It was a great day for science-loving Geeks the world over. Here are the day’s big haps, in no particular order:

Opportunity reminds Curiosity (and us) that it’s still kickin’ Martian rocks

For all of you who forgot that Curiosity wasn’t our first (or second) rover on the Red Planet, Opportunity popped in to remind us today that it’s still alive, figuratively speaking. And what better way to do so than by uncovering yet another Mars mystery, this time in the shape of blueberries. That’s what NASA investigators are calling the thousands of bizarre, spherical objects shown in the image above, which was beamed back on Sep 6. So what the hell are they? No one has even the faintest idea.

“They seem to be crunchy on the outside, and softer in the middle,” Squyres said. “They are different in concentration. They are different in structure. They are different in composition. They are different in distribution. So, we have a wonderful geological puzzle in front of us. We have multiple working hypotheses, and we have no favorite hypothesis at this time. It’s going to take a while to work this out, so the thing to do now is keep an open mind and let the rocks do the talking.”

This shot is a 2.5-square-inch section of the surface taken by Opportunity near the western rim of Endeavour Crater. Opportunity’s next target is an area called Cape York, home to a light-colored patch of clay that researchers are eager to get some roving eyes on. [NASA]

And this is why you shouldn’t introduce a new species to an established ecosystem

Thanks a lot, people in the 1940s. A totally great idea to introduce a new variety of bird-eating snake to the isolated rainforest of Guam back in the 40s has resulted in a weird imbalance in local fauna, specifically a boom in spider populations. The island is now home to FORTY times as many spiders as neighboring islands, which are not home to the alien snake. (Is anyone else reminded of that episode where the Simpsons go to Australia?) [Discovery News]

Time to call in those pool numbers — the Astronomical Unit now has a fixed value

If, for whatever (sad, sad) reason you were taking bets on where the Very Official measure of one Astronomical Unit (AU) would land, it’s time to pony up some cash or buy yourself a new fancy calculator. The new standard measurement was adopted by the International Astronomical Union as 149,597,870,700 metres — no more, no less. Formerly, the AU was an equation derived from the radius of “an unperturbed circular Newtonian orbit about the Sun of a particle having infinitesimal mass, moving with a mean motion of 0.01720209895 radians per day (known as the Gaussian constant).” And now it’s a nice, normal, totally uniform number. You’re welcome Geeks, and thank you, Science. Was that so difficult?

For the wobbly history of the Astronomical Unit’s value (which is far more interesting than it reads here), check out the full story on [Nature].