The transit of Venus is almost upon us!
If you live in the United States, you've got from just after 3 p.m. Pacific time Tuesday until sunset to get your solar glasses, or No. 14 welder's glass, and watch as the planet Venus crosses in front of the sun. It won't do that again for 105 years.
The planet will appear as a moving black dot on the surface of the sun. Some have described it as looking like a little black hole has been punched through the sun, according to NASA.
Those who would like to turn this real-world astrological event into a social media experience can download the Transit of Venus app, which was brought to you by Astronomers Without Borders, the Venus Transit Project and GIS software company ESRI.
The app allows citizen scientists to see where on Earth the transit is visible and at what times. It also lets users record their own observations about the transit of Venus -- noting when it hits the edge of the sun -- and share pictures of the transit via Twitter, Flickr, and YouTube.