Astrophysics

Black hole theory was a natural consequence of Einstein's general theory of relativity, which was an extension to his earlier special theory of relativity that incorporated gravity. This was presented as a group of field equations, the first solution to which, done by astrophysicist Karl Schwarzchild, led to the understanding of the final stages of gravitational collapse of a massive object like a star.

Relativity predicted that if a mass was compact enough, spacetime would be sufficiently distorted that gravity would prevent anything, including light, from escaping. After Schwarzchild's solution, other solutions were found for charged and spinning black holes (such as those of Roy Kerr). Various other scientists continued development from within the relativistic framework and more fully described properties of black holes, including Penrose, Eddington, Chandresekhar, and many others. Further contributions such as those from Hawking extended black hole theory based on quantum mechanical effects.

Prior to publication of the theories of relativity there was conjecture that an object massive enough could potentially gravitationally attract another object such that its rate of fall would accelerate until it approached the speed of light - and thus considered in reverse, there might be an object massive enough to prevent light from escaping; while in essence this would be a black hole, but many of the implications were not described before the extensions to Einstein's work.

Black holes are located throughout the universe, often at the centers of galaxies. They can also be found in binary systems with other stars. Some black holes are remnants of massive stars that have collapsed, while others are supermassive black holes at the center of galaxies like our own Milky Way.

A star is formed into a black hole by exploding into it. Here is how it works when a star gets to old it grows a little bigger and then smaller then explodes this scientific process is known as a super nova. In order to become a black hole it needs to have a proper size. For example, when the sun has a super nova it will move or destroy about the first four planets in the solar system and when might become a black hole (even though its a midsized star) it might even swallow the last four planets. The end of a black holes life might create another solar system. But first the black hole has to become or form into nothing but just a cloud in space, just two atoms and or cells. Keep this in mind. when there are just two atoms or cells in space that are together, they just start hitting each other again and again until they combine there self's then star of as a really small star. For more information go to http://www.universetoday.com/24190/how-does-a-star-form/

PS I'm a ten year old fifth grader and I know all this stuff since first grade and I answer a lot of questions here.

And i just created an account here too.

It is currently believed that most, if not all, galaxies contain supermassive black holes at their centers. These black holes can vary in size, with some being relatively small and inactive. However, the presence of supermassive black holes in galaxies is a common feature in the universe.

The holes reduce the air resistance acting on the ball by allowing air to flow through them. This decreases the drag force on the ball, enabling it to travel farther than a ball without holes.

The electromagnetic spectrum represents the complete range of frequencies of light energy, spanning from radio waves with the lowest frequencies to cosmic rays with the highest frequencies. This spectrum includes various types of electromagnetic radiation such as microwaves, infrared, visible light, ultraviolet, X-rays, and gamma rays.

It is unlikely that the planets will align with both the sun and a black hole due to the vast distances and different orbital mechanics involved. The gravitational influence of a black hole is significant but typically only affects objects very close to it, while the planets in our solar system have stable orbits around the sun.

We really don't know; we never see it again. There are a few theories about where the matter could go. Some believe that black holes are connected to white holes, or rabbit holes, which end in some parallel universe or galaxy. Or, the matter could simply be destroyed. A major flaw with the latter, is that fermions (matter particles) cannot be created or destroyed in the normal sense. Also, it can depend on the type of black hole in question, because there are two main types; 'Schwarzchild' and 'Kerr' black holes.

The 'Scwarzchild' black hole does not rotate in as much as the motion of it doesn't form a spiral, this means all the fermions (and when bosons past the event horizon) are drawn into the strongest point of gravity called a 'Singularity'. This means there is absolutely no escape for the matter as it will collide; thus the previous definition is what is understood. However, if the black hole does spin as with 'Kerr' black holes, then it is possible for the matter to avoid colliding, even when reaching colossal speeds. These particles, when given enough energy by the gravitational pull around the singularity in a near light speed/light speed spin may escape the black holes during the course of millions or billions of years.

If the question was what is the biggest star in the universe it would be Canis Majoris, which is HUGE. We can fit 1 million Earths inside our sun, and you can fit 7 QUADRILLION Earths inside Canis Majoris!

Georges Lemaître seems to get credit for this proposal in 1927; by 1928 Edwin Hubble's observation that redshift increases with distance (Hubble's Law) seemed the first scientific evidence that the universe was expanding in all directions and thus, at some time in the past, observable matter must have originated from a single point in a cosmic-scale explosion.

Yes, scientists have discovered many new planets outside the solar system, known as exoplanets. Statistical models indicate there are hundreds of billions of such planets within the Milky Way.

There is not a black hole at the center of the Canis Major constellation. Canis Major is a constellation in the night sky and does not have a physical center like a galaxy that could potentially contain a black hole.

To get the Black Hole badges in Khan Academy, you need to complete three different kinds of improbable tasks on the site. These tasks involve answering questions that are extremely unlikely to come up during normal use of the site. The challenges to earn Black Hole badges are intentionally difficult and rare to achieve.

Eris, Pluto and Ceres are dwarf planets within our own solar system.

A wormhole is often likened to a whirlpool because both are characterized by a swirling or twisting motion that draws objects in. Just as a whirlpool creates a pathway through which things can be pulled in and transported elsewhere, a wormhole is a theoretical tunnel-like structure in spacetime that could provide a shortcut for spacetime travel between two distant points.

I guess you mean the centripetal acceleration in its orbit around the Sun. That's not something that will usually be found in references such as the Wikipedia, but you can calculate it in several ways.

1) Use the law of gravitation to calculate the force between an object of mass 1 kg. at Mercury's distance from the Sun, and the Sun. Any other mass will do as well, but after calculating the force, you need to calculate the acceleration, so the mass of Mercury (or another object at the same distance) cancels in the calculation.

2) Look up Mercury's orbital data. Assuming a circular orbit, calculate the centripetal acceleration as v2/r.

Black holes are created when a star runs out of fuel and collapses.

That is a nova, A black hole is made when a neutron star goes SuperNova and the energy tears a hole in space, creating a strong gravitational singularity.

White holes were derived from the theory of relativity by Albert Einstein though never proven. Einstein's theory was expanded by the Schwarzschild metric. Theorists today are attempting to theorize that there is a big bang everyday in black holes where light and matter is released and might answer on how our universe was formed.

There have been holes in the ozone layer, particularly over Antarctica. These holes were caused by the release of chlorofluorocarbons (CFCs) in the atmosphere. Efforts to reduce CFC emissions have helped in repairing the ozone layer over time.

Everything star eventually has an end. A black hole is the last stage of some stars. When the fuel of star ends it converts into core and then finally into either a white dwarf, a neutron star, or a black hole.

The universe certainly encompasses a lot of space, certainly all of known space and our galaxy. Many physicists think that our universe is all there is. However, a fair number of physicists also believe in the multiverse theory which states that there are many universes each with separate laws of physics. Therefore, for all practical reasons there is only one universe. Yet, there are still many highly qualified people who ould say that there are many universes out there each with there own "space."

Big Bang: When space started. Gas, dust and rock particles explode from it and eventually forms celestial bodies.

Black Hole: When a star dies or loses its brightness, develops into a dead star or a black hole.

Black holes have immense gravity that can distort space and time, pulling in anything that comes too close. Once an object crosses the event horizon of a black hole, it cannot escape, as not even light can travel fast enough to overcome the pull. This means that entering a black hole would lead to certain destruction due to the extreme forces involved.

Consider the case of a family of planets in orbit around a star. The orbital speed of each planet depends on the mass of the star and the distance of the planet from the star (presuming that the mass of the planet is negligible in comparison to that of the star). This means that if you know the speed of a planet in orbit, and you know its distance from the star, you can compute the mass of the star.

Now consider an active supermassive black hole at the center of a distant galaxy. The black hole is "active" because there is matter swirling around it, being heated as it is compressed, and thus radiating light (much of it as x-rays).

We can measure the speed of the material orbiting the black hole by measuring differences in the frequency of the light as the material orbits away from us on one side of the black hole and toward us on the other side. If we have a good idea of the distance to the black hole from Earth, we can calculate the distance of the material from the black hole.

So we know the orbital speed of the material and we know its distance from the black hole. It is then easy to calculate how massive the black hole must be.

Yes and No - While the current measure for the mass of a black hole is based on an indirect measuring of the speed of the orbiting material, there is no direct measuring of the density of a black hole.

Density is a concept involving mass divided by volume. While one can abstract the mass of a black hole, measuring the volume is a little tricky. We know there is a boundary at the Schwarzschild radius (Schwarzschild horizon) and this is also called the event horizon. Bascially, anything that happens beyond that point is unknown to us. Supermassive black holes have properties which distinguish them from lower-mass classifications. First, the average density of a supermassive black hole (defined as the mass of the black hole divided by the volume within its Schwarzschild radius) can be less than the density of water in the case of some supermassive black holes. This is because the Schwarzschild radius is directly proportional to mass, while density is inversely proportional to the volume. Since the volume of a spherical object (such as the event horizon of a non-rotating black hole) is directly proportional to the cube of the radius, the density of a black hole is inversely proportional to the square of the mass, and thus higher mass black holes have lower average density.

To complicate things even more, space-time is highly distorted around a black hole, so even asking how big it is, adds further complexity to this answer. Nonetheless, black holes have a mass and size. However one can not know if the mass inside is accreted all at one point or more spread out and distibuted. It appears the inner dynamics of the black hole provide for a plasma like accretion disk, which that pretty much changes (or distorts) our traditional dimensional frame of reference. It could be that the black hole merely suspends acquire mass in a medium of energy state. Consequently this medium of energy may preclude its growth or shrinkage.