In sports and in cosmology, the rules of the game aren't supposed to change as you go along. Athletes call this playing fair. Cosmologists call it the cosmological principle, and it means that the rules that govern atoms here on Earth also hold in every corner of the universe and at every point in time.

Imagine the universe as a basketball court: The hoop on one end of the hardwood is supposed to be the exact same height as the one on the opposite side. But what if the basket on the home side of the court always skews a few centimeters lower than the visitors' rim? It wouldn't be very fair. But now, cosmologists led by John Webb (University of New South Wales, Sydney) think they've spotted evidence that the rules of the cosmos might be similarly partisan.

Is DNA destiny? NOVA's Ghost In Your Genes, which will be rebroadcast this Tuesday on many PBS stations (check local listings), provides fresh hope that our fate isn't inscribed in our genes. A "second genome," or epigenome, which has only recently caught scientists' attention, can switch genes on and off with chemical tags. And though you can't rewrite your genes, you just might be able to change your epigenome.

How? Diet and exposure to toxins, like those in cigarettes, probably play a role. But Moshe Szyf and Michael Meaney, scientists at McGill University in Montreal, wanted to find out if a person's upbringing could influence his epigenome. Would abuse, neglect, and stress leave an imprint? Meaney and Szyf thought so, and set out to test their hypothesis on rat pups.

Have scientists created a real-life prototype of a tractor beam, that glowing shaft of green light that the folks on the Starship Enterprise use to seize hold of enemy vessels? I'm a sucker for any innovation that brings us a step closer to gallivanting around the universe, boldly going where no one has gone before. But this tractor beam won't be coming standard on next year's spaceships. That's because it works by heating up the air around the tiny particle it's trying to move. In the vacuum of space, that's a deal-breaker.

The new tractor beam was built by researchers at the Australian National University, and it can manipulate tiny (0.1 millimeter) carbon-coated glass beads from more than five feet away. Scientists have long been using devices called optical tweezers to move even smaller objects, right down to  the size of single atoms, but the new beam extends the maximum distance over which particles can be prodded a thousand-fold. It also operates in plain air, unlike optical tweezers. Compared to a delicate  tweezer, the new tractor beam looks like a pair of overgrown kitchen tongs.

The other day I had the honor of speaking with Buzz Aldrin, the first man on the moon along with Neil Armstrong.

I was interviewing Aldrin for an article I'm writing for the NOVA website on whether we should consider a one-way manned mission to Mars -- one in which pioneer astronauts remained on the Red Planet to launch a colony that would later grow into permanent settlement. (Initial shock aside, most experts agree we could do a manned mission a lot sooner and a lot cheaper if it wasn't round-trip.)

With the 50th anniversary of President Kennedy's famous go-to-the-moon speech approaching in 2012, I asked Aldrin if he thought we should, to paraphrase Kennedy, go to Mars in this decade.


"No, it's probably going to take three decades," Aldrin said, and went on to outline his proposal for securing a lasting human presence on Mars.