Astronomy - Measuring Distance, Size, and Luminosity (5 of 30) Distance to Our Sun: 1

In this video I will explain how Aristarchus calculated the distance to our Sun using a coin.

[Norman]

The ancient Greek scientists were amazing thinkers. Too bad that knowledge was lost or forgotten for nearly two thousand years. Just think where we would be today.

[JavierBonillaC]

I think you are skipping key explanations. You are totally right, I have no doubt, but half the people in the comments are getting lost here.

[appresley]

I really enjoyed that presentation, thanks Michel....

[yoshirider]

I saw a video that said if the earth had a small thin ring we’d be on Jupiter now just because of the math that would have been able to have been calculated

[MussieTekie]

Please could you explain how you got 57.3??/

[rottenasspranksters]

okay but how he knew the distance to the moon????

[carlmanis]

There is a better way it uses a micrometer and a bar on a 10 foot square board. on one end of the board you make a sight on the other end the bar moves with a sight on it that is also pointed in the center of the object. the distance of the bar from the left give the distance. take 5 4 inch squares place a moving bar on one end place one more square in front of it point the moving bar at the right corner of the second square. it will be exactly 2 inches from the right Note from that point it halves when it doubles. place 2 4 inches squares in front of the first square and the bar will be at exactly 3 inches from the right. Every time you double the distance the bar on a 4 inch square would move a 1/2 inch then double it again and it would move a 1/4 of an inch double it again and it would move a 1/8 of an inch double the distance and it would move a 1/16 of an inch. by making a simple chart and a micrometer you could tell any distance. from that point you would need a micrometer and you could measure any distance. note: looking from the sight on the right to the sight on the moving bar at any distance it will never be moved to it full left travel. I would recommend a 10 foot square board. This is how i believe they laid out the pyramids. They orientate the square to the sun and have a man place the stakes using the moving bar and line of sight. the first time on a 4 inch square it doubled it was 2 inches then it moved 1 inch then a 1/2 then 1/4 inch. on a 10 foot one 5 foot from the right of the moving bar would be the first double 2.5 foot more would be the 2 double the bar would move over 1.25 feet to double again and so on. Note: all great distance would be in the last inch on the travel of the moving bar. now if you use a 15 inch wheel that moved 3 times around for every inch of the moving bar travel that could easily give you millionth of inch travel. The chart would tell you the distance the object you are looking at exactly.

[albertbatfinder]

Are there folk out there smarter than I who are totally convinced by this explanation? I had three questions before he even got to the bit about the diameter of the moon. What’s really needed is a field trip on the half moon, with the same set of tools Aristarchus had. One obvious point is that our mate Ari probably measured the angle over an entire month or perhaps an entire year (give or take viewing opportunities) until the angle reached some maxima. Ari didn’t have YouTube videos to watch, so he would have had spare time to burn.

[othomile]

how do you figure out the diameter of the moon?, i haven't gone through the other videos of recent methods, do they also base on diameter of the moon?

[pauldavey]

could you please explain how the parallax angle is worked out....how is it measured. looking from earth over six months the star moves left to right in relation to the background star....how can 3 points on a horizontal line...fixed star(1) near star 6 mths apart, 2nd and 3rd point be used to work out an angle....

[johnstevens]

The first angle of 87 seems a bit arbitrary...
where did he get this info?
I would love to figure this out so I can do the math myself .
I don’t like plucking convenient numbers from the air when I want to find a solid scientific process or mathematical formula!

[joseparedes]

I don't understand the appearing of 57.3 . I know that is equivalent to a radian . But why it appears here ? That relation has anything to do with the origin of trigonometrics ?

[DaiGrepher]

This method shows the Sun to be 2-3 million miles away. Which method confirms the correct figure of 93 million?

[superpoo]

Can someone explain how the measured angles before? Like when Eratosthenes measured the shadow. They didn't have trigonometri at that time

[prasadovhal]

where did the angle 57.3 degree came from?

[RingRoadSessions]

at 1:21 when you explain the 87 degree angle and say, "that was not an easy thing to do." PLEASE elaborate. How did he find that angle By the way I totally believe you but how do you explain this to someone who doesn't believe. How do you explain how that angle was found?? thanks!

[backyard]

They didn't have trigonometry, but they knew that ratios between certain sides of a triangle remain the same if angles are the same. So he could have drawn a triangle with same angles and measured the ratio with a ruler or smth

[keiferreefer]

I come to these videos after I watch a YouTube video produced by someone who is guessing about planetary distance, I figure they do it for shock value and Internet hits, viewership, but if they truly believe still that the earth is flat, or have a real majorly skewed pereption of reality, knowing what we know now, but the Challenge of thinking right bout something that you have to prove, and can't touch, smell, y know.
I find it absolutely astounding people at the time period could think this concept up for measuring distance, I suppose one did a lot of moon watching at night w no t.v. Eh? Yes, and wouldn't one be curious about the sky and the objects that appear in it. We still are today.

[chigozie]

Can we not just gloss over that 87° angle between the earth and the sun. How did he come up with that?? And is that still true to today?

[seifraslan]

I don't understand why d/D=theta/57.3° .. Is that a rule?