If you make the effort to see it for yourself, you can reap a unique set of both visual and scientific rewards.
On November 11, 2019, Earth will witness Mercury transit across the Sun.
Enjoy these 8 fantastic facts now, as the next transit won’t arrive for 13 years.
1.) Over 3 billion people could experience it. Wherever the Sun is visible between 12:35 and 18:04 UT, it will display Mercury’s silhouette.
2.) Mercurian transits outlast any eclipse. Enduring for nearly 5.5 hours, even the longest lunar eclipses (~4 hours) fall short.
3.) Humanity didn’t witness one until 1631. Only with enhancements to human vision in magnification and/or resolution can Mercurian transits be seen.
4.) A quality “homemade projector” is sufficient. Using one (disposable) binocular lens or a pinhole camera, a sufficiently large projected image of the Sun will reveal Mercury.
5.) A telescope with a solar filter is ideal. Go for 50–100x magnification viewing, put the filters over the front lenses (not the eyepieces), and enjoy!
6.) Only 1-in-23 inferior conjunctions result in Mercury’s transit. Mercury, Earth, and Sol rarely align; Mercury’s orbit is inclined 7.005° to Earth’s.
7.) NASA’s Kepler discovered zero Mercury-like planets around Sun-like stars. Transiting Mercury imperceptibly dims the Sun, reducing its brightness by merely 0.0027%.
8.) Mercury has no atmosphere. Unlike Venus, where atmospherically filtered sunlight appears during transits, Mercury is utterly barren.
Mostly Mute Monday tells an astronomical story in images, visuals, and no more than 200 words. Talk less; smile more.Ethan Siegel is the author of Beyond the Galaxy and Treknology. You can pre-order his third book, currently in development: the Encyclopaedia Cosmologica.