# Mineral astronomy

Mineral astronomy is the use of various astronomical techniques to locate and identify minerals and mineral deposits, especially on astronomical rocky objects.
At right is a thin-section image of a slice through the Allende meteorite. The Allende meteorite "lit up Mexico's skies in 1969 [and] scattered thousands of meteorite bits across the northern Mexico state of Chihuahua. ... Panguite [a titanium dioxide mineral] is believed to be among the oldest minerals in the solar system, which is [estimated to be] about 4.5 billion years old. Panguite belongs to a class of refractory minerals that could have formed only under the extreme temperatures and conditions present in the infant solar system."

## Control groups

The rigorous detection of a specific mineral may serve as a control group.

## Astronomy

"Hibonite (CaAl$_{12}$O$_{19}$) and calcium dialuminate (Ca Al$_4$O$_7$) are among the most refractory minerals observed in calcium-, aluminum-rich inclusions (CAIs) in chondritic meteorites."

## Planets

"Geochemical and spectroscopic evidence for hydrated minerals on main-belt asteroids is best explained if those asteroids were once bathed in liquid water (18, 19)."

## Color astronomy

"Glass particles vary in shape, from spheres to angular fragments. The color varies through colorless, yellow, yellowish-brown and brown to red. Glass colors range from homogeneous to heterogeneous, the latter containing admixed mineral relics."

## Minerals

Def. "a solid, homogeneous, crystalline chemical element or compound that results from natural inorganic processes" or any "naturally occurring inorganic material that has a (more or less) definite chemical composition and characteristic physical properties" is called a mineral.
Def. a "substance that resembles a mineral but does not exhibit crystallinity" is called a mineraloid.

## Mineraloids

"Identifying the minerals and mineraloids that result from aqueous alteration at Gale crater is essential for understanding past aqueous processes at the MSL landing site and hence for interpreting the site's potential habitability."

## Theoretical mineral astronomy

Here's a theoretical definition:
Def. the astronomy of possible mineral occurrences is called theoretical mineral astronomy.
Determining that an astronomical object is a rocky object is the first step to exploring its minerals.

## Objects

Def. a "suspension of dry dust ... in the atmosphere" is called a lithometeor.
"A lithometeor consists of solid particles suspended in the air or lifted by the wind from the ground."
"A lithometeor is the general term for particles suspended in a dry atmosphere; these include dry haze, smoke, dust, and sand."
"Dry haze is an accumulation of very fine dust or salt particles in the atmosphere; it does not block light, but instead causes light rays to scatter. Dry haze particles produce a bluish color when viewed against a dark background, but look yellowish when viewed against a lighter background. This light-scattering phenomenon (called Mie scattering) also causes the visual ranges within a uniformly dense layer of haze to vary depending on whether the observer is looking into the sun or away from it."
Heavy metal pollution may occur in lithometeors.
"The rise of airborne dust is constantly augmenting from the desert (Bilma) to the southern Sahelian stations (Niamey) where it has increased by a factor five. ... the Sahelian zone with airborne dust during the 80s ... All stations have recorded a general increase of wind velocity. The increase of lithometeors frequency as well as the wind velocity during the drought period is not explained by the aridification."

## Meteors

Def. the "solid material thrown into the air by a volcanic eruption that settles on the surrounding areas" is called tephra.
"[T]ephra, is a general term for fragments of volcanic rock and lava that are blasted into the air by volcanic explosions or carried upward in the volcanic plume by hot, hazardous gases. The larger fragments usually fall close to the volcano, but the finer particles can be advected quite some distance. ... [Fine ash] can contain rock, minerals, and volcanic glass fragments smaller than .1 inch in diameter, or slightly larger than the size of a pinhead."

## Cosmic rays

"Bombardment by protostellar cosmic rays may make the rock precursors of [Calcium-aluminum-rich inclusions] CAIs and chondrules radioactive, producing radionuclides found in meteorites that are difficult to obtain with other mechanisms."

## Neutrals

"Measurements by instruments on MESSENGER during the spacecraft's three Mercury flybys have led to discoveries of previously undetected neutral (Mg) and ionized (Ca+) species in Mercury's neutral and ionized exosphere and mapped these and previously known constituents (Na, Ca) on the anti-sunward side of the planet and over the poles. [...] Some ions and neutrals can be released directly from mineral surfaces by electron-stimulated desorption (ESD). Because cross sections of neutrals can be higher than photon-stimulated desorption (PSD) cross sections and because active electron precipitation on both the day and night side of Mercury can produce ESD of ions, at least part of the ionized exosphere is produced directly from surface materials by ESD."

## Neutrinos

"Atmospheric neutrinos can interact with the detector producing also hadrons. The most probable of these reactions is the single pion production [20][21]:"
    $\nu _{\mu }+p\rightarrow \mu ^{-}+\pi ^{+}+p^{'}.$
"There is also a small loss due to inelastic hadronic interactions of the decay particles before they are stopped."
The "optical properties of mixtures of PXE [phenyl-o-xylylethane] and derivatives of mineral oils are under investigation [3]."

## Moon

Lunar origin is established by comparing the mineralogy, the chemical composition, and the isotopic composition between meteorites and samples from the Moon collected by Apollo missions.

## Mars

"Martian meteorites contain a surprising amount of hydrated minerals, which have water incorporated in their crystalline structures. [...] the Martian mantle currently contains between 70 and 300 parts per million of water—enough to cover the planet in liquid 660 to 3,300 feet (200 to 1,000 meters) deep."
"Basically the amount of water we're talking about is equal to or more than the amount in the upper mantle of the Earth," which contains 50 to 300 parts per million of water.
"The meteorites are basaltic, which means the rocks must have formed from deep magmas brought to the surface during volcanic eruptions. By carefully examining a mineral called apatite, McCubbin's team found hydroxyl ions—a form of water that contains an oxygen atom bound to a hydrogen atom." Bold added.
"The presence of hydroxyl means that standard water—oxygen bound to two hydrogens—was also present in Martian magma. But because the hydroxyl is more tightly bound to rock than ordinary water, the ions remained behind when the rest of the water boiled out of the cooling lava."
"We're using apatite as a hydrometer to record how much water was in the rock before it degassed," [...] the Mars meteorites examined in the new study came from extremely young basalts, only 150 to 350 million years old. [...] "That makes these volcanic regions the most promising regions in which to look for past life on Mars".

## Hypotheses

* The first step in determining that an astronomical object is a rocky object is to detect molecules.