# Tag Info

21

The chemistry of Titan's atmosphere is complex, with reactions occurring between carbon dioxide, oxygen, carbon monoxide, hydroxl, and other compounds. This means that carbon dioxide production and destruction takes place through a variety of reactions (Samuelson et al. 1983), some spurred by ultraviolet light from the Sun (and hence photodissociation). In ...

18

According to this 2007 paper, the current research as of the time of their own research had a huge range in possible concentrations of $\text{MgSO}_4$, magnesium-sulfate, with over four orders magnitude (approximately times $30,\!000$) differences between the extreme ends of the predictions. It conducts its own analyses and near the end of the paper makes ...

10

If this is something that you have found (rather than purchased as a meteorite) the chances are very small that it is a meteorite. Even if it is a meteorite, the chances it's a Martian one are even smaller still and none have been found in the United States. According to the Meteorites in the US page, which draws from the Meteoritical Society database, only ...

10

It’s been a while since I studied this, and meteorites are very much not my field, so I’ll share my current understanding but would welcome corrections from those more informed :-) These meteorites are mostly iron with a small amount of nickel. For a given composition of iron and nickel, there are different crystal structures that can be formed. Of ...

8

Getting atoms together into molecules requires two basic things - getting the reactants together and them providing the means to overcome the "activation energy" that is due to the mutual repulsion of the electrons that surround them. Astrophysical chemistry is a rich and complex field of study. Most molecules are produced by a wide variety of processes. ...

8

It is not true to say that the CNO cycle produces these elements. It is more like a catalytic chain that aids the conversion of hydrogen to helium. Thus pre-existing CNO nuclei are required and all the reactions do is change the balance of these elements because the reaction steps in the chain have differing timescales. Sulphur is mainly produced by alpha ...

8

The Sun is a small main sequence star. It does not produce oxygen via fusion. It can't. The temperature and pressure in the Sun's core are too low. Fusion in the Sun is currently limited to production of helium. This will remain the case for several billion years. That said, there is oxygen in the Sun, about 1% by mass. This oxygen was produced long ago by ...

7

At the risk of self-plagiarism: (https://physics.stackexchange.com/a/532568/43351 with a bit added). Molecular chemistry in the early universe requires species with bound electrons. Helium hydride is the first molecule to form because neutral helium atoms, formed about 120,000 years after the big bang, could combine with plentiful protons; but it was another ...

7

The answer is yes. Molecule formation is common in the outer photospheres of cool stars, and those molecules frequently contain oxygen. Obvious and common examples are TiO, VO. This chemistry almost entirely happens when temperatures fall below 5000K, because otherwise the molecules are dissociated. Therefore it never occurs in stellar interiors. The Sun ...

6

Your argument (large temperature leads to greater mixing) is correct so long as there are no other large scale forces acting on the system. This isn't true in planet formation, because gravity plays a very important role. I'm not an expert on planet formation, but I think the argument goes something like this: As a planet forms from material from the ...

6

Unlike the saturated hydrocarbons in kerosene, carbynes are unsaturated carbon chains with alternating single and triple bonds. Molecules containing such chains are called polyynes, e.g. the short cyanopolyyne HC5N: H−C≡C−C≡C−C≡N Those carbon atoms readily interact, and long chains (if they form; see comments) are more ...

5

People have demonstrated high-pressure diamond formation using laser-driven shocks, much in line with the original idea. The diamond rain idea seems to be doing well (popular science article about it, with references). However, it is quite likely that the diamonds could have different properties because of formation mechanisms. There are a lot of unusual ...

5

The detection of complex organic molecules, often abbreviated as COM in astrochemical literature, has only taken up pace in the last couple of decades since substantial advances were only made possible with the advent of new, high-end observational facilities (Green Bank Telescope (GBT), Very Large Array (VLA), Atacama Large Millimeter/Sub-Millimeter Array (...

5

Yes, they are created through stellar nucleosynthesis. Sulfur is created from silicon via an alpha process, with the reaction $$_{14}^{28}\text{Si }+\text{ } _2^4\text{He}\to _{16}^{32}\text{S }+\gamma$$ Oxygen burning can also create $_{16}^{31}\text{S}$, as well as other elements like $_{15}^{31}\text{P}$. Additionally, both oxygen and phosphorus can be ...

5

Protium is a proton + an electron. Under enormously high pressure, it's energetically favorable for electrons to merge with protons and become neutrons - see here. are stars mostly protons By mass, yes, at least before they get too old. The mass of the universe is more complicated, but anything solid that we think of as matter is made of atoms, ...

4

How much specific elements sink inside a planetary caldron with variations of heat and thermals and chemistry, depends not just on their density but also the element's chemistry. This question discusses Uranium in Earth's core and the top answer suggests (I believe correctly) there's essentially no Uranium in Earth's core, it's largely in the crust because ...

4

OK, I did a bit of research on this. The LA Times article you quoted says something a little bit useful. While the scientists aren’t sure exactly what the compounds are, the fingerprint is characteristic of material containing carbon-hydrogen bonds, and may include components like methyl and methylene. Methyl means a carbon with at least 3 hydrogen ...

4

The initial stars were made of hydrogen and helium. These enriched the interstellar medium (ISM) with some chemical elements right across the periodic table, when massive primordial stars ended their lives as supernovae. Subsequent generations of stars continue to enrich the ISM, if their lives are short enough. So the general gist of what you suggest is ...

4

Since water on all planets is in contact with impurities, I would think that the default for water is salty, and a small percentage on Earth (2.5%) gets desalinated by going through the evaporation/condensation cycle. Since no similar cycle is operating on Europa, I imagine its ocean is salty.

4

The most popular hypothesis for explaining the various zigzagged lines (lineae) that cover Europa’s surface is that they are caused by cracks appearing in the ice shell because of tidal deformations, and that these cracks are then filled by water oozing out from the interior. The dark, reddish color of these lineae is thought to be due to magnesium sulfate, ...

3

Shock waves in the interstellar medium (ISM) can be caused by a spiral density wave, supernova shock, or turbulent flow collision. These waves sweep, compress and heat the ISM, thus modifying which chemical reactions can occur. These physical conditions can harbor the chemical reactions to create complex molecules such as NH$_3$, CH$_3$OH, H$_2$O and more. ...

3

If your question is "What elements are in a black hole?" The answer is: The gravity is too great for there to be "elements" (atoms or molecules) inside or near the surface of a black hole. The extreme gravity tears apart everything and compresses it. Some distance away (especially far away, here on Earth) the black hole doesn't alter ...

3

Often for molecules to form in interstellar space, dust is used as a catalyst. The reason is that in typical interstellar environments, densities are so immensely low that even for just two atoms to meet, the probability is so small that formation time scales are very long. For 3+ atoms, the chance decreases rapidly. Instead, an atom can stick to a dust ...

3

The analogy is false. Neutron stars consist mainly of neutrons, with a small fraction of protons and electrons in equal numbers. The fraction is density dependent, but is in the range 1%-10%.$^{*}$ Neutron stars are so-named because neutrons dominate both by mass and number. A "normal" star consists of about 75% Hydrogen and 23% Helium and 2% heavier ...

2

Just to add, while I think Rob Jeffries answer covers it. Now is it expected that in future more stars will be made of more heavy elements or are there causes/laws which prohibit stars forming of e.g. stars made of elements without hydrogen. While this is unlikely to happen because Hydrogen will stick around as the most abundant element for a very ...

2

A column density is just the integral of a (number) density along the line of sight. Often, you would get the same observational absorption or emission signature from a number density of $n$ molecules cm$^{-3}$, spread along a line of sight through a cloud of diameter $x$, as you would with a density of $0.1n$ spread over $10x$. In other words, all we can ...

2

The answer depends on which you are talking about (you mentioned both organic compounds and organic matter, which are two completely different things). Organic compounds we do not have a clear definition of, but is most agreed upon to contain carbon atoms, either on their own (C), bonded with at least one hydrogen atom (C-H), or bonded with at least one ...

2

The kinds of molecules / atoms and the density of those molecules / atoms as a function of altitude in the Earth's upper atmosphere depends very much on the time of day and the activity of the Sun. Time of day: The Earth's upper atmosphere has a marked diurnal bulge. The density variation at a constant altitude can vary by an order of magnitude (a factor of ...

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