How does angular momentum play a role in the formation of planets?

In summary, gas/dust clouds are regions in space filled with gas and dust particles of various sizes and compositions. They are formed through gravitational attraction and play a crucial role in the formation of stars and planetary systems. These clouds can also be used to study the history of the universe by analyzing their composition and movements.
  • #1
SediumDarxide
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This is my first post here, so I'll start off by just saying hi. ^_^

Anyway, I've been in a debate recently with somebody at another website and some interesting topics have come up that I would like to learn more about.

The person I'm in the debate with clearly doesn't understand basic astronomy, saying with confidence that "gravity isn't enough to cause a cloud to collapse" and "Jupiter couldn't have formed unless there was already a large solid object to pull in all the gas". -_- I explained to him the concept of Jeans' length and Jeans' mass, and directed him to various web pages regarding the subject, and he has since disappeared completely.

But there's one thing that came up that I still want to learn about, and any help in explaining it to me or directing me somewhere with an explanation would be nice.

Well, the person said that "if planets were formed naturally then they wouldn't spin at all because collisions between particles in the protoplanetary disc would cause any rotation to be self-canceling. Clearly this person has lacking knowledge of angular momentum. Despite his leaving the debate I still want to learn about this. I know that the initial rotation of the cloud is the origin of the rotation of the subsequent stars and planets due to the conservation of angular momentum, but that's the extent of my knowledge on the matter. If possible I want to be able to know the math that shows his comment to be false, but overall I just want a deeper understanding on the topic.

Can anybody help me out somehow?
 
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  • #2


Hi there!

First of all, welcome to the forum! It's great to see someone with a curiosity for science and a desire to learn more.

Now, let's address the points raised by the person you were debating with. You're absolutely right in explaining the concept of Jeans' length and mass to them. These are important factors in understanding how a cloud collapses under its own gravity to form stars and planets. However, there are a few other factors that also play a role in this process.

One of these factors is the conservation of angular momentum. As you mentioned, the initial rotation of the cloud is responsible for the rotation of the subsequent stars and planets. This is because, as the cloud collapses, it also starts to spin faster due to the conservation of angular momentum.

But how does this happen? Well, let's imagine a spinning ice skater. When they bring their arms closer to their body, they start to spin faster. This is because their angular momentum (which is the product of their mass, velocity, and distance from the axis of rotation) remains constant, but since their distance from the axis of rotation decreases, their velocity must increase to compensate.

Similarly, as a cloud collapses, its mass gets closer to the axis of rotation, causing it to spin faster. This process is known as "angular momentum transfer".

Now, let's address the comment that "collisions between particles in the protoplanetary disc would cause any rotation to be self-canceling". This is not entirely true. While collisions between particles can indeed cause some rotation to be cancelled out, they can also cause the cloud to spin faster in other directions. This is known as "random motion" and it is a common occurrence in the universe.

So, while it is true that collisions between particles can have an effect on the rotation of a cloud, they do not completely cancel it out. In fact, these collisions can actually contribute to the overall rotation of the cloud and the subsequent formation of planets.

As for the math behind this, it involves understanding the equations of motion, conservation of momentum, and conservation of angular momentum. I would recommend looking into some introductory physics or astronomy textbooks for a more in-depth explanation and understanding of these concepts.

I hope this helps to clarify some of the misunderstandings raised by the person you were debating with. Science is all about asking questions and seeking answers, so keep up the curiosity and keep learning!
 

1. What is a gas/dust cloud?

A gas/dust cloud is a region in space that contains a large amount of gas and dust particles. These particles can range in size from tiny grains to larger pebbles and can be made up of various elements and compounds.

2. How are gas/dust clouds formed?

Gas/dust clouds are formed through the gravitational attraction between particles in space. As these particles come together, they begin to clump and form larger structures, eventually becoming gas/dust clouds.

3. What is the role of gas/dust clouds in star formation?

Gas/dust clouds play a crucial role in star formation. As the particles in these clouds become more densely packed, they can collapse under their own gravity and form a protostar. The protostar then continues to gather more mass and eventually becomes a star.

4. How do gas/dust clouds affect the formation of planetary systems?

Gas/dust clouds are the birthplace of planetary systems. As a star forms from a gas/dust cloud, the remaining material in the cloud can also clump together and form planets and other celestial bodies. The composition of these planets is influenced by the elements and compounds present in the original gas/dust cloud.

5. Can gas/dust clouds be used to study the history of the universe?

Yes, gas/dust clouds can provide valuable information about the history of the universe. By studying the composition and movements of particles in these clouds, scientists can learn about the conditions of the early universe and how it has evolved over time.

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