Attractive Science and Nickel Shots

Magnetic carbonThe latest issue of my Spotlight column for the science search and tutorials portal Intute is now online. In it I report on:

Elemental magnetism – Carbon is the element of life, without it we simply would not exist, despite the sci-fi penchant for silicon-based life forms. It is indeed a unique element with many apparently anomalous properties. However, one phenomenon that has not been observed unambiguously in carbon, until now, is magnetism. US and German researchers have used a proton beam and advanced X-ray techniques at the Stanford Linear Accelerator Center (SLAC) to put to rest finally any doubts about carbon’s elemental magnetism.

I asked team leader Hendrik Ohldag about the prospects of utilising magnetic carbon in technological applications. “At the moment only very small quantities of magnetic carbon can be produced,” he conceded, “Also, the magnetic moment of such a spot is still very small.” However, he further explained that the proton bombardment technique not only induces magnetism in the carbon particles but can be used to reveal the underlying process of converting this ubiquitous material into a magnetic material. “We might even find ways to make carbon magnetic without proton bombardment, which is admittedly not very suitable for technological applications,” he added.

Also in the latest issue:

To the tower! – Pollution regulations aimed at protecting human health are having an unexpected effect on the London skyline. Buildings such as the Tower of London complex were soot encrusted from as early as the thirteenth century because of fires and industrial smoke. Today they are turning yellow-brown because of biological activity on the surfaces of the buildings facilitated by the low-sulfur atmosphere of modern London.

Nickel shots and stellar nurseries – A chemical analysis of meteorites almost as old as the Solar system itself suggests that rather than forming from the remnants of a supernova explosion our Solar system was formed from the wind of a nearby star some thirty times the mass of the Sun in a violent stellar nursery. One of the teams involved is led by Rick Carlson, I caught up with him today and he explains the implications of isotopic compositions.

“Our paper showed that C-chondrites and the Earth have a slightly different isotopic composition,2 he told me. “The implication is very much along the lines of the work presented by the Bizzarro paper discussed in your news article on Spotlight, that newly synthesized elements, of unusual isotopic composition, were injected into the Solar nebula so shortly before its collapse to form the solar system, that these new elements did not have the chance to mix perfectly with the preexisting material.” Carlson’s work uniquely revealed that the C-chondrites contain a slight excess in r-process and p-process Ba, Nd and Sm isotopes, both of which are likely made in a supernova.

Ordinary chondrites, however, have the same Ba and Sm isotopic composition as the Earth. The small difference in niodymium-142 isotopic composition between ordinary chondrites and Earth therefore most likely reflects the decay of now extinct radioactive samarium-146. “This provides evidence that the Earth underwent a chemical differentiation event while 146Sm was still alive (likely < 100 Ma after collapse of the solar nebula)," Carlson adds.

Author: bob投注平台

Award-winning freelance science writer, author of Deceived Wisdom. Sharp-shooting photographer and wannabe rockstar.