The embryo, dubbed ‘Baby Yingliang’, was discovered in the Late Cretaceous rocks of Ganzhou, southern China and belongs to a toothless theropod dinosaur, or oviraptorosaur. Among the most complete dinosaur embryos ever found, the fossil suggests that these dinosaurs developed bird-like postures close to hatching.

Scientists found the posture of ‘Baby Yingliang’ unique among known dinosaur embryos — its head lies below the body, with the feet on either side and the back curled along the blunt end of the egg. Previously unrecognised in dinosaurs, this posture is similar to that of modern bird embryos.

In modern birds, such postures are related to ‘tucking’ — a behaviour controlled by the central nervous system and critical for hatching success. After studying egg and embryo, researchers believe that such pre-hatching behaviour, previously considered unique to birds, may have originated among non-avian theropods.

Led by scientists from the University of Birmingham and China University of Geosciences (Beijing), the research team from institutions in China, UK and Canada today published its findings in iScience.

The embryo is articulated in its life position without much disruption from fossilisation. Estimated to be 27 cm long from head to tail, the creature lies inside a 17-cm-long elongatoolithid egg. The specimen is housed in Yingliang Stone Nature History Museum.

Fion Waisum Ma, joint first author and PhD researcher at the University of Birmingham, said: “Dinosaur embryos are some of the rarest fossils and most of them are incomplete with the bones dislocated. We are very excited about the discovery of ‘Baby Yingliang’ — it is preserved in a great condition and helps us answer a lot of questions about dinosaur growth and reproduction with it.

“It is interesting to see this dinosaur embryo and a chicken embryo pose in a similar way inside the egg, which possibly indicates similar prehatching behaviours.”

‘Baby Yingliang’ was identified as an oviraptorosaur based on its deep, toothless skull. Oviraptorosaurs are a group of feathered theropod dinosaurs, closely related to modern-day birds, known from the Cretaceous of Asia and North America. Their variable beak shapes and body sizes are likely to have allowed them to adopt a wide range of diets, including herbivory, omnivory and carnivory.

Birds are known to develop a series of tucking postures, in which they bend their body and bring their head under their wing, soon before hatching. Embryos that fail to attain such postures have a higher chance of death due to unsuccessful hatching.

By comparing ‘Baby Yingliang’ with the embryos of other theropods, long-necked sauropod dinosaurs and birds, the team proposed that tucking behaviour, which was considered unique to birds, first evolved in theropod dinosaurs many tens or hundreds of millions of years ago. Additional discoveries of embryo fossils would be invaluable to further test this hypothesis.

Professor Lida Xing from China University of Geosciences (Beijing), joint first author of the study, said: “This dinosaur embryo was acquired by the director of Yingliang Group, Mr Liang Liu, as suspected egg fossils around the 2000. During the construction of Yingliang Stone Nature History Museum in 2010s, museum staff sorted through the storage and discovered the specimens.

“These specimens were identified as dinosaur egg fossils. Fossil preparation was conducted and eventually unveiled the embryo hidden inside the egg. This is how ‘Baby Yingliang’ was brought to light.”

Professor Steve Brusatte from the University of Edinburgh, part of the research team, said: “This dinosaur embryo inside its egg is one of the most beautiful fossils I have ever seen. This little prenatal dinosaur looks just like a baby bird curled in its egg, which is yet more evidence that many features characteristic of today’s birds first evolved in their dinosaur ancestors.”

Because they lack an atmosphere, the moon and other airless bodies such as asteroids can build up an electric field through direct exposure to the sun and surrounding plasma. On the moon, this surface charge is strong enough to levitate dust more than 1 meter above the ground, much the way static electricity can cause a person’s hair to stand on end.

Engineers at NASA and elsewhere have recently proposed harnessing this natural surface charge to levitate a glider with wings made of Mylar, a material that naturally holds the same charge as surfaces on airless bodies. They reasoned that the similarly charged surfaces should repel each other, with a force that lofts the glider off the ground. But such a design would likely be limited to small asteroids, as larger planetary bodies would have a stronger, counteracting gravitational pull.

The MIT team’s levitating rover could potentially get around this size limitation. The concept, which resembles a retro-style, disc-shaped flying saucer, uses tiny ion beams to both charge up the vehicle and boost the surface’s natural charge. The overall effect is designed to generate a relatively large repulsive force between the vehicle and the ground, in a way that requires very little power. In an initial feasibility study, the researchers show that such an ion boost should be strong enough to levitate a small, 2-pound vehicle on the moon and large asteroids like Psyche.

“We think of using this like the Hayabusa missions that were launched by the Japanese space agency,” says lead author Oliver Jia-Richards, a graduate student in MIT’s Department of Aeronautics and Astronautics. “That spacecraft operated around a small asteroid and deployed small rovers to its surface. Similarly, we think a future mission could send out small hovering rovers to explore the surface of the moon and other asteroids.”

The team’s results appear in the current issue of the Journal of Spacecraft and Rockets. Jia-Richards’ co-authors are Paulo Lozano, the M. Alemán-Velasco Professor of Aeronautics and Astronautics and director of MIT’s Space Propulsion Lab; and former visiting student Sebastian Hampl, now at McGill University.

Ionic force

The team’s levitating design relies on the use of miniature ion thrusters, called ionic-liquid ion sources. These small, microfabricated nozzles are connected to a reservoir containing ionic liquid in the form of room-temperature molten salt. When a voltage is applied, the liquid’s ions are charged and emitted as a beam through the nozzles with a certain force.

Lozano’s team has pioneered the development of ionic thrusters and has used them mainly to propel and physically maneuver small satellites in space. Recently, Lozano had seen research showing the levitating effect of the moon’s charged surface on lunar dust. He also considered the electrostatic glider design by NASA and wondered: Could a rover fitted with ion thrusters produce enough repulsive, electrostatic force to hover on the moon and larger asteroids?

To test the idea, the team initially modeled a small, disk-shaped rover with ion thrusters that charged up the vehicle alone. They modeled the thrusters to beam negatively charged ions out from the vehicle, which effectively gave the vehicle a positive charge, similar to the moon’s positively charged surface. But they found this was not enough to get the vehicle off the ground.

“Then we thought, what if we transfer our own charge to the surface to supplement its natural charge?” Jia-Richards says.

By pointing additional thrusters at the ground and beaming out positive ions to amplify the surface’s charge, the team reasoned that the boost could produce a bigger force against the rover, enough to levitate it off the ground. They drew up a simple mathematical model for the scenario and found that, in principle, it could work.

Based on this simple model, the team predicted that a small rover, weighing about two pounds, could achieve levitation of about one centimeter off the ground, on a large asteroid such as Psyche, using a 10-kilovolt ion source. To get a similar liftoff on the moon, the same rover would need a 50-kilovolt source.

“This kind of ionic design uses very little power to generate a lot of voltage,” Lozano explains. “The power needed is so small, you could do this almost for free.”

In suspension

To be sure the model represented what could happen in a real environment in space, they ran a simple scenario in Lozano’s lab. The researchers manufactured a small hexagonal test vehicle weighing about 60 grams and measuring about the size of a person’s palm. They installed one ion thruster pointing up, and four pointing down, and then suspended the vehicle over an aluminum surface from two springs calibrated to counteract Earth’s gravitational force. The entire setup was placed within a vacuum chamber to simulate the airless environment of the moon and asteroids.

The researchers also suspended a tungsten rod from the experiment’s springs, and used its displacement to measure how much force the thrusters produced each time they were fired. They applied various voltages to the thrusters and measured the resulting forces, which they then used to calculate the height the vehicle alone could have levitated. They found these experimental results matched with predictions of the same scenario from their model, giving them confidence that its predictions for hovering a rover on Psyche and the moon were realistic.

The current model is designed to predict the conditions required to simply achieve levitation, which happened to be about 1 centimeter off the ground for a 2-pound vehicle. The ion thrusters could generate more force with larger voltage to lift a vehicle higher off the ground. But Jia-Richards says the model would need revising, as it doesn’t account for how the emitted ions would behave at higher altitudes.

“In principle, with better modeling, we could levitate to much higher heights,” he says.

In that case, Lozano says future missions to the moon and asteroids could deploy rovers that use ion thrusters to safely hover and maneuver over unknown, uneven terrain.

“With a levitating rover, you don’t have to worry about wheels or moving parts,” Lozano says. “An asteroid’s terrain could be totally uneven, and as long as you had a controlled mechanism to keep your rover floating, then you could go over very rough, unexplored terrain, without having to dodge the asteroid physically.”

This research was supported, in part, by NASA.

The fossil — the remains of a creature called Arthropleura — dates from the Carboniferous Period, about 326 million years ago, over 100 million years before the Age of Dinosaurs. The fossil reveals that Arthropleura was the largest-known invertebrate animal of all time, larger than the ancient sea scorpions that were the previous record holders.

The specimen, found on a Northumberland beach about 40 miles north of Newcastle, is made up of multiple articulated exoskeleton segments, broadly similar in form to modern millipedes. It is just the third such fossil ever found. It is also the oldest and largest: the segment is about 75 centimetres long, while the original creature is estimated to have measured around 2.7 metres long and weighed around 50 kilograms. The results are reported in the Journal of the Geological Society.

The fossil was discovered in January 2018 in a large block of sandstone that had fallen from a cliff to the beach at Howick Bay in Northumberland. “It was a complete fluke of a discovery,” said Dr Neil Davies from Cambridge’s Department of Earth Sciences, the paper’s lead author. “The way the boulder had fallen, it had cracked open and perfectly exposed the fossil, which one of our former PhD students happened to spot when walking by.”

Unlike the cool and wet weather associated with the region today, Northumberland had a more tropical climate in the Carboniferous Period, when Great Britain lay near the Equator. Invertebrates and early amphibians lived off the scattered vegetation around a series of creeks and rivers. The specimen identified by the researchers was found in a fossilised river channel: it was likely a moulted segment of the Arthropleura’s exoskeleton that filled with sand, preserving it for hundreds of millions of years.

The fossil was extracted in May 2018 with permission from Natural England and the landowners, the Howick Estate. “It was an incredibly exciting find, but the fossil is so large it took four of us to carry it up the cliff face,” said Davies.

The fossil was brought back to Cambridge so that it could be examined in detail. It was compared with all previous records and revealed new information about the animal’s habitat and evolution. The animal can be seen to have only existed in places that were once located at the Equator, such as Great Britain during the Carboniferous. Previous reconstructions have suggested that the animal lived in coal swamps, but this specimen showed Arthropleura preferred open woodland habitats near the coast.

There are only two other known Arthropleura fossils, both from Germany, and both much smaller than the new specimen. Although this is the largest Arthropleura fossil skeleton ever found, there is still much to learn about these creatures. “Finding these giant millipede fossils is rare, because once they died, their bodies tend to disarticulate, so it’s likely that the fossil is a moulted carapace that the animal shed as it grew,” said Davies. “We have not yet found a fossilised head, so it’s difficult to know everything about them.”

The great size of Arthropleura has previously been attributed to a peak in atmospheric oxygen during the late Carboniferous and Permian periods, but because the new fossil comes from rocks deposited before this peak, it shows that oxygen cannot be the only explanation.

The researchers believe that to get to such a large size, Arthropleura must have had a high-nutrient diet. “While we can’t know for sure what they ate, there were plenty of nutritious nuts and seeds available in the leaf litter at the time, and they may even have been predators that fed off other invertebrates and even small vertebrates such as amphibians,” said Davies.

Arthropleura animals crawled around Earth’s equatorial region for around 45 million years, before going extinct during the Permian period. The cause of their extinction is uncertain, but could be due to global warming that made the climate too dry for them to survive, or to the rise of reptiles, who out-competed them for food and soon dominated the same habitats.

The fossil will go on public display at Cambridge’s Sedgwick Museum in the New Year.

Neil Davies is a Fellow of Churchill College, Cambridge. The research was supported in part by the Natural Environment Research Council.

Story Source:

Materials provided by University of Cambridge. Original written by Sarah Collins. The original text of this story is licensed under a Creative Commons License. Note: Content may be edited for style and length.

These snowballs — or as we know them, comets — go through a colourful metamorphosis as they cross the sky, with many comets’ heads turning a radiant green colour that gets brighter as they approach the Sun.

But strangely, this green shade disappears before it reaches the one or two tails trailing behind the comet.

Astronomers, scientists and chemists have been puzzled by this mystery for almost a century. In the 1930s, physicist Gerhard Herzberg theorised the phenomenon was due to sunlight destroying diatomic carbon (also known as dicarbon or C₂), a chemical created from the interaction between sunlight and organic matter on the comet’s head — but as dicarbon isn’t stable, this theory has been hard to test.

A new UNSW Sydney-led study, published today in Proceedings of the National Academy of Sciences (PNAS), has finally found a way to test this chemical reaction in a laboratory — and in doing so, has proven this 90-year-old theory correct.

“We’ve proven the mechanism by which dicarbon is broken up by sunlight,” says Timothy Schmidt, a chemistry professor at UNSW Science and senior author of the study.

“This explains why the green coma — the fuzzy layer of gas and dust surrounding the nucleus — shrinks as a comet gets closer to the Sun, and also why the tail of the comet isn’t green.”

The key player at the centre of the mystery, dicarbon, is both highly reactive and responsible for giving many comets their green colour. It’s made up of two carbon atoms stuck together and can only be found in extremely energetic or low oxygen environments like stars, comets and the interstellar medium.

Dicarbon doesn’t exist on comets until they get close to the Sun. As the Sun starts to warm the comet up, the organic matter living on the icy nucleus evaporates and moves to the coma. Sunlight then breaks up these larger organic molecules, creating dicarbon.

The UNSW-led team have now shown that as the comet gets even closer to the Sun, the extreme UV radiation breaks apart the dicarbon molecules it recently created in a process called ‘photodissociation’. This process destroys the dicarbon before it can move far from the nucleus, causing the green coma to get brighter and shrink — and making sure the green tinge never makes it into the tail.

This is the first time this chemical interaction has been studied here on Earth.

“I find incredible that someone in the 1930s thought this is probably what’s happening, down to the level of detail of the mechanism of how it was happening, and then 90 years later, we find out it is what’s happening,” says Ms Jasmin Borsovszky, lead author of the study and former UNSW Science Honours student.

“Herzberg was an incredible physicist and went on to win a Nobel Prize for Chemistry in the 1970s. It’s pretty exciting to be able to prove one of the things that he theorised.”

Prof. Schmidt, who has been studying dicarbon for 15 years, says the findings help us better understand both dicarbon and comets.

“Dicarbon comes from the breakup of larger organic molecules frozen into the nucleus of the comet — the sort of molecules that are the ingredients of life,” he says.

“By understanding its lifetime and destruction, we can better understand how much organic material is evaporating off comets. Discoveries like these might one day help us solve other space mysteries.”

A laser show like no other

To solve this puzzle, the team needed to recreate the same galactic chemical process in a controlled environment on Earth.

They pulled this off with the help of a vacuum chamber, a lot of lasers, and one powerful cosmic reaction.

“First we had to make this molecule which is too reactive to store in a bottle,” says Prof. Schmidt. “It’s not something we could buy from the shops.

“We did this by taking a larger molecule, known as perchloroethylene or C₂Cl₄, and blasting off its chlorine atoms (Cl) with a high-powered UV laser.”

The newly-made dicarbon molecules were sent travelling through a gas beam in a vacuum chamber, which was around two metres long.

The team then pointed another two UV lasers towards the dicarbon: one to flood it with radiation, the other to make its atoms detectable. The radiation hit ripped the dicarbon apart, sending its carbon atoms flying onto a speed detector.

By analysing the speed of these quickly-moving atoms, the team could measure the strength of the carbon bond to about one in 20,000 — which is like measuring 200 metres to the nearest centimetre.

Ms Borsovszky says due to the complexity of the experiment it took nine months before they were able to make their first observation.

“We were about to give up,” she says. “It took so long to make sure everything was precisely lined up in space and time.

“The three lasers were all invisible, so there was a lot of stabbing in the dark — quite literally.”

Prof. Schmidt says this is the first time anyone has ever observed this chemical reaction.

“It’s extremely satisfying to have solved a conundrum that dates back to the 1930s.”

Solving space mysteries

There are around 3700 known comets in the solar system, although it’s suspected there could be billions more. On average, a comet’s nucleus is a whopping 10 kilometres wide — but its coma is often 1000 times bigger.

Bright comets can put on spectacular shows for those lucky enough to see them. But in the past, comets might have done more than that for Earth — in fact, one of the theories about the origin of life is that comets once delivered the building blocks of life right to our doorstep.

“This exciting research shows us just how complex processes in interstellar space are,” says Professor Martin van Kranendonk, a UNSW astrobiologist and geologist who was not involved in the study.

“Early Earth would have experienced a jumble of different carbon-bearing molecules being delivered to its surface, allowing for even more complex reactions to occur in the leadup to life.”

Now that the case of the missing green tail in comets is solved, Prof. Schmidt, who specialises in space chemistry, wants to continue solving other space mysteries.

Next, he hopes to investigate diffuse interstellar bands: patterns of dark lines between stars that don’t match any atom or molecule we know of.

“Diffuse interstellar bands are a pretty big unsolved mystery,” he says. “We don’t know why the light that’s arriving on Earth often has nibbles taken out.

“This is just one more mystery in a huge inventory of bizarre things in space that we’re yet to discover.”

And yet, a new study supports the longstanding idea that if life exists, it might make a home in Venus’ clouds. The study’s authors, from MIT, Cardiff University, and Cambridge University, have identified a chemical pathway by which life could neutralize Venus’ acidic environment, creating a self-sustaining, habitable pocket in the clouds.

Within Venus’ atmosphere, scientists have long observed puzzling anomalies — chemical signatures that are hard to explain, such as small concentrations of oxygen and nonspherical particles unlike sulfuric acid’s round droplets. Perhaps most puzzling is the presence of ammonia, a gas that was tentatively detected in the 1970s, and that by all accounts should not be produced through any chemical process known on Venus.

In their new study, the researchers modeled a set of chemical processes to show that if ammonia is indeed present, the gas would set off a cascade of chemical reactions that would neutralize surrounding droplets of sulfuric acid and could also explain most of the anomalies observed in Venus’ clouds. As for the source of ammonia itself, the authors propose that the most plausible explanation is of biological origin, rather than a nonbiological source such as lightning or volcanic eruptions.

As they write in their study, the chemistry suggests that “life could be making its own environment on Venus.”

This tantalizing new hypothesis is testable, and the researchers provide a list of chemical signatures for future missions to measure in Venus’ clouds, to either confirm or contradict their idea.

“No life that we know of could survive in the Venus droplets,” says study co-author Sara Seager, the Class of 1941 Professor of Planetary Sciences in MIT’s Department of Earth, Atmospheric and Planetary Sciences (EAPS). “But the point is, maybe some life is there, and is modifying its environment so that it is livable.”

The study’s co-authors include Janusz Petkowski, William Bains, and Paul Rimmer, who are affiliated with MIT, Cardiff University, and Cambridge University.

Life suspect

“Life on Venus” was a trending phrase last year, when scientists including Seager and her co-authors reported the detection of phosphine in the planet’s clouds. On Earth, phosphine is a gas that is produced mainly through biological interactions. The discovery of phosphine on Venus leaves room for the possibility of life. Since then, however, the discovery has been widely contested.

“The phosphine detection ended up becoming incredibly controversial,” Seager says. “But phosphine was like a gateway, and there’s been this resurgence in people studying Venus.”

Inspired to look more closely, Rimmer began combing through data from past missions to Venus. In these data, he identified anomalies, or chemical signatures, in the clouds that had gone unexplained for decades. In addition to the presence of oxygen and nonspherical particles, anomalies included unexpected levels of water vapor and sulfur dioxide.

Rimmer proposed the anomalies might be explained by dust. He argued that minerals, swept up from Venus’ surface and into the clouds, could interact with sulfuric acid to produce some, though not all, of the observed anomalies. He showed the chemistry checked out, but the physical requirements were unfeasible: A massive amount of dust would have to loft into the clouds to produce the observed anomalies.

Seager and her colleagues wondered if the anomalies could be explained by ammonia. In the 1970s, the gas was tentatively detected in the planet’s clouds by the Venera 8 and Pioneer Venus probes. The presence of ammonia, or NH_3, was an unsolved mystery.

“Ammonia shouldn’t be on Venus,” Seager says. “It has hydrogen attached to it, and there’s very little hydrogen around. Any gas that doesn’t belong in the context of its environment is automatically suspicious for being made by life.”

Livable clouds

If the team were to assume that life was the source of ammonia, could this explain the other anomalies in Venus’ clouds? The researchers modeled a series of chemical processes in search of an answer.

They found that if life were producing ammonia in the most efficient way possible, the associated chemical reactions would naturally yield oxygen. Once present in the clouds, ammonia would dissolve in droplets of sulfuric acid, effectively neutralizing the acid to make the droplets relatively habitable. The introduction of ammonia into the droplets would transform their formerly round, liquid shape into more of a nonspherical, salt-like slurry. Once ammonia dissolved in sulfuric acid, the reaction would trigger any surrounding sulfur dioxide to dissolve as well.

The presence of ammonia then could indeed explain most of the major anomalies seen in Venus’ clouds. The researchers also show that sources such as lightning, volcanic eruptions, and even a meteorite strike could not chemically produce the amount of ammonia required to explain the anomalies. Life, however, might.

In fact, the team notes that there are life-forms on Earth — particuarly in our own stomachs — that produce ammonia to neutralize and make livable an otherwise highly acidic environment.

“There are very acidic environments on Earth where life does live, but it’s nothing like the environment on Venus — unless life is neutralizing some of those droplets,” Seager says.

Scientists may have a chance to check for the presence of ammonia, and signs of life, in the next several years with the Venus Life Finder Missions, a set of proposed privately funded missions, of which Seager is principal investigator, that plan to send spacecraft to Venus to measure its clouds for ammonia and other signatures of life.

“Venus has lingering, unexplained atmospheric anomalies that are incredible,” Seager says. “It leaves room for the possibility of life.”

This research was supported in part by the Simons Foundation, the Change Happens Foundation, and the Breakthrough Initiatives.