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Oxygen not evidence for exoplanet life?

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Further to: There are millions of habitable planets… no and Rob Sheldon reflects on the hunt for water on Mars, we now hear  from Space.com:

Oxygen on Exoplanets May Not Mean Alien Life

On Earth, plants release oxygen into the air through photosynthesis. If a planet beyond the solar system was found to contain oxygen in its atmosphere, scientists reasoned, that oxygen would have formed as a byproduct of life.

Narita and his team decided to study the role of stellar radiation around stars similar to the sun. They found that, if enough of the mineral titania lay on the surface of a planet, it could dissolve in liquid water, producing oxygen in the atmosphere.

Titania is a naturally occurring substance present in meteorites and on Earth’s moon. It forms as dust outflows around evolving low- and medium-mass stars, and through supernovae, and is thought to be common in exoplanet systems. The amount of titania on the surface of a planet or moon would vary based on the number of impacts each body received.

According to the research, an Earth-like planet orbiting a sunlike star would need only enough titania to cover about 0.05 percent of the planet’s surface to create the same amount of oxygen as in Earth’s atmosphere. More.

Find me a single non-Earth-based organism and this discussion could really go somewhere.

See also: Don’t let Mars fool you. Those exoplanets teem with life!

and The Science Fictions series at your fingertips (origin of life)

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cantor, yes, of course, sorry. Didn't catch the inadvertent break that occurred for some reason when I clipped to UD. As to learning a little bit more about the applications of TiO2 as a Photocatalyst, let me clip this from wiki:
Titanium dioxide, particularly in the anatase form, is a photocatalyst under ultraviolet (UV) light. It has been reported that titanium dioxide, when doped with nitrogen ions or doped with metal oxide like tungsten trioxide, is also a photocatalyst under either visible or UV light.[35] The strong oxidative potential of the positive holes oxidizes water to create hydroxyl radicals. It can also oxidize oxygen or organic materials directly. Hence, in addition to its use as a pigment, titanium dioxide can be added to paints, cements, windows, tiles, or other products for its sterilizing, deodorizing and anti-fouling properties and is used as a hydrolysis catalyst. It is also used in dye-sensitized solar cells, which are a type of chemical solar cell (also known as a Graetzel cell). The photocatalytic properties of titanium dioxide were discovered by Akira Fujishima in 1967[36] and published in 1972.[37] The process on the surface of the titanium dioxide was called the Honda-Fujishima effect (ja:??-????).[36] Titanium dioxide, in thin film and nanoparticle form has potential for use in energy production: as a photocatalyst, it can carry out hydrolysis; i.e., break water into hydrogen and oxygen. With the hydrogen collected, it could be used as a fuel. The efficiency of this process can be greatly improved by doping the oxide with carbon.[38] Further efficiency and durability has been obtained by introducing disorder to the lattice structure of the surface layer of titanium dioxide nanocrystals, permitting infrared absorption.[39] In 1995 Fujishima and his group discovered the superhydrophilicity phenomenon for titanium dioxide coated glass exposed to sun light.[36] This resulted in the development of self-cleaning glass and anti-fogging coatings. TiO2 incorporated into outdoor building materials, such as paving stones in noxer blocks[40] or paints, can substantially reduce concentrations of airborne pollutants such as volatile organic compounds and nitrogen oxides.[41] A photocatalytic cement that uses titanium dioxide as a primary component, produced by Italcementi Group, was included in Time's Top 50 Inventions of 2008.[42] Attempts have been made to photocatalytically mineralize pollutants (to convert into CO2 and H2O) in waste water.[43] TiO2 offers great potential as an industrial technology for detoxification or remediation of wastewater due to several factors:[44] The process uses natural oxygen and sunlight and thus occurs under ambient conditions; it is wavelength selective and is accelerated by UV light. The photocatalyst is inexpensive, readily available, non-toxic, chemically and mechanically stable, and has a high turnover. The formation of photocyclized intermediate products, unlike direct photolysis techniques, is avoided. Oxidation of the substrates to CO2 is complete. Other Applications TiO2 can be supported as thin films on suitable reactor substrates, which can be readily separated from treated water.[45] Titanium dioxide in solution or suspension can be used to cleave protein that contains the amino acid proline at the site where proline is present.[46] Titanium dioxide is also used as a material in the memristor, a new electronic circuit element. It can be employed for solar energy conversion based on dye, polymer, or quantum dot sensitized nanocrystalline TiO2 solar cells using conjugated polymers as solid electrolytes.[47] Synthetic single crystals and films of TiO2 are used as a semiconductor,[48] and also in Bragg-stack style dielectric mirrors due to the high refractive index of TiO2 (2.5–2.9).[49][50] Titanium dioxide is incompatible with strong reducing agents and strong acids.[51] Violent or incandescent reactions occur with molten metals that are very electropositive, e.g. aluminium, calcium, magnesium, potassium, sodium, zinc and lithium.[52] https://en.wikipedia.org/wiki/Titanium_dioxide#Photocatalyst
Amazing little multi-functional element/mineral! bornagain77
1 bornagain77 October 6, 2015 at 4:56 am Titanium dioxide ... chemical formula TiO
. TiO2 . cantor
Titanium dioxide, also known as titanium(IV) oxide or titania, is the naturally occurring oxide of titanium, chemical formula TiO 2. When used as a pigment, it is called titanium white, Pigment White 6 (PW6), or CI 77891. Generally it is sourced from ilmenite, rutile and anatase. It has a wide range of applications, from paint to sunscreen to food colouring. When used as a food colouring, it has E number E171.,,, Applications: https://en.wikipedia.org/wiki/Titanium_dioxide#Applications Essential Elements for Plant Growth List of Essential Elements Excerpt: Other elements that have been proposed as candidates for essential or beneficial elements include chromium, vanadium, and titanium, although strong evidence is lacking at this time. http://soils.wisc.edu/facstaff/barak/soilscience326/listofel.htm Interestingly, for the last 10 million years the oxygen percentage of the Earth's atmosphere has been holding steady around 21%. 21% happens to be a 'very comfortable' oxygen level for humans to exist in. If the oxygen level was only a few percentage lower, large mammals would become severely hampered in their ability to metabolize energy; if only a few percentage higher, forest fires would be far more devastating (Denton; Nature's Destiny). Composition Of Atmosphere - Pie Chart and Percentages: http://www.ux1.eiu.edu/~cfjps/1400/FIG01_010.JPG http://www.ux1.eiu.edu/~cfjps/1400/TBL01_0T2.JPG of related note: Michael Denton: Remarkable Coincidences in Photosynthesis - podcast http://www.idthefuture.com/2012/09/michael_denton_remarkable_coin.html bornagain77

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