Astrophysics

The "no-hair" theorem states that black holes can be described by only three observable properties: mass, electric charge, and angular momentum. Any additional information about the matter that formed the black hole is said to be "lost" to the black hole, making them seem as though they have "no hair" or distinguishing features beyond these three characteristics.

The answer is no. Compared with other objects in space black holes are quite small and emit no light or radiation, which makes them impossible to image across interstellar distances. Theoretically, you could see the event horizon of a black hole as a black ball against a background of stars, with light around it being severely distorted. However, the nearest black holes to us are many light years away, much farther than we are capable of traveling or sending probes. We do have simulated videos based on calculations on how black holes behave.

The black hole at the center of our galaxy, the Milky Way, is about 26,000 light-years away from Earth. It is known as Sagittarius A* and has a mass equivalent to about 4 million times that of our sun.

Black hole formation can not be surreptitiously initiated just anywhere in outer space. Theoretically black holes were formed upon the onset of the Big Bang or can form upon the gravitational collapse of a star of about 3-4 solar masses.

No, black holes do not control polar shifts. Polar shifts are natural phenomena caused by changes in Earth's rotational axis or magnetic field. Black holes are extremely dense objects in space with strong gravitational pulls, but they do not have the capacity to influence the Earth's poles in this way.

Because it takes a large amount of mass for the star to end up that way.

Most stars will become white dwarfs.

A small fraction will become neutron stars.

And even smaller fraction will become black holes.

No, no astronauts have disappeared into a black hole. Black holes are objects in space with such strong gravitational pull that not even light can escape from them. Human space exploration has not led to any incidents involving black holes.

No, black holes are astronomical objects that form in outer space due to the collapse of massive stars. They are not found in Earth's exosphere, which is the outermost layer of the Earth's atmosphere.

Contrary to popular belief, black holes do not "suck in" matter. Just as the Earth's gravity will cause rain to fall downward towards its surface from the clouds above, a black hole will, through gravity, pull in any object that comes too close to it. The speed at which an object is pulled into a black hole isn't a simple, straightforward calculation, simply because there are a number of factors that can influence this (including: initial speed, acceleration, mass, direction of travel, among other things). However, if you were unfortunate enough to get too close to a black hole, you would end up reaching a velocity near or equal to the speed of light once you crossed the event horizon.

If the black hole has the same mass as the sun, and if an object is located at an identical distance from it, the force of gravity acting on that object will be the same. The surface gravityof a black hole, however, is a lot stronger than that of a normal star (including our sun), simply because all of it's mass has been compressed into an infinity small point.

Although most black holes are believed to be associated with stellar evolution (stellar remnants), strictly speaking there are other theoretical methods that could create a black hole which merit a mention - for instance primordial black holes from quantum fluctuations in the early universe, natural and artificial high energy particle collisions, and possible ongoing accumulation of matter onto lighter stellar remnants.

To understand why only the more massive stars (several solar masses) would create a black hole, consider the forces at work: black holes are created when the outward pressure is insufficient to balance against the inward pull of gravity. If the outward pressure is insufficient, a black hole might form. For most of a star's lifetime, collapse is prevented by thermal pressure from nuclear processes which generate significant amounts of heat. Once a star's fuel is exhausted (and allowing for other mechanisms which throw off some of the mass) this effect can no longer balance against the pull of gravity, and some quantum effects may provide the necessary resistance to further gravitational compression; these are referred to as degeneracy pressures. In the case of a large star which has shrunk and cooled to the white dwarf stage, electron degeneracy pressure holds against further collapse; this pressure is a consequence of the Pauli exclusion principle which prevents electrons from occupying the same states (such as already filled energy levels). However, for masses above roughly 1.4 solar masses (called the Chandrasekhar limit) the white dwarf is too massive to resist further collapse and the remnant may collapse further into a neutron star. In this case, the nuclear protons have captured electrons and become neutrons with further collapse resisted by nucleon degeneracy pressure. The upper limit for a mass of a neutron star is not exactly known (see Tolman-Oppenheimer-Volkoff limit) but above this limit, the degeneracy pressure of neutrons is insufficent to prevent further collapse and an object of even greater density may form (such as a 'quark star'). In the case where the mass is sufficient to overcome all forces resisting further compression, gravity will dominate and a black hole may form, with a singularity of infinite compression or density.

Astro-physicist or simply astronomer would probably be the most accurate title.

The event horizon is the point of no return around a black hole where the escape velocity exceeds the speed of light. Light cannot escape from beyond the event horizon because the gravitational pull is so strong that even light cannot overcome it. This is why the event horizon appears to "trap" light within the black hole.

Yes, black holes have gravitational force. This force arises due to the immense mass packed into a small volume, creating a strong gravitational pull that can even prevent light from escaping, giving rise to the phenomenon of an event horizon.

If, in the middle of pitch black night, you hear a squeeling sound, smell the odor of burnt rubber, and the next morning find skid marks in the road; you feel pretty confident that there was fast moving vehicle on your road at some point in the pitch-black night -- even though you never saw one!

It's the same way with black holes: their presence is marked by various, non-optical evidences. The main ones that astronomers look for are "jets" of matter moving so fast that they gives off x-rays.

Stephen Hawking began studying black holes while writing his doctoral thesis in the early 1960s. It wasn't until 1974 that he made groundbreaking contributions to the field with his discovery of Hawking radiation, which revolutionized our understanding of black holes.

Cosmic rays are high-energy radiation that can penetrate through the atmosphere and into human bodies. Exposure to cosmic rays can damage cells, potentially leading to genetic mutations, increased risk of cancer, and other health issues. However, Earth's atmosphere and magnetic field provide some protection from cosmic rays, so the overall impact on human health is minimal for most people.

A broad name for a star which has exhausted its fuel and reached end of its life cycle would be a "stellar remnant." More specific names for stellar remnants, depending on how much they continue to radiate and how advanced their gravitational collapse, would include white dwarf, brown dwarf, (or eventually, black dwarf); neutron star, or black hole. There also may exist more exotic forms of collapsed matter such as a quark star.

b-l-a-c-k h-o-l-e-s = black holes

After black holes, there is not much known in terms of what comes next. Some theories suggest that black holes can evaporate over time through a process called Hawking radiation, eventually leading to their disappearance. Others speculate about the possibility of black holes merging together or transforming into different types of celestial objects. Further research is needed to better understand the fate of black holes and what may come after them.

No, a black hole is not a virus. A black hole is a region in space where gravity is so strong that nothing, not even light, can escape from it. It is formed when a massive star collapses in on itself.

Black holes travel through space like any other object - they move in response to gravitational forces and can be influenced by the presence of other massive objects. As they move, their intense gravitational pull can affect nearby objects and can even distort spacetime around them.

Several things would happen to substance as it goes into a black hole. First and most obvious, it gets accelerated towards the black hole owing to gravitational influence (if it reaches relativistic speeds, this effect alone can cause it to shorten in the direction of acceleration, increase in mass, slow in time for a distant observer, and evidence other effects). Particularly for smaller black holes it would be 'spaghettified', or stretched thin by tidal forces near the black hole. Likely it will interact with the accretion disk and owing to friction and related effects, superheat to plasma temperature and emit significant amount of radiation including at x-ray energy - in fact black holes are quite efficient at converting matter to energy in this manner, perhaps as high as 40 percent of the mass might be lost this way. Once it crosses the event horizon, or boundary at which escape velocity is the speed of light, it would never leave; it must inevitably end up in the singularity at the black hole's center where all mass is concentrated. At that point the nature of the matter changes, our current physical theory does not yet describe the state of the substance at that point - or whether the substance remains matter at all, but theory indicates it occupies zero volume, has infinite density - and for it, due to relativistic effects, time stops entirely.

Big Bang Cosmology was first proposed (although not by that name) in 1930 by Jesuit priest Georges LeMaitre. It became the standard cosmology after the discovery of Cosmic Microwave Background Radiation in 1964, and all alternatives to BBC are now almost pseudo-science.