1. Environmental Science

8.  Scientists have been researching the sky for almost 3000 years!  Early astronomy was centered in Greece.

12. Famous Greek Astronomers

22. Aristarchus first proposed the heliocentric model, but no one believed him.

26.  Retrograde motion is when the planet appears to stop, reverse its direction for a time and then resume the initial, eastward motion.  Retrograde motion cannot happen! Why?

28. Modern Astronomy uses natural laws as opposed to religion or philosophy to determine astronomical theories.

29. The Scientists involved in the modern Astronomical theory were from a variety of European countries.

31.  Determined that the earth is a planet and that it rotates.  Also proposed a heliocentric solar system.

33. Brahe made observations of Mars and made instruments with which to view the skies.

35. Kepler determined the laws of planetary motion and that the orbits of planets are elliptical.

36.  States that the square of the length of time that it takes a planet to orbit the sun (orbital period) is proportional to the cube of its mean distance to the sun.  Huh?

37. T 2 = d 3

38.  For example:  Mars has an orbital period of 1.88 years. The square of 1.88 is 3.54 (T 2 ). The cube root of 3.54 is 1.52. So the distance from Mars to the sun is 1.52 AU.  The AU stands for astronomical unit is the average distance between the earth and sun is about 150 million km.

41.  Jupiter’s four moons;  That planets are circular disks;  That Venus has phases like our moons;  That the surface of our moon is not smooth;  The Sun’s sunspots.

44.  Is a Scientific theory that every body in the universe attracts every other body.  This attraction is proportional to the mass and inversely proportional to the square of the distance between their centers of mass.  This means: the greater the mass, the greater the gravity. The smaller the distance the greater the gravity.

45.  This force (called gravity) decreases with distance (inversely proportional).  The larger the mass, the larger the gravitational pull.  The moon has a strong enough pull that it causes pull that it causes tides, but a satellite does not have a large enough pull to have a measurable effect on Earth.