New Delhi: Scientists have spotted unusual circular sand dunes on the surface of Mars in the images captured by NASA’s Mars Reconnaissance Orbiter (MRO) — a spacecraft that has been exploring the planet for a long time.
The MRO captured the intriguing image of sand dunes with remarkably round shapes using its High-Resolution Imaging Experiment (HiRise) camera.
While dunes of many shapes and sizes are common on Mars, the ones in this image are almost perfectly circular, which is unusual.
The image also shows that the dunes are asymmetrical, with steep slip faces on the south ends. This indicates that sand generally moves to the south, but the winds may be variable.
MRO has been orbiting Mars since 2006. The mission’s primary goal is to investigate the Martian surface, atmosphere, and geology, with the aim of finding evidence of water and possible signs of any past or present life. Read more here
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Rare insect found at US Walmart sets historic record
A giant insect plucked from the façade of a Walmart in the US in 2012 has turned out to be one of its kind — a giant lacewing, the first to be seen in eastern North America in over 50 years, and the first ever to be recorded in the state of Arkansas.
The giant lacewing was formerly widespread across North America, but went mysteriously missing from eastern North America by the 1950s.
This discovery suggests there may be relic populations of this large, Jurassic-Era insect yet to be discovered, explained Michael Skvarla, director of Penn State’s Insect Identification Lab. Skvarla found the specimen in 2012, but misidentified it and only discovered its true identity after teaching an online course based on his personal insect collection in 2020.
“I remember it vividly, because I was walking into Walmart to get milk and I saw this huge insect on the side of the building,” said Skvarla, who was a doctoral student at the University of Arkansas at the time. “I thought it looked interesting, so I put it in my hand and did the rest of my shopping with it between my fingers. I got home, mounted it, and promptly forgot about it for almost a decade.”
It wasn’t until the COVID-19 pandemic that the giant lacewing would find its time to shine. In the fall of 2020, with the world in lockdown, Skvarla was teaching Entomology 432: Insect Biodiversity and Evolution at Penn State. He taught the lab course via Zoom, with students following along remotely on loaner microscopes, and used his own personal insect collection as specimen samples.
As he went to demonstrate the features of a specimen he had previously labeled an “antlion”, Skvarla noticed that the characteristics didn’t quite match those of the dragonfly-like predatory insect. Instead, he thought it looked more like a lacewing.
A giant lacewing has a wingspan of roughly 50 millimeters, which is quite large for an insect — a clear indicator that the specimen was not an antlion. The students got to work comparing features — and a discovery was made, live on Zoom.
For additional confirmation, the team performed molecular DNA analyses on the specimen. Since confirming its true identity, Skvarla has deposited the insect safely in the collections of the Frost Entomological Museum at Penn State, where scientists and students will have access to it for further research. Read more here
Robot provides unprecedented views below the Antarctic ice shelf
A robotic camera high in a narrow, seawater-filled crevasse in the base of Antarctica’s largest ice shelf has revealed more than a century of geological processes beneath it.
The remotely operated Icefin underwater vehicle showed that the walls of smooth, cloudy meteoric ice suddenly turned green and rougher in texture, transitioning to salty marine ice.
Nearly 1,900 feet above, near where the surface of the Ross Ice Shelf meets Kamb Ice Stream, researchers recognised the shift as evidence of “ice pumping” — a process never before directly observed in an ice shelf crevasse, important to its stability.
The study, published in the journal Nature Geoscience, the research is expected to improve models of sea-level rise by providing the first high-resolution views of ice, ocean, and seafloor interactions at contrasting glacier systems on the West Antarctic Ice Sheet.
Thwaites, which is exposed to warm ocean currents, is one of the continent’s most unstable glaciers. Kamb Ice Stream, where the ocean is very cold, has been stagnant since the late 1800s. Kamb currently offsets some of the ice loss from western Antarctica, but if it reactivates could increase the region’s contribution to sea-level rise by 12 per cent.
The team observed diverse ice features that provide valuable information about water mixing and melt rates. They included golf ball-like dimples, ripples, vertical runnels, and the “weirder” formations near the top of the crevasse — globs of ice and finger-like protrusions resembling brinicles.
Ice pumping observed in the crevasse likely contributes to the relative stability of the Ross Ice Shelf — the world’s largest by area, the size of France — compared to Thwaites Glacier, the researchers said. Read more here
New data proves planetary defence possible
Fresh data on NASA’s Double Asteroid Redirection Test (DART) mission shows that Earth’s first planetary defence test was successful, and building such technology is viable.
Last year, NASA’s DART mission tried to find out whether a “kinetic impactor” could smash a 600kg spacecraft the size of a fridge into an asteroid the size of an Aussie Rules football field.
Early results from this first real-world test of our potential planetary defense systems looked promising. However, now the first scientific results are being published – five papers in the journal Nature have recreated the impact, and analysed how it changed the asteroid’s momentum and orbit, while two studies investigate the debris knocked off by the impact.
The conclusion — “Kinetic impactor technology is a viable technique to potentially defend Earth if necessary”.
Our solar system is full of debris, left over from the early days of planet formation. Today, some 31,360 asteroids are known to loiter around Earth’s neighborhood.
Although most of the big, kilometer-sized ones that could wipe out humanity if they hit Earth, are being monitored, the smaller ones go undetected.
Just over ten years ago, an 18-meter asteroid exploded in our atmosphere over Chelyabinsk, Russia. The shockwave smashed thousands of windows, wreaking havoc and injuring some 1,500 people.
A 150-meter asteroid like Dimorphos — a natural satellite or moon of the near-Earth asteroid 65803 Didymos — wouldn’t wipe out civilisation, but it could cause mass casualties and regional devastation.
The DART mission was set out to determine if hitting an asteroid with enough force could throw it off its course. Read more here
(Edited by Uttara Ramaswamy)
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