NASA
Mercury began this journey on Monday at 7:12 a.m. ET and will remain in sight until around 2:42 p.m. ET.
The planet will appear as a tiny black speck ambling across the bright face of the sun.
The timeline of the event, as described by Discovery News, is as follows:
First, Mercury will make contact with the corona, the extended outer atmosphere of the sun. This event, called corona contact, is only visible from space. The next four phases of Mercury's trip are categorized into first, second, transit, third, and fourth contacts. Here they are:
- First contact: Mercury's edge first touches the edge of the sun.
- Second contact: Mercury moves entirely onto the sun's disc. If you're looking through a telescope as Mercury separates from the sun's edge, something called the "black drop effect" will occur, and a thin line will seem to connect Mercury to space. About four hours later, Mercury reaches what's called the transit midpoint, which is halfway across the face of the sun.
- Third contact: On its way out, Mercury crosses the edge of the sun, producing another "black drop" effect.
- Fourth contact: Mercury exits the face of the sun entirely.
Finally, in its last corona contact, Mercury will leave the sun's corona in an event that is, once again, only visible from space.
Nearly everywhere on the globe with the exception of Australia, New Zealand, Indonesia, the Philippines, and a small area of eastern Asia, will be able see Mercury's transit.
It's a very bad idea to try to watch Mercury's transit with your naked eyes due to the sun's harmful ultraviolet rays. But you can watch the event through a telescope or a pair of binoculars, as long as you have a solar filter to avoid damaging your eyes.
Don't have access to a telescope or binoculars with a solar filter? No worries. Slooh Community Observatory is hosting a free, live webcast of the transit from 7 a.m. ET to 2:45 p.m. ET.
Check out their live feed below: