Cutting Edge: Science and Religion News

The Physics World “2014 Breakthrough of the Year” went to the European Space Agency’s Rosetta mission¹ for being the first to land a spacecraft (Philae) on a comet (67P/Churyumov-Gerasimenko), on 12 November. A comet is essentially a big lump of icy space rock. Radiation from the Sun (the “solar wind”) can cause comets to have their famous tails.

This comet is a staggering 511 million kilometres (317 million miles) from Earth and travelling at nearly 55,000kph (34,000mph). It took 10 years for the Rosetta spacecraft to reach a position near the comet so that its robot module, Philae, could then separate and make the seven-hour journey to the comet’s surface.

The surface of the comet, unlike that of the Moon or Earth is highly irregular and rocky. Nothing can travel faster than the speed of light, so communication between Rosetta and its controllers on Earth took 28 minutes each way. Therefore, it was only after nearly an hour that the controllers realised that Philae had bounced hundreds of metres from the landing area. It then landed again a few hours later, bouncing a smaller distance the second time before finally landing about a kilometre from the original landing area (the comet is rotating as well as moving fast).

This meant that Philae landed on its side near shadow areas, so its solar panels did not receive the light required to charge its batteries. Nevertheless, it was able to carry out some experiments and drill into the hard surface. The surface is now known to have a layer of dust about 10 to 20 cm thick on top of an unexpectedly hard material thought to be water ice.

Preliminary data analysis indicates that there are carbon-based organic molecules on the comet. Since the Earth is believed to have been regularly bombarded by comets, this information may provide clues to how life was able to emerge on Earth.

However, the Rosina mass spectrometer aboard Rosetta found that the ratio of deuterium to hydrogen in the comet is far greater than that found on Earth, adding to the growing body of evidence that the water on Earth was delivered not by comets, as previously thought, but by asteroids.

By August 2015 the comet (and Rosetta, which is tracking it) should have reached its perihelion, its closest position to the Sun. The icy materials in 67P will vaporise, emitting gas and dust in a tail that will trail for thousands of kilometres and be observed by Rosetta.

Cynics will argue that at €1.4bn (£1.1bn), the cost is exorbitant. I am not one of those. The incredible achievement of tracking, then landing on, a comet is itself like a work of art, a celebration of our humanity. It is our free, human intelligence that is part of our spiritual nature. There is no biological advantage to humans in carrying out this mission, so why do we do it?

Simply because we are curious and intelligent. We seek to understand the world around us, even in space, to make inductions and deductions, to theorise. The same applies to our Christian faith: credo ut intelligam, the maxim of St Anselm of Canterbury, means “I believe in order to understand” (note the order of the verbs).

The Faith movement has this principle at the heart of its approach to the formation of young Catholics, seeking to foster an inquisitive approach to the faith, just as in the natural sciences, and to develop such intellectual curiosity within a theological framework that is faithful to Christ’s Magisterium and to our understanding of the created universe.

Research biologists have found that there are many more electrical bacteria than originally thought. Experiments growing bacteria on battery electrodes confirm that they are eating and excreting electricity, so to speak. Kenneth Nealson, at the University of Southern California, states that “…life, when you boil it right down, is a flow of electrons”.

The sugars we consume have excess electrons. Our cells break down the sugars, and the electrons flow through them in a complex set of chemical reactions until they are passed on to electron-hungry oxygen. The cells make ATP, a molecule like a biochemical battery.

The discovery of electric bacteria shows that some very basic forms of life can process energy in a very simple form, electrical energy, harvested from the surface of minerals. These bacteria may help to answer fundamental questions about biological life, such as what is the bare minimum of energy needed to maintain life.

Nasa is interested in these organisms because they survive on very little energy, suggesting the exciting prospect of modes of life in other parts of the solar system. Electric bacteria could have practical uses here on Earth, however, such as creating self-powered biomachines that do useful things like cleaning up sewage or contaminated groundwater while drawing their own power from their surroundings.

Dr Gregory Farrelly is a physics teacher at Cambridge Tutors College, Croydon.