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Argon is the most abundant noble gas in Earth's crust, comprising 0.00015% of the crust. Nearly all argon in Earth's atmosphere is radiogenic argon-40, derived from the decay of potassium-40 in Earth's crust. In the universe, argon-36 is by far the most common argon isotope, as it is the most easily produced by stellar nucleosynthesis in ...
Argon (18 Ar) has 26 known isotopes, from 29 Ar to 54 Ar, of which three are stable (36 Ar, 38 Ar, and 40 Ar). On the Earth, 40 Ar makes up 99.6% of natural argon. The longest-lived radioactive isotopes are 39 Ar with a half-life of 268 years, 42 Ar with a half-life of 32.9 years, and 37 Ar with a half-life of 35.04 days.
The abundance of argon, on the other hand, is increased as a result of the beta decay of potassium-40, also found in the Earth's crust, to form argon-40, which is the most abundant isotope of argon on Earth despite being relatively rare in the Solar System. This process is the basis for the potassium-argon dating method. [72]
The argon found in Earth's atmosphere is 99.6% 40 Ar; whereas the argon in the Sun – and presumably in the primordial material that condensed into the planets – is mostly 36 Ar, with less than 15% of 38 Ar. It follows that most of the terrestrial argon derives from potassium-40 that decayed into argon-40, which eventually escaped to the ...
NEON (67A: Two-syllable gas) NEON isn't the only two-syllable gas, but it is the only two-syllable gas with four letters. Argon, xenon, and ozone don't quite fit here.
The composition of Earth's atmosphere is determined by the by-products of the life that it sustains. Dry air (mixture of gases) from Earth's atmosphere contains 78.08% nitrogen, 20.95% oxygen, 0.93% argon, 0.04% carbon dioxide, and traces of hydrogen, helium, and other "noble" gases (by volume), but generally a variable amount of water vapor is ...
It has long been recognized that eruptions contribute much lower total SO 2 emissions than passive degassing does. [ 8 ] [ 9 ] Fischer et al (2019) estimated that, from 2005 to 2015, SO 2 emissions during eruptions were 2.6 teragrams (Tg or 10 12 g or 0.907 gigatons Gt) per year [ 10 ] and during non-eruptive periods of passive degassing were ...
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