<p>Since planets are forming from asteroid collisions, I would say those collisions won't necessarily create small objects.</p>

<p>Imagine throwing a snowball against a window.</p>

<p>If you throw it lightly, some snow will stick to the window and increase the mass of it (at least until it melts away) and the rest of the snowball will be scattered everywhere around but won't stick to the window.</p>

<p>If you throw the snowball too hard, the window will break, resulting in even more tiny pieces. But still, some snow will stick to some pieces of glass.</p>

<p>That's exactly what happens on asteroid impacts and depends on the speed, mass and structure of each asteroid.</p>

<p>The size of those debris should reach from microscopic dust up to gigantic rocks with several kilometer wide diameter.</p>

CC BY-SA 3.0
2017-11-27T15:20:59.440Z
What is "Dach"?
porton
CC BY-SA 3.0
2017-11-27T15:24:07.367Z
@porton Ah sorry didn't see my autocorrection changed this... "Dach" should be "each". So "... structure of each asteroid."
Mugentoki
CC BY-SA 3.0
2017-11-27T11:12:20.447Z
2017-11-27T16:33:09.380Z
2017-11-27T16:33:09.380Z
Mugentoki
<p>The speed of the collision changes everything.   The formation of comets and asteroids is likely to take place the <a href="https://en.wikipedia.org/wiki/Protoplanetary_disk" rel="nofollow noreferrer">circumstellar disk</a> of matter, perhaps even before the fist plant's formed.  As the disk flattens and elliptical orbits tend to lose eccentricity by collision.  Low velocity impacts between objects are more common.   </p>

<p>Protoplanetary disks are made up of rocks and ices.  It's sometimes said that they are made of gas too but that's not very accurate because Gas is high velocity even in low temperature and it doesn't stick around very well.  Ice, however, tends to be sticky and sticky is good.   </p>

<p>These swirling disks are also charged because much in space is charge and there's the solar magnetic field which may play a role in formation.   Once a certain size is reached, gravity takes over, but before then, the formation of objects like asteroids isn't well understood.  </p>

<p>As larger planets form, however, the opposite tends to happen.  Large planets can fling material into more eccentric orbits and impact velocity tends to increase again as the disk forms into planets.</p>

<p>The collision of two asteroids in space is likely to result in two smaller objects and some scattered debris.   A head-on collision can turn both into tiny pieces depending on the velocity.   A more common glancing blow would probably still leave two objects intact with some lost material.  </p>

<p>It's likely that in the solar-system's circumstellar disk, 100 meter and 1 km objects were formed by low velocity collisions, assisted by electrical stickiness.</p>

CC BY-SA 3.0
2017-11-27T19:35:09.863Z
Thanks. But I forgot to tell in my question that I am not interested in milliard years ago crashes, but only in recent (say 100 years) crashes. I am mainly interested whether it is possible to be formed an asteroid which is encircled my many small objects and dust and thus could be similar to a comet (but not consisting of ice)
porton
CC BY-SA 3.0
2017-11-27T19:41:17.133Z
@porton to my knowledge an asteroid on asteroid crash has never been observed so it might be a tough question to get a good answer on.   Pluto's system with Charon and 4 smaller moons orbiting the 2 central objects is believed to be the result of an impact, but that's much bigger than you're talking about.
userLTK
CC BY-SA 3.0
2017-11-27T16:50:18.293Z
2017-11-27T16:50:18.293Z
userLTK
<p>Does collision of two asteroids necessarily create only very small objects? (and how big is it "very small"?)</p>

<p>I am especially interested about collision of two asteroids with similar orbits (and thus relatively small difference of the speed vectors in the moment of collision).</p>

<p>Can such a collision create big (say 1km, or maybe 100m) objects?</p>

<p>Is it in this case likely that a created object would have something like a comet tail consisting of dust and small objects (probably gravitionally attracted to the resulting asteroid remnant)?</p>

<asteroids><asteroid-belt>
What size objects can be created from collision of two asteroids?
porton
# What size objects can be created from collision of two asteroids?

(Asked by: username_0 on 2017-11-27)

Does collision of two asteroids necessarily create only very small objects? (and how big is it "very small"?)

I am especially interested about collision of two asteroids with similar orbits (and thus relatively small difference of the speed vectors in the moment of collision).

Can such a collision create big (say 1km, or maybe 100m) objects?

Is it in this case likely that a created object would have something like a comet tail consisting of dust and small objects (probably gravitionally attracted to the resulting asteroid remnant)?

**Tags:** asteroids, asteroid-belt


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## 2 answers

### Answer by username_1 on 2017-11-27. Score: 2

Since planets are forming from asteroid collisions, I would say those collisions won't necessarily create small objects.

Imagine throwing a snowball against a window.

If you throw it lightly, some snow will stick to the window and increase the mass of it (at least until it melts away) and the rest of the snowball will be scattered everywhere around but won't stick to the window.

If you throw the snowball too hard, the window will break, resulting in even more tiny pieces. But still, some snow will stick to some pieces of glass.

That's exactly what happens on asteroid impacts and depends on the speed, mass and structure of each asteroid.

The size of those debris should reach from microscopic dust up to gigantic rocks with several kilometer wide diameter.

> **Comments:**
> **username_0**: What is "Dach"?  
> **username_1**: @username_0 Ah sorry didn't see my autocorrection changed this... "Dach" should be "each". So "... structure of each asteroid."  

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### Answer by username_2 on 2017-11-27. Score: 2

The speed of the collision changes everything. The formation of comets and asteroids is likely to take place the [circumstellar disk](https://en.wikipedia.org/wiki/Protoplanetary_disk) of matter, perhaps even before the fist plant's formed. As the disk flattens and elliptical orbits tend to lose eccentricity by collision. Low velocity impacts between objects are more common.

Protoplanetary disks are made up of rocks and ices. It's sometimes said that they are made of gas too but that's not very accurate because Gas is high velocity even in low temperature and it doesn't stick around very well. Ice, however, tends to be sticky and sticky is good.

These swirling disks are also charged because much in space is charge and there's the solar magnetic field which may play a role in formation. Once a certain size is reached, gravity takes over, but before then, the formation of objects like asteroids isn't well understood.

As larger planets form, however, the opposite tends to happen. Large planets can fling material into more eccentric orbits and impact velocity tends to increase again as the disk forms into planets.

The collision of two asteroids in space is likely to result in two smaller objects and some scattered debris. A head-on collision can turn both into tiny pieces depending on the velocity. A more common glancing blow would probably still leave two objects intact with some lost material.

It's likely that in the solar-system's circumstellar disk, 100 meter and 1 km objects were formed by low velocity collisions, assisted by electrical stickiness.

> **Comments:**
> **username_0**: Thanks. But I forgot to tell in my question that I am not interested in milliard years ago crashes, but only in recent (say 100 years) crashes. I am mainly interested whether it is possible to be formed an asteroid which is encircled my many small objects and dust and thus could be similar to a comet (but not consisting of ice)  
> **username_2**: @username_0 to my knowledge an asteroid on asteroid crash has never been observed so it might be a tough question to get a good answer on.   Pluto's system with Charon and 4 smaller moons orbiting the 2 central objects is believed to be the result of an impact, but that's much bigger than you're talking about.  

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