On Tuesday, May 10, 2016 at 10:07:38 AM UTC+1, Mike Collins wrote:
oriel36 wrote:
"Put more plainly, pretend you're Earth, watching Mercury run around a
track. As it runs its loop, it will start out moving from the left side
of your field of vision to your right. Then, it rounds the corner and,
although not moving backward, is now running from right to left. This
analogy is oversimplified because it doesn't take into account the fact
that Earth is also moving, but it gives a good idea of how this optical illusion plays out.
To put it even more plainly imagine you're the sun. All the planets go
round you in the same direction. The closer ones move faster. But they
always move in the same direction. If you were on one of the planets they
will sometimes seem to move backwards but that's just an illusion.
You are being left behind as the wider population will come to enjoy the looping circuit of the inner planets as seen from a slower moving Earth such as Venus seen over an 18 month period -
http://www.popastro.com/images/plane...ary%202012.jpg
I cannot be critical of the article which uses the racetrack analogy where a planet 'turns the corner' as it moves out from behind the Sun to its widest point before turning back in front of the Sun but obviously somebody got part of the message that first appeared in this forum and specifically that invaluable animation showing how it appears from the surface of the Earth -
https://www.youtube.com/watch?v=MdFrE7hWj0A
The looping motions of the outer planets rely on relative speeds between a faster moving Earth and slower moving outer planets hence the 'loop ' perspectives are entirely different for the inner and outer planetary motions where the outer looping motions are an illusion but the inner planetary loop is as real as a car running around a racetrack circuit -
http://apod.nasa.gov/apod/ap031216.html
http://www.popastro.com/images/plane...ary%202012.jpg
Two types of looping motions corresponds to a new approach to observations and clearly the world is prepared to accept this new approach and that give me a great sense of satisfaction.