What factors determine whether a planet has atmosphere?

8. What factors determine whether a planet has a thick, thin, or no atmosphere? (Please provide all references and complete Urls)

The discovery of Uranus and Neptune.

The first planets discovered since ancient times were Uranus and Neptune. Compare how they were discovered.

What knowledge do comets, meteors, and meteorites solar system?

10. What knowledge do comets, meteors, and meteorites provide to studies of the origin of the solar system? (Please provide all references and complete Urls)

Working with escape velocity, daytime lunar ground temperatures, and atmospheres between the Earth and the Moon.

What is your weight on the moon relative to here if your weight on Earth is 145 lbs? Is the Moon's escape velocity greater or less then Earth's? Is the daytime lunar ground temperature higher or lower then Earth's? Would astronomers have predicted an atmosphere on the moon?

Working with the angular diameter of the moon.

Devise a means of measuring the angular diameter of the moon. What is it when the moon is high in the sky? What is it when near the horizon? Estimate the angle separating the moon and sun on a given date and note the moons phase.