<p>As one gets farther from the sun, the gravity from the planets themselves becomes relatively stronger. So if a body were in an orbit between, for example, Jupiter and Saturn, those two planets would soon make the intermediate body's orbit change. This is conceptually related to the latest definition of "a planet"; A planet must clear its general vicinity of other stable orbiting bodies. </p>

CC BY-SA 3.0
2016-04-19T13:40:18.030Z
Gravity has nothing to do with the distance from the star.
Nico
CC BY-SA 3.0
2016-04-20T14:45:27.300Z
I read (apparently, I've misinterpretted) the OP's question to be about the relative increase in the spacing of the orbits. The frost line is an explanation of body composition; why are they gas giants versus terrestrial.
Craig Constantine
CC BY-SA 3.0
2016-05-02T08:50:09.600Z
Actually what i asked was about relative increase in spacing of orbits not the relatively large distance of these planets from the star
Suhrid Mulay
CC BY-SA 3.0
2016-04-19T12:34:57.557Z
2016-04-19T12:34:57.557Z
Craig Constantine
<p>The current explanation for this is something called the <a href="https://en.wikipedia.org/wiki/Frost_line_(astrophysics)" rel="nofollow">frost line</a> (which changes over time). At greater distances from the Sun, a body will receive less and less radiation, and so it will be colder than if it were closer to the Sun. Eventually, conditions become cold enough for <a href="https://en.wikipedia.org/wiki/Volatiles" rel="nofollow">volatiles</a> to condense into grains. These volatiles make it possible for large-scale accretion to happen, and thus giant planets are formed. They may become gas giants (like Jupiter and Saturn) or ice giants (like Uranus and Neptune), depending on the composition of the protoplanetary disk at a given distance.</p>

<p>A graphic (from <a href="http://lasp.colorado.edu/education/outerplanets/solsys_planets.php#jovian" rel="nofollow">here</a>) gives a better summary, although it's copyrighted.</p>

CC BY-SA 4.0
2020-05-02T22:30:25.633Z
Note that where a body is _formed_ does not necessarily correlate with where it _ends up_; planets in young solar systems have a tendency to move around quite a lot, and many solar systems _do_ have [gas giants very close to their suns](https://en.wikipedia.org/wiki/Hot_Jupiter).
Vikki
CC BY-SA 3.0
2016-04-20T00:50:43.223Z
2016-07-17T14:30:37.490Z
2016-07-17T14:30:37.490Z
HDE 226868
<p>When the solar system formed, there was an accretion disc, spinning around the newborn Sun.</p>
<p><a href="https://i.sstatic.net/JrxXT.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/JrxXT.jpg" alt="enter image description here" /></a></p>
<p>The Sun was emitting radiations, which pushed the lighter materials of the accretion disk (gases) further away, and kept the heavier materials (rocks) much closer. This is why gas giants are almost always further away than rocky planets. Almost.</p>
<p>In the case of &quot;hot Jupiters&quot;, astronomers think that they simply spiraled their way to their star, &quot;eating&quot; smaller planets on their way. It doesn't happen in our solar system because Saturn holds Jupiter back.</p>
<p>Exact source nowhere to be found on the internet, but everything I wrote here comes from a very interesting movie I watched in &quot;La Cité de L'Espace&quot; (Space City) in Toulouse, France. It is a famous exposition / museum about astronomy and space exploration.</p>

CC BY-SA 3.0
2016-04-19T11:34:40.523Z
Please explain the downvotes, I'd be glad to improve this answer.
Nico
CC BY-SA 3.0
2016-04-19T14:36:41.873Z
Not my downvote, but I think the reason has more to do with temperature than radiation pressure. Closer to the star the gas is hotter, and hence more volatile, so they are more difficult to capture gravitationally. But I suppose you're right that because of this, the gas is eventually blown away.
pela
CC BY-SA 3.0
2016-04-19T09:45:57.063Z
2016-04-19T09:45:57.063Z
2020-06-17T09:47:40.653Z
Nico
<p>Ever since I observed the depictions of the Solar System, I was obsessed with the question of why the gas giants (outer planets) have very large orbits, compared to the planets that are closer to the Sun. Is it because of their mass or something I have ignored?</p>

CC BY-SA 3.0
2016-04-20T14:46:23.737Z
Is your question about why are they *gas giants* in the large, outer orbits? ...or is your question about the relatively larger spacing of the outer orbits?
Craig Constantine
<orbit><solar-system><planet><gas-giants><orbital-migration>
Why do the gas giants in the Solar System have comparatively large orbits compared to the inner planets?
Suhrid Mulay
# Why do the gas giants in the Solar System have comparatively large orbits compared to the inner planets?

(Asked by: username_0 on 2016-04-19)

Ever since I observed the depictions of the Solar System, I was obsessed with the question of why the gas giants (outer planets) have very large orbits, compared to the planets that are closer to the Sun. Is it because of their mass or something I have ignored?

**Tags:** orbit, solar-system, planet, gas-giants, orbital-migration
> **Comments:**
> **username_1**: Is your question about why are they *gas giants* in the large, outer orbits? ...or is your question about the relatively larger spacing of the outer orbits?  

---

## 3 answers

### Answer by username_1 on 2016-04-19. Score: 2 | Accepted answer

As one gets farther from the sun, the gravity from the planets themselves becomes relatively stronger. So if a body were in an orbit between, for example, Jupiter and Saturn, those two planets would soon make the intermediate body's orbit change. This is conceptually related to the latest definition of "a planet"; A planet must clear its general vicinity of other stable orbiting bodies.

> **Comments:**
> **username_2**: Gravity has nothing to do with the distance from the star.  
> **username_1**: I read (apparently, I've misinterpretted) the OP's question to be about the relative increase in the spacing of the orbits. The frost line is an explanation of body composition; why are they gas giants versus terrestrial.  
> **username_0**: Actually what i asked was about relative increase in spacing of orbits not the relatively large distance of these planets from the star  

---

### Answer by username_3 on 2016-04-20. Score: 7

The current explanation for this is something called the [frost line](https://en.wikipedia.org/wiki/Frost_line_(astrophysics)) (which changes over time). At greater distances from the Sun, a body will receive less and less radiation, and so it will be colder than if it were closer to the Sun. Eventually, conditions become cold enough for [volatiles](https://en.wikipedia.org/wiki/Volatiles) to condense into grains. These volatiles make it possible for large-scale accretion to happen, and thus giant planets are formed. They may become gas giants (like Jupiter and Saturn) or ice giants (like Uranus and Neptune), depending on the composition of the protoplanetary disk at a given distance.

A graphic (from [here](http://lasp.colorado.edu/education/outerplanets/solsys_planets.php#jovian)) gives a better summary, although it's copyrighted.

> **Comments:**
> **username_4**: Note that where a body is _formed_ does not necessarily correlate with where it _ends up_; planets in young solar systems have a tendency to move around quite a lot, and many solar systems _do_ have [gas giants very close to their suns](https://en.wikipedia.org/wiki/Hot_Jupiter).  

---

### Answer by username_2 on 2016-04-19. Score: 2

When the solar system formed, there was an accretion disc, spinning around the newborn Sun.

[![enter image description here](https://i.sstatic.net/JrxXT.jpg)](https://i.sstatic.net/JrxXT.jpg)

The Sun was emitting radiations, which pushed the lighter materials of the accretion disk (gases) further away, and kept the heavier materials (rocks) much closer. This is why gas giants are almost always further away than rocky planets. Almost.

In the case of "hot Jupiters", astronomers think that they simply spiraled their way to their star, "eating" smaller planets on their way. It doesn't happen in our solar system because Saturn holds Jupiter back.

Exact source nowhere to be found on the internet, but everything I wrote here comes from a very interesting movie I watched in "La Cité de L'Espace" (Space City) in Toulouse, France. It is a famous exposition / museum about astronomy and space exploration.

> **Comments:**
> **username_2**: Please explain the downvotes, I'd be glad to improve this answer.  
> **username_5**: Not my downvote, but I think the reason has more to do with temperature than radiation pressure. Closer to the star the gas is hotter, and hence more volatile, so they are more difficult to capture gravitationally. But I suppose you're right that because of this, the gas is eventually blown away.  

---

