T3 Science Hit: dinosaur-eating frogs, UV-resistant dye and bubbles of stardust

Scientists reveal ancient amphibians with wolf-like jaws, a star surrounded by an intricate bubble and dyes that don't fade in the sun

TODO alt text

Dinosaur-eating frogs

(Image: © Kristopher Lappin)

Most frogs have a pathetic bite, preferring to catch prey on their sticky tongues, but the 68 million year old Madagascan Beelzebufo had jaws like a wolf.

These extinct amphibians are related to modern-day PacMan frogs, affectionately known as 'hopping heads'. Native to South America, they have huge mouths, massive jaw muscles and a powerful bite that can overpower snakes, birds and small rodents. 

"speaking from experience, horned frogs have quite an impressive bite, and they tend not to let go. The bite of a large Beelzebufo would have been remarkable, definitely not something I would want to experience firsthand."

Professor Kristopher Lappin, California

Scientists from the University of Adelaide, California State Polytechnic University, the University of California and University College London measured the bite force of eight of these formidable frogs, and extrapolated the data to estimate the bite strength of their extinct relatives.

Modern frogs with heads measuring 4.5cm can bite down with a force of 30 newtons, suggesting that extinct frogs with a head size of 10cm or more might have chomped through prey with a force of between 500 and 2,200 newtons. 

That’s equivalent to a wolf or a tiger, meaning that they could easily have taken on a young dinosaur.

Stardust bubbles

(Image: © ALMA (ESO/NAOJ/NRAO)/F. Kerschbaum)

2,700 years ago, a red star in the constellation Antlia coughed up a thermal pulse, rapidly losing mass and ejecting a spherical bubble of stardust. And the latest data from the Atacama Large Millimeter/submillimeter Array (ALMA) has revealed its structure in never before seen detail

ALMA is a radio telescope, capable of capturing images in different wavelengths, producing slices of data that show the speed and direction of gas movement within the bubble. In the image below, we can see the side of the star facing Earth.

The blue material is moving away from the star and towards us, whilst the red is shooting away from the star but not in our direction. Unseen, behind the star, the gas is moving the other way.

(Image: © ALMA (ESO/NAOJ/NRAO), F. Kerschbaum)

The star, known as U Antliae, is an asymptotic giant branch star that's running out of fuel. The red giant is burning through helium to form carbon, but periodically the gas runs low. The star then uses hydrogen to make more helium, which ignites in a flash, releasing mass in a high-speed thermal pulse. U Antilae's last pulse lasted just a few hundred years, spewing filaments of gas to form the thin shell we can see today.

According to the European Space Agency, the shells around stars like this one are rich in carbon compounds. Learning more about how they work could shed light on stellar evolution and the creation of cosmic dust.

UV-resistant dye

Most of the dyes that tint paints, cosmetics and foods are based on organic pigments or metal oxides that break down under harsh UV light, but scientists from the University of Akron, Northwestern University, and University of Ghent have created structural colours that don’t fade

Pigments are colourful because they absorb and reflect specific wavelengths of light, but structural colours are based on nano-structures that scatter the incoming rays. They are responsible for the bright shades of bird feathers, soap bubbles and butterfly wings, but they are often iridescent, producing different colours depending on the angle. 

This feature isn't much use in dyes and inks, but now nanoparticle tech is being applied to stabilise structural colours, tweaking the way that light is scattered to produce solid hues.

(Image: © Tagishsimon)

The new ink contains artificial melanin packed together into semi-ordered light-scattering 'supraballs' coated in shells of silica. Melanin is the pigment that gives skin and hair its brown and red tones, but by tweaking the spacing between the melanin cores using different thicknesses of silica, the team have generated a full colour spectrum.

The resulting inks could be added to paints and plastics to make colours that that naturally dissipate incoming UV, resisting the effects of the sun.

"Melanin is an important biomaterial that has so far been underutilized in materials science and technological applications,"

Dr. Ali Dhinojwala