The accidental scientist

        Weather permitting, we should be able to observe a Red Moon tonight Wednesday May 26 th between 9:18 and 9:25 pm. What is a Red Moon? The Romans used to call that a Blood Moon. This is what happens during a perfect Moon eclipse when the Sun, the Earth and the Moon are perfectly aligned, which is rather uncommon. The Earth rotates around the Sun in a plane called the ecliptic. The Moon orbit is not quite in the same plane, it is inclined (about 5 degrees). So most of the time, the Moon is either above or below the ecliptic. The points where the Moon hits the ecliptic going up, or down are called the ascending node and the descending node, respectively.    The nodes slowly rotate around the Earth. So to get a moon eclipse, you need a full moon to occur right on one of these nodes. Predictably, when this happens, the next (or previous) new moon will be a sun eclipse. Sure enough a total Sun eclipse will happen on June 10 th . Unfortunately it won’t be visible in Aus

  Why is a land mile different from a nautical mile? The old land mile dates back from Roman times. The Romans called it a “mille passuum” which means a thousand paces. Not steps. It was the total distance of the left foot of a Roman legionnaire hitting the ground 1000 times. Put is simply it is 2000 steps. If your average legionnaire’s step was, say, 0.74m, a Roman mile would have been 1,480 m. A bit shorter than the international mile that was defined at the 1959 International Yard and Pound Agreement reached by the USA, UK, Canada, Australia, NZ and South Africa. This one is about 1,609m. A legionnaire on steroids, maybe? The nautical mile is used for air, marine and space navigation. Historically, it was defined in the 1500’s as one minute of arc on the Earth meridian. Very convenient. The Earth circumference is about 40,000km. Divide that by 360 to get one degree, then again by 60 for one minute. You get about 1,852 m. A knot is a nautical mile per hour. The orig

      I was having a nice hot chocolate with my mates last Tuesday. Mike surprised us saying: “I have great news; climate change has just reversed. The Earth temperature has actually gone down 0.5 degree”. It was a bit cool that day but it got cold, rainy and miserable the next day. I stayed home and my trusted woodfire going all day! With a bit of time on my hands I decided to look into all this again. In September last year, the Bureau of Meteorology announced a La Niña event. We certainly got wetter than average conditions in the last few months. There is a lot of clouds and less sunlight also means lower day temperatures. This is why I was freezing my butt last week. These conditions apply to most of Eastern Australia. On a global level, La Niña brings a lot of cool water to the surface of the East end of the Pacific Ocean. This is a huge area of our planet. So while this situation lasts, it does look like the global temperature goes down a bit. The latest NOAA* report explains