My feeling is that scientific method has the power to account for and interlink all phenomena in the universe, including its origin, using the laws of nature. But that still leaves the laws unexplained.

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.

Perhaps the best motivation for going to Mars is political. It is obvious that no single nation currently has either the will or the resources to do it alone, but a consortium of nations and space agencies could achieve it within 20 years.

Science, we are repeatedly told, is the most reliable form of knowledge about the world because it is based on testable hypotheses. Religion, by contrast, is based on faith. The term 'doubting Thomas' well illustrates the difference.

Scientists are slowly waking up to an inconvenient truth - the universe looks suspiciously like a fix. The issue concerns the very laws of nature themselves.

Scientists have no agreed theory of the origin of life - plenty of scenarios, conjectures and just-so stories, but nothing with solid experimental support.

Searching for alternative life on Earth might seem misconceived, because there is excellent evidence that every kind of life so far studied evolved from a common ancestor that lived billions of years ago. Yet most of the life that exists on Earth has never been properly classified.

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.

So how can we test the idea that the transition from nonlife to life is simple enough to happen repeatedly? The most obvious and straightforward way is to search for a second form of life on Earth. No planet is more Earth-like than Earth itself, so if the path to life is easy, then life should have started up many times over right here.

The language of chemistry simply does not mesh with that of biology. Chemistry is about substances and how they react, whereas biology appeals to concepts such as information and organisation. Informational narratives permeate biology.

The vast majority of terrestrial species are in fact microbes, and scientists have only begun scratching the surface of the microbial realm. It is entirely possible that examples of life as we don't know it have so far been overlooked.

The way life manages information involves a logical structure that differs fundamentally from mere complex chemistry. Therefore chemistry alone will not explain life's origin, any more than a study of silicon, copper and plastic will explain how a computer can execute a program.

Things changed with the discovery of neutron stars and black holes - objects with gravitational fields so intense that dramatic space and time-warping effects occur.

Traditionally, scientists have treated the laws of physics as simply 'given,' elegant mathematical relationships that were somehow imprinted on the universe at its birth, and fixed thereafter. Inquiry into the origin and nature of the laws was not regarded as a proper part of science.

We will never fully explain the world by appealing to something outside it that must simply be accepted on faith, be it an unexplained God or an unexplained set of mathematical laws.

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.

A universe that came from nothing in the big bang will disappear into nothing at the big crunch. Its glorious few zillion years of existence not even a memory.

Cancer cells come pre-programmed to execute a well-defined cascade of changes, seemingly designed to facilitate both their enhanced survival and their dissemination through the bloodstream. There is even an air of conspiracy in the way that tumours use chemical signals to create cancer-friendly niches in remote organs.

The birth of science as we know it arguably began with Isaac Newton's formulation of the laws of gravitation and motion. It is no exaggeration to say that physics was reborn in the early 20th-century with the twin revolutions of quantum mechanics and the theory of relativity.

Although the elusive 'cure' may be a distant dream, understanding the true nature of cancer will enable it to be better controlled and less menacing.