London, the Royal Society of Canada and the National Academy of Sciences. Tremaine is widely regarded as one of the world's leading astrophysicists for his contributions to the theory of Solar System and galactic dynamics. Tremaine is the namesake of asteroid 3806 Tremaine. He is credited with coining the name "Kuiper belt".
A gravity tractor is a theoretical spacecraft that would deflect another object in space, typically a potentially hazardous asteroid that might impact Earth, without physically contacting it, using only its gravitational field to transmit the required impulse. The gravitational force of a nearby space vehicle, though small, is able to alter the path of a much larger asteroid if the vehicle spends enough time close to it; all that is required is that the vehicle thrust in a consistent direction relative to the asteroid's path, and that neither the vehicle nor its expelled reaction mass come in direct contact with the asteroid. The tractor spacecraft could either hover near the object being deflected, or orbit it, directing its exhaust perpendicular to the plane of the orbit.
Geraint Francis Lewis, FLSW is a Welsh astrophysicist, who is best known for his work on dark energy, gravitational lensing and galactic cannibalism. Lewis is a Professor of Astrophysics at the Sydney Institute for Astronomy, part of the University of Sydney's School of Physics. He is head of the Gravitational Astrophysics Group. He was previously the Associate Head for Research at the School of Physics, and held an Australian Research Council Future Fellowship between 2011 and 2015. Lewis won the 2016 Walter Boas Medal in recognition of excellence in research in Physics. In 2021, he was awarded the David Allen Prize of the Astronomical Society of Australia for exceptional achievement in astronomy communication.
Stanislav George Djorgovski is an American scientist and scholar. He obtained his B.A. in astrophysics in 1979 at the University of Belgrade. After receiving his PhD in astronomy from U.C. Berkeley in 1985, he was a Harvard Junior Fellow until 1987 when he joined the faculty at the California Institute of Technology, where he is currently a professor of astronomy and data science.
The Sentinel Space Telescope was a space observatory to be developed by Ball Aerospace & Technologies for the B612 Foundation. The B612 Foundation is dedicated to protecting the Earth from dangerous asteroid strikes and Sentinel was to be the Foundation's first spacecraft tangibly to address that mission.
Marc Kamionkowski is an American theoretical physicist and currently the William R. Kenan, Jr. Professor of Physics and Astronomy at Johns Hopkins University. His research interests include particle physics, dark matter, inflation, the cosmic microwave background and gravitational waves.
Shashikumar Madhusudan Chitre FNA, FASc, FNASc, FRAS was an Indian mathematician and astrophysicist, known for his research in Astronomy and Astrophysics. The Government of India honored him, in 2012, with Padma Bhushan, the third highest civilian award, for his services to the sciences.
Vassiliki Kalogera is a Greek astrophysicist. She is a professor at Northwestern University and the director of the Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA). She is a leading member of the LIGO Collaboration that observed gravitational waves in 2015.
Ajit Kembhavi is an Indian astrophysicist. He is presently a Professor Emeritus at the Inter-University Centre for Astronomy and Astrophysics, (IUCAA) at Pune, India, of which he was also a founder member. He also serves as a Vice President of the International Astronomical Union. He is the Principal Investigator of Pune Knowledge Cluster along with Professor L. S. Shashidhara.
Douglas Cameron Heggie is a Scottish applied mathematician and astronomer, formerly holding the Personal Chair of Mathematical Astronomy at the School of Mathematics at the University of Edinburgh. His main research interests are in stellar dynamics.
Ramesh Narayan is an Indian-American theoretical astrophysicist, currently the Thomas Dudley Cabot Professor of the Natural Sciences in the Department of Astronomy at Harvard University. Full member of the National Academy of Sciences, Ramesh Narayan is widely known for his contributions on the theory of black hole accretion processes. Recently he is involved in the Event Horizon Telescope project, which led in 2019 to the first image of the event horizon of a black hole.
Gabrielle D. Allen is a British and American computational astrophysicist known for her work in astrophysical simulations and multi-messenger astronomy, and as one of the original developers of the Cactus Framework for parallel scientific computation. She is a professor of mathematics and statistics at the University of Wyoming.
Enrico Ramirez-Ruiz is a professor of astrophysics, astronomy, and earth sciences at the University of California, Santa Cruz.
