The foul weather Eastern Massachusetts has experienced over the last four days will block our last chance to see something that won't happen again for a century.
Today, June 5, a rare astronomical event, the transit of Venus, will occur when the planet Venus will be visible as it moves across the face of the sun and partially blocks its light from reaching Earth.
Venus, the second planet from the sun, orbits in almost the same plane Earth does, but not exactly. Orbiting the sun once every 225 Earth-days, it often passes between us and the sun, but from our point of view, it usually appears to pass just above or below it.
Tuesday at 6:09 p.m. EDT, though, Earth, Venus and the sun will be in a straight line. For the next six hours and 40 minutes (times will vary slightly depending on your location), it will slowly move from one side of the sun's disc to the other -- appearing, NASA says, as a black dot about 1/32 as wide as the sun itself.
Blake Plantetarium director Monica Ares had planned to set up telescopes on the front lawn of the library on South Street at 5:30 p.m. today, but the weather put a stop to that.
A few dozen people witness the 2004 event from the Plymouth waterfront near the Mayflower. Much of the transit event was visible after the fog cleared about an hour after sunrise. Many of the people at that event signed a book to indicate their presence at this event....This book will be saved for the 2117 event for descendants to check their families' continuing participation.
According to ABC News the Transit of Venus is:
a last-time-in-a-lifetime spectacle, one that only happens when Venus, the second planet in the solar system, comes directly between Earth and the sun. Because of the complexities of orbital mechanics, there are two such alignments in a period of eight years -- the last was on June 8, 2004 -- followed by a break of more than a century. If it's cloudy where you are today, you'll have to hang on until the next transit on December 10, 2117.
Unfortunately, unless there's a breakthrough in cryogenics or scientists learn to reverse the aging process, very few of us will be alive to see the next one.
If the sky does clear, you will be able to see the little black dot of our neighbor, but use caution. Sunglasses and binoculars with filers are not enough to protect your eyes, according to the American Academy of Ophthalmology.
You can creaate a pin-hole camera using two sheets of paper: Make a pinhole in the center of one sheet; then stand with your back to the sun, holding that sheet so that the sun shines through the pinhole onto the second piece of paper. You'll see an image of the transit of Venus projected on the second sheet.
Or, even better, since the sun probably won't come out til tomorrow, you can watch the entire show on NASA's website.