Astronomical Unit atmosphere

Arrhenius activation energy 55 astronomical unit 110 asymmetry parameter 23 atmosphere 112 atomic mass 20, 41, 94 atomic mass constant 20, 41, 89 atomic mass unit 20, 41, 75, 89, 111 atomic masses of nuclides 98-104 atomic number 20, 44 atomic orbital basis function 17, 19 atomic scattering factor 36 atomic states 28 atomic units 76, 120 atomic weight 41, 94 atomization 51, 53 attenuance 32 atto 74... 

Fig. 1. The theoretical extraterrestrial solar spectral distribution (at the top of the Earth s atmosphere at the mean Earth-Sun distance of one astronomical unit) of Kurucz at high and low...

The first attempted measurements of the astronomical unit during the 1761 transit were unsuccessful. However, several observers reported a halo around Venus as it entered and exited the Sun s disk. Thomas Bergman in Uppsala and Mikhail Lomonosov in St. Petersburg, independently speculated that the halo was due to an atmosphere on Venus. Eight years later observations of the 1769 solar transit (including those made by Captain Cook s expedition to Tahiti) gave a value of 1 AU = 153 million kilometers, —2.3% larger than the actual size (149.6 million kilometers) of the astronomical unit (Woolf, 1959 Maor, 2000). 

Photo/thermal Degradation. Samples of etched ( <2.5 pm) and unetched ( X/7.5 pm) POP film were placed in quartz tubes which were continuously evacuated while being heated at temperatures >450 C in a constant temperature block, controlled to 2 C. Other film samples contained in quartz tubes evacuated to <10 Torr were exposed to a Hanovia 450-watt mercury lamp with the etched side facing the lamp. At 14 cm from the lamp, the intensity of the uv radiation incident on the films was equivalent to <5.9 times that of the Sun in the 2000-3500-A range at 1 astronomical unit, i.e., just outside the atmosphere. At that distance from the lamp, the temperature of... 

The solar constant is defined as the total radiative energy flux outside the Earth s atmosphere. This parameter is used to characterize the total solar radiation input. The magnitude of this constant is estimated by Brusa and Frohlich (1982) to be 1367 W m-2, at 1 AU (astronomical unit), which corresponds to an effective solar temperature of 5780 K. 

Recently, I wanted to refer to an account of some calculations made by Harlow Shapley, the eminent American astronomer, which showed very clearly the huge number of molecules in any small parcel of matter. The story was based on the fact that in any volume of air, four fifths of the particles are molecules of nitrogen and that when a deep breath is exhaled, the nitrogen molecules in it are rapidly dispersed. After a certain period, probably not more than a few years, perhaps less, they will be equally distributed throughout the atmosphere. By this time, each unit volume of air at the surface of the earth will contain between two and three of the nitrogen molecules that were present in the original volume exhaled. To make it more dramatic, the author of this account selected the breath that Shakespeare exhaled as he wrote the first line of the second act of Hamlet. As you inhale a breath today it will contain two of the actual molecules exhaled by Shakespeare at that particular moment. You would be most unlucky were you to get only one molecule were you to capture three, you would belong to a fortunate minority. 

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