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The idea for the polar wind originated with the desire to solve the paradox of the terrestrial helium budget. This paradox consists of the fact that helium in the Earth's atmosphere seems to be produced (via radioactive decay of uranium and thorium) faster than it is lost by escaping from the upper atmosphere. The realization that some helium ...
The atmospheres on hycean planets are thought to be made up of hydrogen, helium, and water vapor. [1] Dark hycean planets thought to be common around red dwarf stars. [13] Red dwarf stars are the most common type of star in the Milky Way galaxy. [14] They are considered to be a promising place to search for life beyond Earth.
An observation of the new yellow line had been made earlier by Janssen at the 18 August 1868 solar eclipse [13], and because their papers reached the French academy on the same day, he and Lockyer usually are awarded joint credit for helium's discovery. Terrestrial helium was found about 27 years later by the Scottish chemist William Ramsay.
Terrestrial planets are substantially different from the giant planets, which might not have solid surfaces and are composed mostly of some combination of hydrogen, helium, and water existing in various physical states. Terrestrial planets have a compact, rocky surfaces, and Venus, Earth, and Mars each also has an atmosphere. Their size, radius ...
Helium is inert - it does not react with other substances or combust - and its atomic number is 2, making it the second lightest element after hydrogen. Rockets need to achieve specific speeds and ...
Space physics, also known as space plasma physics, is the study of naturally occurring plasmas within Earth's upper atmosphere and the rest of the Solar System.It includes the topics of aeronomy, aurorae, planetary ionospheres and magnetospheres, radiation belts, and space weather (collectively known as solar-terrestrial physics [1]).
Terrestrial helium consists almost exclusively (all but ~2ppm) [16] of 4 He. 4 He's boiling point of 4.2 K is the lowest of all known substances except 3 He. When cooled further to 2.17 K, it becomes a unique superfluid with zero viscosity. It solidifies only at pressures above 25 atmospheres, where it melts at 0.95 K.
Helium is a commonly used carrier gas for gas chromatography. The age of rocks and minerals that contain uranium and thorium can be estimated by measuring the level of helium with a process known as helium dating. [28] [30] Helium at low temperatures is used in cryogenics and in certain cryogenic applications.