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Solar system
Solar system
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Reality 1:

The largest object in the solar system is the sun. It contains 99 percent of the mass of the solar system. Jupiter is the largest planet in the solar system, and Earth is the fifth-largest.


Reality 2:

The sun is at the center of the solar system, and the planets, asteroids, moons, and comets orbit the sun. The Earth is the third planet from the sun.


Reality 3:

Earth and Venus have a couple of things in common: they are rocky planets and are about the same size. But Venus is different in many ways from Earth. Venus has a harsh environment, is very hot, and has a poisonous atmosphere with "acid clouds."


Reality 4:

Mars is about half the size of Earth.


Reality 5:

The planets are different sizes. From smallest to largest they are: Mercury, Mars, Venus, Earth, Neptune, Uranus, Saturn and Jupiter. Jupiter is roughly 10 times larger than Earth. Mars is about half the size of Earth. Venus and Earth are roughly the same size.


Reality 6:

The sun is the closest star to Earth and provides us with most of our energy and light. Earth turns on its axis once every day. When we experience darkness, we are facing away from the sun. When we experience daylight, we are facing the sun. We can't see other stars during the day because the sun's light illuminates Earth's atmosphere.


Reality 7:

The sun is glowing, not burning like a fire. The sun glows because its temperature is about 5,500 degrees Celsius (about 10,000 degrees Fahrenheit). This heat is not produced by burning (a chemical reaction), but rather by fusion (a nuclear reaction). This nuclear fusion takes place deep in the sun's core at a temperature of about 15 million degrees Celsius (about 27 million degrees Fahrenheit). As the heat travels out through the sun's layers, it becomes much cooler, but still hot enough to glow in visible light. For comparison, the temperature of a wood fire is less than a thousand degrees Fahrenheit.


Reality 8:

These giant planets are made mostly of gas. They may have solid cores, but the temperature and pressure of the gas would increase as the spacecraft moved toward the core. It would be destroyed before it reached that solid surface.


Reality 9:

Thousands of rings, made of pieces of ice, orbit the planet. The pieces of ice are about one meter apart, and can be as small as dust specks or as big as a house. The ice pieces collect into ring shapes because of gravity. The rings are usually divided into seven regions, labeled A to G. The total mass of the rings is that of a 100-kilometer-sized comet.


Reality 10:

No, Pluto is not the last object in the solar system. Pluto resides within a region of icy objects called the Kuiper Belt. The Kuiper Belt extends from Neptune's orbit outward. Beyond Pluto's orbit is another vast region of icy objects called the Oort Cloud, which, like the Kuiper Belt, is a home to comets.


Reality 11:

The inner planets (Mercury, Venus, Earth and Mars) are closer together than the outer ones (Jupiter, Saturn, Uranus, and Neptune). The inner planets are closest to the sun. The outer planets are farthest away from the sun. The distance between planets generally increases as one looks farther from the sun. The planets in the inner solar system are tens of millions of kilometers apart; the planets in the outer solar system are hundreds of millions of kilometers apart.


Reality 12:

The solar system also contains the planets' moons, scattered gas and dust, asteroids, and comets. Comets occasionally visit the inner solar system — the region closest to the sun — from their home in the Kuiper Belt or Oort Cloud.


Reality 13:

Although comets and asteroids are both tiny objects that orbit in the solar system, their composition differs. Asteroids are mostly rock with some ice, while comets are mostly ice with some rock.


Reality 14:

Comets do not always have tails. They develop a fuzzy, shell-like cloud called a coma, and one, two, or three tails when near the sun. Comets have no coma or tail when far away from the sun.


Reality 15:

Comets are part of the solar system. Scientists believe they come from one of two locations within the solar system: the Kuiper Belt and the Oort Cloud. The comets that we see often — every 100 years — come from the Kuiper Belt. The comets that we see rarely — every few thousand — years come from the Oort Cloud.


Reality 16:

Meteors are the bright flashes of light seen in the night sky. They are caused by meteoroids — small, solid objects moving through space that have entered Earth's atmosphere. Usually, the meteoroids burn up in the atmosphere and never reach the ground. A meteorite is the chunk of material that does reach the ground.


Reality 17:

A meteor is a bright streak of light in the sky caused when a meteoroid (a small chunk of rock or ice) enters the Earth's atmosphere and heats up.


Reality 18:

Asteroids are not close to each other. They are roughly 1 million miles from each other.


Reality 19:

There is only one star, the sun, in the solar system. Besides the sun, the solar system consists of planets, moons, asteroids, and comets. The solar system resides in the Milky Way galaxy. Many other stars are outside our solar system, but part of our Milky Way galaxy. About 50 billion galaxies are outside our galaxy. Galaxies contain from tens of millions to trillions of stars.


Reality 20:

Scientists are sending out spacecraft and pointing telescopes to learn more about the solar system. Among the many questions scientists are trying to answer are whether Mars has liquid water and how the solar system was formed.


"Myths vs. realities: Solar system" contains common misconceptions about the solar system. The misconception is presented as the “myth” and an explanation of the true concept is the “reality.” Teachers should be aware of the misconceptions students harbor because they impede students' ability to see the “big picture” in the various sciences; hamper students' ability to apply science principles meaningfully to everyday life; and diminish students' ability to appreciate the links among science concepts and generalizations.

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How to use in the classroom

This resource aids teachers in identifying and remedying student misconceptions about our solar system. The best way to learn how students think is to ask them. Below are two strategies that can be employed to identify your students' misconceptions concerning our solar system. The first is an individual writing activity that allows students to think independently. The other is a group activity that allows students to share their ideas verbally.

An individual writing activity. To prepare for a study of the solar system, explain that you are interested in finding out what your students already know about this topic before you start. Ask students to write down what they know about the solar system and why they know it. For example, they may say that Saturn is the only planet with rings, and they know this because they've seen pictures of the planets. Collect their papers and compile a list of misconceptions the students display in their writing.

The next day, start your unit by explaining that it is common for people both children and adults to have misconceptions about their world. Explain that you have a list of misconceptions that you would like to discuss with the class. You can read the misconceptions that appear in Myths vs. realities as well as the ones compiled from the students' papers. Ask the students to comment on the misconceptions and discuss the reality of the situation. If your students have misconceptions about the solar system that we haven't included on our list, you can send them to us through the Contact us section of this web site, and we'll add them to our list. You may want to make special mention of any new misconceptions the students revealed, and let them know you'll submit them to us for addition to our list.

A group activity. Begin your study of the solar system by explaining to students that sometimes the ideas they have about this topic may not be entirely true, and that you are going to try to identify these ideas. Explain that some of these ideas are very hard to remove, and that even their parents may have some of these misconceptions Tell the students that you will read a statement (either a myth or a reality) and they must decide whether it is true or false. Ask them to explain their decision in writing.

Once students have written their responses, discuss their thoughts and the accuracy of the statement. Be sure to establish some ground rules concerning student responses to the thoughts of their peers. Remind them that almost anyone can hold these misconceptions, but they need to be identified and removed before true learning can begin. Ask students if they have any other misconceptions that are not covered in the activity, so you can submit them to us for addition to our list through the Contact us section of this web site. It might help students feel more invested in the activity.

Related materials

Amazing Space resources by topic: Solar system

HubbleSite: Press releases on the Solar System