Neanderthals have long been seen as uber-masculine hunks, at least compared with their lightweight human cousins, with whom they competed for food, territory, and mates. But a new study finds Homo sapiens men essentially emasculated their brawny brethren when they mated with Neanderthal women more than 100,000 years ago. Those unions caused the modern Y chromosomes to sweep through future generations of Neanderthal boys, eventually replacing the Neanderthal Y.

The new finding may solve the decade-old mystery of why researchers have been unable to find a Neanderthal Y chromosome. Part of the problem was the dearth of DNA from men: Of the dozen Neanderthals whose DNA has been sequenced so far, most is from women, as the DNA in male Neanderthal fossils happened to be poorly preserved or contaminated with bacteria. "We began to wonder if there were any male Neanderthals," jokes Janet Kelso, a computational biologist at the Max Planck Institute for Evolutionary Anthropology and senior author of the new study.

Meteorologists track hurricanes over the oceans, forecasting where and when landfall might occur so residents can prepare for disaster before it strikes. What if they could do the same thing for droughts?

Stanford scientists have now shown that may be possible in some instances — the researchers have identified a new kind of "landfalling drought" that can potentially be predicted before it impacts people and ecosystems on land. They found that these droughts, which form over the ocean and then migrate landward, can cause larger and drier conditions than droughts that occur solely over the land. Of all the droughts affecting land areas worldwide from 1981 to 2018, roughly one in six were landfalling droughts, according to the study published Sept. 21 in Water Resources Research.

"We normally don't think about droughts over the ocean — it may even sound counterintuitive. But just as over land, there can be times where large regions in the ocean experience less rainfall than normal," said lead author Julio Herrera-Estrada, a research collaborator with Water in the West who conducted research for the study while he was a postdoctoral researcher at Stanford's School of Earth, Energy & Environmental Sciences (Stanford Earth). "Finding that some droughts start offshore will hopefully motivate conversations about the benefits of monitoring and forecasting droughts beyond the continents."

An asteroid the size of a bus is set to fly past Earth in the coming hours.

The object, known as 2020 SW, will fly just 13,000 miles above the Earth's surface on 24 September, Nasa has said. That is closer than the artificial objects that are in orbit around our planet.

The object was only discovered on 18 September by a Nasa-funded project in Arizona, and further observations were able to track its trajectory and rule out any chance that it might collide with Earth. Those estimates showed that it would make its closest pass around noon UK time on Thursday.

It will then fly off to continue its trip around the solar system. It will not come back anywhere near Earth until 2041, when it will be at an even further distance.

The asteroid is thought to be about five to ten meters wide, roughly the size of a "small school bus", the space agency said. The size is estimated from the brightness of the object.

Toxins in water produced by cyanobacteria killed more than 300 elephants in Botswana this year, officials said on Monday, announcing the result of an investigation into the deaths which had baffled and alarmed conservationists.

Cyanobacteria are microscopic organisms common in water and sometimes found in soil. Not all produce toxins but scientists say toxic ones are occurring more frequently as climate change drives up global temperatures.

Cyril Taolo, deputy director of the Department of Wildlife and National Parks, told a news conference the number of elephant carcasses found since deaths were first reported around early May had risen to 330, from 281 in July.

Physicists from Lancaster University have established why objects moving through superfluid helium-3 lack a speed limit in a continuation of earlier Lancaster research.

Helium-3 is a rare isotope of helium, in which one neutron is missing. It becomes superfluid at extremely low temperatures, enabling unusual properties such as a lack of friction for moving objects.

It was thought that the speed of objects moving through superfluid helium-3 was fundamentally limited to the critical Landau velocity, and that exceeding this speed limit would destroy the superfluid. Prior experiments in Lancaster have found that it is not a strict rule and objects can move at much greater speeds without destroying the fragile superfluid state.

Now scientists from Lancaster University have found the reason for the absence of the speed limit: exotic particles that stick to all surfaces in the superfluid.

The discovery may guide applications in quantum technology, even quantum computing, where multiple research groups already aim to make use of these unusual particles.

Researchers at King's have developed a material that allows transplantation of bone-forming stem cells into severe bone fractures and speeds up the healing process.
This new method improves repair and may change how broken bones are treated.

The study, published today in Nature Materials and supported by the NIHR Guy's and St Thomas' BRC, describes stem cells and mature bone cells grown on a biomaterial, in a structure that simulates parts of the healthy bone. The breakthrough could lead to less complications, infections and poor outcomes for serious injuries.

The biomaterial, like a bandage, is coated in a protein that is used throughout the body for growth and repair. This bandage can be stuck to the fracture like a plaster and enhance the bone's natural ability to heal, which speeds up the repair process. The process can be accelerated even more by growing bone stem cells that generate bone cells in a three-dimensional gel on the bandage and transplanting this bone-like bandage into the fracture.

The breakthrough could make a drastic difference in recovery times for patients with serious bone fractures. The healing process from a serious fracture can be slow or can even fail in vulnerable patients such as the elderly or those with underlying health conditions.

Current methods to repair bone is to use synthetic implants or donor tissue - where bone is taken from elsewhere in the body - to repair the break. This method relies on the body's own capability to heal, which can be weakened after serious injury.

Aurora - the dancing glow of ionised particles in Earth's upper atmosphere - is not unique to our planet.

The phenomenon has been spotted shining in the atmospheres of every other planet except Mercury. Even Jupiter's moons Ganymede and Europa have auroras.

Never, until now, had an aurora been detected on a comet.

But, in a new analysis of data collected by the Rosetta spacecraft, the space around Comet 67P Churyumov-Gerasimenko (67P/C-G) has been observed glowing with far-ultraviolet auroral radiation.

"I've been studying the Earth's auroras for five decades," said physicist Jim Burch of the Southwest Research Institute.

"Finding auroras around 67P, which lacks a magnetic field, is surprising and fascinating."

Auroras are generated by the excitation of charged particles in an atmosphere.

Here on Earth, for instance, the solar wind blows into the magnetosphere and interacts with charged particles there.

These particles rain down into the upper atmosphere and are funneled up the magnetic field lines to the poles, where they manifest as rippling curtains of light.

It works differently on different bodies, though. The auroras of Ganymede and Europa are generated by interactions with Jupiter's magnetic field.

Venus doesn't have a magnetic field of its own that we know of, but interactions with the solar wind creates one strong enough to trigger auroras.

Mars' atmosphere is extremely thin, but its weak magnetic field can support auroras.

I never expected to be writing something like this. I am an ordinary person, recently semi-retired from a career in the pharmaceutical industry and biotech, where I spent over 30 years trying to solve problems of disease understanding and seek new treatments for allergic and inflammatory disorders of lung and skin. I've always been interested in problem solving, so when anything biological comes along, my attention is drawn to it. Come 2020, came SARS-CoV-2. I've written about the pandemic as objectively as I could. The scientific method never leaves a person who trained and worked as a professional scientist. Please do read that piece. My co-authors & I will submit it to the normal rigours of peer review, but that process is slow and many pieces of new science this year have come to attention through pre-print servers and other less conventional outlets.

While paying close attention to data, we all initially focused on the sad matter of deaths. I found it remarkable that, in discussing the COVID-19 related deaths, most people I spoke to had no idea of large numbers. Asked approximately how many people a year die in the UK in the ordinary course of events, each a personal tragedy, They usually didn't know. I had to inform them it is around 620,000, sometimes less if we had a mild winter, sometimes quite a bit higher if we had a severe 'flu season. I mention this number because we know that around 42,000 people have died with or of COVID-19. While it's a huge number of people, its 'only' 0.06% of the UK population. Its not a coincidence that this is almost the same proportion who have died with or of COVID-19 in each of the heavily infected European countries - for example, Sweden. The annual all-causes mortality of 620,000 amounts to 1,700 per day, lower in summer and higher in winter. That has always been the lot of humans in the temperate zones. So for context, 42,000 is about ~24 days worth of normal mortality. Please know I am not minimising it, just trying to get some perspective on it. Deaths of this magnitude are not uncommon, and can occur in the more severe flu seasons. Flu vaccines help a little, but on only three occasions in the last decade did vaccination reach 50% effectiveness. They're good, but they've never been magic bullets for respiratory viruses. Instead, we have learned to live with such viruses, ranging from numerous common colds all the way to pneumonias which can kill. Medicines and human caring do their best.

A new study finds a trigger for the Little Ice Age that cooled Europe from the 1300s through mid-1800s, and supports surprising model results suggesting that under the right conditions sudden climate changes can occur spontaneously, without external forcing.

The study, published in Science Advances, reports a comprehensive reconstruction of sea ice transported from the Arctic Ocean through the Fram Strait, by Greenland, and into the North Atlantic Ocean over the last 1400 years. The reconstruction suggests that the Little Ice Age — which was not a true ice age but a regional cooling centered on Europe — was triggered by an exceptionally large outflow of sea ice from the Arctic Ocean into the North Atlantic in the 1300s.


While previous experiments using numerical climate models showed that increased sea ice was necessary to explain long-lasting climate anomalies like the Little Ice Age, physical evidence was missing. This study digs into the geological record for confirmation of model results.

CBET 4885 & MPEC 2020-S119, issued on 2020, September 20, announce the discovery of a comet (magnitude ~18.5) by Nicolas Erasmus (South African Astronomical Observatory), in four 30-s CCD images taken in 5" seeing on Sept. 17.6 UT with a 0.5-m f/2 Schmidt reflector at Mauna Loa, Hawaii, in the course of the "Asteroid Terrestrial-Impact Last Alert System" (ATLAS) search program. The new comet has been designated C/2020 S3 (Erasmus).

We performed follow-up measurements of this object while it was still on the PCCP webpage.

Stacking of 151 unfiltered exposures, 30 seconds each, obtained remotely on 2020, September 19.1 from L07 (Osservatorio Salvatore di Giacomo, Agerola) through a 0.5 m f/8 Ritchey Chretien + CCD FLI PL4240, shows that this object is a comet with a diffuse coma about 20" in diameter.

Our confirmation image (click on it for a bigger version)