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Last broadcast on Mon, 27 Feb 2012, 21:00 on BBC Radio 4 (see all broadcasts).
Synopsis
Quentin Cooper hears that men may not be heading for extinction after all! The male Y-chromosome is degenerate but, according to a new study, has been stable since we diverged from monkeys 25 million years ago. But the fundamental unit of mass, the kilogram, may not be stable. Attempts to redefine it in terms of fundamental constants are fraught with difficulty. But there is hope on the horizon for mimicking one of nature's greatest secrets, photosynthesis, the ability to turn sunshine into fuel.
Producer: Martin Redfern.
Redefining the Kilogram
Ian Robinson with Watt Balance
The kilogramme is the last of the SI units – the fundamental units of measurement in science – to be defined by a physical artefact. It is a small lump of metal in a vault in Paris, and its mass is… exactly a kilogramme – by definition! But for some years efforts have been made around the world to instead couple the kilogramme to a more fundamental constant of nature. Dr Ian Robinson of the UK’s National Physical Laboratory has been working on one technique – the “Watt Balance” for some decades now, and has published a paper in the journal Metrologia which outlines how the new owners of the apparatus – Canada’s NRC-INMS – might make the leap in accuracy sufficient for us to define the kg not by the Paris prototype, but by a quantity known as Planck’s constant. That could happen in as little as two years.
Men may not be doomed!
Full set of chromosomes
Creative commons image
The human Y-chromosome that carries the genes that determine the male sex has degenerated from that of our distant ancestors, but is the degeneration continuing, condemning males to eventual extinction? Not according to new research comparing us with monkeys whose evolutionary lineage diverged 25 million years ago. Dr Jennifer Hughes of the Whitehead Institute in Cambridge USA, lead author of the new study, in the journal ‘Nature’, discusses her results with geneticist Dr Max Reuter of UCL.
Neutrinos probably don't break the cosmic speed limit
The OPERA experiment at CERN that sent neutrinos speeding towards underground detectors in Italy.
Photograph: CERN
Members of CERN's 'OPERA' experiment, who announced strange results last year that suggested that ghostly particles called neutrinos may travel fractionally faster than the speed of light have now issued a statement saying that they have identified two sources of possible error, one in an oscillator used to time-stamp the particles, the other a loose connection to a GPS receiver. Subject to further tests, this strange phenomenon may disappear, to the relief of many phsicists but the disappointment of those enjoying the challenge. Physics journalist Edwin Cartlidge comments.
Fuel From Sunshine
Photosynthesis is the secret to all life on earth. It is nature’s way of taking the energy from sunlight and storing it chemically for use later. At last week’s AAAS meeting, several teams from around the world outlined work aimed at creating some kind of “artificial leaf”. On an industrial scale, such a thing would allow the creation of so called solar fuels – fuels which, unlike the electricity generated by a standard solar cell, would be storable, transportable and applicable to many of our energy needs. Glasgow University’s Solar Fuel Group are optimistic that their approach – a type of accelerated natural photosynthesis – might provide the way forward. But many different approaches are being explored, and many millions of pounds are being spent worldwide on this “holy grail” of energy research: the secrets of synthetic photosynthesis.
Broadcasts
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Thu 23 Feb 201216:30
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Mon 27 Feb 201221:00
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