- #1
rollingstone
- 7
- 0
Can you get a thing like that within the sol's closest space? I mean, if there was one somewhere between us and say alpha centauri or barnard's star, is it possible that you cannot feel it's gravity force?
Not so. I forgot the "size" that our sun would have for an EH if compressed to a black hole, but it is very small. For example, for a star with a mass of 19.9 x 10^30Kg (A mass of about 10 times that of our Sun) would have a Schwarzschild radius of about 30 kilometers. That's only about 18.6 miles!Dr.Brain said:Black Holes's gravitational field is nothing special.If a black hole has an event horizon radius same as that of sun , its gravitational field would be same as that of sun
This is true, it is just another source of gravity that we may, or may not, detect.Dr.Brain said:I doubt that Gravitational field of a BH at such a distance would make a major impact on field around us , and may go undetected unless BH is itself massive.
If the Sun were somehow compressed enough to become a black hole, it would be less than 6 kilometers (well under 4 miles) across.
Labguy said:Not so. I forgot the "size" that our sun would have for an EH if compressed to a black hole, but it is very small. For example, for a star with a mass of 19.9 x 10^30Kg (A mass of about 10 times that of our Sun) would have a Schwarzschild radius of about 30 kilometers. That's only about 18.6 miles!.
Your description is correct, but I took his statement to mean an EH radius equal to the sun's radius, which would mean a massive BH. Not sure that's what he meant.George Jones said:I think you and Dr. Brain are saying the same thing. The Schwarzschild radius for any (spherically symmetric) massive object can be calculated. If the the Schwarzschild radius lies within the object (i.e., the object has mass outside), then the object is not a black hole; if all the mass lies inside its Schwarzschild radius, then the object is a black hole. By Birkhoff's theorem, a distant observer cannot use gravity to tell the difference between equal mass (spherically symmetric) objects, be they stars, black holes, or even stars collapsing (spherically symmetrically) to form black holes.
Regards,
George
Labguy said:Not so. I forgot the "size" that our sun would have for an EH if compressed to a black hole, but it is very small. For example, for a star with a mass of 19.9 x 10^30Kg (A mass of about 10 times that of our Sun) would have a Schwarzschild radius of about 30 kilometers. That's only about 18.6 miles!
This is true, it is just another source of gravity that we may, or may not, detect.
EDIT: Found it (too lazy to calculate)
I agree, but you said size instead of mass. Mass would be a more accurate description as size implies a measure of distance and mass is "a quantity of matter", regardless of size.Dr.Brain said:I was trying to imply that whenever you are outside a black hole having a size of some star A, its gravitational field would be no different from that star . I mean that if the poster above had asked me if a star's gravitational field between us and alpha centauri could be detected , the answer would have been the same.
Concluding that as long as you are outside a black hole , it can be treated as just another body carrying massive mass just like a star.
BJ
A black hole within 20 light years refers to a black hole that is located within a distance of 20 light years from Earth. A black hole is an extremely dense and compact region in space where the gravitational pull is so strong that not even light can escape from it.
A black hole within 20 light years can be formed through the collapse of a massive star. When a star runs out of fuel, it can no longer sustain its own weight and collapses under its own gravity, forming a black hole. This usually happens with stars that are at least 20 times more massive than our sun.
The effects of a black hole within 20 light years can vary depending on its size and distance from Earth. At a distance of 20 light years, the gravitational effects of a black hole would not be significant enough to cause any major disturbances in our solar system. However, if it were to approach closer, it could potentially disrupt the orbits of planets and other objects in our solar system.
As mentioned earlier, the effects of a black hole within 20 light years would not be significant enough to affect Earth. However, if a black hole were to approach closer to our solar system, it could potentially cause disruptions in the orbits of planets and other objects, which could have indirect effects on Earth.
Currently, there are no known black holes within 20 light years from Earth. However, with advancements in technology, it is possible that we may be able to observe and study black holes within this distance in the future. As of now, the closest black hole to Earth is about 3,000 light years away.