Asteroids and the formation of planets

In summary, it is thought that the asteroid belt didn't collide together because of the way Jupiter acted on the matter, and that rings can't form because the particles are going too fast.
  • #1
Yaymy
1
0
I was watching How the Universe Works, and they mentioned that planets were formed by dust particles that came together to form rocks, and that those rocks collided with one another and became larger and larger eventually forming planets. My question is why did the asteroids in the asteroid belt never collide to form planets as well? Does the answer to this question also relate to why some planets have rings? Why haven't the rings collided together to form a rocky/icy moon?
 
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  • #2
Probably to do with the temperature of early solar system is different to the temperature now?

I know hot rocks and metal like magma flows like a liquid. And maybe this is more likely to merge to form round bodies.
 
  • #3
Yaymy said:
I was watching How the Universe Works, and they mentioned that planets were formed by dust particles that came together to form rocks, and that those rocks collided with one another and became larger and larger eventually forming planets. My question is why did the asteroids in the asteroid belt never collide to form planets as well? Does the answer to this question also relate to why some planets have rings? Why haven't the rings collided together to form a rocky/icy moon?

It's thought that Jupiter is responsible for the asteroid belt. Once the planetesimals reached a fairly large mass Jupiter began to accelerate them quite significantly such that when they impacted with each other they smashed each other apart rather than combine. We have got evidence for this in the form of http://en.wikipedia.org/wiki/Asteroid_families" [Broken], where a group of asteroids shares similar orbits and are relatively close to each other.

For your second question, there are several possible reasons.
Rings can be formed when a ring of dust is within the planet's Roche limit, so that it can't coalesce into a moon. Another method is that small rings can be formed by impacts with already formed moons, so that the moon shares its orbit with some dust from the impact. Rings can also form if a moon passes through the Roche limit of the central planet, which can cause the moon to split apart and form a ring.
http://en.wikipedia.org/wiki/Planetary_ring

The rings are maintained through several processes also.
There's some points in the ring systems where there are orbital resonances with the larger moons of the central planet, which will throw any dust in a resonant orbit out of the system. The rings can also be maintained by the presence of shepherd moons on either side of a ring, or the presence of a moonlet inside a gap, which causes a narrow ring of dust to form in the same orbit as the moonlet.
 
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  • #4
Welcome to PF!

Hey Yaymy! Welcome to PF! :smile:

The asteroid belt is too close to Jupiter (the largest planet), and anything orbiting there is likely to be disrupted, either by being ejected to a more distant orbit, or by being broken up.

See http://en.wikipedia.org/wiki/Asteroid_belt#Origin" for details, including …

The current asteroid belt is believed to contain only a small fraction of the mass of the primordial belt. Computer simulations suggest that the original asteroid belt may have contained mass equivalent to the Earth. Primarily because of gravitational perturbations, most of the material was ejected from the belt within about a million years of formation, leaving behind less than 0.1% of the original mass.[26] Since their formation, the size distribution of the asteroid belt has remained relatively stable: there has been no significant increase or decrease in the typical dimensions of the main-belt asteroids​
Yaymy said:
… why did the asteroids in the asteroid belt never collide to form planets as well? Does the answer to this question also relate to why some planets have rings? Why haven't the rings collided together to form a rocky/icy moon?

To stick together, the particles must have a reasonably high relative speed (but not too high) …

planet formation needs quite a lot of chaos! …

the matter in the rings is all going at virtually the same velocity, and any collisions will be far too gentle. :wink:
 
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  • #5


I can provide some insights into the formation of planets and the role of asteroids in this process. The theory of planet formation suggests that planets are formed from the accumulation of dust and gas in a protoplanetary disk around a young star. This dust and gas eventually clump together to form larger objects, known as planetesimals. These planetesimals then collide and merge to form larger bodies, eventually leading to the formation of planets.

The asteroid belt, located between Mars and Jupiter, is a region of the solar system where many small bodies, including asteroids, are found. These asteroids are believed to be remnants of the early stages of planet formation, when the gravitational pull of Jupiter prevented them from coalescing into a planet.

One possible explanation for why the asteroids in the asteroid belt did not collide to form planets is the influence of Jupiter's strong gravitational pull. As these asteroids orbited the sun, they would have come under the influence of Jupiter's gravity, causing their orbits to become unstable and preventing them from merging to form larger bodies.

As for the presence of rings around some planets, such as Saturn, this is also thought to be a result of the planet's formation process. It is believed that these rings are made up of debris left over from the formation of the planet, which was not able to coalesce into a moon due to the strong tidal forces from the planet.

In summary, the formation of planets and the presence of asteroids and rings are all interconnected and can be explained by the same processes of gravitational pull and collisions in the early stages of a solar system's formation. The unique characteristics of each planet, such as the presence of rings or moons, can be attributed to the specific conditions and dynamics of its formation.
 

1. What are asteroids?

Asteroids are rocky objects that orbit the sun, typically found in the asteroid belt between Mars and Jupiter. They are remnants of the early solar system and can range in size from a few feet to several hundred miles in diameter.

2. How do asteroids form?

Asteroids are believed to form from the leftover material that did not form into planets during the early stages of our solar system. This material clumped together due to gravity, forming rocky objects that we now know as asteroids.

3. Can asteroids collide with Earth?

Yes, asteroids can collide with Earth. However, the chances of a large asteroid colliding with Earth are quite low. Most asteroids that enter Earth's atmosphere are small and burn up before reaching the ground. NASA actively tracks and studies asteroids to identify any potential threats to our planet.

4. How do asteroids play a role in the formation of planets?

Asteroids played a crucial role in the formation of planets by providing the building blocks for planets to form. As planets grew in size, their gravitational pull began to attract nearby asteroids, incorporating them into their structure. This process helped shape the planets we know today.

5. Are all asteroids the same composition?

No, not all asteroids are the same composition. There are three main types of asteroids: C-type (carbonaceous), S-type (silicaceous), and M-type (metallic). These types differ in their chemical composition and physical characteristics, such as color and reflectivity.

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