Black holes are gloriously weird. Formed as the death state of heavy stars, they can be as small as cities or as big as solar systems. This has been the century for black hole discoveries. We have had the good fortune to host scientists central to many of those discoveries at Pioneer Works in various conversations over recent years. Here is a round up of our 5 favorites.
The sounds of a black hole collision
In 2016, the LIGO team announced they had recorded the collision of two black holes over a billion years ago. Like mallets on a drum, the black holes bang out waves in the shape of spacetime, gravitational waves. If you were near enough, it’s conceivable that the waves would ring your eardrum. You would actually hear the collision unaided, even in the vacuum of empty space. From our great distance, the sound was so faint that the two LIGO instruments recorded modulations of less than a thousandth the width of a proton over the span of 4 kilometers. Yet the merger of those black holes was the most powerful event detected since the Big Bang, more powerful than the luminosity of all the stars in the observable universe combined. For more, watch the conversation with principal architect of the experiment, Nobel Laureate Rai Weiss.
Our lives are anchored by a supermassive black hole
Our very existence may be contingent on the shepherding role of black holes in the history of the cosmos. Our own Milky Way galaxy is anchored at its center by a black hole four million times the mass of our sun but less than 20 sun widths across. The rest of our galaxy could harbor billions of city-sized black holes. There are hundreds of billions of galaxies in the observable universe, each one replete with billions of stellar mass black holes and at least one supermassive black hole. Beyond their oddity, black holes may play an essential role in sculpting the universe on the largest scales. Black holes may have carved a world that we could live in. In 2018, Yale professor and astrophysicist Priyamvada Natarajan and the University of Arizona professor and astrophysicist Feryal Özel were our guests in a Scientific Controversies event: Black Holes. Watch the full conversation, accompanied by a meditation on the elusive cosmic phenomenon by Priyamvada Natarajan.
Astronomy’s greatest image
In 2019, Shep Doeleman revealed the first ever human-procured image of a black hole at the National Press Club. This supermassive black hole resides in the neighboring galaxy M87, 55 million light years away. A gargantuan object, 6.5 billion times the mass of the sun, M87’s supermassive black hole is so far away that the detection required observatories around the globe to operate in concert as one effective telescope the size of the entire Earth. One billion people took in the sight of this extraordinary phenomenon on the day of the reveal. Doeleman joined us, alongside renowned black hole theorist Andy Strominger, for a conversation in the Scientific Controversies series on May 29, 2019, the centenary of the Eddington eclipse expedition that confirmed the predictions of general relativity and catapulted Einstein to fame. For more, watch the video above.
Gravity’s inevitable consequence
In October, 2020, the Nobel prize in Physics was awarded to Sir Roger Penrose for his work proving that black holes were not a mathematical quirk, but were in fact the inevitable consequence of unhindered gravitational collapse. Sir Roger shared the prize with Andrea Ghez and Rheinhard Genzel for their discovery of a supermassive black hole 4 million times the mass of the sun in the center of our own Milky Way galaxy. Our central black hole is nicknamed Sag A* for its location beyond the constellation Saggitarius from the perspective of the Earth. Sir Roger joined our director of sciences in conversation a few months before the Nobel announcement.
Black hole holograms
Black holes exist out there in the universe, real astronomical phenomena, the death state of very massive stars as well as supermassive anchors of mysterious origin. Yet unlike any other astrophysical object, black holes are flawless, featureless, like idealized fundamental particles of gravity. They offer an eerie terrain, perhaps the only terrain, on which theoretical physicists can explore an elusive Theory of Everything. The event horizon of a black hole, long believed to be an empty and unspectacular shadow, might be a quantum Hologram: a two-dimensional surface that encodes all of the black hole’s defining information that deceptively projects the illusion of a three-dimensional reality. At the forefront of contemporary exploration in physics, black holes are the surreal and spectacular frontier for discovery. For more, check out Black Hole Survival Guide, an evocative exploration of black holes, provoking us to imagine the visceral experience of a black hole encounter.
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The Pioneer Works Broadcast is supported in part by Science Sandbox, a Simons Foundation initiative dedicated to engaging everyone with the process of science, and the Alfred P. Sloan Foundation Program in Public Understanding of Science and Technology, bridging the two cultures of science and the arts.