Astronomy | Astrophysics Answers

What is the magnitude of the gravitational force that acts between the Sun and the Earth? (Include a diagram)
How fast does the Earth need to be moving to stay in orbit around the sun?

Assume the diameter of the Earth (12,700 km) is scaled down to 1 cm and answer the following:
(a) How large is the Sun (diameter: 1.4×106 km) on this scale?
(b) How far away is the nearest star (distance: 4.24 light-years) on this scale?

Two satellites are at the same distance from the Earth. If one of the satellites has a mass of (m) and the other has mass of (2m), which one will have the smaller acceleration?

When the gravitational force of attraction between 2 protons is compared to the electrostatic force of repulsion between the 2 protons, the electrostatic force of repulsion will be what?

Phobos, the larger of Mars’ two moons, orbits 5.99×10 3 km above the planet surface.
Given that the mass of Mars is 6.42×10 23 kg and the radius of Mars is 3.39×10 3 km, what are
the orbital speed and period of Phobos?

what is rate of spontaneous emission to stimulated emission in sun??

How was all the uranium-235 in the universe created?
A - By lighter nuclei slowly absorbing neutrons during a supernova explosion.
B - By the nuclear fusion of lighter elements in the cores of main sequence stars.
C - By lighter nuclei rapidly absorbing neutrons during a supernova explosion.
D - By the nuclear fusion of lighter elements in the cores of red giants.

On the straight line path from earth to moon. the gravitational energy of the projectile of mass m increases as the distance from the earth increases, reaches a maximum at point X somewhere between the two both., and then decreases again as the projectile approaches the surface of the moon Find the distance of point X from the earth's center. With what minimum kinetic energy must we launch a I-kg projectile from the moon's surface if we want it to reach the earth

NASA’s newest exoplanet-hunting telescope, the Transiting Exoplanet Survey Satellite (TESS), has now found its first Earth-sized world. This is another exciting step towards finding worlds beyond our solar system that might be capable of supporting life. The planet – labeled HD 21749c – orbits the star HD 21749, about 52 light-years from Earth. a) What is the force between this planet and its star? The planet has a mass of kg, the star a mass of kg, and the distance the planet orbits the star is m. b) If the radius of the planet is 4842 km then what is the gravitational acceleration on the planet?

Show the horizon coordinates of a star X on a celestial sphere for a location at latitude 60°N . Would these coordinates be same at latitude 30°N.