<p>If enough time has passed for gravitational forces to allow the formation of planetesimals(proto-planets) in orbit around the proto-star, how likely is it that two of them would collide with one another? If they do collide, would a head-on collision be more likely than a glancing collision?</p>

<p>What would be the observable effect of such a phenomena? </p>

CC BY-SA 4.0
2020-12-22T19:06:35.583Z
How do you understand that “gravitational forces” are responsible for the formation of planetesimals? It sounds ambiguous because both star–planetesimal and planetesimal–planetesimal forces can be assumed in that statement.
Incnis Mrsi
CC BY-SA 4.0
2021-07-23T06:55:10.320Z
I apologize if the question wasn't clear enough. Since the assumption states that enough time has passed for a proto-sun to be formed, I would suppose both the forces (star-planetesimal and planetesimal-planetesimal) would act. In that case, what are the chances that two proto-planets in orbit would collide? Head-on or otherwise?
Ammanuel
CC BY-SA 4.0
2021-07-25T05:08:33.403Z
The “head-on” label makes no quantitative sense without specific threshold. An ideal head-on collision has probability 0. Every practical collision brings or takes some angular momentum for the bodies involved.
Incnis Mrsi
<astrophysics><collision><protostar><space-debris><proto-planetary-disk>
How common is it for large objects (few kilometers wide) in a young protoplanetary disk or debris disk to collide with one another?
Ammanuel
# How common is it for large objects (few kilometers wide) in a young protoplanetary disk or debris disk to collide with one another?

(Asked by: username_0 on 2020-04-30)

If enough time has passed for gravitational forces to allow the formation of planetesimals(proto-planets) in orbit around the proto-star, how likely is it that two of them would collide with one another? If they do collide, would a head-on collision be more likely than a glancing collision?

What would be the observable effect of such a phenomena?

**Tags:** astrophysics, collision, protostar, space-debris, proto-planetary-disk
> **Comments:**
> **username_1**: How do you understand that “gravitational forces” are responsible for the formation of planetesimals? It sounds ambiguous because both star–planetesimal and planetesimal–planetesimal forces can be assumed in that statement.  
> **username_0**: I apologize if the question wasn't clear enough. Since the assumption states that enough time has passed for a proto-sun to be formed, I would suppose both the forces (star-planetesimal and planetesimal-planetesimal) would act. In that case, what are the chances that two proto-planets in orbit would collide? Head-on or otherwise?  
> **username_1**: The “head-on” label makes no quantitative sense without specific threshold. An ideal head-on collision has probability 0. Every practical collision brings or takes some angular momentum for the bodies involved.  

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## 0 answers

