# The gravitational radius of a black hole is visible from its satellite at an angle of 1 “.

The gravitational radius of a black hole is visible from its satellite at an angle of 1 “. Determine the linear velocity of the satellite’s circular revolution. Since the gravitational radius is visible at an angle of 1 ‘or (1/3400) radians, the satellite orbits with a radius of 3400 gravitational radii. At this distance, we can use the formulas of classical celestial mechanics. The second cosmic velocity is (2GM / r) ^ 1/2, that is, it decreases in inverse proportion to r ^ 1/2. At a given distance, it will be (3400) ^ 1/2 ~ 58 times less than the speed of light and will be 5100 km / s. The first cosmic (circular) speed will be 2 ^ 1/2 times less and will amount to 3600 km / s. Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.