In the case that your ICA file doesn't open, it is highly likely that you do not have the correct software application installed on your PC to view or edit ICA file extensions. If your PC opens the ICA file, but it's the wrong application, you'll need to change your Windows registry file association settings.
He found the period of the planet's revolution around the Sun in years would be equal to the cube of its average distance from the Sun in astronomical units. Let us suppose we find an asteroid with a perihelion distance of 3 AU, and aphelion distance of 5 AU. Calculate its semimajor axis (average distance from the Sun) and use Kepler's Third Law to find its orbital period in years.
Sidereal time is a measure of the position of the Earth in its rotation around its axis, or time measured by the apparent diurnal motion of the vernal equinox, which is very close to, but not identical to, the motion of stars. They differ by the precession of the vernal equinox in right ascension relative to the stars. Earth's sidereal day also differs from its rotation period relative to the background stars by the amount of precession in right ascension during one day (8.4 ms). Its J2000 mean value is 23 h 56 m 4.090 530 833 s.