When a high-mass star dies, it violently blows apart in a titanic explosion (called a supernova) that can be seen from across the Universe. The remnant is either a tiny, extremely dense object called a neutron star, or a black hole. What if the Sun were to collapse in a supernova (it won’t, but let’s pretend)? Find the period of rotation of the remnant left behind if we model the Sun as a solid sphere, and it compresses from its current radius of approximately 7.0 × 105 km to a new radius of 10 km (a reasonable estimate for the size of a neutron star). The Sun’s current rotation period is 25 days. For simplicity, assume no mass loss.

(Astronomy) Black Hole Gravity II. If a person was falling feet first into a 10-solar-mass black hole and his feet were at the Schwarzschild radius, what is the gravitational acceleration at his head? Assume the person is 2 m tall. Express your answer in units of m/s2. Assume gravitational acceleration is g=GM/r^2

If we were to design a space station for long term habitation by humans, we will need to find some way to replicate the force of gravity on the station. Without this artificial gravity, human growth would be stunted and biological functions will break down. One method of creating artificial gravity is by designing your cylindrically shaped and having it rotate. Human beings can then walk on the inside of the outer edge of the cylinder. (See the diagram below) Let's assume that your space station has a diameter of D = 2535 m such that it is large enough that the curvature is not noticeable by the inhabitants. How many minutes will it take for the space station to spin one complete revolution in order for the artificial gravity to be equivalent to that of earth? IMM5740 2-UJ6ODS.pdf Open file search 112 pause breo 18 19 F10 LEI 14 E38 & 9 R T Y K 00 16 5

the answer should be in expanded form

Neptune has a mass of 1.0 × 1026 kg and is 4.5 × 109 km from the Sun with an orbital period of 165 years. Planetesimals in the outer primordial solar system 4.5 billion years ago coalesced into Neptune over hundreds of millions of years. If the primordial disk that evolved into our present day solar system had a radius of 1011 km and if the matter that made up these planetesimals that later became Neptune was spread out evenly on the edges of it, what was the orbital period of the outer edges of the primordial disk?