Black holes: what we think we know, we don't

Space

It took , but . Schwarzschild’s solution describes the gravity of an isolated, spherical and unchanging object — the enigmatic black hole — but it was not understood for many years.

Black holes helped to explain new astronomical discoveries, becoming essential ingredients of astrophysics. Science regarded . The recent experimental discovery of gravitational waves has changed our understanding of what black holes are.

In 2016, the LIGO-Virgo collaboration detected , opening a new era of astronomy celebrated by the 2017 Nobel Prize in physics.

In 2019, the released an image of the supermassive black hole in the nearby galaxy M87. The following year, the Nobel Prize in physics recognized .

What is a black hole?

The notion of black hole reflected in popular science hinges on the idea of event horizon — this is when the velocity needed to escape the gravitational pull of the black hole exceeds the speed of light. Whatever falls into the event horizon is lost forever.

The Schwarzschild radius is the radius of the event horizon, . But Schwarzschild’s definition has a pitfall: it requires us to know that nothing will emerge from the black hole. This means that the black hole must be monitored forever to know that nothing exits. In practice, this is impossible.

Another mathematical solution to Einstein’s equations . An event horizon forms at its centre, expands outwards, — et voilà! — a black hole is formed.

New black holes

Perfectly isolated or unchanging black holes do not exist. Real-world black holes are surrounded by disks orbiting them, stellar winds and dark matter, all of which produce infalling matter that increases their masses.

Black holes often exist in pairs, spiraling closer and closer to each other and emitting gravitational waves until they merge into a larger black hole, the horizon changing in time, dramatically so at the merger.

Space
Two black holes surrounded by yellow and orange flames spiraling into each other. Image via NASA

The originated in the spectacular merger of two black holes. By the time these waves reached Earth, they were weaker than the ambient noise and could only be identified by matching theoretical templates of the expected signal to the data.

Large banks of templates are generated in computer simulations that obviously cannot run forever, as would be necessary if the black hole was characterized by the eternal event horizon. Instead, simulations use the , characterized by the property that nothing can escape from it now.

Apparent horizons have played a crucial role in the newly born , but are surprisingly little known.

Black holes change because they live in an . Theoretical physicist Stephen Hawking predicted that all black holes , which makes them shrink. Although negligible for practical purposes, this radiation is unavoidable in principle.

New understandings

Our understanding of black holes is based on the mathematical definition of horizon. The apparent horizon : rays cannot escape (and since nothing moves faster than light, nothing escapes) at the present moment.

But how light rays behave depends on the observer describing them using mathematical simulations. Since, in relativity, time and space depend on the observer, the location where rays stop and the present time are different for different observers. So, the apparent horizon itself depends on the observer.

The very existence of the black hole has come to depend on the observer, while the old event horizon was universal.

The mathematics expressing the new black hole concept tells us that, even in Schwarzschild’s case, according to whom there is no apparent horizon and, therefore, no black hole! Admittedly, these mathematical observers are very artificial. All natural observations (those that occur through observing the actual behavior of a black hole) that perceive the Schwarzschild geometry as spherical, agree on .

Scientists have finally detected gravitational waves from black holes but had to change the way they understand them. The essence of black hole theory is now different.

This article by , Professor, Physics & Astronomy, , is republished from under a Creative Commons license. Read the .

News Related

OTHER NEWS

Pulisic admits prominence on US, Chelsea sometimes a burden

COLUMBUS, Ohio (AP) — Christian Pulisic has been on a roller coaster. © Provided by The Canadian Press America’s top player won the Champions League, then was sidelined for nearly ... Read more »

Volkswagen e-Up! prepara su regreso en Europa

A pesar de que la ofensiva eléctrica de Volkswagen planeó y trabajó para llegar en tiempo y forma con las entregas de la familia ID. La pandemia no ha dejado ... Read more »

Prohíben exhibiciones de aviones militares en los GP de Fórmula 1

A dos meses de iniciar la temporada 2022 de la Fórmula 1, el comité organizador comunicó a los promotores de los Grandes Premios que quedan prohibidas las exhibiciones con aviones militares ... Read more »

Woman accused of throwing kids in lake charged with murder

The Associated PressFILE – This undated provided by Caddo Correctional Center in Shreveport, La., shows Ureka Black. Black, accused of throwing two of her children into a lake was indicted ... Read more »

Rob Gronkowski contempla fijamente el retiro

© Proporcionado por AS Una de las principales preocupaciones de los Buccaneers para 2022 es el posible retiro de Tom Brady. No obstante, Bruce Arians también debe estar pendiente de ... Read more »

Pohjois-Koreasta laukaistiin tunnistamaton ammus mereen, kertoo Etelä-Korea

AFP Pohjois-Koreasta on laukaistu tunnistamaton ammus kohti itää, kertoo Etelä-Korean armeija. Ammuksen kerrotaan laskeutuneen Japaninmereen. Kyseessä on jo kuudes tänä vuonna havaittu asetesti Pohjois-Koreassa. Viimeksi maa on tehnyt asetestejä yhtä ... Read more »

Burritos, inflación y privilegios: conforme suben los precios de los alimentos, un alboroto en las redes sociales destaca quién realmente la pasa mal

© Raquel Zaldivar/Chicago Tribune/TNS Desde la izq., Kenneth Ludwig, Kris Haramaras y Melinda Pacha, voluntarias de Lakeview Pantry, organizan artículos de abarrotes en los estantes de la despensa de alimentos ... Read more »

Pilot fighting for life after helicopter hit powerlines and crashed into field while mustering cattle

Police are on the scene of a helicopter crash that has critically injured two  Around 1pm on Thursday police responded to a helicopter crash at Grosmont It is understood the two injured were the helicopter's pilot and sole occupant  Read more »

DS Automobiles continuará como patrocinador del Paris Fashion Week por dos años más

DS Automobiles es una marca de lujo que le queda muy bien a eventos como el Paris Fashion Week. Parte de la propuesta premium que hace la marca francesa está ... Read more »

Toyota Sequoia 2023, la nueva generación mejora en diseño, confort, desempeño y equipamiento

Después de una segunda generación con casi 15 años de antigüedad, el doble de la primera, la Toyota Sequoia 2023 es renovada desde cero para evolucionar en confort, desempeño, eficiencia ... Read more »

Mercedes GLS preparado para el fin del mundo

En la última década, el preparador letón Dartz nos supo sorprender con varios de sus trabajos, que se distinguieron por su alto grado de lujo y seguridad. Por ejemplo, con ... Read more »

Paulo Sousa e comissão técnica interagem com a torcida do Flamengo na estreia do Carioca

O Flamengo fez sua estreia na temporada nesta quarta, diante da Portuguesa pelo Carioca, com uma equipe alternativa sob o comando de Fabio Matias, técnico do Sub-20. Contudo, Paulo Sousa ... Read more »

Bentley acelera su plan de convertirse en una marca de autos eléctricos

Ante la vertiginosa competencia y demanda que existe por los autos eléctricos en todo el mundo, Bentley Motors ha acelerado su estrategia de visión de futuro Beyond100. En este plan ... Read more »

¿A qué se debe que el Volkswagen Golf ha perdido popularidad en los últimos años?

De acuerdo con datos de JATO Dynamics, el Golf fue el auto más vendido en Europa durante 2021, con esto el hatchback de Volkswagen continúa siendo el modelo más popular. ... Read more »

Volkswagen Jetta GLI vs Ford Mustang EcoBoost ¿Cuál es más rápido en un arrancón?

El Ford Mustang es conocido por sus potentes motores de ocho cilindros y la actual generación no la excepción. Sin embargo, en el line up actual también podemos encontrar un ... Read more »

Após tropeço, auxiliar de Carille no Santos busca visão positiva do empate

Leandro Silva, auxiliar de Carille, comandou a equipe do Santos no empate em 0 a 0 com a Inter de Limeira, fora de casa, no Estádio Major José Levy Sobrinho, ... Read more »

Chevrolet Corvette 70th Anniversary Edition, una celebración al auto deportivo más longevo

Durante ocho generaciones, Corvette ha superado los límites de la tecnología, el desempeño y el estilo sin dejar de ser un ícono cultural alcanzable. Debido a que, en 2023, el ... Read more »

ENAP informó nueva alza en el precio de las bencinas: Solo baja el GLP

© 24horas.cl ENAP informó nueva alza en el precio de las bencinas: Solo baja el GLP La Empresa Nacional del Petróleo (ENAP) informó cambios en el precio de las bencinas ... Read more »

BBB22: ‘Nunca foi', diz João Guilherme sobre boato de relacionamento tóxico com Jade Picon

João Guilherme, ex-namorado de Jade Picon, ficou irritado com a fala de Pedro Scooby no Big Brother Brasil 22. O surfista comentava sobre o namoro do filho de Leonardo com ... Read more »

Juninho celebra primeiro gol como profissional do Vasco e cita meta: 'Quero fazer de 2022 o meu ano'

O Vasco estreou com o pé direito na temporada 2022 ao derrotar o Volta Redonda por 4 a 2, no Raulino de Oliveira. Um dos destaques do triunfo foi o ... Read more »

Com show de Mikael, Sport goleia Sete de Setembro em estreia do Pernambucano

O Sport enfrentou o Sete de Setembro-PE na noite desta quarta-feira (26). Jogando na Ilha do Retiro, em Recife (PE), os times estrearam no Campeonato Pernambucano. Com destaque para Jaderson ... Read more »

Kozlinski, Giovanni Augusto e mais; Daniel Paulista monta escalação do Guarani para duelo contra São Paulo

Três semanas depois, sendo uma delas em Sorocaba, o Guarani finalizou nesta quarta (26) suas atividades de pré-temporada para a estreia no Campeonato Paulista. No último treino antes do duelo ... Read more »

Ronaldinho aparece em vídeo com a camisa do Vasco e torcedores 'brincam': 'Comprou o Vasco?'

O ex-jogador Ronaldinho Gaúcho apareceu em um vídeo com a camisa do Vasco, nesta quarta-feira (26), convocando a torcida para a novidade anunciada nas redes sociais do clube. © (Foto: ... Read more »

Гарем похож на ад: почему ты была в ужасе, если бы стала наложницей султана

Судя по сериалу «Великолепный век», попасть в гарем для любой девушки — великое счастье. Но так ли это на самом деле? © кадр из сериала «Великолепный век» валиде султан личная жизнь ... Read more »

White Breaks His Silence, Explains UFC 270 Disappearing Act

Ultimate Fighting Championship (UFC) president Dana White held a special Q&A earlier today (Weds., Jan 26, 2022) hosted by Laura Sanko to field fan-submitted questions. After answering a couple of ... Read more »

6 prenatal and postnatal procedures that are actually optional

When Emily Boros-Rausch began reading and attending birth classes while expecting her son, now eight months old, the Moncton, NB mother of one was surprised at the number of choices ... Read more »

Canada extends, expands mission to train Ukraine soldiers but won't arm them

OTTAWA — Canada is extending and expanding its mission to train Ukrainian soldiers but it is not, so far, prepared to help arm them with lethal defensive weapons as Ukraine ... Read more »

Government's decision not to review lithium company takeover a 'mistake': expert

OTTAWA — An intelligence expert said the federal government’s decision not to conduct a formal national security review on the takeover of a Canadian lithium mining company by a Chinese ... Read more »

Elks sign all-star receivers Bowman, Arceneaux, three others

EDMONTON — The Edmonton Elks signed former all-star receivers Adarius Bowman and Emmanuel Arceneaux on Wednesday. © Provided by The Canadian Press The Elks also added veteran receiver Caleb Holley, ... Read more »

Canelo Álvarez tiene ofertas para pelear con GGG, Bivol y Charlo

© MICHELLE FARSI/MATCHROOM via MEXSPORT (Mexsport) Sául Álvarez después de la pelea contra Billy Joe Saunders Saúl ‘Canelo’ Álvarez quiere seguir haciendo historia en el boxeo y tiene en mente ... Read more »

Chile vs. Argentina EN VIVO: ¿qué canal transmite las Eliminatorias Qatar 2022 en el país vecino?

© Deportes Chile vs. Argentina EN VIVO: ¿qué canal transmite las Eliminatorias Qatar 2022 en el país vecino? El proceso mundialista ya casi acaba. Comienza la décimo quinta fecha de ... Read more »

Copa NotiAuto 2022 regresará de nuevo a Puebla

Este fin de semana en la capital del país, arranca la edición 2022 de la Copa NotiAuto, que en esta ocasión, contempla de nueva cuenta a Puebla y al Autódromo ... Read more »

Australian Open 2022: quiénes clasificaron a semifinales, qué partidos hay y cuándo juegan

Se acerca su final. El Australian Open 2022 se encuentra en su recta final luego de que el martes 25 y miércoles 26 de enero se hayan disputado los partidos ... Read more »

Uruguay vs. Paraguay EN VIVO: conoce cómo ver el partido por Eliminatorias Qatar 2022 vía VTV

© Deportes Uruguay vs. Paraguay EN VIVO: conoce cómo ver el partido por Eliminatorias Qatar 2022 vía VTV Uruguay vs. Paraguay juegan EN VIVO este viernes 27 de enero por ... Read more »

Tom Brady: “Mis hijos me necesitan más que el futbol”

© Mike Ehrmann Brady cumplirá en agosto 45 años y todavía tiene un año de contrato con los Bucs Tom Brady, quarterback de los Buccaneers de Tampa Bay, sigue sin ... Read more »

La Volpe, Boy y Romano, entre los candidatos para tomar al Atlético de San Luis

La directiva del Atlético de San Luis ha comenzado la búsqueda para contratar a un técnico después de la destitución de Marcelo Méndez y de momento ya tienen cuatro posibles ... Read more »

FREEDOM 2022: el Festival electrónico presenta el line up de la edición 13 | Eventos | Shock

El Festival Internacional de Música Electrónica de Medellín, FREEDOM, regresa para celebrar su edición 13. Freedom in the Jungle será el reencuentro de la escena electrónica en Medellín. Durante tres ... Read more »

Police prepare for possible violence as fringe groups latch on to truckers convoy

OTTAWA — A convoy of truckers set to descend upon Ottawa to protest mandatory vaccinations is prompting police to prepare for violence and politicians to warn against escalating rhetoric linked ... Read more »

San Luis da de baja a su técnico, ¿qué otros entrenadores corren peligro?

Con el parón que tendrá la Liga MX en los próximos días por las Eliminatorias Mundialistas que habrá, el Atlético de San Luis optó por hacer un ajuste con la ... Read more »

INE aprueba voto electrónico en elecciones de Aguascalientes y Tamaulipas

© Proporcionado por El Universal Online INE aprueba voto electrónico en elecciones de Aguascalientes y Tamaulipas El Consejo General del Instituto Nacional Electoral (INE) aprobó la instrumentación del voto electrónico, ... Read more »
On free-english-test.com you will find lots of free English exam practice materials to help you improve your English skills: grammar, listening, reading, writing, ielts, toeic