1. Big Idea 5: Earth in Space and Time
Our Solar System part 3…
Big Idea 5: Earth in Space and Time

2. Comets: Dirty balls of Ice
Comets are mountain-size chunks of ice and dust that orbit the sun.
They travel in a different orbit than the planets.
Some orbit the sun again and again.
Others crash into the Sun.
Some make a trip around the Sun and never return.
They look like a star with a ghostly white tail.

3. Halley’s Comet (the most famous) Fun Facts
Halley's Comet is arguably the most famous comet. It is a "periodic" comet and returns to Earth's vicinity about every 75 years, making it possible for a human to see it twice in his or her lifetime. The last time it was here was in 1986, and it is projected to return in 2061.

4. Comets………Dirty Balls of Ice
They can be seen by us only when they pass by the sun and the sun’s heat melts them.
The comet's tail is made of material from the comet; gas from the ices and dust that is mixed in with the ice. They escape as the comet melts.
The tail always points away from the sun due to the solar winds (movement of heat away from sun)
If a comet has a large orbit, it takes a long time to go around the Sun. Some comets are "short-period" comets that take five or ten years to complete an orbit. Some comets are "long-period" comets that take decades, centuries, or millennia to orbit the Sun.

5. Comets………Dirty Balls of Ice
After 500 or so passes near the Sun, most of a comet's ice and gas is lost, leaving a rocky object very much like an asteroid in appearance.

6. Comets………Dirty Balls of Ice
What are scientists doing to learn more about comets?
Deep Impact: NASA’s space probe: The mission is attempting to bring a spacecraft and a comet together at truly out-of-this-world speeds so we can learn about the interior of a comet. or

8. Asteroids……Rockin’ Around
Asteroids are LARGE chunks of rock and metal that orbit the sun.
They range from just over ½ a mile (1km) to a few hundred miles in diameter (diameter = how wide across)

9. Asteroids……Rockin’ Around
Most of the chunks or rock and metal in space came together long ago to form the planets and moons.
Asteroids are left-over pieces of rock from when the solar system was formed.

10. Asteroids……Rockin’ Around
Most asteroids travel in the wide gap between the inner planets and outer planets (between Mars and Jupiter-asteroid belt).
But a few travel in paths across Mar’s orbit and some even cross in Earth’s orbit.

11. Meteoroids, Meteors, Meteorites
A meteoroid is a small piece of stone-like or metal-like debris which travels in outer space. Most meteoroids are no bigger than a pebble. Large meteoroids are believed to come from the asteroid belt. Some of the smaller meteoroids may have come from the Moon or even Mars.

12. If a meteoroid falls into the Earth’s atmosphere, it will begin to heat up and start to glow. This is called a Meteor.
If it survives falling through the Earth’s atmosphere and collides with the Earth’s surface it is known as a meteorite.
. If a meteoroid falls into theMEarth's atmosphere, it will begin to heat up and start to glow. This is called a meteor. If you have ever seen a "falling star", you were actually seeing a meteor. Most of the original object burns up before it strikes the surface of the Earth. Any leftover part that does strike the Earth is called a meteorite. A meteorite can make a hole, or crater, in the ground when it hits it. The larger the meteorite, the bigger the hole.

13. A meteoroid that burns up as it passes through the Earth’s atmosphere is known as a meteor. If you’ve ever looked up at the sky at night and seen a streak of light or ‘shooting star’ what you are actually seeing is a meteor.
Sometimes there are
many meteors known
as meteor showers.

14. A meteoroid that survives falling through the Earth’s atmosphere and colliding with the Earth’s surface is known as a meteorite.

15. Meteors…Shooting Stars or Space Garbage
Meteors are also called shooting stars
Meteors are small pieces of space debris (junk) pulled into Earth’s atmosphere by gravity.
Meteorites are metallic rocks broken off from asteroids and comets
Meteors fall to Earth at speeds from 22,000 MPH to 64,000 MPH (8x shuttle speed)
You Can Buy Meteors-

16. Meteors…Shooting Stars or Space Garbage
Most meteors are only as big as a grain of sand.
Most burn up while entering Earth’s Atmosphere
However………………
They can be bigger. Craters in the Earth and ones studied below the surface show that one about the size of a house landed about 250,000 years ago! Is that what killed the dinosaurs???

17. Meteors…Shooting Stars or Space Garbage
Meteors are falling all the time.
On a clear, dark night you may see one.
During the annual meteor storms, you may see 100 per hour.

18. Meteors…Shooting Stars or Space Garbage
How can something as small as a grain of sand light up so brightly?
Entering the Earth’s atmosphere so fast creates a lot of friction. The friction causes them to heat up and give off light.
The light trail may stay in the sky for up to 30 minutes and end with a “POP”.
REALLY bright meteors are called
FIREBALLS

19. Department of Mathematics and Science
What’s the Difference?
Comet
Asteroid
Comets are balls of ice –mostly frozen gases and rock
A comet's body has two parts, a head and a tail.
As they revolve around the Sun, their tail grows longer because the ice in the head boils away.
Move in orbits that take them far from the Sun.
Asteroids are irregularly shaped objects made up of rocks and metals too small to be classified as planets.
Revolve around the Sun.
Most are present in a band located between the orbits of Mars and Jupiter, known as the asteroid belt.
Explain/Evaluate: Ask students to compare comets to asteroids: What are they both made of? What is their orbit? Where can they each be found? . Have students make a T-chart and work in a group to compare asteroids to comets together. Allow time and then check together.
Department of Mathematics and Science

20. What’s That Up In The Sky???
COMETS
ASTEROIDS
METEORS
Made of ice-have tails
Made of rock and metal
Stay in space
Fall into Earth’s atmosphere
Orbit the sun
Gravity pulls to Earth; they burn up as they fall

21. The Movement of the Earth Around the Sun
How is the Earth moving?
It turns or rotates spinning on its axis in a 24 hour day.
2. It revolves around the sun.
Explore: Do the Cycle of Day and Night online Discovery exploration.
Explore and Explain: Have students make the foldable It’s Apparent. Then read It’s Apparent with students and model the movements of the Earth. pp. 4-5
Materials: tennis ball or styrofoam ball or apple skewer or stick thumbtack
How long does it take for the Earth to complete one whole spin on its axis? It takes about 24 hours or a day to complete a rotation. This rotation causes day and night. As the Earth spins the part of Earth that sun’s rays hit is lit up and has daytime. As the Earth keeps rotating, the side facing the Sun begins to turn away from the sun making it night.
You can model how day changes into night using a bare lit light bulb in a lamp and an apple on a stick. The light bulb models the Sun. An apple or a tennis ball is the Earth and the stick represents its invisible axis.
Let’s mark Miami’s location on the apple. This side of the apple with Miami faces the “Sun” and is lit up having daytime while the other side of the apple is dark. As the Earth keeps rotating, Miami begins to turn away from the Sun making it night.
When we return to where we started, a whole day and night has passed. We can’t feel the Earth rotating. But we can tell it is moving because of the changes in the sky. Ask your students to describe the changes they see in the sky from morning until night.
Elaborate: In our model, ________________ represented the _________, the __________ represented the _________, and the __________ represented the _________.The model showed__________________________________________________________________.

22. Why do we have Leap Year? Fun Fact!
2017
365 ¼
2018
2019
2020
Add ¼ + ¼ + ¼ + ¼ =
1 whole (1 whole extra day)
This is Leap Year!