When you saw the title of this piece, did you think, “What? Have they located a hitherto unknown moon?” I know I did when my chum Jay Dowling pointed me to this video with the same name.
In reality, as we soon discover, one portion of this excellent Numberphile video focuses on an asteroid called Cruithne. In turn, from the Wikipedia we learn that:
3753 Cruithne is a Q-type, Aten asteroid in orbit around the Sun in 1:1 orbital resonance with Earth, making it a co-orbital object. It is an asteroid that, relative to Earth, orbits the Sun in a bean-shaped orbit that effectively describes a horseshoe, and that can change into a quasi-satellite orbit. Cruithne does not orbit Earth and at times it is on the other side of the Sun, placing Cruithne well outside of Earth’s Hill sphere. Its orbit takes it near the orbit of Mercury and outside the orbit of Mars. Cruithne orbits the Sun in about one year, but it takes 770 years for the series to complete a horseshoe-shaped movement around Earth. The name Cruithne is from Irish and refers to the early Picts (Old Irish: Cruthin) in the Annals of Ulster and their eponymous king (“Cruidne, son of Cinge”) in the Pictish Chronicle.
As Matt Henderson, who is the creator of this video, says about Cruithne: “[…] that has been referred to Earth’s ‘second moon,’ but that’s just sensationalist kind of thing.” Of course, this makes it all the more ironic that he should title his video, “The Strange Orbit of Earth’s Second Moon”; and only slightly less ironic that I should follow his lead in naming this blog. It really is a funny old world when you come to think about it, and no mistake.
But we digress… In this video, Matt shows graphical representations of computer simulations of the ways in which the patterns of the paths of other planets might be perceived from the perspective of persons propagating on the Earth. The results are amazing concatenations of curves formed from combinations of circular and elliptical elements, all coming together in Spirograph-esque structures. In fact, one of the commenters to the video noted, “A minute in and I’m getting all nostalgic for Spirograph.”
I don’t know about you, but I find the fact that these sorts of patterns are hidden in plain sight — also, that they (and other mathematical constructs) appear to underlie everything we see — to be strangely comforting. It’s almost as though someone, somewhere has a plan. What say you about all of this?
“It’s almost as though someone, somewhere has a plan.”
Or that reality is founded on mathematics.
If there is indeed any such thing as reality — did you see my columns “Is Time Truly an Illusion?” (https://www.clivemaxfield.com/is-time-truly-an-illusion/) and “Swimming in a Sea of Quantum Foam” (https://www.eeweb.com/swimming-in-a-sea-of-quantum-foam/). I often think of Edgar Allan Poe’s poem “A Dream Within a Dream” (https://www.poetryfoundation.org/poems/52829/a-dream-within-a-dream)
I had a Spirograph when I was a kid. I’d love to play with one again (it’s never too late to have a happy childhood 🙂 . But it’s amazing that the planets and Cruithne make such similar patterns.
Cruithne seems to come awfully close to earth sometimes. I looked up a bit more on it and it apparently comes 40 times further away than the moon at it’s closest (and that’s under the south pole) but in astronomical terms that’s still too close for comfort if you ask me (especially if it goes a bit too close to something else and its orbit gets bent a bit). It’s 5 km in diameter, which could ruin our day a bit if it collided with us. Now if it collided with the moon, that would give us a show!
I cannot tell you how many hours I spent playing with a Spirograph as a kid, using different colored pens or pencils to create the most amazing patterns. We should both get one and pretend we’re young again 🙂
Easily done – you can get them on Ebay for $15 or less, they look like they are the real thing. They might not have the cork board that you pin the wheels to, but that’s easily organised. I do remember working out how many points the patterns would have based on the numbers of teeth on the wheels. Clever sod who thought of it, for sure. The Wikipedia article is interesting.
Elektor Magazine years ago had a project called “Spirographics” which produced similar patterns on an oscilloscope screen – basically lissajous-type figures. but bnoth that and the original set would take up too much of my precious time….. 🙁
I guess if your programming skills were up to it you could program the figures, it would be a matter of starting with points on a circle (the big wheel) and calculating where the hole on the little wheel would be as it moved around…. but I think it would be easier and cheaper (and less stressful) to spend $15 on a Spirograph set…..
There are so many fun things we could do — and so little time to do them all in (said Max, sadly)