Chemistry
Amino Acid Glycine Found in Comet Material
Confirmation appeared in Astrophysical Journal in May (and reported today) that the amino acid glycine had been found in a cometary halo. The material was captured during a fly-through of comet 81P/Wild 2 by the spacecraft Stardust in 2004.
The glycine molecules that Stardust found came from gas the comet released as the sun warmed it. It was captured in the spacecraft’s sampling gear — akin to an oversized circular ice-cube tray filled with aerogel, a remarkably spongy material that can withstand high heat while at the same time slowing, then cradling, comet material that zips into it at faster-than-bullet speeds.
Stardust passed through the comet’s coma — a halo of dust and gas that surrounds the comet’s core. The team found glycine in the aerogel as well as on some of the foil that lines the aerogel-filled collection chambers.
But the researchers still had to rule out possible contamination from Earth. Glycine consists of carbon, hydrogen, nitrogen, and oxygen. By analyzing the forms of carbon in the glycine molecules, they found that the samples had much higher proportions of a heavy isotope of carbon than does glycine on Earth. The verdict: It’s extraterrestrial, born and bred on the comet itself.
New State of Matter Proclaimed in Transparent Aluminium Experiments
Tantilizing details about an engineered aluminum lattice described as a "new state of matter nobody has seen before."
The Oxford team, along with their international colleagues, focused all this power down into a spot with a diameter less than a twentieth of the width of a human hair. At such high intensities the aluminium turned transparent.
Whilst the invisible effect lasted for only an extremely brief period - an estimated 40 femtoseconds - it demonstrates that such an exotic state of matter can be created using very high power X-ray sources.
Professor Wark added: 'What is particularly remarkable about our experiment is that we have turned ordinary aluminium into this exotic new material in a single step by using this very powerful laser. For a brief period the sample looks and behaves in every way like a new form of matter. In certain respects, the way it reacts is as though we had changed every aluminium atom into silicon: it’s almost as surprising as finding that you can turn lead into gold with light!'
Book Review: A World on Fire: A Heretic, an Aristocrat, and the Race to Discover Oxygen by Joe Jackson
(out of 5 stars)
The history in A World on Fire centers on two men whose scientific curiousity led them to discover vital new clues about the air we breath and eventually, oxygen. Joseph Priestley, a British minister, and Antoine Lavoisier, a French aristocrat, worked independent of each other, and often fed off (or directly challenged) each other's work to drive forward in the search for the components of breathable and combustable air. Lavoisier's work sparked the Chemical Revolution even as Priestley fought stidently for a theory ('phlogiston') that quickly began to lose favor with chemists.
This book is not deep with science, though there are a few very basic formulas and descriptions of methodology. The narrative instead focuses largely on the setting and context of the discoveries made by the two men. Revolution in France and America, as well as the madness of King George in Britain and the fall of the monarchy in France led to a unique atmosphere in which this scientific story progressed.
As a history of scientists, this book is an easy read and one that is both enlightening and enjoyable. My primary complaint, and the reason for a 3/5 star review, is the author's insistence in placing his own speculation into the story. Many instances of 'One might imagine...' or 'It isn't hard to believe...' or 'Perhaps he saw...'. This is a major turn off for me in book on history. This doesn't greatly detract from the value of the book and its story, but it does make the reader wonder which facts are documented and which the author has chosen to include despite flimsy or non-existent evidence.
