Noel Meier - Ch. 11 Lesson 1 Science Notes: Fill in the Blank

Chapter 11: Exploring Space

Lesson 1- The Solar System (p. D56)

* The Sun and the bodies that revolve around it make up the solar system. The solar system is a small part of a much larger system call the Milky Way galaxy.

1. _The Sun and its Neighbors_

1. The Solar System

• Solar system- __the sun and all the bodies that travel, or revolve, around it.__

• Our solar system includes the Sun, the 8 planets, their moons, asteroids, comets, and meteors.
• Scientists believe that the solar system is about

 __4.6__ billion years old.

2. The Sun

• The _largest and most massive part of the solar system__
• The Sun’s __gravity__ holds the planets and the moons in their place
• The planets do not make their light, but shine by __reflecting_ the Sun’s light.

1. Planets

• Planets-  __large bodies that revolve around the sun__
• The eight planets from the sun are:

1. __Mercury__
2. __Venus __
3. __Earth_
4. __Mars__
5. __Jupiter__
6. __Saturn__
7. __Uranus__
8. __Neptune__

(Pluto used to be considered the 9th planet.)

• The paths, or __orbits__ of all of the bodies that travel around the sun are shaped like slightly flattened circles called __ellipses__
• Many planets have one or more __moons__.
• All but __two__ of the planets have moons.
• Planets __closest__ to the Sun formed from heavy, rocky material.
• __Farther__ from the Sun, planets are able to hold onto lighter __gases__ and form much larger planets.

2. __Moons__

1. Earth’s Moon

• Earth has __one__ moon

2. Gravity

• All __moons__ are held in their orbits by the gravitational attraction to their __planets__.

3. Other Moons

• There are about 140 other moons in the solar system.
• Mercury and Venus have __0__ moons.
• Mars has __2__ moons.
• Jupiter has __79__ moons.
• Saturn has __82__ moons.
• Uranus has __27__ moons.
• Neptune has __14__ moons.

3. __Asteroid__

1. Asteroid

• An __asteroid___ is a relatively small, rocky object that orbits the sun.
• Scientists estimate that millions of chunks of __rocks__ and __debri_ exist in the solar system.

2. Location

• Most of them orbit in a band called the __asteroid belt__,  located between the orbits of __mars__ and __jupiter__

3. Size

• Asteroids can range from __1__ mile long to __hundreds __ of miles long.

4. ___Comets_

1. Comet

• A __comet__ is a small, orbiting body made of dust, ice, and frozen gases.
• The solid, frozen center is called the __nucleus__
• It’s glowing tail is called the ___coma_.
• Comets orbit around the __sun__ in a long, __elliptical__ path.
• A comet’s tail always points __away__ from the sun, regardless of the direction it is moving.

2. Coma

• When a comet approaches the sun, frozen solid pieces in its nucleus vaporize.
• A __coma__ is when gases and dust are released from a comet, producing the glowing region.
• This is what we see when we look into the sky and see a __shoting __ star. It is a comet’s tail.

3. Short-period comets

• The orbit of some comets extend to just beyond the planet of ___neptune_
• These comets make one complete trip around the Sun in fewer than __200_ years.
• Ex= Halley's Comet which takes __7__ years to orbit the sun. (next time you can see it from Earth is 2061!)

4. Long-period comets

• These comets can take up to __30__ million years to orbit the sun.
• Scientists believe that most of these comets are found beyond __pluto__.
• Ex= Hale-Bopp takes 2,500 years to orbit the sun. It was last seen in 1995.

Q. What causes the “tail” of a comet to form?

1.  _When a comet approaches the sun, frozen solid pieces in its nucleus vaporize___

5. __Meteors Meteorites__

1. Shooting stars

• A bright light that shoots across the sky is not a moving star, it is a meteor.
• A meteor is a chunk of matter that enters Earth’s atmosphere and is heated by friction with the air, causing a streak of light.

2. Meteor Showers

• Meteor showers occur when Earth passes through clouds of dust and particles that were left from a passing comet.

3. Meteorites

• If the meteors stay intact during their trip through Earth’s atmosphere and they strike the ___ground_, they are called __meteorites__

4. Impact Craters

• When large meteorites hit earth’s surface and make a dent in the ground, they form impact craters.
• __impact craters __ are large, bowl shaped depressions in the ground.
• Ex= The Barringer Crater in __20,000-50,000 years ago__ formed 20,000-50,000 years ago.