How did our solar system come to be? An interactive educational diagram from NASA explaining the formation process.

Let's solve this step-by-step based on the diagram titled "How did our solar system come to be?". The image shows a timeline of events in the formation of the solar system, starting 4.6 billion years ago and ending at the present. We need to drag and drop the correct events into the appropriate boxes along the timeline.

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🌟 Overview of Solar System Formation (Nebular Hypothesis)

The accepted scientific theory for the formation of the solar system is the Nebular Hypothesis, which includes these key stages:

1. A large cloud of gas and dust (a nebula) collapses under gravity.
2. It forms a spinning disk with a dense center.
3. The center becomes the Sun.
4. Planets, moons, asteroids, and comets form from leftover material.

Now, let’s match the events to their correct positions in the diagram.

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🔤 Step-by-Step Placement

We'll go from left to right, following the timeline from 4.6 billion years ago to the present.

#### 1. First Box (Far Left – Start of Timeline):
> "Cloud of gas and dust formed."

This is the very beginning — the original nebula that existed before anything else.

✔ Place: First box on the far left.

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#### 2. Second Box:
> "Cloud collapsed in on itself."

After the cloud formed, gravity caused it to collapse inward, leading to rotation and flattening.

✔ Place: Second box.

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#### 3. Third Box:
> "Creation of flat spinning disk of dust and gas."

As the cloud collapsed, it spun faster and flattened into a disk — the protoplanetary disk.

✔ Place: Third box.

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#### 4. Fourth Box:
> "Rocky stuff surviving near Sun."
> "Gases and ice surviving away from Sun."

In the disk:
- Near the Sun: high temperature → only rocky materials could survive.
- Farther out: colder → gases and ices could condense.

These are two related events that happen simultaneously as the disk settles.

✔ Place both in the fourth box.

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#### 5. Fifth Box:
> "Left-overs from Sun clumped together."

Material that didn’t go into the Sun began to clump together due to gravity — forming planetesimals.

✔ Place: Fifth box.

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#### 6. Sixth Box:
> "Planets form."
> "Moons form."
> "Asteroids form."
> "Comets form."

Planetesimals collide and grow into planets, moons, asteroids, and comets.

- Planets form from larger clumps.
- Moons form around planets.
- Asteroids are remnants in the asteroid belt.
- Comets form in outer regions (Kuiper Belt, Oort Cloud).

✔ These all occur during this stage — place them in the sixth box.

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#### 7. Seventh Box:
> "Sun was born and gobbled up 99.8% of all material."

The central mass ignites nuclear fusion and becomes the Sun.

✔ Place: Seventh box.

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#### 8. Eighth Box:
> "Nuclear fusion begins."

This is when the Sun starts fusing hydrogen into helium — marking its birth as a star.

✔ Place: Eighth box.

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#### 9. Ninth Box (Final – Present):
> "Comets and asteroids are the left overs."

These are remnants of the formation process that never became part of planets.

✔ Place: Final box (Present).

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✔ Final Answer: Correct Event Placement

| Box Number | Events |
|-----------|--------|
| 1 | Cloud of gas and dust formed. |
| 2 | Cloud collapsed in on itself. |
| 3 | Creation of flat spinning disk of dust and gas. |
| 4 | Rocky stuff surviving near Sun. <br> Gases and ice surviving away from Sun. |
| 5 | Left-overs from Sun clumped together. |
| 6 | Planets form. <br> Moons form. <br> Asteroids form. <br> Comets form. |
| 7 | Sun was born and gobbled up 99.8% of all material. |
| 8 | Nuclear fusion begins. |
| 9 | Comets and asteroids are the left overs. |

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📝 Summary Explanation

The solar system formed from a giant molecular cloud. Gravity caused it to collapse, forming a spinning disk. The center became the Sun via nuclear fusion. Around it, planets, moons, asteroids, and comets formed from leftover material. The inner region had rocky planets; outer regions had icy bodies. Over time, most material was used up, leaving behind asteroids and comets.

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