I know that this blog is titled “johnsmachines”, but I do get interested in “other stuff” too.
I came across this video on YouTube yesterday. It runs for 4 hours.
The footage was shot by an amateur astronomer, through telescopes which anyone can buy. A 9.5″ Celestron reflector (Schmitt Cassegrain I think), and an 80mm Orion refractor.
I used to be an amateur astronomer, and still retain an interest. One of my worst decisions ever was to give away an Orion 10″ reflector about 10 years ago.
Anyway, back to the video. It shows the surface of the moon, concentrating on some interesting areas. Following are some screen shots. It is titled “Live Moon Surface Observation”. Worth a look. Suggest jumping to 28minutes and watch maybe 5 minutes, zooming in and out.
Earth’s moon is strange.
It is the largest moon in the solar system relative to the parent planet.
It is much less dense than earth.
(why? if it is made of the same rock). (5.51g/cm vs 3.34g/cm. Thought to be due to Earth’s metal core.)
It almost exactly blocks the disk of the sun during a lunar eclipse. Coincidence?
The other side of the moon always faces away from earth. Until the space program, no human had ever seen the other side of the moon. The other side, incidentally, is quite different from the side which we see. Much more cratered, no large flat areas. Presumably most meteors come from the direction away from the sun (because they are scooped up by the gravitational field of the sun).
One moon day is exactly the same length as a lunar month. It is the only moon in the solar system where this applies. That is why the other side of the moon always faces away from earth. Another coincidence? (correction. Pluto – Charon also exhibit this behaviour, so it is not unique, just unusual. Thought to be due to “tidal locking”- thanks Gene).
OK. I know. You came to this site to look at my machines, particularly the Trevithick dredger engine. I am still fiddling with small details which are not very photogenic, but necessary before I run it on steam. Currently hooking up the boiler feed pump.