<p>You are confusing the "mass" with "solid". All matter has mass, and all mass produces a gravitational field. That includes gasses, liquids and plasmas.</p>

<p>Although gasses are much less dense than solids, gasses also have mass, and if you have enough gas it will have a measurable gravitational field. </p>

<p>Jupiter is big, it is composed of lots of Hydrogen and Helium (and some other gasses), and deep within the planet, the gasses are compressed into strange states. There may even be a rocky core, but it is under such extreme pressure that it is not much like "rock" as we understand it. But it is not necessary for a planet to have a solid core to produce a gravitational field, because all matter has mass not just solid matter.</p>

CC BY-SA 3.0
2016-01-08T18:06:06.913Z
2016-01-08T18:06:06.913Z
James K
<p>Gravitational force is the attractive force between any two masses.</p>

<p>What about gaseous planets, where do they get their attractive force from?</p>

<p>While the big rocky planets don't have enough attractive force to keep enough gases in their gravitational field, Jupiter has lots of gases.</p>

<p>Does this means there is a concentrated mass inside, under which gravitational field the gases are kept 'in'? And if so, then why are gaseous planets not also considered to be rocky ones?</p>

CC BY-SA 3.0
2016-01-08T08:54:35.507Z
Gas has mass too. There's no difference between the gravitational force of an atom bound in a rocky planet, and that of an atom freely floating in a gas.
pela
CC BY-SA 3.0
2016-01-08T18:21:04.107Z
Jupiter has 320 Earth masses in Mass, this makes it harder for anything to escape his gravity well. It makes no difference if the mass is solid, fluid, gaseous, ...
AtmosphericPrisonEscape
<gravity><planet>
Where does Jupiter's gravitational force come from? Why don't Jupiters gasses fly away?
Sujay Kumar
# Where does Jupiter's gravitational force come from? Why don't Jupiters gasses fly away?

(Asked by: username_0 on 2016-01-08)

Gravitational force is the attractive force between any two masses.

What about gaseous planets, where do they get their attractive force from?

While the big rocky planets don't have enough attractive force to keep enough gases in their gravitational field, Jupiter has lots of gases.

Does this means there is a concentrated mass inside, under which gravitational field the gases are kept 'in'? And if so, then why are gaseous planets not also considered to be rocky ones?

**Tags:** gravity, planet
> **Comments:**
> **username_1**: Gas has mass too. There's no difference between the gravitational force of an atom bound in a rocky planet, and that of an atom freely floating in a gas.  
> **username_2**: Jupiter has 320 Earth masses in Mass, this makes it harder for anything to escape his gravity well. It makes no difference if the mass is solid, fluid, gaseous, ...  

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## 1 answers

### Answer by username_3 on 2016-01-08. Score: 5

You are confusing the "mass" with "solid". All matter has mass, and all mass produces a gravitational field. That includes gasses, liquids and plasmas.

Although gasses are much less dense than solids, gasses also have mass, and if you have enough gas it will have a measurable gravitational field.

Jupiter is big, it is composed of lots of Hydrogen and Helium (and some other gasses), and deep within the planet, the gasses are compressed into strange states. There may even be a rocky core, but it is under such extreme pressure that it is not much like "rock" as we understand it. But it is not necessary for a planet to have a solid core to produce a gravitational field, because all matter has mass not just solid matter.


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