Notes Solar System
A planet is any body in orbit around the Sun that a) has
enough mass to form itself into a spherical shape and b) has cleared its
immediate neighborhood of all smaller objects. A dwarf planet is not
required to clear its neighborhood of other celestial bodies. The three dwarf
planets are Pluto, Ceres,
Kepler’s laws of planetary motion.
law The orbits of the planets in our solar system are elliptical, not circular
Second Law A
joining a planet and the sun sweeps out equal areas during equal intervals of
time as the planet travels along its orbit. This means that the planet travels
faster while close to the sun and slows down when it is farther from the sun.
Establishes a universal relationship
between the orbital properties of all the planets orbiting the sun. For the
planets, the cubes of their distances from the sun are proportional to the
squares of their orbital periods.
showed that the bodies revolve about their common center of mass. Where one body is much more
massive than the other, it is a convenient approximation to take the center of
mass as coinciding with the center of the more massive body. e.g. Sun in Solar
noon is the time or point in the sun's path
at which the sun is on the local meridian. Obviously all the places on a meridian
will experience solar noon simultaneously.
At the equator, the sun is directly
overhead at twice a year during the equinoxes; March 21 (Vernal
Equinox), and September 23 (Autumnal Equinox). During the equinoxes,the circle
of passes through the poles to give equal lengths of day and night
is the nearest point in the earth’s or any other planet orbit to the Sun. Earth reaches its perihelion on January 3
is the farthest point from the Sun and the Earth reaches it on July 4
traveling at the escape velocity, or faster, can escape into space. Gravity
pulls back anything traveling more slowly. Earth's escape velocity is 11
kilometers/second. With less surface gravity, the Moon's escape velocity is 2.4
kilometers/second. Hence it is much easier to escape into space from the Moon
than from Earth.
Pictures for Better Understanding
1 Solar System
2 Asteroid Belt
5 Ursa Major
5 Ursa Major
7 Kepler 2nd Law
8 Effects of earth's rotation
Pictures taken from Internet for Illustrative Purpose