What is the difference between the geocentric and Heliocentric Model of our solar system? https://www.youtube.com/watch?v=UtOEnTiAZlU

Geocentric Model The Greek astronomer Ptolemy (c90-168AD) used measurements of the sky to create his geocentric model. A model of the universe in which the stationary earth lies in the center and all other celestial objects orbit it. Earth Centered Model

Galileo Galilei (1564-1642) was an Italian astronomer working at a time when all Scientists believed the earth was the center of the Universe and all planets orbited it (the geocentric model). Using the newly invented telescope (Hans Lippershey) he discovered that Jupiter had four moons. As these moons were orbiting Jupiter itself, this showed that not everything orbited the Earth. Galileo’s findings put him into conflict with the Catholic Church as they believed the geocentric model. He spent a large amount of his life under house arrest as a result of his beliefs.

Nicolaus Copernicus It wasn’t until the mid 18th century that Nicolaus Copernicus (1473-1543) came up with a different model. His heliocentric theory put the sun at the center if the universe. It was based on observations with the telescope – work pioneered by the Italian astronomer Galileo Galilei (1564-1642).

Heliocentric Model A model of the universe in which the sun lies in the center and other celestial objects, including earth, orbit it. In this model, the earth both rotates and revolves. Revolves around sun Rotates on its axis Sun centered model

Jupiter Jupiter is the 5th planet from the sun, and has the most moons out of all the planets in our solar system. Some of the planets (Mercury and Venus) have no moons, while Jupiter has 63! These are just the known moons-so there’s always a chance that more will be discovered.

Lunar Cycle During the course of a month, we see many different faces of the Moon. These changes in appearance occur because the Sun illuminates the Moon’s surface as the Moon revolves around Earth. This change in the illuminated surface of the Moon is called the lunar cycle. This cycle has eight different phases.

New Moon Waxing Crescent This cycle has eight different phases. First is the new moon, which occurs when the Moon lies between Earth and the Sun. The side of the Moon that we see on Earth receives no sunlight, so it appears dark. As the Moon rotates around Earth and more of the surface facing Earth receives sunlight, we see more of its surface. This process of the Moon appearing to grow is known as waxing. After the new moon phase is the waxing crescent moon phase, where the Moon grows into a crescent (looks like a thumbnail).

Waxing Crescent First Quarter Waxing Gibbous  Full Moon Next is the first quarter moon, where only half of the surface of the Moon that faces Earth is illuminated; because half of the Moon’s surface faces Earth, and half of that is illuminated, we can see a quarter of the Moon. This looks like a half circle in the sky. This stage is referred to as first quarter because it represents a quarter of the time it takes for the entire lunar cycle to occur. A waxing gibbous moon occurs when the majority of the Moon is illuminated, but not quite all of it. Half way through the lunar cycle is the full moon, when the entire surface of the moon that faces the Earth is illuminated, and the Moon looks like a full, white circle in the sky.

Moon Phases are caused by 2 factors: Half of the moon is always illuminated by the sun We see more or less of the illuminated side depending on the moon’s position

Tricks to Remember If the right side is illuminated it is waxing If the left side is illuminated it is waning As you move from the North Pole to the Equator, the moon will appear to “tilt” more and more.

An eclipse happens when a planet or a moon gets in the way of the sun’s light. Eclipses occur when the Sun, Earth and the Moon are all aligned, and one body casts a shadow on another body. A solar eclipse happens when the new moon passes directly between the Earth and the sun. A lunar eclipse happens when the Earth passes between the sun and a full moon.

In a solar eclipse, the sun gets darker In a solar eclipse, the sun gets darker. In a lunar eclipse, the moon gets darker.

Total Lunar Eclipse-The moon Gets Darker

Total Solar Eclipse-The Sun gets darker

Solar Eclipse The next full Solar Eclipse will occur on August 21, 2017 (right in time for my birthday) We should be able to see it.

Lunar Eclipse You might be wondering why we don’t have a lunar eclipse every month as the moon orbits Earth. It’s true that the moon goes around Earth every month, but it doesn’t always get in Earth’s shadow. The moon’s path around Earth is tilted compared to Earth’s orbit around the sun. The moon can be behind Earth but still get hit by light from the sun.