As part of trying to sort out what’s important in life, I’m not going to be posting any more Friday Fun videos. Partly because it can sometimes consume and hour or 2 to put the post together (however fun browsing videos online is!) but also because they don’t bring any extra traffic to this blog. My webstats don’t show any kind of peak on a Fridays, which they would if people swung by to check them out. I conclude then, that they aren’t worthwhile and the the time could be better spent doing other things. I am still committed to putting at least one new post up every week however, and will continue to do that.
Having said that, I read this at lunchtime today and thought it was very cool. It’s the actual statement Galileo used to announce to the world that he’d discovered moons around Jupiter. You gotta love the 400 year old language:
I should disclose and publish to the world the occasion of discovering and observing four Planets, never seen from the beginning of the world up to our own times, their positions, and the observations made during the last two months about their movements and their changes of magnitude; and I summon all astronomers to apply themselves to examine and determine their periodic times, which it has not been permitted me to achieve up to this day…
On the 7th day of January in the present year, 1610, in the first hour of the following night, when I was viewing the constellations of the heavens through a telescope, the planet Jupiter presented itself to my view, and as I had prepared for myself a very excellent instrument, I noticed a circumstance which I had never been able to notice before, namely that three little stars, small but very bright, were near the planet; and although I believed them to belong to a number of the fixed stars, yet they made me somewhat wonder, because they seemed to be arranged exactly in a straight line, parallel to the ecliptic, and to be brighter than the rest of the stars, equal to them in magnitude…
When on January 8th, led by some fatality, I turned again to look at the same part of the heavens, I found a very different state of things, for there were three little stars all west of Jupiter, and nearer together than on the previous night. I therefore concluded, and decided unhesitatingly, that there are three stars in the heavens moving about Jupiter, as Venus and Mercury around the Sun; which was at length established as clear as daylight by numerous other subsequent observations. These observations also established that there are not only three, but four, erratic sidereal bodies performing their revolutions around Jupiter.
Galileo Galilei, author of Sidereus Nuncius (‘Starry Messenger’) March 1610
What is most amazing perhaps is that the discovery of the moons of Jupiter, lead to other scientific discoveries and influenced historical events, e.g.:
– a reasonably accurate estimate for the speed of light;
– a calculation of the size of the earth that was only 28km out;
– the determination of the Mason-Dixon line which symbolised the split between northern and southern states that led to the American Civil War.