Oldest Known Land Fossil

It is smaller than a human hair, resembles a mushroom, and is thought to be the earliest fossil of a land-dwelling organism. The fungus, which dates back 440 million years, spent its life under the ground rotting down matter. Even the scientist who analysed it - Dr Martin Smith - admits it is a ''humble little fungus''. But the pioneer, known as Tortotubus, could help explain how early life colonised the rocky barren Earth. Most scientists agree that life moved from the sea to the land between 500 and 450 million years ago. But in order for plants and animals to gain a foothold on terra firma there needed to be nutrients and soil to support them. Fungi kick-started this process, by getting nitrogen and oxygen into the rudimentary soil.

Hubble Sets New Cosmic Distance Record
The Hubble Space Telescope has spied the most distant galaxy yet. It is so far away that the light from this extremely faint collection of stars, catalogued as GN-z11, has taken some 13.4 billion years to reach us. Or to put that another way - Hubble sees the galaxy as it was just 400 million years after the Big Bang. Astronomers say they are confident about the measurement because they have been able to tease apart and analyse the object's light. Such spectroscopic assessments are difficult to perform on the most far-flung sources, but if it can be done it produces the most reliable distance estimates. The details of the discovery appear in an edition of the Astrophysical Journal.

Treating Severe Head Injury
Treating severe head injury and why a commonly used intervention used in intensive care units across the world is being questioned. Professor Peter Andrews is the man behind a new trial looking at the outcomes of inducing hypothermia, or cooling people with head trauma to prevent damage. The trial was stopped because early evidence suggested harm from this hitherto commonly used practice. Dr Mark Porter discusses the implications for critical care medicine across the world with Peter Andrews and Professor John Myburgh who is at the University of New South Wales in Sydney.

Flying Robots Aid Farmers
At the University of Pennsylvania in the US, a variety of flying robots are being developed which have the potential to help famers monitor crops, help rescue crews deliver aid after disasters, and even help doctors guide drugs around our bodies. Jack Stewart visits the labs to find out more.

Einstein's Ice Box
In the late 1920s Einstein was working on a grand unified theory of the universe, having given us E=mc2, space-time and the fourth dimension. He was also working on a refrigerator. Perhaps motivated by a story in the Berlin newspapers about a family who died when toxic fumes leaked from their state-of the-art refrigerator, Einstein teamed up with another physicist Leo Szilard and designed a new, safer refrigerating technology. And so it was that in 1930, the man who had once famously worked in the patent office in Bern was granted a patent of his own. Number: 1, 781, 541. Title: refrigeration. Phil Ball explores this little known period of Einstein's life to try and find out why he turned his extraordinary mind to making fridges safer. Despite considerable commercial interest in the patent, Einstein's fridge did not get built in his lifetime.

The Brain Prize
A team of British scientists has picked up 1 million euros from The Brain Prize, which is issued by a Danish Charity annually. Tim Bliss, Graham Collingridge and Richard Morris have won for their work on how memories are formed.

Zika Virus
New experimental evidence bolsters the notion that Zika virus is the cause of an outbreak of underdeveloped brains (microcephaly) in newborns in South America.

Grey Hair Gene Discovered by Scientists
Grey hair and mono-brows have been all over the news this week with some follicular genetics. A team from UCL assessed the hair types of several thousand Latin Americans and their genomes to see what bits of DNA are associated with those characteristics. They found a set of gene variants that appear to explain, in part, grey hair, straight and curly hair, bushy beards and mono-brows. Lead researcher Dr Kaustubh Adhikari discusses the implications.

(Image caption: 440 million year old fossil - credit: Martin R. Smith/Cambridge University/PA Wire)

The Science Hour was presented by Roland Pease with comments from BBC News science reporter Victoria Gill

Producer: Alex Mansfield

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