Did the seeds of life come from above or below?<\/p>\n
Anslow, Richard J. et al. \u201cCometary impacts are an unlikely pathway towards the origins of life on Earth.\u201d Scientific Reports.\u00a0<\/a><\/p>\n Carl Sagan eloquently said that we are all made of \u201cstar stuff,\u201d but just how much of us is really comet vomit? This is a hotly debated question in science due to the popular theory that comets delivered essential ingredients for life to Earth during impacts more than four billion years ago, paving the way for the curious emergence of Earthlings.<\/p>\n But scientists have thrown cold primordial water on this idea in a new study that challenges \u201cthe long-held assumption that cometary impacts played an important role in the origins of life on Earth.\u201d By running more than 100,000 advanced simulations of comet impacts, the team found that key prebiotic molecules found in comets, such as hydrogen cyanide, would be smashed to smithereens during impacts with Earth\u2019s ancient surface in most cases.\u00a0<\/p>\n Moreover, while Earth was pummeled by these snowballs during its youth\u2014relatable!\u2014this bombardment doesn\u2019t neatly line up with the timeline of abiogenesis, the term of the origin of life. For these reasons, it\u2019s much more likely that life assembled from earthly molecules that leaked out from our planet\u2019s interior, according to the study.\u00a0<\/p>\n \u201cThe most probable timing of successful cometary impact is in the early Hadean\u2026more than 100 [million years] earlier than the estimated emergence of the last universal common ancestor (LUCA) at\u00a0 4.2 [billion years ago],\u201d said researchers led by Richard Anslow of the University of Cambridge.<\/p>\n \u201cTaken together, the rapid decline in Earth\u2019s 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,\u201d the team added.\u00a0<\/p>\n The researchers didn\u2019t rule out the possibility altogether, but concluded that any impact that had a direct influence on abiogenesis would be an edge case. That said, 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.<\/p>\n \u201cMars would have been the more favourable target for the cometary delivery of prebiotic feedstock molecules\u201d which \u201cstrengthens the possibility that life could have emerged on Mars,\u201d the study concluded.\u00a0<\/p>\n In other news\u2026<\/p>\n The tip of an alien iceberg<\/p>\n Barrier, Edouard et al \u201cSea Ice as an Origin of Life Location for Hycean and Ocean Worlds.\u201d Monthly Notices of the Royal Astronomical Society.<\/a><\/p>\n While we\u2019re on the topic of prebiotic feedstock molecules\u2014a household conversation, no doubt\u2014let\u2019s speculate about their accumulation on weird exoplanets. In a new study, scientists suggest that these molecules might build up in sea ice on a variety of extraterrestrial ocean worlds, providing a pathway to the emergence of aliens.\u00a0<\/p>\n \u201cWater worlds with potential deep oceans are at the forefront of currently observable exoplanetary habitability,\u201d said researchers led by Edouard Barrier of the University of Cambridge. \u201cHere we outline a location where nutrients could be concentrated in sufficiently high quantities to make abiogenesis possible\u2014at the interface between the open ocean and the surface ice shelf.\u201d\u00a0<\/p>\n 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 \u201cHycean\u201d planets. These are worlds more massive than Earth, but smaller than Neptune, making them part of the \u201csub-Neptune\u201d class of exoplanets.\u00a0<\/p>\n The results revealed mechanisms that \u201cmay plausibly provide concentrated chemical feedstock for prebiotic chemistry\u201d on many of these exoplanets, suggesting they could be a substrate for the emergence of alien life. This \u201crich avenue of research\u2026has the potential to significantly advance our understanding of aquaplanet habitability, and particularly to improve the prospects of abiogenesis on sub-Neptunes,\u201d the team concluded.\u00a0<\/p>\n What a week for the prebiotic feedstock beat! Taken together, these studies point to multiple onramps for life on worlds like Earth, Mars, exotic sub-Neptunes, and more, upping odds that life exists elsewhere in the universe\u2014regardless of whether we ever find it.\u00a0<\/p>\n Drink the mummy wine<\/p>\n Berger, Tim, and Naimi, Amira et al.\u201cNew molecular and historical evidence on ancient Egyptian embalming.\u201d Proceedings of the National Academy of Sciences.<\/a><\/p>\n To celebrate Halloween, here\u2019s a trick and a treat all wrapped up in one delightfully grotesque story about mummies. Roughly 700 years ago, someone had the interesting 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.\u00a0\u00a0<\/p>\n This resulting product, known as Mumia vera aegyptiaca, circulated in Arabic and European markets for centuries, but its exact composition and pharmacology remain unclear. You know what that means: It\u2019s time to do science on the medieval mummy cocktails.\u00a0<\/p>\n Researchers analyzed 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.\u00a0<\/p>\n The results demonstrate that \u201can apparently uninformative powdered material can be chemically linked to a specific mummified head,\u201d said researchers co-led by Tim Berger and Amira Naimi of Marburg University. \u201cThis 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.\u201d<\/p>\n So if you are really committed to the spirit of this season, break out some Mumia vera aegyptiaca to pair with your Halloween candy and witches\u2019 brew. Bottoms up\u2014or more accurately: mummified-heads up.\u00a0<\/p>\n Advances in hug science\u00a0<\/p>\nConcept art of a Hycean planet. Image: Pablo Carlos Budassi<\/a><\/p>\n
Two historic apothecary vessels of Mumia vera from Hamburg Museum (left) and Deutsches Apothekenmuseum Heidelberg, Germany (right). Images: Christoph Braun<\/a> and Bullenw\u00e4chter<\/a><\/p>\n