Daughter of a rocket engineer, granddaughter of a planetarium director, I've been a huge fan of astronomy and space exploration all my life.
Actual Photo of Black Hole
Black Holes Are Real
Black holes are, simply, a place where so much matter has come together that its massive gravity draws everything near it towards it— even light. Once matter or light passes the "event horizon" of the black hole, it cannot escape (usually). However, we can see stars, gas and dust falling towards that point. Objects being drawn in by a black hole are heated up and emit bursts of visible light, x-rays, gamma rays and other wavelengths as they are torn apart.
Black holes were once theoretical, suggested by the mathematical equations of physics and Einstein's relativity, which predicted what would happen if too much mass collected in one spot. There was debate about whether black holes really existed; Einstein himself thought they were "too strange to be real."
"When I was a PhD student, people used to giggle when you hear[d] about black holes. They're like unicorns, mythical creatures. We call this the 'giggle factor.' People would say, 'Beam me up, Scotty.' Well, no one is laughing anymore."
The first known black hole was Cygnus X-1, discovered in 1964 as a powerful, mysterious source of x-rays. Since then, thousands of black holes have been discovered through the energy emissions of their dying prey or their tugs on nearby stars, dust, gas, and even galaxies. So we usually have to content ourselves with artist's depictions or a graph of the black hole's vital signs. However, our most powerful telescopes can sometimes detect the "accretion discs" of matter circling around black holes:
REALLY Supermassive Black Hole: Heart of NGC 1277
If Black Holes Are Black, Then What Are We Seeing?
This video gives us a simple demonstration of how a black hole works. Once something falls into the hole, the "event horizion," its light can't escape, but until then we can see it.
Notice how the coins speed up more and more as they get close to the "event horizon" (around 0:50). With a black hole, this acceleration can be thousands of miles per hour! At that speed, matter heats up, gets ripped apart, collides with other particles, and whips out all kinds of energy and particles at speeds approaching the speed of light. This energy can squirt out at a black hole's poles as massive jets, following the magnetic lines of force generated by the material speeding around the black hole.
Simulation of Black Hole
A Black Hole to Be?
Stellar Mass Black Holes
"Stellar Mass" black holes started out as giant stars at least twenty times the mass of our sun. (The black hole left behind may be as small as 2.5 times the sun's mass, and some are less than 20 miles wide).
All stars are engaged in a deadly tug-of-war between the force of gravity, which tries to make them contract under their own mass, and the outward thrust of their core's thermonuclear explosions. Once their fuel is used up, stars implode. Stars the size of our sun pack down into white dwarfs, small cold cores. Stars larger than our sun compact into neutron stars, super-dense remnants. The biggest stars explode their outer shells in a supernova, while their massive core collapses all the way into a black hole.
At the moment of collapse, massive stars emit extremely high energy bursts of gamma rays for a few seconds. Astronomers now know that these gamma ray bursts are the signal of the birth of a black hole. NASA's Swift telescope is designed specifically to pick up these bursts. It has also discovered some short gamma ray bursts caused by the collision and fusion of two neutron stars or by a black hole eating a neutron star.
In slightly over five years, Swift detected 500 gamma ray bursts, most of them the cries of newborn black holes. As of January 2012, that number is up to 738. The inescapable conclusion: black holes are not as rare as unicorns; they're actually fairly common, in a place as big as the whole universe.
Swift Spots a Black Hole Flare-Up
A Whopper Gamma Ray Burst
March 19, 2008 was a very special day in the life of NASA's Swift telescope. Not only did it detect four gamma ray bursts on the same day, a record, but also, one was the most luminous ever seen.
It was halfway across the universe, 7.5 billion light years away, and it was briefly so bright that it was visible to the naked eye. By comparison, the faintest naked-eye object we can normally see is galaxy M33, 2.9 billion light years away. (One light year is 5,878,625,373,183.61 miles).
A Black Hole in Andromeda Galaxy
How to See Mature Black Holes
We don't just see black holes being born; we can also glimpse older ones snacking on their neighbors.
The Hubble Space Telescope has actually spotted the flickering visible light of a blob of matter swirling "down the drain" of a black hole — oscillating as it spiraled towards and away from us, growing brighter and darker and brighter again in ever tightening repetitions — and then vanishing from sight.
More often, X-ray telescopes catch brief bursts of energy from the matter being shredded by the black hole (right).
Remember Einstein's equation, E=MC2? The energy is the amount released. The M is the mass of the star or other object disintegrating in the black hole's demolition derby. C is the speed of light, which is 670,616,629 mph. Remember how much energy the Hiroshima bomb released, converting just a minute amount of matter into energy? A sun's mass compared to a bomb-sized chunk of plutonium is... well... inconceivable. No wonder the resulting explosions flare so brightly.
A Black Hole Chomps on Its Companion Star
Close-Up of Black Hole
Most star systems in the universe are binary, so many black holes have a sibling to snack on. As this material is accelerated and ripped apart, it gives off a steady stream of x-rays. Sometimes an especially tasty chunk causes the whole accretion disc swirling around the black hole to brighten not only on x-ray wavelengths but even extending into visible light.
In April 2012, NASA's Chandra x-ray telescope detected a black hole in the galaxy M83 that was chewing off a big chunk of material from its companion star. Hubble and the European Southern Observatory's "Very Large Telescope" spotted the resulting glow in visible wavelengths.
Photo of a Supermassive Black Hole
Stars Orbiting Center of Milky Way
Supermassive Black Holes
Astronomers have been shocked to discover that most galaxies have a supermassive black hole at their center, far more massive than stellar mass black holes. Astronomers are still wrestling over competing theories about how these monsters formed. We do know that there is one in the center of the Milky Way!
There's so much dust and matter packed near the center of our galaxy that it's mostly obscured in visible light, although we know where it is: it's in the direction of the constellation Sagittarius. However, telescopes that use alternate wavelengths of energy like x-rays and infrared can peer through the murk and image what's at the center.
What they've found is surprising, and awe-inspiring. By taking images of the center of the Milky Way galaxy for over a decade, several teams of astronomers have pinpointed its central black hole, named Sgr A*. The Keck Observatory's timelapse photos (see more info) show stars whipping around...something... that is invisible, yet its supermassive gravitational pull is accelerating them to thousands of miles an hour.
Now and then telescopes glimpse the "burp" as something is drawn in, torn to shreds, and emits a dying burst of energy. (As Bad Astronomy's Dr. Phil Plait notes, it's not technically a burp, but "more like your food screaming loudly and incoherently and flailing around while you’re actually eating it.")
X-Ray Flare of Milky Way's Black Hole
Documentary on Milky Way's Black Hole
Scary! Luckily, as we can see from the stars orbiting the Milky Way's hidden monster, you only get devoured if you get too close. Farther away, the pull of gravity is less, so stars can orbit the black hole just like our solar system's planets orbiting the Sun. Thankfully, our Sun is far away from the danger zone, orbiting the black hole safely from 26,000 light years away.
The European Southern Observatory has produced a slick video showing off its own timelapse photos of the center of the Milky Way:
ESO's Video of Stars Orbiting Black Hole in Center of Milky Way
Visible-Light Jet from Black Hole in M87
Supermassive Black Holes: Cosmic Blow Torches
The matter and gas falling towards black holes spins nearly the speed of light. With some supermassive black holes, small particles of that chewed-up matter squirt outward, streaming away from the poles of black holes as enormous jets, like potato peelings flying out of a food disposal when it's fed too quickly.
Astronomers and physicists are still struggling to explain the exact cause and physics of these jets, but telescopes have imaged many of them. The jets are visible at many wavelengths, including visible light (right)
Another Beautiful Photo of Supermassive Black Hole Jets
A Quasar in Double Vision
The Mystery of Quasars Solved
Studying supermassive black holes has helped astronomers untangle a decades-old mystery.
In the early 1960s, scientists puzzled over quasars, "quasi-stellar objects," that appeared to be as bright as nearby stars but were incredibly distant. They produced especially strong signals at radio wavelengths, yet another part of the electromagnetic spectrum along with light, gamma rays and x-rays.
Most astronomers now agree that quasars are actually the highly energetic, glowing discs of matter orbiting supermassive black holes at the cores of distant galaxies. From our vantage point, they shine brighter than all the stars in the rest of the galaxy.
There are some hints that these quasars are glimpses of what galaxies looked like when they were very young. We only see quasars extremely far away from the Milky Way. Remember, even light can only travel so far each year, so looking far out into the universe means looking back in time.
Great Black Hole Video
- HubbleSite - Black Holes FAQ
The Hubble Space Telescope's website explains what black holes are, what we know about them, and how we can detect them.
- McDonald Observatory's Black Hole Encyclopedia
Great site all about black holes. It includes a directory of known black holes, from stellar mass sized black holes to supermassive black holes.
- Black Hole Accretion | Berkeley Science Magazine
This 2005 scholarly article on black holes is pretty technical, but it's an excellent summary — if you can decipher it — of the science of black holes and their accretion discs, their physical structure, and how we can detect them.
Some-Bloke on April 11, 2019:
So, you have real photos of black holes up six years before the official "first" photo? Has anyone pressured you to take them down or remove your claim that they're real photos? I find it odd that they're making claims of the first photo of a black hole while all these other photos already exist..
Sarah Switalski from Iowa on August 30, 2014:
I used to be terrified of black holes as a kid after my brother convinced me that we were all doomed to be sucked into one and ripped apart. I've struggled to understand them ever since that time. This article provides a very easy way to understand the nature of black holes and it's fascinating to see the photos! I hope they can figure out what happens to the matter inside before I die. Thank you for this article!
sunny on December 26, 2013:
it wa awesome
Ellen (author) from California on March 04, 2013:
So did I! And so did everybody, I think; it's only been in the last decade or so that astronomers started finding evidence of them all over the place.
farmloft from Michigan on March 04, 2013:
I thought black holes were much more rare than they are! String theory sounds very interesting - who knew math is such a growing subject. Black holes on one side and white holes on the other? I learned about the six hidden dimensions from your link to mkakuk.org -- thanks for a well done hub. Voted up.
Shea on February 01, 2013:
I learned more from this one hub on black holes than I have in the last ten years. Excellent information and interesting to read. Now I'm going to have to visit NASA's site!
jaydene from Alberta, Canada on February 01, 2013:
Very Fascinating, I have not studied in depth on these black holes in the universe, but i sure know what it feels like to fall into one of them on this planet. :) sorry a little humor there.
I did start to read Steven Hawkins universe, but i found it was too heavy for me at the time. I`d much rather come here to your hub, of which you have done an excellent job. and I can learn so much from.
Thank you for this great information.
Ellen (author) from California on February 01, 2013:
I don't know, and I'd love to know the answer to that question, too!
It's my understanding that the matter is not totally annihilated, but what happens to it is a topic of intense debate among physicists. The problem is that even Einstein's laws of relativity start breaking down inside such extreme conditions. So trying to figure out what happens inside a black hole is like trying to solve a calculus equation using only algebra. One physicist -- I can't remember which, but he was speaking on that "How the Universe Works" black holes episode I linked to above -- said that we need a new law of physics to help crack this puzzle.
String theory may solve the problem, but this is where I get lost. Some string theory experts think that the black hole actually connects to a "white hole" or wormhole into another universe, functioning there like a Big Bang. Dr. Michio Kaku -- one of my favorite popular physicists, who helps mere mortals like me understand a little of this, gives this overview of what string theory says about the inside of black holes:
Stephen Hawking also discovered that, technically, something CAN escape a black hole: Hawking Radiation. This 2004 article explains a little more:
Hawking's excellent 2009 lecture, "Into A Black Hole", is a little over my head, but mostly very readable, so forgive one last link drop:
As you can tell, I'm not an expert, just a tenaciously curious person and well-read parrot. I keep an eye out for astronomy news and good documentaries from NOVA and the Discovery channel, then I root around on the websites of NASA, the European Space Agency, and popular physicists like Kaku and Hawking trying to learn more. However, I'm just Jane Q. Public with a couple humanities M.A.s that taught me how to research what OTHER people have said. ;)
Andrew Spacey from Sheffield, UK on February 01, 2013:
You've created a great hub here, one that is readable for beginners yet advanced enough for those with a little knowledge to appreciate and get their teeth into. I love your descriptives - flying out like potatoe peelings - and grounded language!
How I loved to hear Patrick Moore, the late British astronomer, rattle on about black holes. Superb.
Am I being too stupid when I ask - beyond the event horizon is matter 'recycled' or once in the black hole is matter (as light or waves?) digested or simply annihilated? That is, does a black hole actually swallow, and if so, how does digestion take place?
Votes for this stellar article.
JP Carlos from Quezon CIty, Phlippines on January 31, 2013:
Black holes are really fascinating. I remember reading them as a kid and I still have the same awe now.