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Cavendish's result provided additional evidence for a planetary core made of metal, an idea first proposed by Charles Hutton based on his analysis of the 1774 Schiehallion experiment. [18] Cavendish's result of 5.4 g·cm −3 , 23% bigger than Hutton's, is close to 80% of the density of liquid iron , and 80% higher than the density of the Earth ...
In astronomy, metallicity is the abundance of elements present in an object that are heavier than hydrogen and helium. Most of the normal currently detectable (i.e. non-dark) matter in the universe is either hydrogen or helium, and astronomers use the word "metals" as convenient shorthand for "all elements except hydrogen and helium".
Dust astronomy is a subfield of astronomy that uses the information contained in individual cosmic dust particles ranging from their dynamical state to its isotopic, elemental, molecular, and mineralogical composition in order to obtain information on the astronomical objects occurring in outer space.
At these high frequencies, molecules in the Earth's atmosphere can block transmissions from space, and telescopes must be located in dry (water is an important atmospheric blocker), high sites. Radio telescopes must have very accurate surfaces to produce high fidelity images.
A high proportion of metals in a star correlates to the amount of heavy material initially available in the protoplanetary disk. A smaller amount of metal makes the formation of planets much less likely, under the solar nebula theory of planetary system formation. Any planets that did form around a metal-poor star would probably be low in mass ...
Gas drag slows the pebbles below the escape velocity of the massive body causing them to spiral toward and to be accreted by it. Pebble accretion may accelerate the formation of planets by a factor of 1000 compared to the accretion of planetesimals, allowing giant planets to form before the dissipation of the gas disk.
HH 151 is a bright jet of glowing material trailed by an intricate, orange-hued plume of gas and dust. [ 24 ] A dust particle interacts with electromagnetic radiation in a way that depends on its cross section , the wavelength of the electromagnetic radiation, and on the nature of the grain: its refractive index , size, etc.
This results in compositional evolution of cosmic gas in and between stars and galaxies, enriching such gas with heavier elements. Nuclear astrophysics is the science to describe and understand the nuclear and astrophysical processes within such cosmic and galactic chemical evolution, linking it to knowledge from nuclear physics and astrophysics.