<p>There is not much doubt that the abundance of carbon in the protosolar nebula was not abnormal. We can tell that by looking at the carbon abundance in the atmosphere of the Sun - it has an abundance of 8.43 on a logarithmic (base 10) scale where hydrogen has an abundance of 12 (<a href="http://arxiv.org/pdf/0909.0948v1.pdf" rel="noreferrer">Asplund et al. 2009</a>). This is typical for stars in the solar neighbourhood.</p>

<p>However carbon in the solids of the solar system - i.e. in the Earth, moon, meteorites etc. is underabundant with respect to this by something like a factor of 10. Nitrogen is similarly underabundant in the Earth and oxygen to a lesser extent (a factor of two). (<a href="http://adsabs.harvard.edu/abs/2009LanB...4B...44L" rel="noreferrer">Lodders et al. 2009)</a></p>

<p>The reason for this is that C,N,O are all capable of remaining in the gaseous phase at the kinds of condensation temperatures that are typical for forming most of the "rocks" that make up the Earth and other solids in the solar system. In particular, carbon monoxide is readily formed at high temperatures and cannot easily be captured into terrestrial planets and other rocky materials.</p>

CC BY-SA 4.0
2019-02-06T13:30:21.323Z
Maybe mention that typical rock-forming temperatures are below $~$$1200$K, while N,C,O remain volatile down to $0-200$K.
AtmosphericPrisonEscape
CC BY-SA 4.0
2020-01-19T17:53:24.560Z
I guess you meant carbon compounds, pure carbon condenses at very high temperatures.
Calmarius
CC BY-SA 3.0
2014-12-03T21:01:21.193Z
2014-12-09T21:26:27.843Z
2014-12-09T21:26:27.843Z
ProfRob
<p>Although carbon is highly abundant in the universe, it is not homogeneously distributed.  Some regions of the interstellar medium could be rich in carbon and others rich in silicon or oxygen, depending on the source of the heavier elements ("metals").  The region could be enriched from mass loss of evolved stars, or from a SN of a massive star, or from a SN from a white dwarf.  Each of these bring different elemental abundances.<br>
Also, if the region of the protoplanetary disk where the Earth formed was warm, then the carbon would be in the gaseous phase or in gaseous phase molecules like CO, CO$_2$ and CH$_4$.  Perhaps, where the terrestial planets formed much of the carbon was in gaseous form rather than in dust particles, and therefore only a small fraction of the carbon was incorporated into the rocky planets.</p>

<p>Furthermore, much of the Earth's carbon is not in the crust. <a href="http://science.howstuffworks.com/environmental/green-science/earth-carbon-stored.htm" rel="noreferrer">It is in trees, the atmosphere and mostly in the oceans, dissolved as carbonates and in shells etc.</a></p>

CC BY-SA 3.0
2014-12-03T04:22:12.423Z
2014-12-09T18:50:35.953Z
2014-12-09T18:50:35.953Z
eshaya
<p>Atmophile… atmophile… atmophile…</p>
<p><a href="https://lmgtfy.app/?q=atmophile" rel="nofollow noreferrer">https://lmgtfy.app/?q=atmophile</a></p>
<p>On the moon in particular, Earth differentiated, then the moon formed… which then differentiated. The moon is thus <em>double</em> depleted.</p>
<p>On Mars in particular, infall from the Main Belt replenishes carbon and other elements a bit.</p>

CC BY-SA 4.0
2022-08-02T00:41:35.117Z
As it’s currently written, your answer is unclear. Please [edit] to add additional details that will help others understand how this addresses the question asked. You can find more information on how to write good answers [in the help center](/help/how-to-answer).
Community
CC BY-SA 4.0
2022-08-01T22:07:52.127Z
2022-08-01T22:23:01.980Z
2022-08-01T22:23:01.980Z
caInstrument
<p>Carbon is the fourth <a href="https://en.wikipedia.org/wiki/Abundance_of_the_chemical_elements#Earth.27s_crustal_elemental_abundance">most common element</a> in the universe and in the Solar system. It is about the ninth most common element in Earth's crust. It doesn't seem to be part of any of the ten <a href="http://education.jlab.org/glossary/abund_com.html">most common compounds</a> in the Earth's crust. </p>

<p>So where is all the carbon hiding?
Why isn't it more common in planetary and lunar crusts?</p>

<p>Is it maybe mostly occurring in volatiles together with hydrogen and oxygen, and has left bodies which lack atmosphere or freezing temperatures? Is it primarily biological processes which binds carbon to solid molecules? Having a look around on Earth's natural surface today, there's lots of solid carbon compounds everywhere, so the contrast is interesting.</p>

CC BY-SA 3.0
2014-11-30T18:17:24.427Z
[Related, but probably not an answer](http://www.researchgate.net/publication/45893686_The_Solar_Nebula_on_Fire_A_Solution_to_the_Carbon_Deficit_in_the_Inner_Solar_System).
HDE 226868
<earth-like-planet><carbon-cycle><elemental-abundances>
Why is carbon so rare on the Moon and on Mars?
LocalFluff
# Why is carbon so rare on the Moon and on Mars?

(Asked by: username_0 on 2014-11-30)

Carbon is the fourth [most common element](https://en.wikipedia.org/wiki/Abundance_of_the_chemical_elements#Earth.27s_crustal_elemental_abundance) in the universe and in the Solar system. It is about the ninth most common element in Earth's crust. It doesn't seem to be part of any of the ten [most common compounds](http://education.jlab.org/glossary/abund_com.html) in the Earth's crust.

So where is all the carbon hiding?
Why isn't it more common in planetary and lunar crusts?

Is it maybe mostly occurring in volatiles together with hydrogen and oxygen, and has left bodies which lack atmosphere or freezing temperatures? Is it primarily biological processes which binds carbon to solid molecules? Having a look around on Earth's natural surface today, there's lots of solid carbon compounds everywhere, so the contrast is interesting.

**Tags:** earth-like-planet, carbon-cycle, elemental-abundances
> **Comments:**
> **username_1**: [Related, but probably not an answer](http://www.researchgate.net/publication/45893686_The_Solar_Nebula_on_Fire_A_Solution_to_the_Carbon_Deficit_in_the_Inner_Solar_System).  

---

## 3 answers

### Answer by username_2 on 2014-12-03. Score: 13

There is not much doubt that the abundance of carbon in the protosolar nebula was not abnormal. We can tell that by looking at the carbon abundance in the atmosphere of the Sun - it has an abundance of 8.43 on a logarithmic (base 10) scale where hydrogen has an abundance of 12 ([Asplund et al. 2009](http://arxiv.org/pdf/0909.0948v1.pdf)). This is typical for stars in the solar neighbourhood.

However carbon in the solids of the solar system - i.e. in the Earth, moon, meteorites etc. is underabundant with respect to this by something like a factor of 10. Nitrogen is similarly underabundant in the Earth and oxygen to a lesser extent (a factor of two). ([Lodders et al. 2009)](http://adsabs.harvard.edu/abs/2009LanB...4B...44L)

The reason for this is that C,N,O are all capable of remaining in the gaseous phase at the kinds of condensation temperatures that are typical for forming most of the "rocks" that make up the Earth and other solids in the solar system. In particular, carbon monoxide is readily formed at high temperatures and cannot easily be captured into terrestrial planets and other rocky materials.

> **Comments:**
> **username_3**: Maybe mention that typical rock-forming temperatures are below $~$$1200$K, while N,C,O remain volatile down to $0-200$K.  
> **username_4**: I guess you meant carbon compounds, pure carbon condenses at very high temperatures.  

---

### Answer by username_5 on 2014-12-03. Score: 7

Although carbon is highly abundant in the universe, it is not homogeneously distributed. Some regions of the interstellar medium could be rich in carbon and others rich in silicon or oxygen, depending on the source of the heavier elements ("metals"). The region could be enriched from mass loss of evolved stars, or from a SN of a massive star, or from a SN from a white dwarf. Each of these bring different elemental abundances.  
Also, if the region of the protoplanetary disk where the Earth formed was warm, then the carbon would be in the gaseous phase or in gaseous phase molecules like CO, CO$\_2$ and CH$\_4$. Perhaps, where the terrestial planets formed much of the carbon was in gaseous form rather than in dust particles, and therefore only a small fraction of the carbon was incorporated into the rocky planets.

Furthermore, much of the Earth's carbon is not in the crust. [It is in trees, the atmosphere and mostly in the oceans, dissolved as carbonates and in shells etc.](http://science.howstuffworks.com/environmental/green-science/earth-carbon-stored.htm)


---

### Answer by username_6 on 2022-08-01. Score: -7

Atmophile… atmophile… atmophile…

<https://lmgtfy.app/?q=atmophile>

On the moon in particular, Earth differentiated, then the moon formed… which then differentiated. The moon is thus *double* depleted.

On Mars in particular, infall from the Main Belt replenishes carbon and other elements a bit.

> **Comments:**
> **username_7**: As it’s currently written, your answer is unclear. Please [edit] to add additional details that will help others understand how this addresses the question asked. You can find more information on how to write good answers [in the help center](/help/how-to-answer).  

---

