From Torsbu, Norway
From Torsbu, Norway
Eric did a quiz last week (21st Jan). He gave us a heads-up of the subject matter and I did some research in preparation. So rather than dispose of it I thought I would dump it here for future reference.
Vital Statistics
The Moon has an average distance from the Earth of 240,250 miles. The orbit is elliptical - at the perigee it is only 225,700 miles away and 252,000 miles away at the apogee. This explains why some eclipses are not quite full but annular - it's too far away!
The orbital distance is 1,499,618 miles. It covers this distance in 27.3 days giving a speed of 2,287 mph.
It has a diameter of 2,172 miles, about a quarter that of the Earth. It has a mass of 7.35x1022kg, approximately 1/81th of the Earth.
It is the fifth largest satellite in the solar system, orbiting the fifth largest planet. This makes it the largest satellite relative to its parent body. Its bigger relatives are Callisto, Ganymede, Io (Jupiter) and Titan (Saturn).
It spins on an axis of 1.5 degrees.
From the Earth we see it going through eight phases - new (not visible), waxing crescent, first quarter, waxing gibbous, full, waning gibbous, last quarter, waning crescent.
The Moon is moving away from the Earth by 1.5 inches per annum.
Its biggest crater is the South Pole-Aitken basin about 1,500 miles across and 5 miles deep. There are 9,136 other craters.
Seas
There are 23 named 'seas' or Mare on the Moon with some very strange names:
Space Missions
There have been more than 105 launches to the Moon.
The first was the Soviet Luna 1 in 1959. It missed and headed off into space! Luna 2, the same year, did hit its target.
Twenty four men have been to the Moon but only twelve of them have walked on its surface - famously Neil Armstrong was the first in 1969, the last was Gene Cernan in 1972 (Apollo 17).
The first robotic rover was the Soviet Lunokhod 1 in 1970. Lunokhod 2 arrived in 1973 and set off on a journey that lasted forty years, which has only recently been surpassed. How is it that some vehicles can go so long without maintenance whilst a commercially-built earth car can barely make it to its second MOT without falling apart?
The US proposed detonating a nuclear weapon on the Moon (Project A119).
What we Learned from Eric
The Earth is 43 to 55 times brighter than the Moon. I thought surprising given that the Moon is covered in glass-like silica.
Many of the craters have a central peak, like a drop of water splashing into more water.
The Earth is travelling at 67,000 mph. How fast is the Moon travelling relative to the Sun at A) Full Moon and B) New Moon? Answers (approx) A) 67,000 + 2,300 and B) 67,000 - 2,300.
The Earth and the Moon in its orbit will fit inside the Sun.
And finally - if the Sun was reduced to the size of a golf ball and the Earth to a grain of sand how far away would the next star be? A. 78.6 miles!