One of my favorite things about physics is its universality. A hydrogen atom in the laboratory behaves exactly the same as a hydrogen atom on the back end of the Milky Way galaxy. Gravity is gravity is gravity; the force that keeps your feet planted to the ground is the same force that keeps planets in orbit around the sun, and that's the same force that has shaped the largest structures in the universe.

This key concept allows us to make enormous leaps in understanding. We can understand the state of the first few minutes of the Big Bang because we know how high-density plasmas work, so we can make testable predictions. We can figure out how stars die and blow up without having to visit one, because we can run a computer simulation of the fundamental physics.

Pretty handy, if you ask me.

Ah, the question asked since the dawn of human civilization: Should we go to Mars? Earth is getting pretty crowded, we're using up all the easily-accessible resources, and we're pretty much done exploring here. So let's go somewhere new!

Hence the anonymous question asked on the whiteboard by my desk recently. Mars seems like a good place to visit, and maybe even move to. But should we?

Mars certainly has a lot going for it. As planets go it's not too far away. It's bigger than the moon, which gives it a more Earth-like gravity. There's a lot of water on the surface just laying around. You could certainly pick a worse place to plant your interplanetary feet.

On the other hand, there's no air. Well, a little bit, and it's all carbon dioxide. The water is frozen. The gravity, while stronger than the moon's, is only about a third that of the Earth. And "not too far away" in space is...really, really far away.

Getting to Mars is certainly technologically feasible. Building a colony there? Possible, but it will take some major leaps and bounds, not to mention a century or two of solid investment, before it could be self-sustaining.

But in the end, should we go to Mars? Maybe.

We can all admit that superconductors are pretty nifty. They carry electrical currents with zero resistance (hence the "super" part of their name), so anytime you want to build The City Of The Future, you'll want to include superconductors to transmit electricity from your ecologically-friendly power station to your self-driving car without any losses.

Because of that lack of resistance, superconductors repel magnetic fields - in other words, they prevent any magnetic field lines from penetrating their surface. This feature makes superconductors double-nifty: if you place one on top of a magnet, the field lines envelope the superconductor like a net, overcoming gravity and making it levitate.

The downside is that we've only been able to make superconductors that do their thing at very cold temperatures, which is why The City Of The Future isn't The City Of Today. But the hunt is on for the right combination of materials that superconduct at everyday lukewarm temperatures, which will make free electrical transmission - and levitation - routine.