To whet your brain buds for the launch of Getafix (soon to be made available for Windows users too), I thought I’d show you a couple of screen grabs from the program that reveal how stars move relative to each other over time, how they are not fixed and ergo how the constellations we now know as dog (Canis major) and Big Dipper (Ursa Major) have all changed over time and how it looked to our ancestors.
Using Getafix you can find the positions of stars at any point in history and plot the constellations. This will be great to get children (or adults even) interested in the night sky in an interactive way. Here’s what the constellation Canis Major (the dog) looked like 6700 years ago and what it looks like now. That’s about 4700 B.C at a time when the wheel was invented in India and Mesapotamia, predynastic Egypt, neolithic farmers in Malta.
From plotting the constellation as it looks today, you can see that as compared to 4700BC Canis Major looks quite stretched. This is because the stars are moving. 6700 years ago Canis Major looked like a big hound, today he looks like a Jack Russell puppy.
Canis Major (the dog) changing over time
Fascinating… If you need any proof that the universe and all that’s in it is changing and moving and morphing, well then this is it. Stars not only appear to “move” across the night sky because of the earth’s rotation but they actually do move with relative to other stars in the galaxy around the galactic centre just like the earth moves around the sun and the sun moves around the galactic centre (with our whole solar system).
I guess Shakespeare’s Julius Caesar was wrong when he said, ”I am constant as the Northern Star, Of whose true fixed and resting quality, There is no other fellow in the firmament.” (Act 3, Scene 1) Eventually it was this arrogance that sealed Ceasar’s fate as he refused to heed the three warnings of his impending death.
We did this for the Big Dipper (the seven brightest stars in the constellation Ursa Major or Saptarishi as known in India, plough or butcher’s cleaver in England) and found that what today looks like a plough or a ladle (or a pipe in my opinion), 6700 years ago looked like a foot.looked pretty much like it does today. Owing to an error in calculations (please see comments section below) what looked like a foot was actually a bug in the program. So the picture below of the 6700 year ago foot is inaccurate.
Big Dipper constellation, then and now
This is a photograph of the constellation as it looks in the night sky today (a tail at the top or the handle or the spoon and then lower down four stars forming the bowl/ladle part)
Big Dipper image in night sky taken from Wikipedia
This was just to show you what discoveries you can come up with on your own using Getafix. If you are an Ubuntu user go to this website to download the first version of the program (enter your latitude/longitude and proceed according to instructions). Windows users, you’re next.
Hi Stuart, following up on your comments, investigations into the source code have revealed a tiny little error that was causing the ‘bloated’ effects proper motion of stars. heh….i had typed RA0 instead of RA1 in one of my equations, so the program was using the wrong value of right ascension to predict star positions!!! with the error rectified, things look a lot more familiar in the night sky. Thanks for the very helpful debugging info, corrections will be made to the main post and to Getafix of course.
Ha ha ha ha! RA0 instead of RA1! Ha ha! That’s hilarious! Bwah ha ha ha ha! Oh, dear…
Sorry – to explain a little – this is one of my favourite comedy sketches of all time – http://www.youtube.com/watch?v=2un9rO2ZF4g –
(not sure how well it translates overseas though…)
I didn’t think the cponstellations changed so much over 6,700 years, to be honest.
I mean, I know they change gradually over time, but 6,700 years seeems like a very short time to be able to see those changes – I assumed we were talking hundreds of thousands or millions of years…