1.33-1.35

1.33
Use the relationship between orbital speed, orbital radius and time period

Orbital speed = 2 x Pi x Orbital radius
                                time period
v = 2 x pi x r
             T




1.34
Describe how the orbit of a comet differs from that of a planet

1) Comets have sharply turning, elliptical, oval-like orbits, as opposed to the rounder, more circular shape of a   planet's orbit
2) Planets are in much shorter orbits than comets. Although a comet may pass fairly close to the sun at its perihelion it travels much deeper into space than any planets do.




1.35
Recall that the solar system is part of the milky way galaxy
   - Describe a galaxy as a large collection of billions of stars
   - State that the universe is a large collection of billions of galaxies.

Galaxies are large systems of stars and interstellar matter, typically containing several million to some trillion stars, of masses between several million and several trillion times that of our Sun, of an extension of a few thousands to several hundred thousands light years, typically separated by light years distance.

The Universe contains billions of galaxies, there are many different types of galaxy's such as Lenticular, Elliptical, Irregular, and the one that we live in, the spiral galaxy.