New Delhi: Astronomers using the W.M. Keck Observatory on Mauna Kea in Hawaii have discovered aurorae – natural light displays that shimmer in the sky – at visible wavelengths appearing on all four major moons of Jupiter: Io, Europa, Ganymede and Callisto.
Using the observatory’s High-Resolution Echelle Spectrometer (HIRES) as well as high-resolution spectrographs at the Large Binocular Telescope and Apache Point Observatory, a team of researchers led by Caltech and Boston University observed the moons in Jupiter’s shadow so that their faint aurorae, which are caused by the gas giant’s strong magnetic field, could be spotted without competition from the bright sunlight reflected off their surfaces.
The research is documented in two papers published in The Planetary Science Journal.
All four of the Galilean moons show the same oxygen aurora we see in skies near the earth’s poles, but gases on Jupiter’s moons are much thinner, allowing a deep red colour to glow nearly 15 times brighter than the familiar green light.
At Europa and Ganymede, oxygen also lights up infrared wavelengths, just a little redder than the human eye can see – the first time this phenomenon has been seen in the atmosphere of a body other than earth.
At Io, Jupiter’s innermost moon, volcanic plumes of gas and dust are vast in size, reaching hundreds of kilometres in height. These plumes contain salts like sodium chloride and potassium chloride, which break down to produce additional colours.
Sodium gives Io’s aurora the same yellowy-orange glow that we see in urban streetlamps. The new measurements also show the potassium aurora at Io in infrared light, which has not been detected anywhere else previously. Read More
Also read: Potential alien life to ocean on Saturn’s moon — here are this week’s scientific revelations
Robotic finch can teach birds how to sing
Scientists at VU Amsterdam and Freie Universität Berlin have created a robotic bird that can teach young zebra finches how to sing.
To investigate when and how birds learn to sing, researchers have mostly played birdsong through loudspeakers. However, singing involves much more, such as beak and throat movements and posture.
The research team thought this might be why young birds learn less well from a loudspeaker than from another bird.
The team of scientists developed the RoboFinch starting with a 3D scan and 3D print of an adult male bird. As birds see colours differently from humans, the paint that was used for the robots was adjusted to how zebra finches see colour. This made the robot seem life-like to zebra finches.
Using high-speed cameras, the research group filmed and then precisely measured the beak movements of zebra finches to make an exact copy.
The RoboFinch was an immediate success with the birds.
They come and sit next to the robotic bird on the perch and twitter at it. More importantly, the young birds sit still and study the RoboFinch when it starts moving and playing birdsong.
The team, which was funded by Human Frontiers Science Program, can now put together the different components of birdsong like a building kit. The research has been published in Methods of Ecology and Evolution. Read More
James Webb telescope maps out gas and dust patterns of nearby galaxies
NASA’s James Webb Space Telescope has mapped out the distribution of gas and dust in nearby galaxies – revealing distinct patterns and structures.
The largest survey of nearby galaxies in Webb’s first year of science operations is being carried out by the Physics at High Angular resolution in Nearby Galaxies (PHANGS) collaboration, involving more than 100 researchers from around the globe.
The data has enabled the collection of 21 research papers which provide new insight into how some of the smallest-scale processes in our universe – the beginnings of star formation – impact the evolution of galaxies. The team’s initial findings were recently published in The Astrophysical Journal Letters.
The team is studying a diverse sample of 19 spiral galaxies and, in Webb’s first few months of science operations, observations of five of those targets – M74, NGC 7496, IC 5332, NGC 1365, and NGC 1433 – have taken place.
The images from Webb’s Mid-Infrared Instrument reveal the presence of a network of highly structured features within these galaxies – glowing cavities of dust and huge cavernous bubbles of gas that line the spiral arms.
In some regions of the nearby galaxies observed, this web of features appears to be built from both individual and overlapping shells and bubbles where young stars are releasing energy. Read More
Heavy metals seeped into earth’s core like coffee drip
Scientists at Carnegie Institution for Science have discovered a new process by which the materials that form the Earth’s core descended into the depths of our planet, leaving behind geochemical traces that have long mystified researchers.
The planet Earth accreted from the disk of dust and gas that surrounded the Sun in its youth. As the Earth grew from smaller objects over time, the densest material sank inward, separating the planet into distinct layers – including the iron-rich metal core and silicate mantle.
Each of our planet’s layers has its own composition. Although the core is predominantly iron, seismic data indicates that some lighter elements, like oxygen, sulphur, silicon and carbon, were dissolved into it and brought along for the ride into the planet’s centre.
Likewise, the mantle is predominately silicate, but its concentrations of so-called “iron-loving”, or siderophile, elements have mystified scientists for decades.
In the lab, scientists Lin Wang and Yingwei Fei used heavy hydraulic presses, like the ones used to make synthetic diamonds, to bring samples of material to high pressures, mimicking the conditions found in the Earth’s interior.
This enabled them to recreate the Earth’s differentiation process in miniature and to probe the different possible ways by which the core was formed.
Using these tools, Wang and Fei developed a new method of tracing the movement of the core-forming liquid metal in their sample as it migrated inward.
They showed that much like water filtering through coffee grounds, iron melts, under the dynamic conditions found on early Earth, could have passed through the cracks between a layer of solid silicate crystals – called a grain boundary – and exchanged chemical elements.
The research is published in Science Advances. Read More
Large dinosaur print found in UK is 166 million years old
A record-breaking dinosaur print found on the Yorkshire Coast in the UK may have been left by a predator stopping for a rest 166 million years ago, according to researchers.
The metre-long fossil, which was found in 2021 by local archaeologist Marie Woods, is the largest ever discovered in the region.
The study describing the footprint, in which Woods is coauthor, was published Thursday in Proceedings of the Yorkshire Geological Society.
The team that studied the track concluded it was made by a giant carnivore like a Megalosaurus. The footprint is the largest left by a theropod – a group of bipedal dinosaurs which also included Tyrannosaurus Rex – found to date in Yorkshire.
Features of the footprint even suggest the large predator was squatting down before standing up, according to the archaeologists.
A team of fossil collectors rescued the fragile print from the shoreline after scientists warned it was at risk of being lost to erosion or landslips. Read More
(Edited by Nida Fatima Siddiqui)
Also Read: How are stars like Sun formed? James Webb Space Telescope images hold key to new investigations