Educational worksheet on the Solar System and universe concepts.

Let's solve the worksheet step by step.

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The Solar System

#### The universe
Complete the definitions:

a) The universe is an infinite open space that contains stars, planets, and all the celestial bodies. There are billions of galaxies in the universe. The universe is constantly expanding.

> ✔ Explanation:
> - The universe is often described as infinite or vast, containing everything: stars, planets, galaxies, etc.
> - "Celestial bodies" refers to objects in space like stars, planets, moons, asteroids, etc.
> - There are estimated to be over 100 billion galaxies in the observable universe.
> - The universe is expanding due to the Big Bang theory.

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b) A galaxy is a group of stars, planets, dust, and gas that orbits a center of mass (or central point). There are billions of stars in one galaxy. Scientists who study galaxies are called astronomers.

> ✔ Explanation:
> - Galaxies consist of stars, interstellar gas, dust, and dark matter, all bound together by gravity.
> - They rotate around a central point (often a supermassive black hole).
> - Each galaxy can contain hundreds of billions of stars.
> - Astronomers study celestial objects and phenomena, including galaxies.

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c) Our galaxy is called the Milky Way. It contains billions of stars. The most important star for us is the Sun. We can see the Milky Way from the Earth.

> ✔ Explanation:
> - The Milky Way is our home galaxy.
> - It contains about 100–400 billion stars.
> - The Sun is the central star of our solar system and essential for life on Earth.
> - From Earth, especially in dark skies, we can see the Milky Way as a band of light across the night sky.

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#### Write the names:

Now, let’s identify each image:

1. First image (top left): Shows the Sun with planets orbiting it — this is the Solar System.
2. Second image (top middle): Shows multiple bright stars — this represents Stars.
3. Third image (top right): A spiral-shaped galaxy — this is The Milky Way.
4. Fourth image (bottom left): Another spiral galaxy — also The Milky Way (or a similar galaxy; but since it's labeled separately, likely still referring to The Milky Way or a generic spiral galaxy — but based on context, probably The Milky Way again).
- However, given that there are two spiral galaxies shown, and one is clearly labeled in the word bank, likely both are meant to represent The Milky Way or Galaxy.
- But since only one is mentioned in the word bank, perhaps the second spiral is just a Galaxy.
5. Fifth image (bottom middle): A bright orange sphere with sunspots — this is The Sun.
6. Sixth image (bottom right): A planet with rings — this is Saturn, which is a Planet.

But the word bank says:
Planet – The Milky Way – Solar System – The Sun – Stars – a
(Note: “a” might be a typo or placeholder.)

So, let's match the images using the available words:

- Top left: Solar System
- Top middle: Stars
- Top right: The Milky Way
- Bottom left: The Milky Way (same type)
- Bottom middle: The Sun
- Bottom right: Planet

Wait — but there are only 6 images, and the word bank has 6 items (including "a", which may be incomplete).

Let’s list them properly:

1. Image 1 (solar system diagram): → Solar System
2. Image 2 (cluster of stars): → Stars
3. Image 3 (spiral galaxy): → The Milky Way
4. Image 4 (another spiral galaxy): → The Milky Way (or possibly "a galaxy", but since "The Milky Way" is listed, it could be repeated)
5. Image 5 (Sun): → The Sun
6. Image 6 (Saturn): → Planet

But the word bank includes:
Planet – The Milky Way – Solar System – The Sun – Stars – a

The last word is "a" — likely a typo or missing word. Possibly meant to be "a galaxy" or "galaxy".

Given the options, here's the best match:

| Image | Description | Correct Label |
|-------|-------------|---------------|
| 1 | Planets orbiting the Sun | Solar System |
| 2 | Group of stars | Stars |
| 3 | Spiral galaxy | The Milky Way |
| 4 | Spiral galaxy | The Milky Way |
| 5 | Bright yellow-orange star | The Sun |
| 6 | Planet with rings | Planet |

✔ So, fill in the blanks under each image:

1. Solar System
2. Stars
3. The Milky Way
4. The Milky Way
5. The Sun
6. Planet

Note: Two images show spiral galaxies. Since our galaxy is the Milky Way, and the image resembles it, both can be labeled The Milky Way. Alternatively, if the second is meant to be a general galaxy, but since the word bank doesn't include "galaxy", and "The Milky Way" is present, it's acceptable to use it twice.

Alternatively, maybe the word bank has a typo. But based on what's given, we go with:

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✔ Final Answers:

#### Definitions:

a) The universe is an infinite open space that contains stars, planets, and all the celestial bodies. There are billions of galaxies in the universe. The universe is constantly expanding.

b) A galaxy is a group of stars, planets, dust, and gas that orbits a center of mass. There are billions of stars in one galaxy. Scientists who study galaxies are called astronomers.

c) Our galaxy is called the Milky Way. It contains billions of stars. The most important star for us is the Sun. We can see the Milky Way from the Earth.

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#### Write the names:

1. Solar System
2. Stars
3. The Milky Way
4. The Milky Way
5. The Sun
6. Planet

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✔ All answers are now filled in logically and scientifically accurate.