12am:The Iron Mountain, MI forecast for Apr 14 is 53 degrees and Overcast. There is 49 percentage chance of rain and 11 mph winds from the Southeast. 3pm:The Iron Mountain, MI forecast for Apr 14 is 53 degrees and Patchy rain possible. There is 49 percentage chance of rain and 11 mph winds from the Southeast.
The earth's orbit around the sun is elliptical, so the earth moves at a constantly varying velocity as it moves closer to the sun (perihelion) or further away (aphelion). The earth's angular velocity (speed of movement) is considerably greater at perihelion than it is at aphelion.he earth gets through 10% of its path in the same length of time whether it is at aphelion (moving slowly) or perihelion (moving fast). The absolute speed at which the earth moves varies, but the rate at which it orbits is constant.
1 - The solar constant is the amount of energy received at the top of the Earth's atmosphere on a surface oriented perpendicular to the Suns rays (at the mean distance of the Earth from the Sun). 2  The generally accepted solar constant of 1368 W/m 2 is a satellite measured yearly average.nce the surface irradiance of the Sun is determined the amount of energy reaching the top of the Earth's atmosphere can be calculated using the Inverse Square Law. The average amount of energy received on a surface perpendicular to incoming radiation at the top of the atmosphere is the solar constant.