Introduction. Before we get started, let’s look at what we need to do in order to complete the tutorial: You can go straight through the tutorial by clicking the next arrow at the bottom right of each slide. Click the previous arrow to go to the slide before.
Before we get started, let’s look at what we need to do in order to complete the tutorial:
You can go straight through the tutorial by clicking the next arrow at the bottom right of each slide. Click the previous arrow to go to the slide before.
2. On the menu slide (next page) you can jump around to any topic. You can return to the menu page at any time by clicking the “home” button.
3. There will be a small quiz at the end, so take your time while completing the tutorial.
Click on the name of any topic to skip right to that section. If you prefer to continue straight through, click the next arrow at the bottom. Remember, clicking the “home” button at any time will bring you back to this page.
Earth- Moon- Sun
Day and Night
Phases of the Moon
At the End
Have you ever believed that something is correct only to find out later that it is actually wrong? That is called a misconception.
Everyone has a misconception about something. Misconceptions are often very common beliefs. Many people don’t even know that their misconceptions even exist.
Astronomy may have more misconceptions than any other field of science.
Why do you think that the sky is blue? Many people believe that the sky is blue because the blue from water is reflected up into the sky.
This is not true and is an example of a misconception.
The sky is actually blue because of sunlight. When it passes through our atmosphere, it creates a blue color.
When you hear something that is different from your misconception, does that automatically fix it? Sometimes it might, but normally it will not.
It can actually take hearing and seeing new information seven times in order to correct the misconception.
People that have misconceptions must work hard to overcome them. Unfortunately, astronomy is filled with misconceptions.
Do you know why this diagram of Earth’s orbit around the sun is a misconception?
With scale, we are not talking about the kind that you weigh yourself with. Think back to geography and scale should start to sound familiar.
A map scale simply helps you to understand how large or far something is in real life. Take a look at the scale in the picture. The scale is 1inch = 100 miles.
So, that means that every inch on the map is 100 miles in real life.
Our solar system isn’t quite like a map you are used to using. It is much larger and things are not always in the same place. The distances between places require huge measurements.
The size and distances are almost too large to completely understand. That is why we need a scale to help give us an idea of how large and far the solar system is.
Let’s take a look at what our normal scale in the solar system will look like.
In this scale, 1mm =1,000 miles
When using a map, the scale may often be 1 inch = 100 miles. However with the solar system, that scale is much too small.
The scale that we will be using the most (but not all the time) will be the scale of 1inch = 1,000 miles.
So for example, the earth is about 8,000 miles in diameter in real life, so according to our scale, how large would the earth be? If you said 8 inches, you are correct. If 1 inch = 1,000 miles, then 8 inches = 8,000 miles.
8 inch model of the Earth
From space, some say that earth looks like a blue marble. The combination of water, breathable air, and the perfect temperature make Earth unlike any other planet in our solar system.
While there is still much to be discovered, Earth is the only known planet in the universe that is able to sustain life.
Earth is the third planet from the sun. A HUGE misconception is that the earth has an oval-shaped orbit around the sun. That is not true at all. Earth actually has a circular orbit around the sun.
Earth is the perfect distance from the sun. It’s not too hot or too cold. The distance that we are from the sun is actually referred to as the “Goldilocks’ Zone”.
Earth has a diameter of about 8,000 miles.
When we often think of the earth, we view it as a huge place. While Earth is very large, it is actually extremely tiny when we look at the big picture.
The next few slides will be taking you on a journey away from Earth. This will help to show just how small we really are.
The first picture shows the earth from our moon. Here, the distance is about 240,000 miles.
This next image shows how the Earth looks from Saturn. As you can see, the earth looks no larger than just a small dot. Without the arrow, you probably wouldn’t have even realized that you were looking at your home planet.
This is about 800,000,000 miles (that’s 800 million) miles away from Earth.
This next image shows Earth in comparison to our entire galaxy (we will discuss galaxies later). Although this is a computer generated image, it is still generally accurate.
From this far away, Earth, the other planets, and even the sun are impossible to see.
Do you know what this last picture is? It looks like many stars, but it is not. These are all galaxies! In the last picture, we saw our own galaxy and couldn’t even see our sun. Here, we have billions of galaxies and ours is just a tiny speck.
Each galaxy has billions of stars and potentially billions of planets. In the grand scheme of things, Earth is invisible.
The sun is the center of our solar system. The planets are all caught in the sun’s gravitational pull.
Solar means sun, so a solar system is a ‘system of the sun’. Without the sun’s gravity, all of the planets (including Earth) would be floating randomly throughout space.
Most importantly, without the sun, there would be no life on Earth.
The sun is about 870,000 miles in diameter. If you remember, the Earth is only about 8,000 miles in diameter. Without a scale, it is hard to realize just how large the sun actually is.
Let’s use the scale we discussed before, 1in. =1,000 miles. Here the earth has a diameter of 8 inches. In this scale, the sun has a diameter of over 72 feet!
Let’s make a smaller scale; this time 1millimeter = 1,000 miles. The earth now has a diameter of 8mm (that’s not even 1 cm.), while the sun has a diameter of 87cm. The image to the right shows the size comparison using this scale.
The sun is by far the closest star to the earth. Other stars are so far away that is it extremely difficult to really tell just how massive they are.
While we saw in our last slide that our sun is huge, in reality it is only an average sized star. Some stars are much smaller than our sun. However, there are also stars that make our sun look tiny (see picture to the right).
Our sun is actually very small when compared to these larger stars.
But how does the Sun compare to the largest stars? Take a look for yourself.
In this picture, the Sun is basically invisible.
Compared to Earth, the Sun is massive. Compare the Sun to other stars and…the picture to the left says it all.
Location of the sun
The earth is about 93 million (93,000,000) miles away from the sun. It is so far that is takes the light from the sun 8 minutes to reach Earth (we will discuss light speed later)!
Let’s use out scale to help us see just how far 93 million miles really is. For this, we need to use our 1mm = 1,000 miles scale. Remember, the earth is 8mm and the sun is 87 cm. In this scale, they are about 93 meters apart. The picture to the right shows this distance. (The light pole represents the correct distance).
We have day and night on Earth because the earth rotates. Rotation means that the earth spins on its axis in place. It takes about 24 hours for the earth to complete one rotation.
Half of the earth is always light and half is always dark. The light side has daytime and it is night on the dark side.
The Earth and the sun work together to give us seasons. The most common misconception is that the earth is closer to the sun in the summer and farther away during the winter.
This is not correct at all. In reality, we are actually closer to the sun during the winter and farther away during the summer.
This is NOT how we have seasons
The main reason that we have seasons is due to the tilt of the earth. This means that poles of the earth are not straight up and down, but are slightly titled to the side instead.
This means that half of the earth is always facing the sun a little bit more than the other half.
Because of the tilt, different parts of the earth face towards the sun at different times of the year.
During our summer, the northern hemisphere is tilted towards the sun and is receiving direct rays of sunlight. During our summer, the southern hemisphere is actually having their winter because they are tilted away and are receiving indirect rays.
During our winter, the northern hemisphere is titled away from the sun and therefore receives indirect rays. The southern hemisphere however is now titled towards the sun.
When we are having winter, the southern hemisphere is enjoying summer.
Northern H. = winter
Southern H. = summer
The other factor that causes seasons is the earth’s revolution around the sun. Revolution simply means that Earth orbits or travels around the sun. The orbit is like a circle, NOT like an oval.
The revolution allows for a different end of the earth to be titled towards the sun at different times of the year.
A complete revolution takes one year.
Let’s review some key ideas with the earth and the sun:
We have day and night because the earth rotates. Half of the earth is always light, while half is always dark.
We have seasons because of the earth’s tilt and revolution around the sun. The hemisphere tilted towards the sun has summer, while the hemisphere tilted away has winter.
The moon is a natural satellite that orbits the earth. A satellite is an object that orbits another. Just like how the earth revolves around the sun, the moon revolves around the earth. The moon is caught in the gravitational pull of the earth.
The moon has an effect on the earth too. The gravitational pull from the moon gives us tides on earth.
In the sky at night, the moon looks very large, but just how large is it? The moon has a diameter of about 2,000 miles. In order to compare it to earth, let’s use our scale of
1 inch = 1,000 miles.
Remember, the earth is a sphere 8 inches in diameter using this scale. That means that the moon would be 2 inches.
When we see the moon, it is very difficult to tell just how far away it really is from earth. The actual distance is 240,000 miles. Let’s use our scale to get a better idea of that distance.
Just like the last slide, we are still using the 1 in. = 1,000 miles scale. So the 8 inch earth and the 2 inch moon would be 240 inches apart, or 20 feet! The picture to the right shows the distance using our scale.
A huge misconception is that the earth’s shadow on the moon is the cause of the moon phases. This is NOT true at all.
The actual cause of the moon phases is how much of the light side of the moon we can see from earth. Just like the earth, half of the moon is always light and half of it is dark.
The first phase in the moon cycle is called the New Moon. At this part of the of the cycle, the moon is between the earth and the sun.
Because the entire lighted side is facing away from Earth, the moon is not visible during this phase.
The moon phases will always go right to left. The waxing crescent shows the very right side of the moon lit up. “Waxing” phases will always mean that the moon is gaining light.
As you can see by this image, only a very small portion of the moon is visible from Earth.
The next phase in the cycle is the First Quarter. Here, the right half of the moon is lit and visible from Earth.
Notice the position of the moon orbiting Earth is changing. This allows for more of the moon to be visible from the dark side of the Earth.
The next phase in the cycle is the Waxing Gibbous. The waxing gibbous is almost a full moon, but not quite yet. The majority of the moon is lit, except for a small portion on the left side.
Notice so far that the moon has been gradually getting lighter from the right to the left.
Also, remember that waxing means more and more of the moon is becoming visible from Earth.
The Full Moon is probably the most recognizable moon phase. Here, the complete lighted side of the moon is visible from Earth. The moon is lined up directly behind the Earth.
Remember, even though the moon is full, we can still only see half of the moon. The dark side is not visible from Earth.
The Waning Gibbous comes after the full moon. Here, only a slight part of the moon is not visible. This time however, it is the right side that is getting darker.
Where waxing meant that the moon is getting lighter, waning refers to the moon now getting darker.
Remember, the phases always work right to left. Now the moon will be getting darker starting on the right side and moving left.
The Third Quarter is a half moon, but now with the left side visible from earth and the right side is now dark.
Notice how the moon is not getting darker from the right side moving left. The phases are essentially now going backwards from earlier.
The Waning Crescent is the final phase before the process starts over again with the new moon. Here, only a small sliver of the moon is visible on the left side of the moon. The complete cycle is just about completed.
It takes 27 days for the entire moon cycle to occur.
Let’s do a quick review of the moon:
The moon is about 2,000 miles is diameter and 240,000 miles from Earth.
Half of the moon is always lit by the sun.
Phases are caused by the amount of the lighted half of the moon that we can see from Earth.
Phases of the moon always for right to left when getting lighter (waxing) and getting darker (waning). The entire process takes 27 days.
For one final review, click on the link at the bottom to review your knowledge of the moon phases.
This site is a great way to either learn about the phases or to simply review and refresh your memory.
Moon Phase Review
Nine planets (including Earth and Pluto) orbit or revolve around the sun. This makes up most of our solar system. Some of the planets are similar to each other, while others are quite different. All of them are very different from Earth in a number of ways.
We will be looking at all of the planets, starting with the closest to the sun (Mercury) and working all the way back to the farthest (Pluto).
Mercury is the closest planet to the sun. It orbits at only 36 million miles away (remember the Earth orbits at around 93 million miles).
The diameter of Mercury is about 3,000 miles, only one thousand miles larger than our moon.
Mercury completes a revolution around the sun in only 88 days, but it also takes Mercury 59 days to make one rotation. However, because the orbit around the sun is so short, it actually causes a day to last for 176 days!
Mercury is so close to the sun that it is not possible for it to even have an atmosphere (the atmosphere would just burn away). Because of this, the temperature on Mercury is a little crazy.
During the day (side facing the sun) it is about 662 degrees F., However, the temperature at night (facing away from the sun) averages -274 degrees F. because there is no atmosphere to hold in the heat.
Venus has been called Earth’s sister planet because it is very similar in size. Size however, is where the similarities end.
The diameter of Venus is just slightly smaller than Earth at 7,500 miles. Venus is also about 67 million miles away from the sun. It takes the planet 225 days to make a revolution around the sun and 243 days to make one rotation…that’s a long day.
Mercury has no atmosphere to hold in heat, but Venus has the complete opposite problem. The atmosphere on Venus is so thick, that no heat at all can escape. Because of this, the temperature averages 900 degrees F. This makes it the hottest place in the solar system other than the sun. (The picture to the left show what Venus looks like under the clouds).
At times during the year, Venus can be easily seen in the night sky. Aside from the moon, Venus is the brightest light in the sky.
Mars is often called the “Red Planet” due to its red color.
Mars has a diameter of over 4,200 miles, a little larger than half the Earth. Mars is about 142 million miles from the sun.
A day on Mars is a little over 24 hours, almost the same as on Earth. It takes Mars 687 days to make a revolution around the sun.
The surface temperature (soil) on Mars is a surprising 73 degrees F. in some locations. The air temperature rarely reaches 32 degrees. At the poles, the temperature becomes much colder.
Mars is the next major destination to travel to in the solar system. Within your lifetime, people may actually walk on the Red Planet.
Jupiter is the largest planet in our solar system. With a diameter of nearly 90,000 miles, it makes Earth seem very small.
On average, Jupiter is about 484 million miles away from the sun. A year on Jupiter lasts for almost 12 earth years. However, a day lasts less than 10 hours!
Probably the most notable feature on Jupiter is the Red Spot. The Red Spot (picture to the right) is an ongoing storm that is 3x larger than earth! Winds in this storm can reach up to 250 mph.
The average temperature in the clouds of Jupiter is about -238 degrees.
Jupiter has at least 66 moons orbiting the planet. Chances are that there are other moons that just have not been discovered yet.
Saturn is the second largest planet in the solar system with a diameter of almost 75,000 miles. Saturn is an average distance of 887 million miles from the sun.
It takes Saturn almost 30 years to make one revolution around the sun. Similar to Jupiter, Saturn has a short rotation time of only about 11 hours.
Saturn is most noted for its massive and stunning rings (picture to the right). The rings however are not solid. They are actually formed from a large collection of dust, rocks, and ice.
Also like Jupiter, Saturn is called a gas giant. The average temperature in the clouds of Saturn is -292 degrees.
Saturn has 62 known moons. One of the moons, Titan, is actually larger than Mars!
Uranus comes next in our journey to the planets. Although it is much smaller than Saturn and Jupiter, it is still much larger than Earth with a diameter of about 32,400 miles.
Uranus averages a distance of 1.78 billion (that’s 1,780,000,000) miles from the sun. It takes about 84 years to make one revolution around the sun, and only about 17 hours to complete a rotation.
The feature of Uranus that really stands out is its tilt. If you notice in the picture, Uranus has a 90 degree tilt so it is actually sideways. The exact reason for the extreme tilt is unknown, but scientists believe that it could have been the result of a major collision.
The average cloud temperature on Uranus is about -346 degrees. There are 27 known moons that orbit Uranus.
In size, Neptune is almost identical to Uranus. Neptune has a diameter of about 30,800 miles.
On average, Neptune is about 2.78 billion miles away from the sun. It takes Neptune almost 165 years to make a complete revolution around the sun. A day though, only lasts for a little over 16 hours.
Like Jupiter, Neptune also has very powerful storms. Some of the winds (like in the former Dark Spot) can reach speeds over 1,000 mph!
The cloud temperature on Neptune averages around -346 degrees.
At certain times, Neptune is actually farther away from the sun than Pluto. The path of the orbits allows for this to occur.
Much is not known about Pluto. It has a diameter less than our own moon at about 1,400 miles.
It takes Pluto 248 years to make a revolution around the sun, and over 6 days to make a rotation.
Pluto was officially downgraded to a dwarf planet in 2006. Pluto even has its own moon named Charon (both pictured to the right).
From this section, these are some of the key ideas to remember:
All planets revolve around the sun. In other words, this is their path/orbit in space.
Rotation is when a planet spins on its axis. This causes day and night.
The larger planets are primarily gas giants. The smaller planets (and moons) are rocky.
Planets do not give off their own light. They just reflect light from the sun.
A light year is simply a way to measure distance in space. It refers to the amount of distance that light can travel in one year.
Space is so large that using miles or kilometers would just be too small.
A light years is the distance that light travels in the time of one year.
Light travels at an amazing speed of 186,000 miles per second! That means that a beam of light could travel around the equator of the Earth 7 times in one second.
In one year, light can travel 5.8 trillion (5,800,000,000,000) miles. A distance that large is almost too much to truly grasp.
Let’s look at an example of deep space. This picture is of a galaxy named the Sombrero Galaxy..
Traveling at 186,000 miles per second or 5.8 trillion miles a year, how long do you think it would take light to get from one end to the other?
These objects in deep space are much larger than they appear.
If we were to travel from one end of this galaxy to the other, it would take 50,000 years of light travel to go complete the trip. Not to mention that this galaxy is only about 28 million light years away from Earth!
This is just a glimpse of how massive the universe is.
50,000 light years
Every time that you look at the stars at night, you are actually looking back into the past.
Let’s say a star that you see is 70 light years away from Earth. That means that it takes the light from the star 70 years to actually reach Earth. So, the light from that star is actually how it looked 70 years ago! Other stars are hundreds of light years away.
Confusing? Yes, I know. Let’s take a look at a much closer example.
The sun is actually about 8 light minutes from Earth. That means that it takes the light from the sun 8 minutes to actually reach Earth.
For example, if the sun were to suddenly go dark this moment, we would not notice on Earth for 8 minutes.
So when you see the sun, you are really seeing the sun how it was 8 minutes ago.
We live in the Milky Way Galaxy. Our entire solar system is a part of this galaxy.
A galaxy is a very large collection of stars and other bodies in space.
Our solar system only makes up a very small part of the galaxy. There are billions of other stars and possible planets.
Our galaxy is only one of billions of other galaxies. Each galaxy has billions of stars and probably billions of planets.
Although each galaxy is massive, they only make up a very small section of the entire universe.
As said before, each galaxy contains billions of stars and therefore billions of planets. Have you ever wondered what those other planets could be like?
Here is one example of another planet in our own galaxy, Wasp-17. Although the picture is just a created image, this planet is unlike any in our solar system. It is slowly being drawn into its own sun.
Here is another example of another planet discovered named Kepler.-22b. What makes this planet so different from others is that it is in the “Goldilocks Zone”. Scientists believe that the surface temperature of this planet could be around 72 degrees F.
Is there life on this planet? Nobody has that answer. This planet is 600 light years away from Earth.
In simple terms, the universe contains absolutely everything. Every planet, star, solar system, and galaxy are part of the universe.
The universe it simply HUGE! There is no number large enough to give its size. The picture to the right is not of stars, but rather entire galaxies! This section of the universe only makes up a very small portion.
As we saw, the universe contains everything. Think about it…there are billions of galaxies, with billions of stars, with billions of planets. If we look at the big picture, the Earth is a microscopic speck.
Although we have not found any other planets with life, do you think that it is possible? In my opinion, the universe is just too massive just for us.
Misconception: a belief someone has that is incorrect
Scale: a smaller version used to represent actual distance and size
Star: a large body in space that gives off heat and light
Planet: a body that orbits a star, but does not give off its own light
Moon: a natural satellite that orbits a planet
Gravity: the force that keeps planets and moons in orbit
Rotation: a planet spinning on its axis; the reason that we have day and night
Revolution: a planet traveling around the sun, or a moon traveling around a planet
Tilt: responsible for the Earth’s seasons along with revolution; Earth is not straight up and down, but rather slightly on its side
Moon Phases: the part of the light side of the moon that we can see from Earth; takes about a month to complete the entire cycle
Light Year: Distance that light can travel in one year
Galaxy: a large collection of stars and planets
Universe: everything in space; most of the universe contains nothing
Click on the best answer for each question
About how far is Earth from the sun?
a) 240,000 milesc) 3 light years
b) 93 million milesd) 8,000 miles
2. A natural satellite of Earth is:
a) the sun c) the moon
b) the planetsd) the atmosphere
3. What is rotation?
traveling around the sunc) moon phases
Earth’s tiltd) spinning on its axis
a) Traveling around the sunc) scale
b) Earth’s tiltd) spinning on axis
5. Why do we have seasons?
a) rotationc) tilt
b) revolutiond) tilt and revolution
6. A way to measure distance in space is:
Click on the best answer for each question
7. What is the solar system?
a) everything in the universec) a galaxy
b) Everything revolving d) planet and around a starmoon
8. The universe mostly contains:
a) nothingc) stars
b) galaxiesd) nebulas
9. Our galaxy is named:
Andromedac) Milky Way
P.S 90d) Universe
The Earth is about 93 million miles away from the sun.
240,000 miles refers to the distance that the Earth is from the moon.
3 light years is not the correct distance. This amount of distance would end up being over 16 trillion miles. In reality, the Earth is 8 light minutes from the sun.
8,000 miles refers to the diameter of the Earth.
The moon is a natural satellite of the Earth. The moon is a satellite because it orbits (or travels) around Earth.
The sun is not a satellite of the Earth. Actually, the Earth is a satellite of the sun. Remember, a satellite is the one orbiting another body in space.
The planets are not satellites of Earth. All the planets are actually satellites of the sun. A satellite is the one that orbits another body in space.
The atmosphere is not a satellite of the Earth. The atmosphere is the layer of gases that surrounds a planet.
Rotation means a planet or other body spinning on its axis. On Earth, this is what helps to give us day and night.
Earth traveling around the sun refers to revolution.
The tilt of the Earth is not rotation. While the Earth is tilted, is has nothing to do with rotation.
The moon orbiting the Earth is not rotation. In this case, the moon is revolving around the Earth.
Revolution means that the Earth is orbiting (or traveling) around the sun. All the planets revolve around the sun.
The tilt of the Earth is not called revolution. The tilt and revolution do work together though to help something else happen.
Revolution is not a form of scale. Scale is what helps us see what actual distance and size look like in a smaller way.
Spinning on its axis is not revolution. When the Earth spins, it is referred to as rotation.
We have seasons because of both the tilt of the Earth and the revolution around the sun. Without both, our weather would remain pretty much the same.
Rotation does not cause seasons. Rotation helps to give us day and night.
Revolution is a part of the reason that we have seasons, but it is not the only reason.
The Earth’s tilt is part of the reason that we have seasons, but it is not the only reason.
A light year is a way to measure distance in space. Other units of measurement are just too small.
A galaxy is a large collection of stars and planets. It is not a unit of measurement in space.
A nebula is created during the death of a star. It is not a unit of measurement in space.
Cosmos is a term that can be used to define space.
A solar system involves everything revolving around a star. The sun is the center of our solar system.
A solar system does not contain everything in the universe. A solar system is much much smaller.
A galaxy is not a solar system. Galaxies actually contain billions of solar systems.
A planet and a moon are a part of a solar system, but not the entire thing.
The universe mostly contains nothing. Although stars and galaxies are massive, they do not take up a lot of space in the universe.
There are billions of galaxies in the universe, but they don’t take up too much space.
There are an infinite amount of stars in all the galaxies, but they don’t take up too much space.
There are billions of nebulas in the universe, but they do not take up too much space.
Our galaxy is named the Milky Way Galaxy.
Andromeda is a name for a nearby galaxy, but not ours.
P.S. 90 is not the name of our galaxy.
The universe is not the name of our galaxy. Our galaxy is part of the universe.
The moon has phases because the lighted amount of the moon we see from Earth changes.
The Earth’s shadow does not block light from the sun on the moon. This is a huge misconception. When this does happen, we see a lunar eclipse.
The moon never changes its actual shape. The only thing that changes is the part of the moon we are able to see.
The sun does not block the moon from our view. The sun is 93 million miles away, while the moon is only 240,000 miles away from Earth.
A star gives off its own heat and light. While other planets and moons may appear to have light, they are just reflecting the light of the star (sun).
The moon does not give off its own light. The light we see from the moon is reflected light from another source.
A planet does not give off its own light. Some planets appear to be very bright in the night sky, but they are just reflecting light from another source.
Titan is a moon of Saturn and it does not give off its own light.
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