Scientists conclude comets are unlikely to have delivered the building blocks of life to Earth
New models of ancient impacts suggest comets would have destroyed prebiotic molecules rather than delivering them to our planet.
A study led by Richard Anslow of the University of Cambridge challenges the idea that cometary impacts played an important role in the origins of life on Earth. The research team ran more than 100,000 advanced simulations of these impacts.
The results indicate that key prebiotic molecules found in comets, such as hydrogen cyanide, would be smashed during collisions with Earth’s ancient surface in most cases. While Earth was pummeled by these objects during its youth, this bombardment does not neatly align with the timeline of abiogenesis, the term for the origin of life.
“The most probable timing of successful cometary impact is in the early Hadean…more than 100 [million years] earlier than the estimated emergence of the last universal common ancestor (LUCA) at 4.2 [billion years ago],” said researchers led by Richard Anslow of the University of Cambridge.
“Taken together, the rapid decline in Earth’s cometary impact bombardment and the efficient destruction of fragile cometary organics indicate that the successful delivery of prebiotic feedstock molecules was an exceedingly rare event,” the team added.
The researchers did not rule out the possibility altogether, but concluded that any impact that had a direct influence on abiogenesis would be an edge case. Comets might serve as prebiotic wellsprings on other planets, such as Mars, where key molecules might have faced better odds of survival upon impact due to the red planet’s smaller mass and thin atmosphere.
“Mars would have been the more favourable target for the cometary delivery of prebiotic feedstock molecules” which “strengthens the possibility that life could have emerged on Mars,” the study concluded.
Sea ice on alien worlds could concentrate nutrients for life
Scientists suggest prebiotic molecules might build up in sea ice on a variety of extraterrestrial ocean worlds, providing a pathway to the emergence of aliens.
“Water worlds with potential deep oceans are at the forefront of currently observable exoplanetary habitability,” said researchers led by Edouard Barrier of the University of Cambridge. “Here we outline a location where nutrients could be concentrated in sufficiently high quantities to make abiogenesis possible—at the interface between the open ocean and the surface ice shelf.”
Concept art of a Hycean planet. Image: Pablo Carlos Budassi
The team studied the dynamics of sea ice on Earth, and modelled how similar features might form on a range of different exoplanets, including hypothetical “Hycean” planets. These are worlds more massive than Earth, but smaller than Neptune, making them part of the “sub-Neptune” class of exoplanets.
The results revealed mechanisms that “may plausibly provide concentrated chemical feedstock for prebiotic chemistry” on many of these exoplanets, suggesting they could be a substrate for the emergence of alien life. This “rich avenue of research…has the potential to significantly advance our understanding of aquaplanet habitability, and particularly to improve the prospects of abiogenesis on sub-Neptunes,” the team concluded.
Researchers analyse medieval mummy wine for historical and chemical clues
Approximately 700 years ago, someone had the idea of grinding up parts of Egyptian mummies, mixing the residue with wine or other liquids, and prescribing it as a medicinal elixir for people to drink.
This resulting product, known as Mumia vera aegyptiaca, circulated in Arabic and European markets for centuries, but its exact composition and pharmacology remain unclear.
Two historic apothecary vessels of Mumia vera from Hamburg Museum (left) and Deutsches Apothekenmuseum Heidelberg, Germany (right). Images: Christoph Braun and Bullenwächter
Researchers analysed historical Mumia vera products, mummified body parts, embalming residues, bandages, and two mummified skulls. The team discovered a wide range of formulas for this medicine, including one powdered product that appears to have been derived from a mummified head.
The results demonstrate that “an apparently uninformative powdered material can be chemically linked to a specific mummified head,” said researchers co-led by Tim Berger and Amira Naimi of Marburg University. “This study shows that linking historical texts, material culture, molecular composition, and bioactivity, can open new routes for decoding historical medicines and reconstructing the material biographies of human remains and museum objects.”
Study finds gender differences in how people remember hugs
Scientists analysed survey responses from 15,049 adult participants in the United Kingdom who were recruited in a public broadcasting campaign that included the BBC.
The volunteers reported that their most memorable hugs were “for comfort, support, and understanding” and there was a noticeable gender split, as men were more likely to remember hugs that were “arousing” than women.
“Regarding hugs, men have shown different lateralisation and arm crossing patterns when hugging other men compared to women,” said researchers led by Anna Lena Dueren of the University of Bristol. “Furthermore, women were found to experience a stress buffering effect of hugs that was absent in men.”
And for anyone who considers themselves not a “hugger,” you are not alone. Plenty of participants expressed that they found hugs difficult or unpleasant. So whether you love bear hugs or cannot bear hugs, this study has something for you.
