Why the Venus Transit Is One of the Most Important Events in Scientific History

[JMH]

On June 5, the planet Venus will appear to pass in front of the Sun as seen from the surface of the Earth. This phenomenon, called a transit of Venus, happens only a few times in 250 years. The next one will be in 2117 AD. Here's a guide to watching the once-in-a-lifetime event. But why does it matter? [h=4]It provides interplanetary perspective.[/h] Transits of Venus were scientific gold for early astronomers, who used them to derive an accurate measurement of the size of the solar system. By noting the time each planet took to go around the sun, and then crunching that data via methods developed by 17th century mathematician Johannes Kepler, these telescope-equipped boffins could determine each planet's relative distance from the sun, as measured in terms of astronomical units (the distance from the Earth to the Sun). Collecting such data during a transit was the reason Captain Cook was able to travel halfway around the world from London to Tahiti in 1769.

http://gizmodo.com/5915920/why-the-...e-most-important-events-in-scientific-history

 

[JMH]

How and When to Watch the Venus Transit Today

How to watch with your own eyes

• Whatever you do, DO NOT LOOK DIRECTLY INTO THE SUN WITHOUT PROTECTION.
Staring at the Sun can damage your eyes permanently.


• DO NOT use your sunglasses as protection. While sunglasses can protect your eyes under normal use, they will not protect your eyes while staring directly at the Sun.


• Even if you have adequate protection, don't look at the Sun for a long time, so remember to stop looking from time to time.


• The best protection is wearing welding goggles with No. 14 glass.


• The next best is buying an eclipse filter. They are inexpensive, but they are good enough to protect you. Make sure they are the good stuff, and not just dark plastic. You can see some brands and models here.


• Use a telescope or binoculars. Again, these MUST have the proper filter. Most brands come with eclipse filters, so you will be safe. But if you have any of these, you probably know what you are doing anyway.


• Use a pinhole projector. This will allow you to look at the Sun projected on a piece of paper, so it's perfectly safe. You will see the Venus shadow travelling on the paper. You can make these yourself following the instructions here.


• Use a reflected pinhole projector. This is pretty awesome, as it will create a big image of the Sun on any wall. Use the instructions here. It's also perfectly safe.

http://gizmodo.com/5915887/how-to-watch-the-venus-transit-today

 

[JMH]

[h=1]Relive the Venus transit now in photo and video on NASA's website[/h]

If you missed the transit of Venus yesterday or want to relive the planet's nearly seven hour journey across the Sun, NASA has some beautiful images and video of the event up now. The transit began at about 6PM EST, and millions watched it worldwide both live and via NASA's live stream of the event. Venus transits happen in pairs with more than a century in between — yesterday's followed the 2004 transit, with the one before that taking place in 1882. The next transit won't happen for another 105 years, but you can watch this video of NASA's compiled footage while you wait around for the next one.

http://www.theverge.com/2012/6/6/3068335/venus-transit-photo-video-nasa