Australasian Science: Australia's authority on science since 1938

Briefs

By Stephen Luntz

Chocolate, mango and blueberry benefits, forensic advances and more.

The full text of this article can be purchased from Informit.

An Atom’s Shadow
For the first time the shadow of a single atom has been photographed, an event recorded in Nature Communications.

“We wanted to investigate how few atoms are required to cast a shadow, and we proved it takes just one,” said Prof Kielpinski of Griffith University’s Centre for Quantum Dynamics. An ytterbium atom was chosen because lasers with the appropriate frequency for absorption are relatively cheap.

“If we change the frequency of the light we shine on the atom by just one part in a billion, the image can no longer be seen,” Kielpinski said.

Co-author Dr Erik Streed explained that when atoms are bound to other objects the absorption frequency becomes smeared, so the atom was kept in free space by electric fields to ensure that only the exact absorption frequency would work.

The achievement required delicate work to hold the atom steady and an ultra-high resolution microscope to reveal the darkness cast on the detector where the atom blocked the light.

Chocolate Benefits Quantified
Many previous studies have touted the benefits of dark chocolate for health (AS, Nov 2010, p.12), but Monash PhD student Ella Zomer has upped the ante both in how much should be consumed and by quantifying the gains.

“We’ve predicted significant health benefits of eating 100 grams of dark...

The full text of this article can be purchased from Informit.