The accidental scientist

 If you look at the sky just past sunset, Mars is still running the show somewhere in mid-sky. But the second brightest object is Jupiter. If you look at the Western sky to-night (9 Dec.) around 8 pm, he will be right there at 30 degrees above the horizon, with his mate Saturn very close, just a bit higher and on the right. Jupiter is chasing Saturn at the moment and it ’ s getting a bit closer every day. On next Thursday night (17 Dec.) at 8pm, the Moon crescent will be right there too. Weather permitting it will be dead easy to find the Moon, then the Jupiter Saturn pair just under it a bit to the right. Why do I make a fuss about this? Well by then it will be almost impossible to separate Jupiter and Saturn by naked eye. This is called a conjunction. Jupiter goes around the Sun in about 10 years, and Saturn in about 30 years. So a conjunction occurs more or less every 20 years. How close the two planets get is variable as it depends on the inclination of their respective orbits. T

It looks like we will get a few hot days soon so I am looking forward to keeping cool and not doing much when the sun is high up. I keep the active stuff for early morning and late afternoon when things are cooler. I live in an old Queenslander which is a very good summer house. Shocking insulation but high ceilings and a pretty low thermal mass. What does that mean? Well it is made of wood mainly, nothing that stores heat like bricks and stones. It cools quickly. It is a good idea to open everything at night. Then we close everything mid morning and start the air conditioning if and when the temperature hits 26 ° inside. Why 26? It is a sensible temperature to set the A/C to. It is reasonable and the power use would get 10% up per degree if it was set lower. Beside, the solar panels go full blast in the middle of the day and easily provide the A/C power required. I like to stop the A/C some time before sunset, then open everything again when the outside temperature is bearable (2

  I am a notoriously incompetent gardener. I am a member of the Casino Forest Garden group but all I do is follow instructions and assemble the odd wood structure like compost bins and the pergola in the middle of it all. And yet there was a year in my life when I grew and harvested about 100kg of edible stuff for 27 hungry people, some of them vegetarian. Where? At the Macquarie Island station (Australian Antarctic Division). How? Running a small hydroponic system. Hydroponic is not exactly gardening, it is engineering which is right in my comfort zone. The Macquarie Island hydroponic “ garden ” is a very well insulated room, about 20m 2 . All plants grow in pots filled with clay pellets and immersed into water enriched with the right amount of nutrients. All this worked fantastically well, even with me as head gardener. It can ’ t be that hard! I used to start lettuce seeds in a tray full of vermiculite half immersed in water. When the young plants appeared, I just put each on

How does it work? The solar array on the roof spits out power at about 300V DC. The inverter converts that to good old 240V AC. Some of this power can be used directly in the house. We call it self-used. The good news is that it doesn ’ t not go through the Meter, so I don ’ t pay for it. My Inverter delivers up up to 5000 watts, so there is excess power most of the time. This Excess Power goes through the Meter (as Exported Power), so I get paid (a little bit) for it. At night, or if there is a big cloud, I don ’ t get enough (or any) solar power, so I need to import it (grrr!) and pay a lot for it. This Imported Power needs to go through the Meter. Grid connected system without batteries: How much does it cost? These days you can get the equivalent of what I have (6.6kW of solar panels feeding a 5kW inverter) for about $3400. Most salespersons would tell you that around Casino, the yield of a system is about 4.1 times its rated output. My system yields 22.6kWh a day (not fa

Back in the 90 ’ s what is now called the Djanbung Gardens was a degraded compacted cow pasture. It is now an incredibly productive 5-acre garden. This transformation was achieved by applying the principles of Permaculture. The term Permaculture was coined by Bill Mollison in 1978. Bill was no ordinary boffin. Before becoming a senior university lecturer, he left school at 15 and did all sorts of sensible jobs (shark fisherman, forester, millworker, trapper, snarer, tractor driver and finally naturalist). Bill realised that we needed sustainable agriculture, or Permaculture. If you look at a simple egg, for example, there are two ways to get it: it is an industrial egg bought from a supermarket or it was laid by one of your chooks. The industrial version comes from a battery chicken factory. The chooks in there eat pellet from some pellet mill where they mix tons of industrially harvested grain and fish waste. Every step in that process works against nature and the result is rather