A black hole is a region of spacetime where gravity is so strong that nothing, including light and other electromagnetic waves, has enough energy to escape it. Einstein's theory of general relativity predicts that a sufficiently compact mass can deform spacetime to form a black hole. The boundary of no escape is called the event horizon. A black hole has a great effect on the fate and circumstances of an object crossing it, but it has no locally detectable features according to general relativity. In many ways, a black hole acts like an ideal black body, as it reflects no light. Moreover, quantum field theory in curved spacetime predicts that event horizons emit Hawking radiation, with the same spectrum as a black body of a temperature inversely proportional to its mass. This temperature is of the order of billionths of a kelvin for stellar black holes, making it essentially impossible to observe directly.
Star formation is the process by which dense regions within molecular clouds in interstellar space, sometimes referred to as "stellar nurseries" or "star-forming regions", collapse and form stars. As a branch of astronomy, star formation includes the study of the interstellar medium (ISM) and giant molecular clouds (GMC) as precursors to the star formation process, and the study of protostars and young stellar objects as its immediate products. It is closely related to planet formation, another branch of astronomy. Star formation theory, as well as accounting for the formation of a single star, must also account for the statistics of binary stars and the initial mass function. Most stars do not form in isolation but as part of a group of stars referred as star clusters or stellar associations.
Extragalactic astronomy is the branch of astronomy concerned with objects outside the Milky Way galaxy. In other words, it is the study of all astronomical objects which are not covered by galactic astronomy.
A supermassive black hole is the largest type of black hole, with its mass being on the order of hundreds of thousands, or millions to billions, of times the mass of the Sun (M☉). Black holes are a class of astronomical objects that have undergone gravitational collapse, leaving behind spheroidal regions of space from which nothing can escape, not even light. Observational evidence indicates that almost every large galaxy has a supermassive black hole at its center. For example, the Milky Way galaxy has a supermassive black hole at its center, corresponding to the radio source Sagittarius A*. Accretion of interstellar gas onto supermassive black holes is the process responsible for powering active galactic nuclei (AGNs) and quasars.
Kip Stephen Thorne is an American theoretical physicist known for his contributions in gravitational physics and astrophysics. Along with Rainer Weiss and Barry C. Barish, he was awarded the 2017 Nobel Prize in Physics for his contributions to the LIGO detector and the observation of gravitational waves.
Alan Harvey Guth is an American theoretical physicist and cosmologist who is the Victor Weisskopf Professor of Physics at the Massachusetts Institute of Technology. Along with Alexei Starobinsky and Andrei Linde, he won the 2014 Kavli Prize "for pioneering the theory of cosmic inflation." Guth's research focuses on elementary particle theory and how particle theory is applicable to the early universe.
In astrophysics, accretion is the accumulation of particles into a massive object by gravitationally attracting more matter, typically gaseous matter, into an accretion disk. Most astronomical objects, such as galaxies, stars, and planets, are formed by accretion processes.
Einstein's Dreams is a 1992 novel by Alan Lightman that was an international bestseller and has been translated into thirty languages. It was runner up for the 1994 L. L. Winship/PEN New England Award. Einstein's Dreams was also the March 1998 selection for National Public Radio's "Talk of the Nation" Book Club. The novel has been used in numerous colleges and universities, in many cases for university-wide adoptions in "common-book" programs. New York Times book critic Michiko Kakutani wrote about the book: "As in Calvino's work, the fantastical elements of the stories are grounded in precise, crystalline prose. As in Jorge Luis Borges's ficciones, carefully observed particulars open out, like doors in an advent calendar, to disclose a magical, metaphysical realm beyond."
John Peter Huchra was an American astronomer and professor. He was the Vice Provost for Research Policy at Harvard University and a Professor of Astronomy at the Center for Astrophysics | Harvard & Smithsonian. He was also a former chair of the United States National Committee for the International Astronomical Union. and past president of the American Astronomical Society.
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.
Priyamvada (Priya) Natarajan is a professor in the departments of astronomy and physics at Yale University. She is noted for her work in mapping dark matter and dark energy, particularly with her work in gravitational lensing, and in models describing the assembly and accretion histories of supermassive black holes. She authored the book Mapping the Heavens: The Radical Scientific Ideas That Reveal the Cosmos.
David I. Kaiser is an American physicist and historian of science. He is Germeshausen Professor of the History of Science at the Massachusetts Institute of Technology (MIT) and a full professor in MIT's department of physics. He also served as an inaugural associate dean for MIT's cross-disciplinary program in Social and Ethical Responsibilities of Computing.
Steven Andrew Balbus is an American-born astrophysicist who is the Savilian Professor of Astronomy at the University of Oxford and a professorial fellow at New College, Oxford. In 2013, he shared the Shaw Prize for Astronomy with John F. Hawley.
Oded Regev is a physicist and astrophysicist, professor emeritus of the Technion, Israel Institute of Technology. He is best known for his theoretical application of fluid dynamics and dynamical systems theory to astrophysics.
Jacqueline Nina Hewitt is an American astrophysicist. She was the first person to discover an Einstein ring. She is a Fellow of the American Astronomical Society.
An accretion disk is a structure formed by diffuse material in orbital motion around a massive central body. The central body is most frequently a star. Friction, uneven irradiance, magnetohydrodynamic effects, and other forces induce instabilities causing orbiting material in the disk to spiral inward toward the central body. Gravitational and frictional forces compress and raise the temperature of the material, causing the emission of electromagnetic radiation. The frequency range of that radiation depends on the central object's mass. Accretion disks of young stars and protostars radiate in the infrared; those around neutron stars and black holes in the X-ray part of the spectrum. The study of oscillation modes in accretion disks is referred to as diskoseismology.
Stuart Louis Shapiro is an American theoretical astrophysicist, who works on numerical relativity with applications in astrophysics, specialising in compact objects such as neutron stars and black holes.
Giuseppe Bertin is an Italian physicist, known for his work in the explanation of the spiral structure of galaxies, and in the use of these as cosmological probes and gravitational lenses. Bertin is currently Professor at the University of Milan. He won the Premio Presidente della Repubblica in 2013 for his contribute in the latest discoveries in the dynamics of galaxies.
Nicolás Yunes is an Argentinian theoretical physicist who is a professor at the University of Illinois Urbana-Champaign and the founding director of the Illinois Center for Advanced Studies of the Universe (ICASU). He is particularly interested in extreme gravity, gravitational waves, and compact binaries.
