Fly me to the moon

This is a pretty cool, if Flash heavy site: We Choose the Moon.

This month is the 40th anniversary of the Apollo 11 moon landing, and the above site recreates the event for "real-time" (that is, real time minus 40 years) tracking of the mission, with video, images and audio (including astronaut chatter) from 1969.

It's a neat way to let those of us who are too young experience that exciting piece of history.

At the same time, you can check out the NASA gallery featuring current photos of the landing site from the Lunar Reconnaissance Orbiter Camera that reached lunar orbit late last month.

[h/t: Bad Astronomy]

Fact or Fiction: Eclipse Blindness

Today, August 1 2008, a total solar eclipse will be visible in parts of northern Canada, Greenland, Russia, China and Mongolia, with a partial eclipse visible in other parts of the the country.

I remember in elementary school, a big deal was made of not looking directly at a solar eclipse. A very big deal. Even a quick, unprotected glimpse could cause blindness. At the time, it didn't make sense to me - why would looking at an eclipse be any worse than looking at an uneclipsed sun? Was the seemingly heightened paranoia because it's an event that people are likely to want to look at? Or is there something else about an eclipse that warrants the extra attention? Even NASA acknowledges that eclipse warnings may be a bit hyperbolic:

In the days and weeks preceding a solar eclipse, there are often news stories and announcements in the media, warning about the dangers of looking at the eclipse. Unfortunately, despite the good intentions behind these messages, they frequently contain misinformation, and may be designed to scare people from seeing the eclipse at all.

The fact of the matter is yes, you can do serious damage to your eyesight looking directly at a partial solar eclipse. During the period of total eclipse - when the moon completely obscures the sun - it's safe to observe with the naked eye (see also NASA link above). However, this isn't without risk since the shadow will continue to pass and without proper timing you could find yourself looking directly at a partial eclipse. Even when 99% of the sun is obscured, the remaining 1% is intense enough to cause serious retinal damage.

Is looking at a partially-eclipsed sun more hazardous than an unobscured sun? In a way, yes. Because even a mostly blocked sun can be damaging and the surrounding illumination in these conditions can actually be quite dim. In this case the eyes natural defense - constriction of the pupil - doesn't kick in right away. The pupil is exposed to the sun in a dilated state, allowing more of the damaging light to enter the eye. (Of course an unobscured sun will be sending that much more light to your eye, so this isn't a proper comparison.)

The bottom line is that there's nothing magical about a solar eclipse, and nothing special about the light it gives off, but after every eclipse there's a spike in cases of retinal injury and eyesight damage. Take proper precautions when viewing an eclipse and don't stare directly at the sun - eclipsed or not.

[Image source: Wikipedia]

Happy Leap Day!

Today is February 29th. Bad Astronomy has a great post explaining the leap day in great detail. And if that's not enough for you, check out this (even greater) earlier post about how we define years and days in the first place.

Two Cool Resources

Doing some surfing, I came across some pretty neat resources. For armchair astronomers, the first is WikiSky, a sort of Google Earth of the heavens. Overlay constellations, find and view photos of celestial objects or just see what stars are overhead right now.

The second is the Encyclopedia of Life. This site aims to be a wikipedia of known species, including photos, maps and including links to journal articles and published genomes. This 'interactive zoo' will have different layers of access from 'novice' to 'expert' featuring more detailed species information. The site isn't up and running yet, but the demo pages (like those linked above) look pretty slick. Read more about it over at Wired magazine.