Quote:
Originally Posted by jdhpa
I would've thought it would cross between Earth and sun every cycle, is it that far out of Earth's plane?
|
There's just enough tilt in the orbits of Mercury, Venus, and the Earth that most of the time when Mercury or Venus are between the Earth and the Sun, they end up either just above or just below the sun. The Sun's a huge object, but it's also a long distance away (mercifully!) so its disk only covers a half-degree of sky. That's a pretty small target; the planet doesn't have to be off by much not to cross it.
(We don't have total solar eclipses every month for the same reason. The Moon's angular disk is also 1/2 degree, but usually the alignment is off by just enough to keep it from crossing over the disk of the Sun at New Moon.)
Please register to participate in our discussions with 2 million other members - it's free and quick! Some forums can only be seen by registered members. After you create your account, you'll be able to customize options and access all our 15,000 new posts/day with fewer ads.
