Paul Davies

The origin of life is one of the great outstanding mysteries of science.

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.

Cancer is such a ruthless adversary because it behaves as if it has its own fiendishly cunning agenda.

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 touches every family in one way or another. As other diseases are brought under control, cancer is set to become the number one killer, and is already in epidemic proportions worldwide.

Many investigators feel uneasy stating in public that the origin of life is a mystery even though behind closed doors they admit they are baffled.

In science, a healthy skepticism is a professional necessity, whereas in religion, having belief without evidence is regarded as a virtue.

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.

In the frantic search for an elusive 'cure,' few researchers stand back and ask a very basic question: why does cancer exist? What is its place in the grand story of life?

General relativity is the cornerstone of cosmology and astrophysics. It has also provided the conceptual basis for string theory and other attempts to unify all the forces of nature in terms of geometrical structures.

The development of artificial intelligence may well imply that man will relinquish his intellectual supremacy in favor of thinking machines. With oceans of time available for future innovation, there seems to be no reason why machines cannot achieve and surpass anything of which the human brain is capable.

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

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.

For me, science is already fantastical enough. Unlocking the secrets of nature with fundamental physics or cosmology or astrobiology leads you into a wonderland compared with which beliefs in things like alien abductions pale into insignificance.

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.

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.

Cosmologists have attempted to account for the day-to-day laws you find in textbooks in terms of fundamental 'superlaws,' but the superlaws themselves must still be accepted as brute facts. So maybe the ultimate laws of nature will always be off-limits to science.

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.

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.

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.

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.

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

A permanent base on Mars would have a number of advantages beyond being a bonanza for planetary science and geology. If, as some evidence suggests, exotic micro-organisms have arisen independently of terrestrial life, studying them could revolutionise biology, medicine and biotechnology.

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.

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.

Is there anything science should not try to explain? Science is knowledge and knowledge is power - power to do good or evil. Sometimes ignorance is bliss.

Astonishingly, in spite of decades of research, there is no agreed theory of cancer, no explanation for why, inside almost all healthy cells, there lurks a highly efficient cancer subroutine that can be activated by a variety of agents - radiation, chemicals, inflammation and infection.

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.