ASTA01H3 Chapter : Solar System
Document Summary
I ntro to astronomy and astro part i. The 20th century saw the rise of: non-optical observing aids: Infrared: improvements in telescopes which led to the observation of continuously smaller objects (such as asteroids, spacecraft exploration, as well as space flight, manned missions to the moon. Through the discovery of other planets in the universe (mostly in our galaxy) astronomers have a whole new set of proving grounds in which to compare theory and reality. The sun contains about 99. 9% of all mass in our solar system. Nevertheless, it is possible to measure their masses by careful observations of their gravitational influence on other planets or nearby bodies: these techniques for determining mass were available to astronomers well over a century ago. although the solar system is immense and even though many objects are many au apart, the planets all lie very close to the sun, astronomically speaking.
