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Concretely, about black holes.

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  • Concretely, about black holes.

    Now i know that there is a post but i wanted to put some compiled information out there.
    Don't let the name fool you: a black hole is anything but empty space. Rather, it is a great amount of matter packed into a very small area - think of a star ten times more massive than the Sun squeezed into a sphere approximately the diameter of New York City. The result is a gravitational field so strong that nothing, not even light, can escape. In recent years, NASA instruments have painted a new picture of these strange objects that are, to many, the most fascinating objects in space.


    Although the term was not coined until 1967 by Princeton physicist John Wheeler, the idea of an object in space so massive and dense that light could not escape it has been around for centuries. Most famously, black holes were predicted by Einstein's theory of general relativity, which showed that when a massive star dies, it leaves behind a small, dense remnant core. If the core's mass is more than about three times the mass of the Sun, the equations showed, the force of gravity overwhelms all other forces and produces a black hole.





    Scientists can't directly observe black holes with telescopes that detect x-rays, light, or other forms of electromagnetic radiation. We can, however, infer the presence of black holes and study them by detecting their effect on other matter nearby. If a black hole passes through a cloud of interstellar matter, for example, it will draw matter inward in a process known as accretion. A similar process can occur if a normal star passes close to a black hole. In this case, the black hole can tear the star apart as it pulls it toward itself. As the attracted matter accelerates and heats up, it emits x-rays that radiate into space. Recent discoveries offer some tantalizing evidence that black holes have a dramatic influence on the neighborhoods around them - emitting powerful gamma ray bursts, devouring nearby stars, and spurring the growth of new stars in some areas while stalling it in others.

    One Star's End is a Black Hole's Beginning

    Most black holes form from the remnants of a large star that dies in a supernova explosion. (Smaller stars become dense neutron stars, which are not massive enough to trap light.) If the total mass of the star is large enough (about three times the mass of the Sun), it can be proven theoretically that no force can keep the star from collapsing under the influence of gravity. However, as the star collapses, a strange thing occurs. As the surface of the star nears an imaginary surface called the "event horizon," time on the star slows relative to the time kept by observers far away. When the surface reaches the event horizon, time stands still, and the star can collapse no more - it is a frozen collapsing object.

  • #2
    For me, personally Black holes are places of mystery. The laws of physics predict their existence but cannot explain what happens inside a black hole. Once we can do that, we will have stepped beyond the work of Albert Einstein and taken the next big leap in our understanding of the Universe.

    Put simply, black holes are places where gravity is so strong that nothing can escape once it gets too close. This sets them apart from all other celestial objects, where you would always – in principle – be able to build a rocket strong enough to escape into space.

    With a black hole, it would take an infinite amount of energy to pull away.
    The boundary of no return is called the event horizon. Once across this invisible threshold you will be in the black hole’s clutches forever. It’s the celestial equivalent of a lobster pot – easy to get into but impossible to leave.

    The concept of a black hole follows naturally from Albert Einstein’s General Theory published in 1915. It states that the strength of a celestial object’s gravitational field is determined by the density of matter it contains: the higher the density, the stronger the gravity.

    The dilemma is where does this process stop? In a black hole, there is nothing known that can resist the overwhelming gravity, and we are forced to believe that the matter is simply crushed out of existence.

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    • #3
      Black holes do exist, but there is nothing that can capture it i think as it would be captured itself, its force is way too great to allow anything to escape, and in the middle is the event horizon, or the point of no return.

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      • #4
        Originally posted by Ospina View Post
        Black holes do exist, but there is nothing that can capture it i think as it would be captured itself, its force is way too great to allow anything to escape, and in the middle is the event horizon, or the point of no return.
        Nice that you mentioned the Event horizon, as i failed to mention it.

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        • #5
          The defining feature of a black hole is the appearance of an event horizon—a boundary in spacetime through which matter and light can only pass inward towards the mass of the black hole. Nothing, not even light, can escape from inside the event horizon.

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          • #6
            Originally posted by WizardOu View Post
            The defining feature of a black hole is the appearance of an event horizon—a boundary in spacetime through which matter and light can only pass inward towards the mass of the black hole. Nothing, not even light, can escape from inside the event horizon.
            The event horizon though, is just theoretical at this point but scientists all but confirm it in their studies, it has to exist.. and i am scared of that thought that nothing can escape a singularity.

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            • #7
              It always interested me what happens after this event horizon, we will talk theoretically and highly improbable here - What if you survive and your eyes can see, what would they see, except from the black?

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