|Fighter pilot Liu Yang. China's first taikonaut in space|
We can breath!
Astronaut's spacesuite reminds us that it is actually the same way down here upon the surface of Earth.
Without the rather invisible oxygen mask of atmosphere containing 20% O2 there would no be life as we know it on this planet. (Go look at Mars, for example; it does have a carbon-dioxide CO2 atmosphere but this does not sustain life. Curiosity rover has confirmed with spectacular images of ancient conglomerates that there once may have been water streams and life in the past of the Red Planet.)
Usually we breath without paying much attention to respiration. But no air, and the situation gets immediately our attention!
God of Israel, who is the only real God there is, went to special arrangements in order to provide oxygen to His living creatures by letting cyanoabacteria generate a heavenly oxygen mask. It all apparently started with the first life forms known to paleobiology - the cyanobacteria - that first appear some three billion years ago and immediately went into the all-important business of doing photosynthesis.
Plenty of oxygen down here
Oxygen is the most abundant element by mass in the Earth's crust, making up almost half of the crust's mass. There is oxygen in the water H2O and there is oxygen in the atmosphere O2 and we are protected from cosmic rays by the fragile ozone layer O3 and oxygen is the most abundant element in our human bodies, as well.
So where is the catch?
Free oxygen is too chemically reactive to appear on Earth without the photosynthetic action of living organisms, which use the energy of sunlight to produce elemental oxygen from water. Elemental O2 only began to accumulate in the atmosphere after the evolutionary appearance of these organisms, roughly 2.5 billion years ago.
The genious of our Creator can be seen so clearly in His works providing breathable air for inhaling and plants to convert the exhaled carbon dioxide back to oxygen through the engine of photosynthesis that runs on energy from the Sun. True recycling!
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But is there oxygen in the space?
The possibly surprising answer is that "Yes, there is an enormous amount of oxygen in the space!"
In fact, by mass oxygen is the third-most abundant element in the entire universe, after hydrogen and helium. (wikipedia)
Stellar origins of oxygen
Naturally occurring oxygen is composed of three stable isotopes, 16O, 17O, and 18O, with 16O being the most abundant (99.762% natural abundance).
- Most 16O is synthesized at the end of the helium fusion process in massive stars but some is made in the neon burning process.
- 17O is primarily made by the burning of hydrogen into helium during the CNO cycle, making it a common isotope in the hydrogen burning zones of stars.
- Most 18O is produced when 14N (made abundant from CNO burning) captures a 4He nucleus, making 18O common in the helium-rich zones of evolved, massive stars.