Aristotle lived about 2,300 years ago. He came up with this model of the solar system.

About 500 years ago, a man named Copernicus came up with this new model of the solar system. What do you notice about it?

Take a look and compare – what do you notice?

Ancient people liked the idea that the Earth was at the center of the solar system. They also thought that the orbits of the planets were perfect circles. (They aren’t.) But when people made observations, some things didn’t make sense. They often tried to make their theories fit what they wanted to believe.

The Earth tilts in the same direction no matter where it is compared to the sun. The Earth tilts in the same direction no matter where it is compared to the sun.

The Vernal Equinox occurs today, at 1:36 in the afternoon. The Vernal Equinox occurs today, at 1:36 in the afternoon. What does that mean? What does that mean?

t It is usually warmer in the middle latitudes – near the equator. It is usually warmer in the middle latitudes – near the equator. This model shows part of the reason. This model shows part of the reason.

Here’s another reason that it’s warmer near the equator. Here’s another reason that it’s warmer near the equator. The energy from the sun has to go through a larger layer of the atmosphere.

u The Phases of the Moon New New Waxing crescent Waxing crescent First quarter First quarter Waxing gibbous Waxing gibbous Full Full Waning gibbous Waning gibbous Last quarter Last quarter Waning crescent Waning crescent

waxing = growing waning = shrinking gibbous = “humpbacked” (bigger than half) Full moon rises at sunset & sets at sunrise New moon rises & sets with the Sun 1st quarter rises at noon 3rd quarter rises at midnight

If you’re on the moon… …it’s the Earth that appears to have phases!

Distances are not to scale, and we have idealized the illustration by fixing the Earth in space relative to the Sun. In reality, the Earth will be in motion around its orbit as the Moon moves around the Earth. Distances are not to scale, and we have idealized the illustration by fixing the Earth in space relative to the Sun. In reality, the Earth will be in motion around its orbit as the Moon moves around the Earth. /time/lunar_anim.html

Lunar Eclipse A lunar eclipse occurs when the moon passes through the shadow of the earth. A lunar eclipse can last up to an hour and a half. During a lunar eclipse the moon may turn a reddish color. It is not dangerous at all to look at a lunar eclipse because the moon does not make its own light. Animation by Stephen Gray using photos © James Funkhouser.James Funkhouser

The world's first artificial satellite was about the size of a basketball, weighed only 183 pounds, and took about 98 minutes to orbit the Earth on its elliptical path. Sputnik History changed on October 4, 1957, when the Soviet Union successfully launched Sputnik I.

A month later, Sputnik II was launched, carrying a much heavier payload, including a dog named Laika. The Sputnik launch also led directly to the creation of National Aeronautics and Space Administration.

In 1961, President John F. Kennedy gave a speech. He said that the U.S. should work quickly and meet a goal. The goal was to send people to the Moon and back. The U.S. did meet the goal. And it only took eight years. One day in July, Apollo 11 launched towards the Moon. It had three astronauts on it. They were Neil Armstrong, Edwin (Buzz) Aldrin and Michael Collins. In 1961, President John F. Kennedy gave a speech. He said that the U.S. should work quickly and meet a goal. The goal was to send people to the Moon and back. The U.S. did meet the goal. And it only took eight years. One day in July, Apollo 11 launched towards the Moon. It had three astronauts on it. They were Neil Armstrong, Edwin (Buzz) Aldrin and Michael Collins.

On July 20, 1969, Neil Armstrong put his left foot on the rocky Moon. On July 20, 1969, Neil Armstrong put his left foot on the rocky Moon. It was the first human footprint on the Moon. They had taken TV cameras with them. It was the first human footprint on the Moon. They had taken TV cameras with them.

The Lunar Lander

That’s one small step…

The diameter of the sun is about 100 times larger than the Earth.

The sun is big, but the largest stars are 700 times larger than our sun.

Solar Eclipse It is dangerous to look at a solar eclipse directly, even if you have sun glasses or smoked glass. It is better to view solar eclipses through a pin hole projector. It is dangerous to look at a solar eclipse directly, even if you have sun glasses or smoked glass. It is better to view solar eclipses through a pin hole projector. A Solar Eclipse occurs when the moon goes in front of the sun and blocks most of the sun's light from the earth. During a total eclipse all you can see from earth is a ring of light around the moon which is part of the sun the moon did not cover.

Solar Eclipse Diagram c/o Wikimedia Commons