Black Holes

An artist's impression of a black hole with certain characteristic features, including a whirlpool of infalling matter, called an accretion disk. (Image Credit: NASA/Goddard Space Flight Center)

Black holes are astrophysical objects so named because their strong gravitational pull prevents light from escaping a boundary, known as an event horizon. Astronomers have never directly observed a black hole, but the gravitational effects that black holes exert on their cosmic environments reveal certain properties of these objects, such as mass. In 2015, researchers directly detected ripples in the space-time fabric of the universe, known as gravitational waves, for the first time, and which were apparently generated by the collision of two black holes. Altogether, scientists think that black holes come in three basic varieties. One type, called a "stellar" black hole, is created when a giant star collapses at the end of its life. These black holes have a mass of several to tens of times the mass of the Sun, packed into a volume the size of a city, and have been evidenced form indirect observations and gravitational waves. The second type, often dubbed an intermediate black hole, has more than a hundred times the mass of the Sun, and has not been observationally verified to date. The third kind, dubbed a "supermassive" black hole, is found at the heart of nearly all galaxies and can possess a mass of up to billions of times the Sun's. Matter drawn toward these black holes accelerates to high velocities, giving off prodigious, observable energy in the process. In the case of supermassive black holes, the output of energy and winds is so powerful, the objects can play a key role in the evolution of their host galaxies. Overall, black holes are extreme objects that fundamental laws of physics, such as general relativity and quantum mechanics, have failed to explain completely.

Did a Starry “Mosh Pit” Spawn LIGO’s Gravitational Waves?

Globular cluster
May 29, 2017

Much to their surprise, scientists are finding dozens of black holes deep within densely packed collections of stars called globular clusters. We spoke to three astrophysicists—Rainer Spurzem, Carl Rodriguez and Jay Strayder—who are using a record-breaking computer simulation, and other methods, to learn the clusters’ secrets, including whether they gave rise to recently observed ripples in space-time. 

Will a New Discovery Fast-track Our Understanding of the Origins of Galaxies and Gargantuan Black Holes?

Mar 07, 2017

The Kavli Foundation spoke with three astrophysicists—Roberto Maiolino, Linhua Jiang and Marta Volonteri—about how a record haul of new, ultra-distant quasars will transform what we know about the early universe.

Why Dead Galaxies ‘Rest in Peace,’ Never to Form Stars Again

Red geyser galaxy
Sep 15, 2016

Scientists are discovering how powerful eruptions from monster black holes ensure dead galaxies cannot resurrect and make new stars. In a roundtable discussion, astrophysicists Edmond Cheung, Kevin Bundy and Christy Tremonti explain.

2016 Kavli Prize in Astrophysics: A Discussion with Kip Thorne and Rainer Weiss

Two black holes merging
Aug 15, 2016

Two winners of the 2016 Kavli Prize in Astrophysics, Kip S. Thorne and Rainer Weiss, discuss the impact of discovering gravitational waves with the enormous detector they spent more than 40 years developing.

Ripple Effect: Gravitational Waves Begin to Reveal a Hidden Universe

A visualization of a supercomputer simulation of merging black holes sending out gravitational waves. (Credit: NASA/C. Henze)
Feb 11, 2016

Three principal researchers at the Laser Interferometer Gravitational-Wave Observatory (LIGO)—Nergis Mavalvala, Rainer Weiss and Matthew Evans—reflect on the epic discovery of gravitational waves and how it will transform the way we see the cosmos.

Crowdsourcing the Universe: How Citizen Scientists are Driving Discovery

Gravitational lenses
Jan 13, 2016

Legions of volunteer, 'citizen scientists' are training their eyes on the sky and sharing in the thrill of discovery. In this Kavli roundtable, Citizen science leader Chris Lintott joins Anupreeta More and Aprajita Verma of the Space Warps project to discuss the exciting endeavor.

Bubbles From the Center of Our Galaxy: A Key to Understanding Dark Matter and the Milky Way's Past?

Jan 26, 2015

Fresh from the January Rossi Prize Lecture, the scientists who discovered the “Fermi bubbles,” two of the largest structures in the Milky Way, say the bubbles can tell of our galaxy’s past – and even help find dark matter.

Spotlight Live: Falling Into a Black Hole

Black hole
Sep 09, 2013

On September 25, Noon-12:50 PDT, Raphael Bousso, Juan Maldacena, Joseph Polchinski and Leonard Susskind (Stanford University) answer questions about the latest theories about what happens when matter falls into a black hole,.

Spotlight Live: Black Holes & Our Cosmic Evolution

Black hole
Sep 05, 2013

Billions of years ago, a subset of galaxies in the relatively young universe were producing new stars at a rate of 1,000 per year. 

Black Holes Revisited

Black hole
Sep 05, 2013

Andrea Merloni, Priyamvada Natarajan, Tommaso Treu and John Wise discuss the latest findings about black holes, including new questions about how supermassive black holes at the centers of galaxies came into existence.


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