Archive for the CATS Category

How Our Moon Helped Create Humanity and (Hopefully) Allow Us to Escape to Space

Posted in CATS on January 23, 2013 by badhex

Were it not for the Moon, we wouldn’t exist to see the Universe. Life on Earth would probably be no more advanced than the simplest of multi-celled organisms (if that). We may indeed be very rare sentient life because without the relative sizes and distances of our Planet and Moon system, with their almost perfect balanced orbit and gravity, tidal conditions and crustal distortions could have been too severe to allow us temperate enough conditions to develop. So finding another Earth size exoplanet by itself, at the right distance from its parent star to be the right temperature will not point to a planet with complex life unless it also has a satellite analogous to our Moon. Bearing in mind we are the only world of four close to our star with such a large Moon, created by a fluke impact with just the right sized planet to produce the Moon, maybe our system is pretty rare.

It’s believed life may well have formed in tidal pools, with constant replenishment of new water, with oxygen stirred into it in the shallows, allowed the pools to breathe and the chemicals in them mix. By holding the Earth in a steady spin, so it doesn’t waver about chaotically, the Moon gives us stable zones of temperature and the tides help to blend the zones, averaging out any global temperature extremes. The gravity of our Moon also allows us to have Plate Tectonics so our continents can move about, this allows species to roam the planet over millions of years and help provide the stress of subtle change over time forcing evolution to further develop the myriad of species. If populations of living organisms don’t move occasionally the gene pools ‘stagnate’ meaning in breeding and biodiversity suffers as a result. It has been these changes producing mutations within us that have assisted us to develop larger brains, then language with of tools. It was a mutation just over 2 million years ago that altered the way our brains are wired for the language and speech that has allowed us to communicate with a complexity that gave us a tremendous advantage over any other species and become the dominant one. It’s a pity it couldn’t have given us a few more I.Q. points for all to appreciate the importance of our custodianship of our planet rather than the mere plundering of its resources.

The Moon has some very large craters from the not that distant past. It has certainly drawn off some of the asteroids and comets that would otherwise have caused global extinctions, setting back the progress of evolution by many millions of years. I’m not aware if there’s a crater on the Moon that equates to a four kilometer body impacting on it in the last 32.5 million years but wouldn’t be surprised if there were something close to it at some time in the last few tens of millions. If the Moon hadn’t taken that hit for us, maybe our evolution would have been delayed by however many millions of years and so this article be delayed until the year 32,002,013AD (now even I’ve got a head ache).

In terms of our future in space, the Moon may act as a staging post, providing the bases and materials to build ships which could then escape the Moon’s gravity with far more ease than from the Earth, making manned space flight far more efficient.

Simply Watching Our Neighbour.

At the beginning of writing this on January 12th, the Moon is a slender crescent in the south-western sky shortly after Sunset (about 2% lit) and it then quickly follows the Sun over the horizon this evening. As the days go by its crescent will broaden. The thin crescent shortly after the Moons reappearance from conjunction with the Sun is known as ‘The New Moon in the Old Moon’s Arms’. Many of you will have noticed that during the crescent phase, you can see the dark side of the Moon, the Moon’s remaining disc as a subtle dark grey against the backdrop of the more, bluey, still glowing, twilight skies. This is known as Earthshine. Where the Crescent is light reflected off the Moon originating from the Sun, Earthshine is a reflection of the light from the Earth falling on the Moon. If you look carefully you can just about see lighter and darker areas, much more so with binoculars.

The Crescent broadens (this is called a waxing Moon) until it is seen as a hemisphere and this is the First Quarter Moon. Typically this is when it is still high enough in the sky for us to catch it from the Observatory in our evening sessions after 8pm. The Moon will be just shy of First Quarter on Friday 18th January, so if you want to see it you’ll need to get to the Observatory by 8pm as it sets behind trees not long after. The following day it has climbed higher and so is available for longer.

On the weekend starting the 25th January the Moon has climbed to a much higher elevation and more to the south, as it heads towards Full Moon. That weekend the Moon is visible throughout each of our entire sessions.

Full Moon is on the 27th and not worth looking at apart from watching it rise in the east as the Sun sets in the west and you see it placed against landmarks that make it a sensational visual sight. Telescopically the Full Moon is poor though, with the Sun bearing straight down on it, there are no shadows and the disc is just a very bright bland disc.

Everyone imagines the Moon is bigger at this point because it really does look bigger. ‘It’s the light being refracted by the Earth’s atmosphere that makes it bigger’…actually no, Patrick Moore once did a Sky at Night, where they cut a disc in cardboard and placed it at a precise point away from the camera and then filmed the Moon, exactly filling the hole, rising over some buildings. They followed the Moon across the sky with the same ‘Moon mask’ kept at the same distance from the camera. Now if the Moon really had been bigger at the beginning when low down, it would have got smaller throughout the evening as it climbed and so bit by bit, the Moon would have become smaller than the hole. However this did not happen, so proving the Moon had not changed size as it climbed.

Interestingly psychologists have carefully looked into this effect and suspect it is to do with our perception of size of objects in relation to each other. As the Moon rises, the foreground objects we are used to seeing as ‘sizeable’ appear to be dwarfed by the Moon. However when the Moon is high in the sky, we don’t see it in relation to anything and by virtue of it being ‘isolated’, it appears smaller. This is quite difficult to get ones head around and although I can understand it, I can only hope what I’ve said makes sense to you.

Between First Quarter and Full and then Last Quarter, the shape of the Moon is ‘Gibbous’. So towards full it’s called a waxing gibbous Moon and then past full, waning gibbous. Once someone misheard my description of a past first quarter Moon at the Observatory and sent me an e-mail saying… ‘what was that I’d said about waxing gibbons’….ouch, painful imagery!

Shortly after the Moon has entered the waning gibbous stage, it rises too late for us to see it from the Observatory during our session. Although the Moon can be seen during most nights of the month, we only see it for the time we’re not asleep, this creates the illusion it is only around for a fortnight each Lunation (Lunar cycle).

I suppose the dawn, waning crescent with its Earthshine could be called ‘New Moon with the Old Moon Desperately Trying to Hold On’…you heard it here first.

So this explains why we only see the Moon for four of our eight sessions in each month (precluding any cloud that ensures some months we don’t see it at all). If you download the free planetarium software called Stellarium (type this into your preferred search engine) it allows you to surf the sky each night and see what the Moon is up to. After a while of following it (the same is true of the planets) you develop a sense of the time it takes for all these neighbours of ours to move around the sky and after a while you can develop a sense of where they are without needing to check.

“The fool on the hill, sees the Sun going down, and the eyes in his head, see the world spinning round” – Beatles.

You could change ‘the Sun’ for ‘the Moon’ and it would work even better because not only do you see the world spinning around but you can work out how the Moon circles the Earth each Lunar month and because it spins exactely once on its axis for each orbit around us, we are condemned to always see the same face.

Happy Lunacy,


P.s. Promised a 2013 Highlights a while ago….coming soon (before 14, promise)….watch this space….or that one…..or that one….