A black hole doesn't have depth. Despite it being called a "hole", it is actually a spherical object that has a singularity at it's centre (where gravity and mass is infinite), and an event horizon that marks the point at which the force of gravity is so strong that not even light can escape. If, by "depth" you meant "diameter", the answer still isn't certain since the diameter of a black hole depends on it's mass (which can be almost anything).
The way the term "black hole" is used in this context is strictly an astronomical phenomenon, a stellar remnant of extreme density. This should not be confused with the "blue holes" which are sink holes on the ocean floor - basically vertical caves, one of the most famous of which is the Great Blue Hole off the coast of Belize.
None, really. At least, for us, and now. A black hole can be dangerous if it's very massive (such as a supermassive black hole). But mainly, a black hole would be completely harmless, unless it gets close - and the nearest known black hole is at a distance of about 3000 light-years. Even a supermassive black hole would be harmless at such a distance.
Depth and temperature.
The galactic centre is the central region of a galaxy. Most, if not all galaxies have a supermassive black hole at their centre.
An active black hole is a black hole that it by all manner of terms is "feeding". That is, it is accreting matter, or sucking matter into itself. Most black holes are dormant and don't show any signs of accreting matter.
The way the term "black hole" is used in this context is strictly an astronomical phenomenon, a stellar remnant of extreme density. This should not be confused with the "blue holes" which are sink holes on the ocean floor - basically vertical caves, one of the most famous of which is the Great Blue Hole off the coast of Belize.
A black hole.
As a black hole.As a black hole.As a black hole.As a black hole.
Scientists know the depth of the ocean by using technology like the Deep Worker or the "Alvin". It takes them to the bottom of the ocean so they can study ocean life. Also ships use sonar (SOund NAvigation and Ranging) to see what the depth of the ocean is.
Quasars have a large black hole, called a "supermassive black hole". The term "supermassive black hole" simply means that it has millions or even billions of solar masses.
in the indian ocean 1000 feat down
As far as we know, most, if not all galaxies have a massive black hole at their centre.
None, really. At least, for us, and now. A black hole can be dangerous if it's very massive (such as a supermassive black hole). But mainly, a black hole would be completely harmless, unless it gets close - and the nearest known black hole is at a distance of about 3000 light-years. Even a supermassive black hole would be harmless at such a distance.
Depth and temperature.
Black holes are in outer space, far outside our solar system. Most galaxies have a large black hole at the center.
The galactic centre is the central region of a galaxy. Most, if not all galaxies have a supermassive black hole at their centre.
An active black hole is a black hole that it by all manner of terms is "feeding". That is, it is accreting matter, or sucking matter into itself. Most black holes are dormant and don't show any signs of accreting matter.