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Authors: Longcope Dana
Title: Using Kepler's laws and Rutherford scattering to chart the seven gravity assists in the epic sunward journey of the Parker Solar Probe

On August 12, 2018, NASA launched the Parker Solar Probe (PSP) to explore regions very near the Sun. Losing enough energy and angular momentum to approach the Sun requires either an impractical amount of fuel or a maneuver called a gravity assist. A gravity assist is essentially an elastic collision with a massive, moving target—Rutherford scattering from a planet. Gravity assists are often used to gain energy in missions destined for the outer solar system, but they can also be used to lose energy. Reaching an orbit sufficiently close to the Sun requires that PSP undergoes not one but seven successive gravity assists off the planet Venus. This simple description poses several conceptual challenges to the curious physics student. Why is it so much more challenging to get to the Sun th. . .
Date: 01/2020 Publisher: American Journal of Physics Pages: 11 - 19 DOI: 10.1119/10.0000145 Available at:
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Authors: Plus R.
Title: Utilisation des isotopes D, 15N, 26Mg pour l'étude vibrationnelle de Mg(NH3)6Cl2.

The following substituted magnesium chloride hexa-ammines: 24Mg( 14NH 3) 6Cl 2; 26Mg( 14NH 3) 6Cl 2; 24Mg( 15NH 3) 6Cl 2; 24Mg( 14ND 3) 6Cl 2; 24Mg( 14ND 3) 6Cl 2 have been studied by i.r. and Raman spectroscopy. The frequency shifts have been measured for all active vibrational bands predicted by group theory analysis. The results show that measurements made on isotopically substituted compounds can provide confirmation of assignments of vibrational bands previously proposed [2].

Date: 01/1976 Publisher: Spectrochimica Acta Part A: Molecular Spectroscopy Pages: 263 - 268 DOI: 10.1016/0584-8539(76)80076-1 Available at:
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