Orbital velocity

Meteors form when meteoroids enter the atmosphere. The mean orbital velocity of the Earth around the Sun is 29.7 kms-1, so a particle stationary in space will enter the Earth s atmosphere at this velocity. Gravity will further attract the particles up to a maximum of 11 kms-1 (the escape velocity) to make an entry velocity of order 40 kms-1 plus whatever additional velocity the particle may possess. This energy is converted into heat by the drag on the atmosphere, producing temperatures of order 2000 K - the glow seen from a shooting star. The final temperature depends on the properties of the particle, the atmospheric composition and the angle of incidence with the atmosphere. 

Using equation (14) and assuming isotropic orbital velocity distributions / (vi — v ) the corresponding expression to equation (2) for the orbital contribution to the molecular stopping was obtained as... 

At the beginning of the twentieth century, there were several isolated voices claiming for a revision of the Michelson-Morley interpretation. Hicks [52] performed a theoretical analysis of the Michelson-Morley experiment and concluded that data were consistent with a somewhat larger magnitude of the difference of speeds. More importantly, he noted that the data followed a periodic curve proportional to cos 20, where angle 0 refers to a rotation of the interferometer relative to the presumed direction of orbital velocity. The functional dependence present in the results is of the form to be expected if there existed E. 

Numerous unsuccessful measurements were made to determine the motion of earth in the ether. These measurements were not able to give results compatible within the framework of classical Newtonian mechanics, even though that the earth has an orbital velocity v0 30,000 m/s (where v0 is velocity of the earth to the ether). In 1887 Michelson and Morley also determined the earth s orbital velocity by their precision interferometer [11], The updated arrangement of Michelson-Morley experiment (M-M experiment) can be seen in Fig. 1. 

Figure 1. An up-to-date arrangement the of Michelson-Morley experiment. Here LASER means the source of light, BS means beamsplitter, Ml and M2 are mirrors on the end of arms, PD is the phase detector (interferometer), and v is the earth s orbital velocity, which is regarded as the inertial motion for short time periods.

For media more complicated than hydrogen, where the electrons may have different orbital velocities, the Bohr criterion alone is not enough. At present we have no good theory that would explain the influence of a... 

The eddies were formed off the eastern coast of the Black Sea and moved westward showing a decrease in the phase velocity in the narrowest area of the sea south of the Crimea. In the model version with a flat abyssal floor at a depth of 1540 m, the wavelength comprised 250 km in the east and 190 km in the west with a period of 160 days and a phase velocity of - 2.0-2.5kmday-1. The orbital velocities in the eddies in the surface layer reached 0.45 ms 1 and deeper decreased down to 0.25 ms-1 a depth of 70m and to 0.05 - 0.10 m s 1 at a depth of 1100 m. The wave regime was more intensive in the eastern part of the Black Sea in its western part, eddies dissipated above the continental slope and partially reflected from the western coast. In the study [50], the introduction of the abyssal bottom topography increased (reduced) the sizes and intensities of cyclonic (anticyclonic) eddies by a factor of 1.5-2. The cyclonic (anticyclonic) eddies became more alike the SBCGs (NSAEs) in Fig. 1. The period of the eddies grew up to almost two years, while their phase velocity decreased down to 0.4-0.5 km day-1. 

PROBLEM 2.4.1. Given that the average earth-moon distance is Rem = 3.844 x 108 m and that the moon s revolution around the earth is 27.3 days (from which its tangential orbital velocity is vm = 1.0186 x 103 m s 1), compute the mass of the earth. 

The dynamical evolution of solids in protoplanetary disks is controlled by the large-scale flows that develop due to disk evolution, diffusion associated with the turbulence that is related to disk evolution or shear instabilities, gas-drag-induced motions due to different orbital velocities of the gas and solids, and settling towards the mid-plane due to the vertical component of the central star s gravity. As the large-scale flows have already been discussed, we now discuss the other sources of particle motions. 

Solids in a gas-free orbit around a star will follow Keplerian orbits, meaning that their orbital velocity is found by balancing the centrifugal force of their motions with the central force of gravity from the star, or ... 

Keplerian rotation an orbital velocity that matches that of a gravitationally bound object around the central object as described by Kepler s third law. 

The sun is located near the edge of the arm O. It may be noted that this picture of the spiral structure in the vicinity of the sun is based on both optical and radio observations, whereas the large scale structure of the interstellar gas (Fig. 4) is based only on observations of the X21 cm hydrogen line and kinematic distances, which become highly uncertain towards the galactic center and anticenter. Kinematic distances are obtained from a model for the rotation of the Galaxy due to Schmidt. This model relates the circular orbital velocity of the gas to the distance from the galactic center (see Fig. 3). 

In LEO (ca. 300 km altitude), the ambient gas density and temperature are typically 10 cm and 1200 K, respectively although solar activity and diurnal phase can strongly perturb these values. With an orbital velocity of 7.5-8 km/s, the flux of neutral particles on ram surfaces is 10 m s . This corresponds to approximately ten collisions per atomic surface site per second. Atmospheric collisions lead to satellite drag and torques which hinder attitude control. Degradation of materials on ram-facing surfaces can compromise a spacecraft s flight duration as well. ... 

Figure 5. Root mean square charge of positive ions in water as a function of their energy per nucleon according to the Monte Carlo method. Ion charge approaches bare nucleus value at high energies. Generally speaking substantial changes start to occur at around K-orbital velocities...

At high ion velocities, v > VqZ, where Uq = e /h = orbital velocity of the electron in the hydrogen atom, the nuclear energy loss is negligible. The particle has an effective charge equal to Zj, and the energy loss is given by an equation of the form... 

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