Astronomical observations of our Milky Way galaxy indicate that it has a mass of about 8 ✕ 1011 solar masses. A star orbiting near the galaxy's periphery is 5.8 ✕ 104 light years from its center. (a) What should the orbital period (in y) of that star be?  y (b) If its period is 7.0 ✕ 107 y instead, what is the mass (in solar masses) of the galaxy? Such calculations are used to imply the existence of "dark matter" in the universe and have indicated, for example, the existence of very massive black holes at the centers of some galaxies.  solar masses

Schwarzschild radius RS of a black hole is the maximum distance from the black hole’s center at which light cannot escape its gravitational field. The quantity RS (with dimensions of length) is dependent on the mass of the black hole M, the speed of light c, and the gravitational constant G. Based on the dimensions of these four parameters, predict an equation for the Schwarzschild radius. Hint: G has dimensions of [L3/MT2]

We are going to make a simple approximation of the number of atoms in the universe. Assume all the atoms in the universe are hydrogen. (In actual practice, over 75% of the atoms in the universe are hydrogen.) Assume the sun is a typical star (made of pure hydrogen) has a density of 1.4 g/cm3 and is a sphere with a radius of 7.0*108m Assume that there are 100 billion stars in our Milky Way galaxy that are identical to our sun. Assume that there are 10 billion galaxies in the universe identical to our Milky Way galaxy. How many atoms are there in the universe?

Astronomical observations of our Milky Way galaxy indicate that it has a mass of about 8 ✕ 1011 solar masses. A star orbiting near the galaxy's periphery is 6.0✕ 104 light years from its center. (a) What should the orbital period (in y) of that star be?  y (b) If its period is 5.1✕ 107 y instead, what is the mass (in solar masses) of the galaxy? Such calculations are used to imply the existence of "dark matter" in the universe and have indicated, for example, the existence of very massive black holes at the centers of some galaxies.  solar masses

Astronomical observations of our Milky Way galaxy indicate that it has a mass of about 8.0 x 1011 solar masses. A star orbiting near the galaxy's periphery is 5.6 x 104 light-years from its center. (a) What should the orbital period (in y) of that star be? y (b) If its period is 5.3 x 107 years instead, what is the mass (in solar masses) of the galaxy? Such calculations are used to imply the existence of other matter, such as a very massive black hole at the center of the Milky Way. solar masses

Astronomical observations of our Milky Way galaxy indicate that it has a mass of about 8 x 10¹¹ solar masses. A star orbiting near the galaxy's periphery is 5.9 x 104 light years from its center. (For your calculations, assume that the galaxy's mass is concentrated near its center.) What should the orbital period of that star be? yr If its period is 5.8 x 107 years instead, what is the mass of the galaxy? Such calculations are used to imply the existence of "dark matter" in the universe and have indicated, for example, the existence of very massive black holes at the centers of some galaxies. solar masses

A person with a mass of 27 kg is standing on a planet and experiences a weight of XYZ N. If the radius of the planet is 2.7 x 10^5 m. Can you determine the mass of the planet?

Four astronauts are in a spherical space station. (a) If, as is typical, each of them breathes about 500 cm3 of air with each breath, approximately what volume of air (in cubic meters) do these astronauts breathe in a year? (b) What would the diameter (in meters) of the space station have to be to contain all this air?

Suppose that radius RE and mass ME of the Earth is known.Using the known radius of the Earth and that g=9.80 m/s2 at the Earth’s surface, find the average density of the Earth.