Posts Tagged ‘moon’

Heaven in a grain of sand

// July 2nd, 2012 // Comments Off on Heaven in a grain of sand // Science Art

Missing Australia! Image by freeaussiestock.com

I’m in San Pedro de Atacama, Chile, just next door to the Atacama desert, the highest desert in the world. So what better than a post about sand?

To see a world in a grain of sand,
And a heaven in a wild flower,
Hold infinity in the palm of your hand,
And eternity in an hour.
– William Blake, Auguries of Innocence

I actually came off my bike in the Valley of the Moon when I hit a patch of sand on the road, so my feelings about the stuff are somewhat ambivalent. However, HOWEVER, science has come to my aid yet again and opened my eyes.

Because under a microscope, sand is actually quite stunning!

Unfortunately I don’t think I can post the pics myself due to the copyright, but these links are worth clicking through.

Geology.com share a gallery of sand microscopy by Gary Greenberg, in promotion for his book. My favourite is the polished pieces of olivine, found on the green Lumahai Beach of Hawaii.

Gary has also photographed samples of moon sand, collected by Buzz Aldrin and Niel Armstrong. The otherworldly images are in his Moon Sand Gallery.

Without atmosphere or water, sand on the moon goes through a very different process to form. Rather than small sea shells and rocks polished by the oceans, the moon sports fine dust created by meteorite microimpacts. Some impacts are so hot they become molten microdroplets. When these collide with existing sand grains, they create wiggly shaped specks called agglutinates.

Why moths circle lamps, and darkness is our friend

// July 16th, 2010 // 3 Comments » // How Things Work

Sydney Opera House. Image by Froge

I wear my sunglasses at night. It’s for the light pollution. New Scientist today sent out a plea to bring back the night for wildlife’s sake, particularly birds, bats and turtles.

Moths are also at risk to death by light. In Australia, the Bogong moths cause October plagues around Sydney and Canberra. They swarm houses, government buildings, and sometimes land on bosoms of opera singers during the Sydney Olympics (or was that the Hawk moth?)

The reason for the plague is simple, we stupidly built cities near their migratory paths. Every spring the Bogong moth travels from the plains to the mountains, to get away from the heat. They spend the summer lying dormant in caves, aestivating (hibernating in the summer.)

Aboriginal groups would sometimes collect them, cooked they taste nutty and are an excellent source of protein. Unfortunately it’s not an option anymore because they eat stacks of pesticide as caterpillars on the plains.

It’s a common thing to see a moth circling a lightbulb. Why do they do it? They aren’t actually attracted to the bright lights, it’s a mistake in navigation. At least, according to one theory, though there are others I like this one best.

Bogong Moths, Image by Pbpanther

When moths make the migration, they need to know how the hell to get to the mountains. I sail by the stars, but moths fly by the moon. By keeping the moon at a certain angle to the side, they can fly in a particular direction. For example, if you know the moon is in the north and you want to go west, you would keep the moon on your right hand side. I think a similar method was used in Apollo 11, when their navigation systems were down (I’m going by a vague recollection of Tom Hanks following the Earth out the window of the ship.)

It works because the moon is so far away the angle doesn’t change as you move. But imagine you tried the same thing with a street light. If you kept the light on your right, you’d end up going around in circles. Just like moths do.

Some moths don’t fly in circles around light, they just WAP into them. They might be using the same method, but aiming directly for the moon instead of keeping it to one side.

In Adelaide we have trees with lights mounted to shine up on them all night. I would like to know if it damages tree growth or the native wildlife around it. What are your thoughts, and when was the last time you really saw the stars?

A Schooner of Science could be Australia’s best science blog, but only with your vote! If you enjoyed reading, take a second to vote for me here.






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