You may have missed… snowflake shaped zinc crystals; Australian Biodiversity Council; toughest material on Earth; hot ‘hell’ planet

It’s beginning to look a lot light Cryst-mas

Australian researchers have grown zinc crystals that look like snowflakes inside liquid gallium metal. But you won’t be hanging them on your Christmas tree anytime soon, instead, these complex symmetrical zinc crystals can potentially be used in a range of catalysis applications.

Often resembling six-branched snowflake crystals, the structures could be adapted depending on a range of different inputs. For instance, by increasing the temperature or time taken to grow them the crystal size could also be increased.

Higher temperatures also produced many more 12-branched structures, which occur when two overlapping hexagonal crystal seeds grow concurrently. Elevated pressure (5 bar) resulted in simple fractal shapes.

Being able to grow crystals with specific facets is important for their use in catalysis.

Zinc crystals
Images of zinc crystals obtained after one day (left), 10 days (middle) of growth at 350°C initial temperature, and one day of growth at 550°C initial temperature (right) showing how their shapes develop over time. Credit: Dr Jianbo Tang

“In some catalytic reactions, for example in the conversion of carbon dioxide, it happens much faster on one facet of the crystal compared to another,” explains Dr Jianbo Tang, a researcher from the University of New South Wales’ School of Chemical Engineering and co-first author of the new study published in Science.

“Facet engineering is becoming important where there is a need to create a particular facet to improve catalytic efficiency.

“For a certain process it may be better to have a square-shaped crystal for catalysis, or a flatter shape, and we can see from this research how we can synthesise that facet depending on the various inputs.

“This is the same process that happens in the air with snowflakes, but now we are able to do it with crystals in liquid metal.”

Zinc crystals
Different shaped crystals can be synthesised by using a different metal solute, such as nickel (left) and bismuth (right). Credit: Dr Jianbo Tang

How this insanely hot ‘hell planet’ got so scorched

The rocky planet 55 Cancri e (nicknamed ‘Janssen’) orbits its star so closely a ‘year’ lasts just 18 hours – resulting in a giant lava ocean for its surface and an interior that might be full of diamond.

Janssen’s orbit has a minimum radius of roughly 2 million kms – for comparison, Mercury, the closest planet to our sun, is 46 million kms, and Earth’s is around 147 million km.

Now, new research has shed light on how this devilishly hot exoplanet might have become so toasty.

Using a new tool called EXPRES (Exoplanetary and Planetary Radio Emissions Simulator), astronomers captured ultra-precise measurements of slight shifts in the light shining from Janssen’s star, Copernicus.

Illustration of cancri e in front of copernicus
This artist’s impression shows the super-Earth 55 Cancri e in front of its parent star. Using observations made with the NASA/ESA Hubble Space Telescope and new analytic software scientists were able to analyse the composition of its atmosphere. It was the first time this was possible for a super-Earth. 55 Cancri e is about 40 light-years away and orbits a star slightly smaller, cooler and less bright than our Sun. As the planet is so close to its parent star, temperatures on the surface are thought to reach around 2000 degrees Celsius. Credit: ESA/Hubble, M. Kornmesser

Janssen orbits at Copernicus’ equator, but the other exoplanets have extremely different, misaligned orbital paths. The scientists think that Jannsen probably formed in a relatively cooler orbit further out and slowly fell toward the star over time.

The study, published in Nature Astronomy, found that Copernicus is spinning. So, the researchers propose that this caused its midsection to bulge outward slightly, and that asymmetry affected the gravity felt by Janssen – pulling the planet into alignment with the star’s thicker equator.

An animation of Janssen orbiting its star. Credit: Lucy Reading-Ikkanda/Simons Foundation

New council launched to advocate for Australian biodiversity

Leading experts, including Indigenous knowledge holders, from 11 Australian universities have come together to form a new council advocating for Australia’s catastrophically declining biodiversity.

Minister for Environment and Water, Tanya Plibersek, launched the Biodiversity Council on Wednesday 7 December, in line with the federal response to an independent review of the Environment Protection and Biodiversity Conservation (EPBCA) Act.

It will foster public, policy, and industry recognition of the biodiversity crisis in Australia – highlighted in the recently-released State of the Environment report – as well as the importance of biodiversity for wellbeing and prosperity, and positive opportunities and solutions to address its challenges.

“There is currently no specialist biodiversity think-tank providing commentary on the adequacy of current policy, bringing together expertise to support all levels of government and industry to enact solutions, halt extinctions and reverse biodiversity loss. The Council will be Australia’s voice on biodiversity,” says Professor Hugh Possigham, Chief Councillor of the Biodiversity Council.

The Biodiversity Council will be initially hosted by the University of Melbourne and has been established through contributions from six other philanthropic grantees.

This is the toughest material on Earth

Microscopy images of the crconi alloy
Microscopy-generated images showing the path of a fracture and accompanying crystal structure deformation in the CrCoNi alloy at nanometer scale during stress testing at 20 kelvin (-253.15 °C). The fracture is propagating from left to right. Credit: Robert Ritchie/Berkeley Lab

Scientists have measured the toughest material ever recorded – a metallic alloy made of chromium, cobalt, and nickel (CrCoNi).

Not only is the metal extremely malleable (resisting fracture) and impressively strong (meaning it resists permanent deformation), but these qualities also improve as it gets colder – which runs counter to most other materials.

The material is in a subset class of metals called high entropy alloys (HEAs). Basically, while all the alloys in use today contain a high proportion of one element and lower amounts of additional elements, HEAs are made of an equal mix of each.

Scanning electron microscope image of metal alloys
These images, generated from scanning electron microscopy, show the grain structures and crystal lattice orientations of (A) CrMnFeCoNi and (B) CrCoNi alloys. (C) and (D) show examples of fractures in CrCoNi at 293 kelvin and 20 kelvin, respectively. Credit: Robert Ritchie/Berkeley

The toughness of this material near liquid helium temperatures (20 kelvin, -253.15 °C) is as high as 500 megapascals square root meters. In the same units, the toughness of a piece of silicon is one, the aluminium airframe in passenger airplanes is about 35, and the toughness of some of the best steel is around 100. So, 500, it’s a staggering number,” explains research co-leader Robert Ritchie, who is professor of Engineering at the University of California, Berkeley in the US. 

The record-breaking findings have been published in a new study in Science.

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