What is a Black Hole? — Black Holes Explained

What is a Black Hole? — Black Holes Explained

From far away, stars are tiny points of light.
But up close, stars are massive, seething,
fiery balls of burning gas. This fierce display
does not last forever. Eventually, the nuclear
fusion which powers the star will burn all
its fuel. Gravity then collapses the remaining
matter together. For very large stars, what
happens next is a display of extremes. First,
the star explodes in a supernova, scattering
much of its matter throughout the universe.
For a brief moment, the dying star outshines
its entire galaxy. But once the light fades
and darkness returns, the remaining matter
forms an object so dense that anything that
gets too close will completely disappear from
view. THIS is a black hole…
The idea of a black hole originated hundreds
of years ago. In 1687, Isaac Newton published
his landmark work known as The Principia.
Here he detailed his laws of motion and the
universal law of gravitation. Using a thought
experiment involving a cannon placed on a
very tall mountain, Newton derived the notion
of escape velocity. This is the launch speed
required to break free from the pull of gravity.
In 1783, the English clergyman John Michell
found that a star 500 times larger than our
sun would have an escape velocity greater
than the speed of light. He called these giant
objects “dark stars” because they could
not emit starlight. This idea lay dormant
for more than a century.
Then, in the early 20th century, Albert Einstein
developed two theories of relativity that
changed our view of space and time: the special
theory and the general theory. The special
theory is famous for the equation E=mc2. The
general theory painted a new and different
picture of gravity. According to the general
theory of relativity, matter and energy bend
space and time. Because of this, objects which
travel near a large mass will appear to move
along a curved path because of the bending
in spacetime. We call this effect gravity.
One consequence of this idea is that light
is also affected by gravity. After all, if
spacetime is curved, then everything must
follow along a curved path, including light.
Einstein published his general theory of relativity
in 1915. And while Newton’s theory of gravity
could be expressed using a simple formula,
Einstein’s theory required a set of complex
equations known as the “field equations.”
Only a few months after Einstein’s publication,
the German scientist Karl Schwarzschild found
a surprising solution. According to the field
equations, an extremely dense ball of matter
creates a spherical region in space where
nothing can escape, not even light. A curious
result, but did such things actually exist?
At first, the idea of a black sphere in space
from which nothing could escape was considered
purely a mathematical result, but one which
would not really happen. However, as the decades
passed, our understanding of the lifecycle
of stars grew. It was observed that some dying
stars became pulsars, another exotic object
predicted by theory. This suggested that dark
stars could actually be real as well. These
strange spheres were named “black holes,”
and scientists began the hard work of finding
them, describing them and understanding
how they are created.
But how do you find an object in space that
is completely black? Luckily, because black
holes have a large mass, they also have a
large gravitational field. So while we may
not be able to SEE a black hole, we can observe
its gravity pulling on its neighbors. With
this in mind, astronomers looked for a place
where a visible star and a black hole were
in close proximity to one another. One such
place is binary stars.
A binary star is a system of two stars orbiting
one another. We can spot them in several ways.
You can look for stars that change position
back and forth ever-so-slightly. Alternatively,
if you observe a binary star from the side,
the brightness will change when one star passes
behind the other. So it’s possible that
somewhere in space, there’s a binary star
consisting of a black hole and a visible star.
In fact, such binary systems have been observed!
Astronomers have found stars orbiting an invisible
companion. From the size of the visible star
and its orbit, astronomers calculated the
mass of its invisible neighbor. It fit the
profile of a black hole.
Since we can’t see a black hole, is
there a way to find its size? From Einstein’s
field equations, we know that given the mass
of a black hole, we can determine the size
of the sphere that separates the region of
no escape from the rest of space. The radius
of this sphere is called the Schwarzschild
radius in honor of Karl Schwarzschild. The
surface of the sphere is called the event
horizon. If anything crosses the event horizon,
it’s gone forever — hidden from the rest
of the universe.
This means, once you know the MASS of a black
hole, you can compute its SIZE using a simple
formula. And it’s actually quite easy to
measure the mass of a black hole. Just take
a standard issue space probe and shoot it
into orbit around the black hole. Just like
any other system of orbiting bodies — like
the Earth orbiting the Sun, or the Moon orbiting
the Earth — the size and period of the orbit
will tell you the mass of the black hole.
If you don’t have a space probe handy, then
compute the mass and orbit of a companion
star and use that to find the Schwarzschild
Black holes come in many sizes. If it was
made from a dying star, then we call it a
“stellar mass” black hole, because its
mass is in the same range as stars. But we
can go bigger – much bigger. And to do so,
we are going to visit the center of a galaxy.
Galaxies can contain billions and billions
of stars, all orbiting a central point. Scientists
now believe that in the center of most galaxies
lives a black hole which we call a “supermassive
black hole,” because of its tremendous mass.
The size can vary from hundreds of thousands
to even billions of solar masses. For example,
at the center of our own Milky Way galaxy
is a supermassive black hole with a mass 4
million times that of our sun.
Black holes have another property we can measure
– their spin. Just like the planets, stars
rotate. And different stars spin at different
speeds. Imagine we can adjust the size of
this star but keep the mass constant. If we
increase the radius, the spinning slows down…
If we decrease the size, the spinning speeds
up. But while the rotational speed can vary,
the angular momentum never changes – it remains
constant. Even if the star were to collapse
into a black hole, it would still have angular
momentum. We could measure this by firing
two probes into opposite orbits close to the
black hole. Because of their angular momentum,
black holes create a spinning current in spacetime.
The probe orbiting along with the current
will travel faster than the one fighting it,
and by measuring the difference in their orbital
periods we can compute the black hole’s
angular momentum.
This spacetime current is so extreme it creates
a region called the ergosphere where nothing,
including light, can overcome it. Inside the
ergosphere, nothing can stand still. Everything
inside this region is dragged along by the
spinning spacetime. The event horizon fits
inside the ergosphere, and they touch at the
poles. So in one sense, black holes are like
whirlpools of spacetime. Once inside the ergosphere,
you are caught by the current. And after you
cross the event horizon, you disappear.
One final property of black holes we can measure
is electric charge. While most of the matter
we encounter in our day-to-day lives is uncharged,
a black hole may have a net positive or negative
charge. This can easily be measured by seeing
how hard the black hole pulls on a magnet.
But charged black holes are not expected to
exist in nature. This is because the universe
is teeming with charged particles, so a charged
black hole would simply attract oppositely
charged particles until the overall charge
is neutralized.
There are 3 fundamental properties of a black
hole we can measure – mass, angular momentum,
and electric charge. It is believed that once
you know these three values, you can completely
describe the black hole. This result is humorously
known as the “no hair theorem,” since
other than these 3 properties, black holes
have no distinguishing characteristics. It’s
not a blonde, brunette, or a redhead.
We now have a good idea of a black hole from
the outside, but what does it look like on
the inside? Unfortunately we can’t send
a probe inside to take a look. Once any instrument
crosses the event horizon, it’s gone. But!
Don’t forget we have Einstein’s field equations.
If these correctly describe spacetime
outside the black hole, then we can use them
to predict what’s going on inside as well.
To solve the field equations, scientists considered
two separate cases: rotating black holes,
and non-rotating black holes. Non-rotating
black holes are simpler and were the first
to be understood. In this case, all the matter
inside the black hole collapses to a single
point in the center, called a singularity.
At this point, spacetime is infinitely warped.
Rotating black holes have a different interior.
In this case, the mass inside a black hole
will continue to collapse, but because of
the rotation it will coalesce into a circle,
not a point. This circle has no thickness
and is called a ring singularity.
Black hole research continues to this day.
Scientists are actively investigating the
possibility that black holes appeared right
after the big bang, and the idea that black
holes can create bridges called wormholes
connecting distant points of our universe.
We know a great deal about black holes, but
there are many mysteries still to be solved.
It’s a little known fact that all YouTube
videos are stored in a special fabric called
playtime. When you watch a video, it sends
ripples of energy throughout playtime. And
when you subscribe to a channel, it creates
a teeny, tiny black hole. So if you like
Black Holes, then you know what to do…

100 thoughts on “What is a Black Hole? — Black Holes Explained”

  1. How would you see a black hole ? She asked , one way is by seeing gravitational lensing , but strangely you don’t see this at all.

  2. Scientists are investigating the black holes by using equations, and I thought they were supposed to be observing the universe,. It seems that the descriptive equations have become the new reality.

  3. The wormhole hypothesis also predicts that matter and energy that enter a black hole are expelled in the white holes, that are the opposite physical entity to black holes, in another time frame, in another part of the universe, since the physical rules of reality are warped within a black hole, it’s also theorized that black holes are in fact a mass of void, vacuum where patterns and laws of physics don’t exist, so there’s no timespan or physical measurements of mass like weight or density. Thus the possibility of time travel being real and there are numerous research efforts in the topic being conducted 😉

  4. its schwarz "shield" not "child" German "sch" is in English "sh" "i" in German is not the English "eye" it is more like the "i" in "bin" like dust bin or the i in tin like tin foil.

    Be so kind and let an old German Jewish guy have his name being pronounced properly.


  5. so our super massive black hole is pooping off radiation perpendicular to our own galaxie's disc plane? We might be radiating into say andromeda?

  6. I love that the animation of the planets and etc., also the narrator.Her grammar turns me into BlackHole that swallows the informations.

  7. A "Black Hole" is a fictional idea designed to extract taxpayer money for "more research". Swindling scientific authorities use unseeable, invisible, black, dark, inaccessable, deeply buried, hidden objects surrounded by faulty mathematics all the time to bamboozle the public out of their money.

  8. What would undo this entire black hole concept is delta p=h bar/ volume, which means that momentum is inversely Proportional to confinement of matter. Momentum is actually a vector force which would act against any compression of matter and inhibit the matter densities required to achieve a black hole

  9. 01:22 Gotta love the way Newton's map of the globe already had Australia and New Zealand on it…
    …truly a man ahead of his time.

  10. Awesome Chanel. I learned more about black holes in one viewing than I have collectively in all the History and Discovery channel programs combined, and without sensationalism or dumming down. Please keep going with this excellent work.

  11. You can seek knowledge of the function of black holes from the guidance of the Quran by Dr Zaid Kasim Ghazzawi . 😊 Orbit of Sirius star 49.9 years is mentioned in the Quran. 😊

  12. It's obvious what a black hole is the bible makes it very clear

    If you compare what the bible described the lake of fire to be you get a black hole for example a black hole is the definition of located in outer darkness a black hole is the definition of looking like a lake of fire a black hole rips apart energy and light to such a extreme to that all energy all light that enters a black hole ceases to exist aka reference to the second death if a soul was cast into a black hole it would be ripped apart until it ceases to exist like energy like light meaning black holes are lakes of fire https://youtu.be/3AyYItHYmis

  13. I opened the comments to comment on how beautiful you are … I see I'm not the only one. I hope you take all these comments about your appearance as compliments even though a person's looks are largely by chance … so let me compliment you on something that is due to your efforts and tenacity towards knowledge; you explain things well and obviously have excellent skills in learning and understanding, which are surel the result of your hard work and study toward that end. Bravo!!
    Also … you are obviously gorgeous, but part of that is surely your efforts toward fitness and, well, what you choose to wear and what makeup you apply – or DON'T apply, am I right?

  14. Here is something I don`t get : Since light has no mass, how is it that gravity is able to have such an effect upon it as to render it incapable of escape from a black hole ?
    If one takes gravity to mean the curvature of space and nothing but, I think I could see a possible solution in that the light would simply travel parallel to the event horizon with nothing to gain nor lose…
    But we are used to gravity being something tangibly experienced, such as keeping our feet on the ground whilst upright. It seems to me then that, in short, gravity has a direction. In which case I have to wonder whether the direction is constant in some kind of non-Euclidean Space.
    `Hope this makes sense.

  15. I really like the Socratica videos on astro stuff. They go a bit deeper compared to SciShow, yet remain very accessible to many. In this concrete case I also got an answer to something I wondered about rotating black holes.

    In addition it's very well produced and the overall aesthetic is very calm, simple and elegant which I find again refreshing compared to the frenetic and chaotic style you usually find on YouTube.

    Thanks for making it!

  16. This explanation is the best that I have ever gone through, can you please describe sun spots if your time permits. Thanks

  17. So, what about the "tiny black holes" related to the Large Hadron Collider?? Are these tiny black holes an observation or merely a mathematical theory? Are they "black holes" or are they some seperate energy behavior, deserving a different name? Or is it ok to describe them as black holes, and simply use more words to differentiate between "mass driven" black holes and "energy release driven" tiny black holes?

  18. I started watching this video as an atheist, now im a convert to theism
    There must be a god as he did overtime when he made the presenter.

  19. If you're looking for a video to explain Black Holes to kids, we recommend this excellent video from Socratica Kids: http://bit.ly/BlackHoles4Kids

  20. Dear   Friends,   in  YouTube   you can see  and  explore   minimum   250   short  videos  produced   by   me  on     UFOs ,    from   25.07.2017. up  to  09.02.2019., of  the     base   in   Bulgaria  territory  plus   3-4   in  Italy   territory  ( 01. 2014 .  ) ,  in    our    video    chanel     with   name           :        
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  21. Blackholes a hoax – https://www.youtube.com/watch?v=aSX-I5LwFj4&feature=youtu.be&fbclid=IwAR0DsLbXYh2ySnKNORWl19LE86I-gTIDnRTJclw_-Q7nbEtGPzsFRtmbuvc

  22. Reality is not understood in the mere observation of it, but also in the correct interpretation of what is observed..

    "But maybe that is our mistake: maybe there are no particle positions and velocities, but only waves. It is just that we try to fit the waves to our preconceived ideas of positions and velocities.The resulting mismatch is the cause of the apparent unpredictability."
    (Stephen Hawking, "A Brief History of Time" 1988)

    'Black hole' will be most plausibly described as an area in which the clustering of wave-centres that form into 'matter', are eventually returned to pure wave (energy) formed under pressure from the infinitude of space.. As a great 're-cycling' centre of perpetual wave-motion..


  23. Finally a person who questions the bases of "established facts". It should make scientists – with an open mind – think. But it doesn't. WHY? This is where Time, Money and Mathematics, preached in schools and repeated over and over plays its part. Brainwashing and Indoctrination play a very big part in establishing the "truth" of science. Our Brain-Mind complex is so overcome by conditioning over the 300 + years that we don't even realize what's happening. In psychology there's a phenomenon called "suggestion" which works quite readily. Then there's auto-suggestion, which nobody understands. Science recognizes brain but not the mind. For proof of where we are today, just think of the achievements of pre-science civilizations – a great embarrasment to the scientific method. Scientists are completely brain-washed by Time Money and Mathematics, which are man-made conveniences for commerce. They have zero relevance to reality. But that's all science has got. Great ego-boosters! Ask a simple question. Out come a series of equations, what a sham for an elitistic outlook. Look, I've got a Nobel Prize! And then Dawkins, Kaku and Neils make fun of religion. Without spirituology study of matter is a farce. Talk to teenagers. What's their mental status today? For more go to:

    1. For Brain-Mind Complex
    Click https://youtu.be/myxVwrqf0co
    2. For Mind Sciences
    Click https://youtu.be/X0KLgar5o58

    It took many years of research to prepare the material.. Your comments will be helpful as feedback.. They are forward thinking.

  24. One of these days it’ll be neat to see if quantum mechanics and relativity can ever get married. Right now they’re not compatible. That would be quite a hurdle jumped if and when that happens.

  25. FACT !
    Gas Bonding totally destroys Einstein's Space Bending and Newton's mythical Gravity .

    All downward falling motion begins when active rising gas molecules in motion becomes trapped and motionless within the process of making solid objects, with trapped ENERGY LOCK lifeless dead gas molecules, which as dead gas molecules can only fall downward.
    This is scientificly known as the mechanism of GAS BONDING, which take on a state of solid mass, blocking out its electrons motion, it's fire power, thus becomes ENERGY LOCK lifeless dead gas molecules, and falls downward in real time, fallowing it's Electrons Unlimited Potential Velocity, at the speed of light, connects with the earth ENERGY CONSERVATION SYSTEM, establishing a downward falling path, for trapped ENERGY LOCK lifeless dead gas molecules/solid objects only.

    Equating the above FACT with the physical universe, same as Einstein's E = MC2 equates with the physical universe.

    E = ENERGY = MM = MOLECULE MOTION = Molecules in motion within star flames earth gases birds and balloons plains and rocket's, even us humans rise from molecules in motion, creating an ENERGY FLOW, the ruling force of the universe.

    M = MASS = GB = GAS BONDING = Gas Bonding take on a state of solid mass, blocking out its electrons motion, it's fire power, thus becomes ENERGY LOCK lifeless dead gas molecules , and falls downward in real time.

    C2 = LIGHT SPEED = E = ELECTRONS = Electrons Unlimited Potential Velocity, at the speed of light , connects with the earth ENERGY CONSERVATION SYSTEM, establishing a downward falling path, for trapped ENERGY LOCK lifeless dead gas molecules / solid objects only .

    Gravity is a mythical concept that's mentally applied by Newton, solely to guarantee needed results to it's point of origin, the BRAIN !

  26. they're such nice story tellers, but no physical evidence for any of this. bs theories based on manufactured models and some contrived math to complete the novel…and Lord of the Rings is true history.

  27. Why can't we see a blackhole by observing the light that curves around it from any single direction to earth? Find the star nearest to the blackhole, calculate the source trajectory of the light that curves around the blackhole, and bingo, you have an observable blackhole.

  28. black holes DON’T exist…..they’re a non scientific mathematical/gravitational theory….see THUNDERBOLTS PROJECT / ELECTRIC UNIVERSE

  29. A black hole is a ball.Black holes constantly swallow substances, and they are also merging with another black holes,for example, in the future, our Milky Way shall merge with the Vega.Our Milky Way should have been merged with another galaxies many times.Each merger of the black holes emit gamma ray burst.Each time our Milky Way merges with another galaxies could have an influence on the Earth's creatures.As black holes constantly swallow substances and merge with another black holes, the qualities and temperatures of the black holes are constantly rising.When the explosive force inside the black hole is greater than the cohesive compression force (the critical point, it should be a constant), the black hole should explode.The black hole before the explosion was the singularity of the universe , and after the explosion, the new universe formed.We think the universe should be circulating like this.The size of each universe, that is, the size of the universe's space, is determined by the gravitational force of the black hole and should be a constant.

  30. Because of a new theory called Core Theory black holes are just low level particle stars: https://www.youtube.com/watch?v=Jmvb5qm7Nhk

  31. black holes really don't exist just like any absolute/singularity/god/etc. so fill them with imagination like Hollywood/nasa/religion/etc:)-

  32. obtrusive writing and slightly sexism detected:
    – matt8863
    – Ger
    – Patrick P
    – Roberto Eduardo Madrazo Estrada
    – Vladimir Yevsukov
    – The Goodly Dragon

  33. Outstanding work, Socratica. Your production values and explanations are several orders of magnitude above mine. I hope to grow up to be big and awesome like you someday 🙂

  34. This is better than Nova! I started your python tutorial to learn (it's amazing) and I am suddenly stumbling on all this amazing content! Highly recommending this channel to everyone at work these days.

  35. So all thats being saided,after research,study..my question is whats in a black hole,whats on the other side of a black hole?my guess is a death portal to the other side,their is something on the other side,it act as a boundry,
    Pitch black dark gate way final destiny

  36. I love your videos, Socratica!! This one is really well made and it summarizes in a very clear way our understanding of Black Hole Physics. It's so amazing that we have now seen (the event horizon of) one for the first time 🙂.

  37. The photon sphere is a 3D light sphere skining the black hole. The black is Inside, how we can see it through a sphere of light?? I understand now is because the ROTATING light when is at other angles than pointing us do not obstruct the view. Also the video from "Action Lab , Dark Light" help understand.
    Rotating light I read at PBS space and Science Asylum. Other thing, when Matt said "Actual" or "Currently" is the object behavior at 53 Myears ago…

  38. Maybe you'd like to pronounce Schwarzschild properly… you got the first part (Schwarz) right, but it's about "shield", not "child".

    <— native speaker. 🙂

  39. Now we know black hole exist because of the picture we recently got that showed a massive black hole from the Messier galaxy


  41. balls of burning gas? collapsing under gravity? how does space-time curvature compresses a ball of gas?

  42. In this video, you say stars ultimately blow up into a super nova then turn into black holes.

    But in THIS video
    you say they turn into WHITE DWARF STARS.

    Does it become a black hole or a white dwarf?

  43. Does Newton's law of gravitation apply to light photons assuming their mass as being equivalent to their energy (mc^2 = E = h𝜈 for each photon) ? Or does General Relativity deviate in spite of this assumption.

  44. I believe some black holes maybe super intelligent civilizations that have learned to harness nearly 100% energy from stars around them without getting themselves destroyed… no need to move around and conquer if you are advanced… Bring all the energy to yourself by bending space and even time maybe through gravitational waves. I mean, Possible 100,000 black holes in the milky way? That answers the Femi paradox hypothesis that there should be thousands of alien civilizations in this galaxy yet we cant see them. Think about it.

  45. I subbed! But…. I still have two criticisms. The first is not important, but please research how to pronounce Scharzschild correctly. The second is more important. The most defining thing of a black hole is that is sucks up future in spacetime. If you enter, all of your possible futures are inside the black hole. It is not only (or primarily) that you cannot get enough speed to exit a black hole, although that is true. But primarily, the black hole will not give you a future outside it anymore. That is the "time" component of spacetime is completely reversed with the "space" component. Thereby leaving a "hole" in spacetime. The name "black hole" is therefore not badly chosen.

  46. I have always found the term "black hole" misleading. "Black Star" would be better in my opinion.

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