From where did our earth get its initial velocity ?

In summary, the revolution of planets around the sun is due to the conservation of angular momentum, which is caused by the random motions of molecules in the interstellar cloud of gas during the formation of a protoplanetary disk. This also explains why all planets have a similar direction of rotation on their axes. The rotation and revolution of planets are linked through the same mechanism, with the initial rotation likely coming from the random movement of particles in space before the formation of the solar system.
  • #1
Sab95
5
0
I read in a article that Earth revolves around the sun at speed of 30km/s but from where did it get its velocity at the beginning..?
 
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  • #2
From the conservation of the angular momentum.

As the interstellar cloud of gas collapses to form a protoplanetary disk, random motions of the molecules do not perfectly cancel out, causing the emergence of a preferred spin direction in the macroscale. Further collapse exaggerates this initial preferrence, as any initial angular momentum has to be conserved in a closed system.
This is also the reason why all planets revolve around the sun in the same direction, and have generally the same direction of rotation on their axes.
Although in that last case there's obviously more at play than that. Just look at Venus or Uranus.
 
  • #3
@Bandersnatch :

But how that could account into the revolution of planets.. its something related with the rotation of the planet.. how is it related with the revolution..?? that's the part i can't understand..
 
  • #4
I'm not sure where lies your confusion. It's the same mechanism. Only instead of the scale of a single planet it's the whole solar system.

Here's a video showing the simulation of the process:


and the paper from which it's sourced:
http://arxiv.org/abs/1010.1489
 
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  • #5
Your question implies that you think it is strange that the rotation is not exactly 0. Wouldn't it be more strange for the rotation to be exactly a predetermined number, like 0?
 
  • #6
The material the Earth is made of was flying around in space. Dust and gas has some random movement, something had pushed it a little etc or it just happened to move some way since the last place it came from. When it starts collecting toward some center, it is likely that it has some small net rotation around the center, ie it is not likely that for every piece of dust going one way there is one going the other way, there is some imbalance. The falling towards the center makes them speed up and the effect gets exaggerated. You may be aware of the skater speeding up when the arms are pulled in effect, which also happens with the collapsing dust.
 
  • #7
yup.. now i got it.. pls stay tuned for further questions..
 
  • #8
If you want to go back even further, the ultimate source for any momentum of any particle is, of course, whatever caused the big bang.
 

1. What is the initial velocity of the earth?

The initial velocity of the earth was approximately 29.78 km/s, which is the orbital speed around the sun. This speed is a result of the gravitational pull between the earth and the sun.

2. How did the earth acquire its initial velocity?

The earth acquired its initial velocity through the process of accretion during its formation. As dust and debris in the early solar system collided and stuck together, the earth began to gain mass and its gravitational pull increased, resulting in its initial velocity.

3. Did the earth always have the same initial velocity?

No, the earth's initial velocity has changed over time due to various factors such as the gravitational pull of other planets, the moon, and the sun. Additionally, the earth's orbit around the sun is not perfectly circular, causing its velocity to fluctuate slightly.

4. How does the earth's initial velocity affect its orbit?

The initial velocity of the earth plays a crucial role in its orbit around the sun. If the initial velocity were too slow, the earth would fall towards the sun due to its gravitational pull. On the other hand, if the initial velocity were too fast, the earth would escape the sun's gravitational pull and drift into outer space.

5. Can the earth's initial velocity change in the future?

Yes, the earth's initial velocity can change in the future due to various factors such as collisions with other celestial bodies, gravitational interactions, and even human activities such as space missions. However, any changes in the earth's initial velocity are expected to be very small and not significant enough to significantly alter its orbit around the sun.

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