Saturday, August 11, 2012

Weekly Science Roundup #6

Lots of exciting things going on in science lately! I've already geeked out on here about Curiosity's landing on Mars. The newest finds in human evolution warrant their own post (I'll dive into that early next week). So for now, have a few stories that may have fallen through the cracks, but deserve time in the spotlight!

First up, a Mars story that has nothing to do with the new rover.


Holy moly, they've (probably) found plate tectonics on Mars.

For those less geologically geeky, plate tectonics is the motion of chunks of a planet over its inner mantle and core. Earth is naturally divided into seven big plates and a handful of smaller ones (imagine an eggshell with cracks), all slowly moving about and causing fun things like earthquakes.

It now appears that Mars may have at least two plates of its own. This is the first time we've seen evidence for plate tectonics beyond our own planet. Geologist Dr. An Yin has noted multiple peculiarities on Mars, including a linear volcanic zone and a super long series of canyons, that are most easily explained if Mars truly has fault lines. And if you don't already know, science prefers the simplest explanation for things.

Interestingly, it seems that Mars's plate tectonics are much less developed than those of Earth. This could be a cool chance to explore what early plate tectonics may have been like on our own planet.

Speaking of early things...


New fossils in South America suggest that grasslands may have been around 15 million years earlier than previously thought. 

The two new fossils that have given rise to this controversial idea are both rodents: Andemys termasi and Eoviscaccia frassinnetti. The former is an early relative of agoutis, and the latter a relative of chinchillas. They're both dated to be 32 million years old.

So why do these two rodents imply that grasslands were around way back then?

The answer is in their teeth. Both have an adaptation known as hypsodonty: their back teeth have enamel that extends below their gums. This is, in modern times, used by animals who eat tough grasses. Does this HAVE to mean these 32 million year-old rodents were thriving in grasslands that aren't supposed to have shown up on Earth for another 15 million years? Could it have originally evolved for something else? Maybe. But so far, no one can think of any other plausible explanation. It's likely time to revise when grasslands first appeared on our planet.

I love when stuff like this happens. Science! We're always learning new things and overthrowing old ideas when better evidence surfaces.


I'd be remiss if I didn't mention in my last slot that the Perseids are going on this weekend. This is an annual meteor shower that occurs every August when Earth passes through the section of our orbit where the comet Swift-Tuttle crosses. The meteors are actually debris left behind by the comet. We pass through that debris and as the rocky chunks careen through our atmosphere, they compress the air in front of them.

Just like rubbing your hands together creates heat through friction, the space rock heats up the air in our atmosphere as well. Heat and pressure combine to essentially set the air on fire. Light and heat are produced, making a streaking fireball appear in the sky.

If you're looking to catch this cool show, you want to look Northeast tonight (if you live in North America) around midnight. You'll probably be able to see the shower anytime tonight, but the best viewing will be in the early morning hours. Be sure to find someplace free of clouds and light pollution! Us folks stuck in the big cities are usually out of luck for any decent views.

Best of luck!

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