Astronauts have been stuck in low-Earth orbit, boldly going nowhere. American attempts to kick-start a new phase of lunar exploration have stalled amid the realisation that NASA's budget is too small for the job.

When I was a student, the laws of physics were regarded as completely off limits. The job of the scientist, we were told, is to discover the laws and apply them, not inquire into their provenance.

No planet is more earth-like than Earth itself, so if life really does pop up readily in earth-like conditions, then surely it should have arisen many times right here on our home planet? And how do we know it didn't? The truth is, nobody has looked.

Should we find a second form of life right here on our doorstep, we could be confident that life is a truly cosmic phenomenon. If so, there may well be sentient beings somewhere in the galaxy wondering, as do we, if they are not alone in the universe.

Every day online is a new discovery.

Statistical physics or Newtonian physics gives way to quantum physics. Very unusual properties of matter emerge at that scale, and you can think about building products in a very different way. You can think about interfacing to biology in a very different way.

Whatever I learned reading 'Scientific American,' nothing can finally compete with your own observations.

The basic science is very well established; it is well understood that global warming is due to greenhouse gases. What is uncertain is projections about specifics in the next few decades, by how much will the climate change.