Mercury to cross in front of the sun

Mercury is set to make a transit across the sun on Monday morning for the last time until 2032. A pinprick of darkness will puncture a small hole in the sunlight as the planet traverses the solar disk during a 5.5-hour stretch, starting at 7:35 a.m. Eastern time. And while you can’t see it without protective glasses and heavyduty telescope equipment, there are plenty of ways to enjoy the show.

What’s a transit?

Remember the famous solar eclipse of Aug. 21, 2017? That happened because the moon briefly blocked the sun. In a narrow path of totality, day turned to night as the sunlight was extinguished.

This time around, it will be Mercury standing in front of the sun. It’s bigger than the moon but much farther from Earth. As such, it won’t block much sunlight. That’s what distinguishes a transit from an eclipse. During a transit, the interceding body is not sufficiently large to cover whatever it’s moving in front of.

Where can it be seen?

The transit will begin shortly after sunrise on the East Coast. By the time the sun rises on the West Coast, the transit will be well underway, with Mercury nearing its deepest venture into the solar disk. The transit will wrap up at 1:04 p.m. Eastern time.

Over most of South America and the eastern United States/Canada, the whole event will coincide with the daylight hours, so the sun will be visible during the entire event.

Eclipse glasses useful?

Nope. The tiny dot you’re looking for is too small to see, even with eye protection. According to NASA, “Your best bet is a telescope with a certified sun filter, but other options include solar projection boxes and sun funnels.”

You should never, under any circumstances, stare directly at the sun without proper protection.