*Realest black hole picture I could find on the internet*

Since the Hubble Space Telescope was launched in 1990, there have been many observations of what are believed to be black holes, including the photograph below of a suspected black hole in the heart of the galaxy NGC 6251. But the subject of black holes began in theoretical physics, long before there were any observations by astronomers.

The advent of Einstein's General Theory of Relativity gave physicists a mathematical language for describing the gravitational force in a manner consistent with the constant speed of light. Most of what we believe we know about black holes has come from abstract theoretical models in general relativity.

But in order to observe black holes in Nature we need to know how those abstract theoretical models translate to a Universe filled with other stuff.

In the abstract theoretical model of black holes, a black hole is studied as if it were the only thing in the Universe. Using that approximation, the math of general relativity becomes doable, and we can make predictions about black hole behavior that are useful in understanding the black holes we see. In addition, we learn a lot of things about black holes mathematically that we may never get a chance to witness directly through observation.

In general relativity, the paths of light can be calculated for many different distributions of matter and energy using equations call the geodesic equations. The geodesic equations give us the paths that would be followed by freely-falling test particles. For example, a baseball after being hit by Sammy Sosa and before being caught by an eager fan would be a freely falling particle, travelling on a geodesic path through spacetime.

Light travels on geodesics paths through spacetime. When those geodesic paths cross the event horizon of a black hole, they never come back out. Interestingly, in a Universe where the energy density is never negative, this behavior of light leads mathematically to two very crucial properties of black holes:

- The surface area of the event horizon of a black hole can only increase, never decrease. This also means that although two black holes can join to make a bigger black hole, one black hole can never split in two.

- The pull of gravity at the event horizon is constant; it has the same value everywhere on the event horizon.

Black holes terrify me. Then again, so does space in general... we're so small in this huge universe, and who knows how many galaxies, planets, and potential forms of life are really out there. It's amazing.

ResponderEliminarI wonder of we will be able to send probes to a black hole in our lifetime...

ResponderEliminarBasically - it sucks everything.

ResponderEliminarSomeone I used to date took me to see a black hole once. Scary.

ResponderEliminarThe mere ability of the logic surrounding a black hole to blow my mind so beautifully makes me dumbfounded.

ResponderEliminarRelax, we got 1 more year before it happens. Oh wait. People believe those right?

ResponderEliminarMind blowing stuff really

ResponderEliminarHuh, I thought black holes evaporated? No scientist or anything.

ResponderEliminarDude this stuff always fascinates me you are on my morning coffee.

ResponderEliminarThis is insane, but I love the way you wrote this, it makes it really easy to understand! Definitely following you.

ResponderEliminarDo we know what might happen in a black hole?

ResponderEliminarThe mysteries of the universe really dumbfound me

ResponderEliminarfollowed

These things scare and confuse me.

ResponderEliminarblack hole: the perfect junkyard

ResponderEliminarSounds really interesting.

ResponderEliminarBlack holes are a really complex and abstract topic, still you successfully gave me a little insight, thanks!

ResponderEliminarexcellent. I want to see the day where humans fully understand black holes and can utilize them for things.

ResponderEliminarDoes anyone think we will be able to send probes to a black hole in our lifetime...

ResponderEliminarnice. i like to read about stuff like this all the time. blows your mind. +1

ResponderEliminar