Is the moon ever really blue?

It’s a blue moon tonight, though it’s not really blue or green or made of cheese. It’s just that not so rare, second full moon in a month. I asked my local astronomer in residence if the moon ever appears blue. And guess what? Yes, it can be blue! And it is indeed rare and unpredictable, true to the meaning of the phrase “every once in a blue moon.”

There are several definitions of the term “Blue Moon”. Today we have an example of one of them, “the second full moon in a calendar month”. For me, this occurrence is not very interesting – a statistical artifact of our calender that has absolutely nothing to do with the Moon’s color and isn’t even particularly rare (it occurs every 3 years or so and is entirely predictable). A much rarer, far less predictable, and much more interesting situation can lead to a Blue Moon that is true to its name. (more…)

Google sky map

I’m having a great time playing with my new Verizon Droid phone and learning how to interact with a phone that is way smarter than me. My old phone was 6 years old, hip for it’s day, but that day is long gone!

My favorite app so far is Google Sky Map. My local astronomer immediately took it outside to test it against the real sky and gave it two thumbs up. The sky moves with you and zooms in to give you more detail of any section of the sky.

There are options to turn stars, constellations, grids and other sky features on and off. Type a planet or star into the search box and it helpfully suggests objects so you don’t have to type the whole name. Select an object to get a big circle and arrows that point you to that object. Look, I found Mars! I wonder if it will show the location of meteor showers?

My astronomer is now fearing redundancy. I promise that will never happen! Really.

p.s. There’s a web based version of Google Sky and a Sky feature in Google Earth too.

astronomy