Image: Plasma propulsion for small satellites

A test firing of Europe's Helicon Plasma Thruster, developed with ESA by SENER and the Universidad Carlos III's Plasma & Space Propulsion Team (EP2-UC3M) in Spain. This compact, electrodeless and low voltage design is ideal ...

A (much) earlier birth date for tectonic plates

Yale geophysicists reported that Earth's ever-shifting, underground network of tectonic plates was firmly in place more than 4 billion years ago—at least a billion years earlier than scientists generally thought.

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It's 2019. We want our cell phones fast, our computers faster and screens so crisp they rival a morning in the mountains. We're a digital society, and blurry photos from potato-cameras won't cut it for the masses. Physicists, ...

Scientists discover approach to activate inert gases

Inert gases like argon typically do not form chemical bonds except under extreme conditions, such as the icy cold of outer space. As shared in the Proceedings of the National Academy of Sciences, an international team of ...

Researchers make a key discovery on how alpine streams work

An EPFL study has prompted scientists to rethink a standard approach used to calculate the velocity of gas exchange between mountain streams and the atmosphere. Research conducted in streams in Vaud and Valais indicate that ...

Shooting movies in atoms

Researchers of the Laboratory for Attosecond Physics at LMU and the Max Planck Institute for Quantum Optics have developed a microscope that tracks the motion of electrons.

Arapuca device for international neutrino experiment is enhanced

A critical part of one of the largest recent particle physics experiments was developed in Brazil. The Arapuca is a light detector to be installed in the Deep Underground Neutrino Experiment (DUNE), a project seeking to discover ...

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Argon

Argon  /ˈɑrɡɒn/ is a chemical element represented by the symbol Ar. Argon has atomic number 18 and is the third element in group 18 of the periodic table (noble gases). Argon is the third most common gas in the Earth's atmosphere, at 0.93%, making it more common than carbon dioxide. Nearly all of this argon is radiogenic argon-40 derived from the decay of potassium-40 in the Earth's crust. In the universe, argon-36 is by far the most common argon isotope, being the preferred argon isotope produced by stellar nucleosynthesis in supernovas.

The name "argon" is derived from the Greek word αργον meaning "lazy" or "the inactive one", a reference to the fact that the element undergoes almost no chemical reactions. The complete octet (eight electrons) in the outer atomic shell makes argon stable and resistant to bonding with other elements. Its triple point temperature of 83.8058 K is a defining fixed point in the International Temperature Scale of 1990.

Argon is produced industrially by the fractional distillation of liquid air. Argon is mostly used as an inert shielding gas in welding and other high-temperature industrial processes where ordinarily non-reactive substances become reactive; for example, an argon atmosphere is used in graphite electric furnaces to prevent the graphite from burning. Argon gas also has uses in incandescent and fluorescent lighting, and other types of gas discharge tubes. Argon makes a distinctive blue-green gas laser.

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