What is a solar transit?
Anytime an object passes between you and a light source, you're seeing a transit. Most often, it's something like a moth fleeting across a light bulb. But, sometimes an object large enough to notice passes between us and our ultimate light bulb, our own star, the Sun.
There are only three objects that predictably do this: Mercury, Venus and our own Moon.
These are the only objects whose orbits carry them into the field of space between us and the Sun.
The outter planets never cross into this field of view.
Because of the distances involved. The planetary transits can sometimes last many hours, when viewed from planet Earth.
The transit of Venus mentioned in the previous post lasted about 2.5 hours.
On the other hand, that means they occur less often.
On May 9th, 2016, I again took off from work for the more common, transit of Mercury. Unfortunately, it was rainy all day, but luckily another transit of Mercury is on the horizon.
On November 11, 2019, just two years from now, you'll see this spectacle from Baltimore.
As mentioned in the previous post, if you missed the 2012 transit of Venus, you will likely only see in your lifetime the transits of a Mercury and the Moon.
If you travel to the surface of the fourth planet, Mars, you can add three more objects that could eclipse the Sun: The Martian moons of Phobos and Deimos, and our own Earth.
All of the eclipses visible from the surface of Mars are Annular in nature, meaning that they're too small to fully eclipse our Star. Instead, they leave a ring of light, or an annulus around the silhouette of themselves.
Here's a photo taken by NASA's Curiosityrover on August 30, 2013 of the annular eclipse of the irregularly-shaped moon, Phobos:
