NEW YORK —
Scientists say they have finally calculated the age of the youngest known remains of Homo erectus, which is generally considered an ancestor of our species.
The fossilized skull fragments and other bones were uncovered on the Indonesian island of Java in the 1930s. Determining their age has been a scientific challenge, and a wide range has been proposed by numerous studies.
In a report released Wednesday by the journal Nature, scientists conclude the remains are between 108,000 and 117,000 years old. Researchers used five dating techniques on sediments and fossil animal bones from the area, combining 52 age estimates for the analysis. The project took 13 years to complete.
“I don’t see any way to date this site more thoroughly,” said paleoanthropologist Russell Ciochon of the University of Iowa, an author of the study.
H. erectus arose in Africa about 2 million years ago and spread widely there and in Asia, and possibly into Europe. It reached Java more than 1.5 million years ago, and the new dates suggest it died out at least 35,000 years before the arrival there of our own species, Homo sapiens.
H. erectus may have been doomed on Java by climate change that turned its open woodland environment into rain forest, Ciochon said. Still, it evidently existed longer on Earth than any other species on our “Homo” branch of the evolutionary tree.
Susan Anton, a New York University anthropologist who did not participate in the work, called the dating effort “heroic.” But she said she considered the reported age range to be too narrow. She said she preferred a span of less than 550,000 years old to more than 100,000 years old.
That’s roughly what she and co-authors proposed in a paper published in 2011. The younger end of the range in that paper was as recent as 120,000 years, which she said is virtually the same as the new result.
Mars Needs Minerals: Researchers Are Trying to Turn the Red Planet Green – IGN – IGN
It can take seven months – or more – to get to Mars. NASA can send supplies to the International Space Station if need be, but the same isn’t true of the distant planet. Instead, astronauts spending any time on Mars will have to rely on what’s known as in-situ resource utilization (ISRU) – using what’s around to replace objects brought from Earth. That includes food, which will eventually have to be grown there, to support any long-term residents. Instead of hauling bags of fertilizer in the spacecraft, researchers are trying to figure out how to make do with what’s on the ground, that is, Martian soil.
Thanks to NASA’s rovers and landers, scientists know about the pH and mineral makeup of the planet’s soil, which is known as regolith. Mars gets its red color from the oxidation of its rocks, regolith, and dust. Below the dust is the crust, which contains iron, magnesium, calcium, potassium, and more elements, according to NASA. But their presence isn’t enough to ensure plants can thrive there. The nutrients may not exist in a usable, or bioavailable, form. The levels of some may be toxic.
Cosmos: Possible Worlds Gallery
Some studies have shown it’s theoretically possible to grow plants in replicated Martian soil, but there aren’t big enough samples of actual Martian regolith to be certain. Since there’s no way to do farming trials on Mars itself, scientists try to replicate conditions on Earth. Researchers at the Florida Institute of Technology recently tried to grow Arabidopsis thaliana, a weed, and Lactuca sativa, lettuce, in a trio of Martian Regolith Simulants. These simulants are mixtures of artificial and natural materials that mimic the basalt-like Martian surface. The scientists found that neither plant in the synthetic soil without the addition of supplemental nutrients.
“These findings underscore that ISRU food solutions are likely at a lower technological readiness level than previously thought,” the researchers wrote in the study, which will be published in Icarus. For example, it’s a mistake to assume the regolith is uniform over the entire planet. “Our strategy was, rather than saying this simulant grows plants so that means we can grow plants everywhere on Mars, we need to say that Mars is a diverse planet,” ocean engineering and marine sciences associate professor Andrew Palmer told Florida Tech News.
In another new study, also published in Icarus, researchers break down the preparation of five new types of Mars simulants. Laura Fackrell, a doctoral candidate at the University of Georgia in Athens, and her colleagues created the mixtures specifically formulated with characteristics of Martian regolith that might make it difficult to grow plants. TThe soil might have high salinity or a low level of organic matter. Such conditions might require future Mars residents to add other minerals and components to their gardens before planting. “Specific types of bacteria and fungi are known to be beneficial for plants and may be able to support them under stress conditions like we see on Mars,” Fackrell told TNW.
To test the mock Mars dirt, Fackrell tried growing several plants, including a moth bean. They hold up better with less water than other options she tried, “But they’re not necessarily super healthy,” Fackrell told Science News.
It will be years before humans reach Mars, but in the meantime, research into growing plants in difficult environments could translate to Earth, where temperatures are rising. Fackrell studied microbes that live in hot springs. “Anything we learn about farming on Mars could help with farming in challenging environments on Earth that help us build to a sustainable future,” she told Florida Tech News.
Open Windows May Reduce COVID-19 Risk In Cars: Study – Jalopnik
COVID-19 has completely changed the face of travel as we know it, with massively reduced numbers of people taking flights and public transportation—but our cars have remained a mystery. How safe are we in our vehicles? What are our risks?
A study published by Science Advances in early January has begun to answer some of our most pressing questions about COVID-19 transmission in our vehicles. Four scientists from the University of Massachusetts, Amherst and Brown University used computational fluid dynamics to evaluate the risks posed by the virus within a vehicle’s cabin and have also suggested ways to mitigate risk.
If you’re familiar with the design process of a race car or airplane, then you’ve likely encountered computational fluid dynamics before. Essentially, these computer simulations model how gases and liquids move over and through different surfaces. In this particular case, our scientists used CFD to model the way air moves inside a car.
The simulated vehicle used in the study was loosely based on a Toyota Prius traveling at 50 mph carrying two passengers: a driver in the front left of the car and a passenger in the back right. Interestingly, the air flow outside the moving car creates a pressure gradient inside the car that causes air to circulate from the back of the car to the front. Then, they started modeling the interior air flow with different combinations of the windows being open or closed. It’s important to note here that, no matter the combination, the air conditioning was on.
The results probably aren’t going to be surprising. When all four windows were closed, the car was at its most poorly ventilated, so eight to 10 percent of aerosols—on which COVID-19 travels—exhaled by one person in the car traveled to the other. When all the windows were open, the car was at its best ventilated, with just 0.2 to two percent of aerosols swapping between passengers.
Of course, wide open windows aren’t always practical when you’re driving. Up north, you’ll freeze in the winter. Down south, someone with a delicate constitution will melt in the summer. A heavy rain will make things twice as miserable. So, having both the driver and the passenger roll down their windows was found to be better than keeping everything shut tight. That diagonal configuration allows air to flow in and then right back out. It might not be comfortable, but it could save lives.
A later study that hasn’t yet been published found that cracking windows halfway was also a good idea, but only rolling them a quarter of the way down was significantly more dangerous, the New York Times reports. For larger vehicles like minivans or for vehicles transporting more people, the recommendation is to keep everything open.
Opening windows has been recommended since the onset of the virus. The increased ventilation allows virus particles to be whisked away rather than recirculated. And we also know that the smaller the space we share, the more likely we are to swap aerosol particles. This study basically just used science to give us the ideal strategy for, say, rideshares or short jaunts outside your bubble.
Of course, there are still dangers, even when opening your windows. In fact, driving with your windows open increases in-car air pollution by 80 percent, which thus increases your likelihood of dying as a result of air pollution.
The very best option is, of course, to stay home unless absolutely necessary and, when traveling, to do so in off-peak hours.
NASA's 8-Minute Rocket Test Shuts Down After 67 Seconds – KCCU
NASA has more work to do, after a rocket test Saturday for its shuttle replacement ended with a premature and unexpected shutdown.
The test, at NASA’s Stennis Space Center in Mississippi, was part of NASA’s Artemis program, a plan to return to the moon in the coming years. NASA’s test called for four engines to fire for eight minutes — roughly the time it will take for NASA’s long-delayed Space Launch System (SLS) to generate the thrust needed to send the rocket to space.
But the engines shut down after just 67 seconds, when engine number 4 suffered a “major component failure.” Scientists aren’t yet sure what caused the early shutdown, but they plan to analyze and regroup.
Watch all four @NASA_SLS core stage engines roar to life and shake the ground in Mississippi.
Teams are assessing the data on early engine shutdown. pic.twitter.com/U5bNqqbdZd
— NASA (@NASA) January 16, 2021
“Saturday’s test was an important step forward to ensure that the core stage of the SLS rocket is ready for the Artemis I mission, and to carry crew on future missions,” said NASA Administrator Jim Bridenstine, who attended the test.
“Although the engines did not fire for the full duration, the team successfully worked through the countdown, ignited the engines, and gained valuable data to inform our path forward,” he said.
The engines NASA tested are the same ones that would be used to eventually launch the Orion space capsule to the moon. So scientists have to be careful with them.
“The amount of risk that we can take is very, very low,” Bridenstine said. “We can’t afford to have this vehicle fail. And guess what? Because we have done all the work that we have done, this article made the right decision to shut itself down.”
Well MCF was not a call this ascent flight director ever wanted to hear: Major Component Failure is detected by the SSME controller.
— Wayne Hale (@waynehale) January 16, 2021
Now NASA has to figure out what caused the component failure that led to the shutdown. If scientists conduct another test, it will take at least 3-4 weeks to prepare the engines, the agency said.
NASA announced the SLS about 10 years ago, as a successor to the retired Space Shuttle program. It’s a rocket and capsule combo that, when complete, will enable deep space missions. NASA hopes to have astronauts on the moon in 2024, and eventually Mars and beyond.
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