Find The Distance To The Sun Using A Transit Of Venus

[@KurdstanPlanetarium]

Interesting video, I was always fascinated by the measurement of Astronomical Unit suing Venus transit and read many books on the subject, yet this was clear and precise to the point. Thank you

[@Artofkarthik]

I still can't believe how we figured all this out, and how much time and collective human effort it all took!

[@trapidtrap2612]

What if the sun is 2x the distance and 2x the size? Wouldn't you observe the same thing?

[@kitmoore9969]

"Being in orbit" means that two forces are in balance: the gravity of what you're orbiting, pulling you in, against the "centrifugal force" which throws you out into deep space. Isaac Newton figured all this out when an apple fell on his head (no centrifugal force) but the Moon didn't. Close to the Sun, you need more centrifugal force (i.e. orbit speed) to combat the high gravity; far away, the same speed would throw you out, so you must be slower. TL;DR orbital period (a year) is proportional to the distance. Kepler's 3rd law states this more accurately than this, but we can tell that since a year on Venus is 225 (Earth) days than it must be 70% of the Earth's distance from the Sun. If the Earth is 1AU (whatever that is in miles) then Venus must be 0.7AU. Since it's all proportional, the angles stay the same.

[@trapidtrap2612]

@@kitmoore9969 ...this still would give you the same result if it was twice as large and twice as far Or twice as small and twice as close.

[@gerryprendergast8810]

Jeremiah horrocks in 1639 was the first to put forward the transit of Venus to measure the au not Halley.He got a pretty good estimate too.

[@robertethanbowman]

So, I randomly used Sydney, Australi and Dallas, Texas as locations and I got a cut through the earth distance of about 11,350 km. Compared to the antipodal distance of 12,756 km. But the time of exactly 8 minutes seems too clean.

[@Stealthmodeactivated-h8w]

Using radio to measure distance