800ky old human proteome unlocked

https://www.nature.com/articles/s41586-020-2153-8

The dental proteome of the 800k year old archaic human Homo antecessor has been decoded using fancy new methods of extracting ancient biomolecules from their hosts.

If you’re not aware, Homo antecessor was a variant of Homo erectus that inhabited Europe for a time span of ultimately 400ky from 1.2 Ma to 800kya, but were ultimately a dead end in terms of evolution. It was thought they may have been the progenitor species of archaic hominin from which modern humans, Neanderthals, Homo heidelbergensis, and Denisovans arose, but it turns out they were a sister taxon not directly ancestral to any of the populations I listed above.

However, it is known that when the ancestors of the Neanderthals and Denisovans (the so-called “Neandersovans”) left Africa, they intermixed with a so-called “super-archaic” that were the remnants of an extremely early human migration out of Africa, some 1.9 Ma.

Make of that what you will.

Late Heavy Bombardment put under the microscope

https://www.nature.com/articles/d41586-018-01074-6

The article goes over the case against the cataclysm scenario, and it turns out the case isn’t as rock-solid (sorry, had to put a pun in here somehow) as previously thought. It turns out that what we previously thought was evidence for the Late Heavy Bombardment was actually a sampling error, as the article attests to in the quote below:

Yet just when the idea of the LHB finally seemed unimpeachable, holes began to appear. Apollo data and ‘crater counting’, which estimates the order in which craters were laid down on the basis of how they overlap, had indicated that three of the largest crater basins on the Moon’s near side — Imbrium, Nectaris and Serenitatis — might all be about 3.95 billion years old (see ‘Sampling the Moon’). But high-resolution maps from NASA’s Lunar Reconnaissance Orbiter, which started circling the Moon in 2009, spotted rays of debris extending from Imbrium5. This suggested that the impact that formed the crater might have knocked rocks into nearby Serenitatis, contaminating the Apollo samples picked up there. In 2010, a reanalysis of rocks thought to have been ejected from Nectaris indicated that they were also chemically and geologically similar to Imbrium material6. “We started realizing that maybe we were sampling Imbrium over and over,” says Zellner.

The article goes on further, saying that “we find no evidence of a large spike in impacts occurring around the 3.9 billion year mark” (slight paraphrasing). It also mentions the existence of crystals dated to 4.1 Ga that “demonstrate the existence of relatively calm pools of liquid water,” which would’ve been supposedly evaporated from the surface of the Earth from that period of if the LHB hypothesis is correct.

The article concludes by saying that at the most the evidence indicates a “more prolonged period of bombardment, as opposed to the sudden spike in impact events as predicted by the cataclysm hypothesis.” Others are skeptical of even that, instead believing that there was one single rapid spike that occurred very shortly after the solar system formed, whereas others believe there was no spike nor period of bombardment at all.

Sulfur played vital role in the development of life on earth

https://www.astrobio.net/origins/how-sulfur-helped-make-earth-habitable-before-the-rise-of-oxygen/

Sulfur played a vital role in the history of life on earth a new study says, and the fact that sulfur was abundant in the early earth, meaning plenty of material for microbes to metabolize to serve as fuel for photosynthesis, means that the abundance of sulfur in the early earth played a vital role in the oxygenation of the earth’s atmosphere.

However, because sulfur quickly degrades in an oxidized environment, the sulfur chemistry of early life on earth was “quickly lost to time,” as the article says.

Because sulfur is quickly oxidized in an oxygen-rich environment, and then removed from the atmosphere by precipitation and run-off into the ocean, the sulfur chemistry of early Archean life was phased out and lost to time. However, by understanding the mass independent fractionation process, it should be possible to learn more about the atmosphere of the pre-oxygenated Earth and the conditions in which the first life on Earth lived.

The process behind the mass independent fractionation of sulfur remains uncertain, but the two most popular hypotheses are either photolysis (the breaking apart of molecules) by ultraviolet light from the Sun, or reactions between elemental sulfur. “However, the actual phenomenon, reaction or mechanism is still to be identified,” says Dmitri Babikov, a Professor of Physical Chemistry and Molecular Physics at Marquette University in Milwaukee, Wisconsin.

The article says that sulfur isotopes could serve as potential indicators of environments similar to that of the early earth’s, but that today’s technology is too limited to be of any help in identifying such indicators in potential exoplanets. Let’s hope the Jim Webb telescope is launched soon, for much is yet to be learned about the universe at large.

New species of “cat-fox” discovered in Sardinia

Apparently a new species of felid has been discovered in Sardinia recently, called the “cat-fox” by locals because of its size and tail, it was known to exist for many years but only recently has it been identified by scientists, it’s very reclusive by nature, being nocturnal and possessing an extremely small population of only 10-16 individuals. Sardinian folklore tells tales of this “cat-fox” sneaking into pastures at night and attacking the udders of ewes and goats. Efforts are underway to protect this mysterious new species of cat, er, “cat-fox.”

Remembering Carl Sagan

If only Sagan were around today to learn of the fascinating insights we have discovered since his untimely death. Since his death we have discovered more than 4,000 exoplanets, we have discovered numerous candidates for harboring extraterrestrial life in our solar system alone (*cough* Europa *cough*), coinciding with that we have discovered that numerous minor planetary bodies have oceans of liquid water inside them, with some (*cough* Europa *cough*) even possessing the right chemical mix for complex life to occur on them, not merely simple life, but complex life, I`d be willing to bet that there are fully fledged animals inside Europa’s oceans.

Sagan would be amazed by what we have discovered since his death. He would be 83 years old today. The work he had done in popularizing science to the masses remains uncontested, he inspired millions of future scientists with his works, he was truly a gift from the gods. Rest in peace, Carl, you have earned it.

Population III stars and solar systems

On Usenet recently someone brought up the possibility of solar systems forming around Pop III stars even though, being huge, they would’ve lived only a few million years. Giant stars have short lifespans of only a few million years, a few tens of millions of years at most, and I am incredulous that any substantial planetary system could develop around stars with such short lifespans.

Pop III stars were the first stars in the universe, none are around today, and thus they’ve never been directly observed because they are so old. (They’ve been indirectly observed tho, including by means such as detecting supermassive black holes.) One is better off looking for solar systems around main sequence and dwarf stars, especially if one is looking for ones with life in them.

Said poster also brought up that only gas giants could’ve presumably been found orbiting Pop III stars, but I would like to point out that the cores of gas giants are still metallic, and so would’ve required heavy elements for the gas to accrete to, which would’ve existed long after the Pop III stars went supernova, since they would’ve lacked the heavier elements in their makeup necessary for even gas giants to form.

Evidence for complex projectiles in Middle Paleolithic Ethiopia

https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0216716

Abstract: Complex projectiles—propulsion via mechanical aid—are considered an important technological innovation, with possible relevance for the successful Out-of-Africa dispersal of our species. Conclusive evidence for the beginning of this technology, however, is lacking from the early Late Pleistocene (ca. 130 to 70 thousand years ago; ka). Given the extremely limited applicability of relatively robust methods for validating stone-tipped projectile use, such as through fracture propagation velocity, converging lines of circumstantial evidence remain the best way to examine early complex projectiles. We assess here suggestions for an early Late Pleistocene origin of complex projectiles in Africa. Results from both previous and present independent approaches suggest a trajectory in which complex projectiles were likely adopted during the early Late Pleistocene in eastern Africa. At Aduma (Middle Awash, Ethiopia), morphometric, hafting, and impact damage patterns in several lithic point assemblages suggest a shift from simple spear technologies (thrusting and/or hand-cast) to complex projectiles. Broadly dated to 80–100 ka, lithic points from later phases of the Aduma succession represent a particularly strong candidate for projectile armatures most comparable to ethnographically known spearthrower darts, lending support for previous suggestions and warranting further investigations.
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Notes: This is interesting, very interesting, because it pushes back the date of the invention of the atlatl back to the Middle Paleolithic, long before modern humans spread out of Africa, and also long before the earliest evidence for the atlatl in the archaeological record, which AFAIK is from Aurignacian Europe, it’s also telling because Native Americans lacked the atlatl until the advent of the Archaic period, so either the ancestors of the Native Americans lost the atlatl sometime prior to the peopling of the Americas or the atlatl wasn’t as common as previously believed. The Tasmanians also lacked the spearthrower or atlatl, despite ultimately coming from the same population that left Africa as the rest of us did, while the Australians *did* possess the spearthrower, called the *woomera* there, although it was of recent (Holocene) derivation.