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  2. Helium-3 - Wikipedia

    en.wikipedia.org/wiki/Helium-3

    Since the atmosphere of the Earth has a mass of about 5.14 × 10 18 kilograms (1.133 × 10 19 lb), [24] the mass of 3 He in the Earth's atmosphere is the product of these numbers, or about 37,000 tonnes (36,000 long tons; 41,000 short tons) of 3 He. (In fact the effective figure is ten times smaller, since the above ppm are ppmv and not ppmw.

  3. Liquid helium - Wikipedia

    en.wikipedia.org/wiki/Liquid_helium

    Liquid helium is a physical state of helium at very low temperatures at standard atmospheric pressures.Liquid helium may show superfluidity.. At standard pressure, the chemical element helium exists in a liquid form only at the extremely low temperature of −269 °C (−452.20 °F; 4.15 K).

  4. Densities of the elements (data page) - Wikipedia

    en.wikipedia.org/wiki/Densities_of_the_elements...

    0.08988 kg/m 3: 0 °C, 101.3 kPa VDW: 0.08988 g/L: 0 °C, 101.325 kPa (lit. source) 0.08988 g/L: 2 He helium; use: 0.1786 g/L: 0 °C, 101.325 kPa CRC (calc. ideal gas) 0.164 g/L: 25 °C, 101.325 kPa LNG: 0.176 g/L: room temperature KCH: 0.1785 kg/m 3: 0 °C, 101.3 kPa VDW: 0.1786 g/L: 0 °C, 101.325 kPa (lit. source) 0.1785 g/L: 0 °C, 1 atm 7 ...

  5. Isotopes of helium - Wikipedia

    en.wikipedia.org/wiki/Isotopes_of_helium

    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.

  6. Orders of magnitude (mass) - Wikipedia

    en.wikipedia.org/wiki/Orders_of_magnitude_(mass)

    Mass equivalent of the energy of a photon at the peak of the spectrum of the cosmic microwave background radiation (0.235 meV/c 2) [3] 10 −36: 1.8 × 10 −36 kg 1 eV/c 2, the mass equivalent of one electronvolt [4] 3.6 × 10 −36 kg Electron neutrino, upper limit on mass (2 eV/c 2) [5] 10 −33 quectogram (qg) 10 −31: 9.11 × 10 −31 kg

  7. Earth mass - Wikipedia

    en.wikipedia.org/wiki/Earth_mass

    An Earth mass (denoted as M 🜨, M ♁ or M E, where 🜨 and ♁ are the astronomical symbols for Earth), is a unit of mass equal to the mass of the planet Earth.The current best estimate for the mass of Earth is M 🜨 = 5.9722 × 10 24 kg, with a relative uncertainty of 10 −4. [2]

  8. What to know about the company behind Puerto Rico's massive ...

    www.aol.com/know-company-behind-puerto-ricos...

    A massive power outage blanketed most of Puerto Rico early Tuesday, leaving more than 1.2 million people without electricity. Here's what to know about the blackout and Luma Energy, which handles ...

  9. Helium-4 - Wikipedia

    en.wikipedia.org/wiki/Helium-4

    Helium-4 makes up about one quarter of the ordinary matter in the universe by mass, with almost all of the rest being hydrogen. While nuclear fusion in stars also produces helium-4, most of the helium-4 in the Sun and in the universe is thought to have been produced during the Big Bang , known as " primordial helium".