worldslaziestbusker
Bio: Nouns - Australian, marine ecologist, caffeine fiend, musician, surfer, diver, atheist, photographer, busker. Adjectives - passionate, energetic, moody. Conjunctions - and, but, or.
worldslaziestbusker
Bio: Nouns - Australian, marine ecologist, caffeine fiend, musician, surfer, diver, atheist, photographer, busker. Adjectives - passionate, energetic, moody. Conjunctions - and, but, or.
Love Prelude, Cook and Birdie!!!
I will have to do some research of my own
To understand the early mathematicians
work … arcs and degrees escape me
But well done Matthew !!!!
Looking forward to hearing more 🙂
Hi Sue
Thanks for listening.
I will try to draw a simple diagram of what Erasthothenes was up to. I think I understand it, but whether or not I can put it on a white board effectively will put that to the test. Watch this space.
Here goes.
An obelisk directly under the sun casts no shadow (in Eratosthenes case, it was a well into which the sun shone vertically). If, at the same moment you know that the obelisk at one point has no shadow, you measure the shadow of an obelisk at another point, the degrees of arc the shadow of the second obelisk makes with a line running vertically to the centre of the Earth is equivalent to the degrees of arc distance between the two obelisks.
If, one fine equinox, you had obelisks in a line running from one pole to the other, as that line passed astronomical noon, the shadows would, between them, cover the full range of possible degrees of arc in a half circle, the length of each shadow being a function of where an obelisk lay relative to the equator. At the poles, the shadows would make a right angle to a nominal line between the obelisk and the centre of the Earth, indicating the obelisk lay ninety degrees of latitude distant from the equatorial obelisk, which would cast no shadow, there being zero degrees difference between it and the incident light. If you knew the distance between the two obelisks, you would simply need to multiply that by the factor necessary to make the ninety degree difference into a full circle, in this case, four.
When we discuss degrees of latitude we are denoting an angle relative to the datum set at the equator, as would be measured from the centre of the Earth. That we can’t be at the centre of the Earth to make the measurement, and that the Earth isn’t spherical, as the system appears to assume, just goes to show how clever geodeticians can be in establishing the models on which we base our navigation systems, territorial claims and geolocated phone apps.
Great blog Matt.
Really enjoying your podcasts. I’m listening to them whilst getting myself ready to go down to the ice.
Looking forward to more.
Anthony
Thanks, Antony.
I’m very excited for you and look forward to reading about your year+ on the ice at Halley. Lotsa pics, please.
Matt
Excellent podcast, very enjoyable!
Thanks Jim.
Really enjoying your podcast, just started at the beginning a few weeks ago. Fun to listen to, great material and interesting guests – really like the interviews! Is there any way to support your podcast?
Alex in Canada
Hi Matt, really enjoying your podcast. Having been pointed to it over a year ago, I’m still diligently catching up in true completest fashion.
Wondering if you could get in touch about potential speaking opportunities in northern NSW?
regards
Phil
Hi Phil
Thanks for listening and thanks for reaching out to let me know you’re enjoying the output.
Happy to discuss speaking opportunities anywhere. I’m about to follow the link in your message to see what’s up.
Cheerio
Matt
Hi Matt, Only just discovered your podcasts (& blog today) and already a few episodes in. Visited the Antarctic Peninsular late last year, still processing what that trip/place meant to me, and keen to learn more. Thanks for sharing.
Hello Robin
Thanks for listening and thanks for getting in touch.
Did we travel together?
Matt
Did an Oceanwide Basecamp charter trip led by Dr Karl Kruszelnicki back in November 2019. Knew was a rare privilege then, even more so now it’s effectively unobtainable.
https://rcd.typepad.com/personal/antarctic-mission-2019.html