When it comes to the weather report, it's not just tomorrow's weather that meteorologists try to discern.
As well as long-term forecasts, weather models are often tasked with predicting meteorological conditions over the next hour or so, known as 'nowcasting'. Over at Google-backed artificial intelligence company DeepMind, researchers have now made a major step forward in the accuracy of precipitation nowcasting.
It's only when you stop and think about it that you realize how important very short-term weather forecasts are – sure, you may just bring your umbrella anyway, but when planning large events, maintaining transport services, dealing with natural disasters, keeping farming running, and much more, minute predictions become crucial.
Specifically, the new model ranks first for accuracy and usefulness in 89 percent of cases when compared against two competitive methods. It uses a type of machine learning called generative modeling, which is able to produce new data points after being trained on existing ones.
The primary job of the new model, called DGMR (Deep Generative Model of Rainfall), is to predict the chance of precipitation across the next one to two hours – and it has been given the nod of approval from more than 50 meteorologists at the Met Office in the UK.
The system produces short 'radar movies'. (DeepMind)
"This collaboration between environmental science and AI focuses on value for decision-makers, opening up new avenues for the nowcasting of rain, and points to the opportunities for AI in supporting our response to the challenges of decision-making in an environment under constant change," writes the DeepMind Nowcasting Team in a blog post.
The researchers behind DGMR describe making short "radar movies" that generate future radar patterns from past radar patterns – the kind of extrapolation that machine learning is good at (for more generative models, see the creation of fake faces).
Many current nowcasting tools, including pySTEPS, make use of numerical weather prediction (NWP) approaches – they essentially put mathematical models to work on current conditions to work out what future conditions will be like. These are powerful models, but they're more accurate over the longer term.
"These models are really amazing from six hours up to about two weeks in terms of weather prediction, but there is an area – especially around zero to two hours – in which the models perform particularly poorly," Suman Ravuri, staff research scientist at DeepMind, told The Guardian.
DGMR aims to leverage the vast number-crunching power of artificial intelligence while removing some of the blurriness or vagueness in existing machine learning-driven forecasting models, including U-Net – these models can struggle to maintain accuracy in every part of the process.
Now that the new and improved DeepMind model has had the thumbs up from actual meteorologists in the UK, the researchers can look at integrating it with existing weather prediction systems.
There's still a lot of work to do though before you'll be able to know with absolute certainty whether you're going to be able to stay dry for the next couple of hours. The DeepMind team is now attempting to further improve the accuracy of DGMR.
"No method is without limitations, and more work is needed to improve the accuracy of long-term predictions and accuracy on rare and intense events," writes the team.
"Future work will require us to develop additional ways of assessing performance, and further specializing these methods for specific real-world applications."
Kilauea volcano is erupting, sending lava and thread-like pieces of volcanic glass, known as Pele's hair, into Hawaii's skies, according to the US Geological Survey (USGS) and the National Weather Service.
The eruption began at about 3:20 pm local Hawaii time Wednesday (Sept. 29), when the USGS Hawaiian Volcano Observatory detected a glow from its webcam at Kilauea summit. That glow indicated a lava eruption happening at Halema'uma'u crater – a pit crater nestled in the much larger Kilauea caldera, or crater.
The webcam footage also revealed fissures at the base of Halema'uma'u crater that were releasing lava flows onto the surface of the lava lake that had been active until May 2021, the USGS said in a statement.
Telephoto image of fissures that opened at Halema'uma'u crater. (M. Patrick/USGS)
However, the eruption at Kilauea – located within Hawaii Volcanoes National Park, on Hawaii's Big Island – is confined to Halema'uma'u crater, meaning it's not currently a threat to the public.
"At this time, we don't believe anybody or any residents are in danger, but we do want to remind folks the park remains open," Cyrus Johnasen, a Hawaii County spokesperson, told Hawaii news station KHON2 on Sept. 29.
"It will remain open until the evening. Please proceed with caution," especially for those with respiratory conditions, he added.
However, the part of the park where the eruption is happening is currently closed to the public, according to the USGS.
Due to the eruption, the Hawaiian Volcano Observatory has elevated Kilauea's volcano alert level from "watch" to "warning" and its aviation color code from orange to red, which warns pilots about possible ash emissions.
Those are the highest warning levels, meaning a "major volcanic eruption is imminent, underway or suspected, with hazardous activity both on the ground and in the air," according to the USGS.
Lava fountains are spurting out at multiple fissure, September 30, Halema'uma'u. (B Carr/USGS)
Meanwhile, several pilots flying aircraft near Kilauea Wednesday evening reported seeing volcanic glass known as Pele's hair, according to the National Weather Service.
The golden, sharp strands of glass – named for Pele, the Hawaiian goddess of fire and volcanoes – form when gas bubbles within lava burst at the surface.
"The skin of the bursting bubbles flies out, and some of the skin becomes stretched into these very long threads, sometime[s] as long as a couple of feet [more than half a meter] or so," Don Swanson, a research geologist at the Hawaiian Volcano Observatory, previously told Live Science.
Pele's hair can be beautiful, but it poses a danger if it's ingested through drinking water, Swanson cautioned.
The current eruption is the latest of a long string of volcanic activity at Kilauea. At an elevation of 4,009 feet (1,222 m) aboveground, the shield-shaped volcano has a magma-pumping system that extends more than 37 miles (60 kilometers) below Earth, according to the USGS. Kilauea has erupted 34 times since 1952, and it erupted almost continuously from 1983 to 2018 along its East Rift Zone.
A vent at Halema'uma'u crater was home to an active lava pond and a vigorous gas plume from 2008 to 2018.
Kilauea's volcanic activity also made headlines in May 2018, when the lava lake at the summit caldera drained just as the Eastern Rift Zone revved to life with lava fountains and new fissures, whose lava created a red-hot river that destroyed hundreds of houses before draining into the ocean.
From December 2020 to May 2021, a summit eruption made a lava lake within Halema'uma'u crater, and in August 2021, a series of small earthquakes rattled the summit.
A monument in Thermopylae to King Leonidas. Bridgeman Images
Ancient Sparta has been held up for the last two and a half millennia as the unmatched warrior city-state, where every male was raised from infancy to fight to the death. This view, as ingrained as it is alluring, is almost entirely false.
The myth of Sparta’s martial prowess owes much of its power to a storied feat of heroism accomplished by Leonidas, king of Sparta and hero of the celebrated Battle of Thermopylae (480 B.C.). In the battle, the Persian Army crushed more than 7,000 Greeks—including 300 Spartans, who are widely and falsely believed to have been the only Greeks fighting in that battle—and went on to capture and burn Athens. Outflanked and hopelessly outnumbered, Leonidas and his men fought to the death, epitomizing Herodotus’ pronouncement that all Spartan soldiers would “abide at their posts and there conquer or die.” This singular episode of self-sacrificing bravery has long obscured our understanding of the real Sparta.
A scene from Thermopylae by the Italian novelist, painter and poet Dino Buzzati. The 300 or so Spartans helped hold off an enormous Persian Army for three days.
Luisa Ricciarini / Bridgeman Images
Actually, Spartans could be as cowardly and corrupt, as likely to surrender or flee, as any other ancient Greeks. The super-warrior myth—most recently bolstered in the special effects extravaganza 300, a movie in which Leonidas, 60 at the time of the battle, was portrayed as a hunky 36—blinds us to the real ancient Spartans. They were fallible men of flesh and bone whose biographies offer important lessons for modern people about heroism and military cunning as well as all-too-human blundering.
There is King Agis II, who bungled various maneuvers against the forces of Argos, Athens and Mantinea at the Battle of Mantinea (418 B.C.) but still managed to pull off a victory. There is the famous Admiral Lysander, whose glorious military career ended with a rash decision to rush into battle against Thebes, probably to deny glory to a domestic rival—a move that cost him his life at the Battle of Haliartus (395 B.C.). There is Callicratidas, whose pragmatism secured critical funding for the Spartan Navy in the Peloponnesian War (431-404 B.C.), but who foolishly ordered his ship to ram the Athenians’ during the Battle of Arginusae (406 B.C.), a move that saw him killed. Perhaps the clearest rebuttal of the super-warrior myth is found in the 120 elite Spartans who fought at the Battle of Sphacteria (425 B.C.); when their Athenian enemies surrounded them, they opted to surrender rather than “conquer or die.”
These Spartans, not particularly better or worse than any other ancient warriors, are just a handful of many examples that paint the real, and utterly average, picture of Spartan arms.
But it is this human reality that makes the actual Spartan warrior relatable, even sympathetic, in a way Leonidas can never be. Take the mostly forgotten general, Brasidas, who, instead of embracing death on the battlefield, was careful to survive and learn from his mistakes. Homer may have hailed Odysseus as the cleverest of the Greeks, but Brasidas was a close second.
Almost no one has heard of Brasidas. He’s not a figure immortalized in Hollywood to prop up fantasies, but a human being whose mistakes form a much more instructive arc.
He burst onto the scene in 425 B.C. during Sparta’s struggle against Athens in the Peloponnesian War, breaking through a large cordon with just 100 men to relieve the beleaguered city of Methone (modern Methoni) in southwest Greece. These heroics might have put him on track for mythic fame, but his next campaign would make that prospect far more complicated.
Storming the beach at Pylos that same year, Brasidas ordered his ship to wreck itself on the rocks so he could assault the Athenians. He then barreled down the gangplank straight into the teeth of the enemy.
It was incredibly brave. It was also incredibly stupid.
Charging packed troops, Brasidas went down in a storm of missiles before he’d made it three feet. Thucydides tells us that Brasidas “received many wounds, fainted; and falling back into the ship, his shield tumbled into the sea.” Many of us are familiar with the famous admonition of a Spartan mother to her son: “Come back with your shield or on it.” While this line is almost certainly apocryphal, losing one’s shield was nevertheless a signal dishonor. One might expect a Spartan warrior who had both lost his shield and fainted in battle to prefer death to dishonor. That’s certainly the kind of choice Leonidas is celebrated for supposedly making.
An 1888 illustration shows a bust of the ancient Greek historian and general Thucydides, known as “the father of scientific history.”
Science Photo Library
Herodotus tells us the two Spartan survivors of Thermopylae received such scorn from their city-state for having lived through a defeat that they took their own lives. But Brasidas, though surely shamed by his survival, did not commit suicide. Instead, he learned.
The following year, we see a recovered Brasidas marching north to conquer Athenian-allied cities at the head of 700 helots, members of Sparta’s reviled slave-caste, who the Spartans constantly feared would revolt. Forming this army of Brasideioi (“Brasidas’ men”) was an innovative idea, and quite possibly a dangerous one. As a solution to the city’s manpower crisis, Sparta had promised them freedom in exchange for military service. And arming and training slaves always threatened to backfire on the slavers.
This revolutionary move was matched by a revolution in Brasidas’ own personality. Far from rushing in, as he once had done, he now captured city after city from the Athenians through cunning—and without a single battle. Thucydides writes that Brasidas, “by showing himself...just and moderate toward the cities, caused most of them to revolt; and some of them he took by treason.” Brasidas let the slaves and citizens of Athenian-held cities do the dirty work for him. After one particularly tense standoff, he won the central Greek city of Megara to Sparta’s cause, then marched north, cleverly outmaneuvering the Athenian-allied Thessalians deliberately to avoid combat.
Brasidas’ foolhardy crash-landing at Pylos, in a 1913 illustration.
Bridgeman Images
Arriving at his destination in northeastern Greece, he used diplomacy, threats, showmanship and outright lies to convince the city of Akanthos to revolt from Athens and join Sparta, deftly playing on their fear of losing a harvest that had not yet been gathered. The nearby city of Stagiros came over immediately after.
But his greatest prize was Amphipolis (modern Amfipoli), a powerful city that controlled the critical crossing of the Strymon River (the modern Struma, stretching from northern Greece into Bulgaria). Launching a surprise attack, he put the city under siege—and then offered concessions that were shocking by the standards of the ancient world: free passage for any who wished to leave and a promise not to pillage the wealth of any who remained.
This incredibly risky move could have tarnished Brasidas’ reputation, making him look weak. It certainly runs counter to the myth of the Spartan super-warrior who scoffed at soft power and prized victory in battle above all else.
But it worked. The city came over to Sparta, and the refugees who fled under Brasidas’ offer of free passage took shelter with Thucydides himself in the nearby city of Eion.
Thucydides describes what happened next: “The cities subject to the Athenians, hearing of the capture of Amphipolis, and what assurance [Brasidas] brought with him, and of his gentleness besides, strongly desired innovation, and sent messengers privately inviting him to come.”
Three more cities came over to Sparta. Brasidas then took Torone (modern Toroni, just south of Thessaloniki) with the help of pro-Spartan traitors who opened the city gates for him.
The mythic Leonidas, failing in battle, consigned himself to death. The very real Brasidas, failing in battle, licked his wounds and tried something different. Charging down the gangplank at Pylos had earned him a face full of javelins. He had been lucky to survive, and the lesson he took from the experience was clear: Battle is uncertain, and bravery a mixed commodity at best. War is, at its heart, not a stage for glory but a means to advance policy and impose one’s will. Brasidas had even discovered that victory could be accomplished best without fighting.
Brasidas would make many more mistakes in his campaigns, including the one that would cost him his life outside Amphipolis, where he successfully fought off the Athenians’ attempt to recapture the greatest triumph of his career. Brasidas daringly took advantage of the enemy’s bungled retreat, attacking them and turning their withdrawal into a rout, but at the cost of his life. His funeral was held inside Amphipolis, where today you can visit his funeral box in the archaeological museum.
That he died after renouncing the caution that had marked most of his career seems fitting, a human end for a man who is the best example of the sympathetic fallibility of his city-state’s true military tradition. He is valuable to historians not just for his individual story, but moreover because he illustrates the humanity of real Spartan warriors, in direct contrast to their overblown legend.
Fallible human beings who learn from their errors can achieve great things, and that is the most inspiring lesson the true history of Sparta can teach us.
When we choose a myth over reality, we commit two crimes. The first is against the past, for truth matters. But the second, more egregious, is against ourselves: Denied the chance to see how Spartans struggled and failed and recovered and overcame, we forget that, if they did it, then maybe we can too.
The Pentagon's trusted capital office was created to help U.S. startups get access to 'clean sources' of capital
BOSTON — Chinese investments in U.S. space startups and use of Chinese software by DoD suppliers are issues of growing concern at the Pentagon, officials said.
“I will tell you that supply chain is one of the most important things that we are focused on right now within DoD,” Colin Supko, director of the Defense Department’s trusted capital program, said Sept. 28 at the Space Sector Market Conference.
DoD created the trusted capital program in January due to concerns that China is using its financial clout to access segments of the U.S. defense industrial base.
The trusted capital office encourages venture capital firms to get vetted by DoD so they can be declared sources of “clean capital.” Space is a sector of interest as billions of dollars pour into the industry, making it harder for the government to identify so-called adversarial capital.
“Everybody’s aware that dependence on potential adversaries for some of our critical systems and technology is not in the best interest of the United States,” said Supko, a U.S. Navy captain and tech entrepreneur.
“I will tell you that this administration is looking hard at how to curtail some of those problems and they have some of the smartest people working on it,” he said.
DoD’s trusted capital office is now working with more than 70 startups and 20 venture firms that have $1.2 billion in capital, he said. “Our office was designed to be a due diligence capability for the benefit of the government. If a company gets through the DoD process, they get a ‘warm introduction’ to venture investors.”
“We try to link startups to VC funds that recognize the importance of clean capital,” said Supko.
He said DoD has significant discretion in determining whether certain sources of capital are acceptable or adversarial, in which case a company could be prevented from competing for military contracts.
When foreign entities seek to merge with U.S. companies or acquire them, the deals are reviewed by the interagency Committee on Foreign Investment in the United States (CFIUS) which has authority to recommend that the U.S. government block a transaction on national security grounds. The Defense Security Cooperation Agency also gets to review transactions where the could be foreign “controlling influence,” Supko said.
But even when there is no outright acquisition, the government may still decide to ban a company from competing for U.S. contracts on grounds that it gets adversarial capital. “There’s a lot of gray areas there,” Supko said. “We have to be really careful not to give one company a greater opportunity than another company as there’s nothing illegal about having foreign ownership or specific types of control within a company.”
“Those things are now being discussed at the very highest levels,” he said. The Biden administration “is going to be moving down that path to work with the legislative branch on how to get after that problem set; it’s a pretty wide open problem set.”
Such gray areas and a lack of clarity on how the government decides what investments are acceptable can be a problem for investors and entrepreneurs, said Brett Rome, managing director of Fidelity Investments’ private venture fund. The company has taken equity investments in 11 startups, including three in the space sector.
Fear of being flagged as having adversarial capital drives some companies to be “overly conservative and turn away sources of capital that would probably be okay, just because there’s any hint that there might be an issue,” Rome said at the conference.
“And that is not good because there’s lots of capital that would be totally acceptable, but the companies don’t understand exactly where that line is, and they err on the side of caution.”
“Legal is not the standard in government procurement,” Rome said. A rush to turn down foreign investments because they can’t be 100% traced “can cause companies to lose out on opportunities, and the government to not be able to procure capabilities that they would want.”
DoD’s space agency to vet supply chains
Another piece of of DoD’s supply chain security involves making sure that contractors know the sources of their software and components.
As it prepares to select satellite suppliers for its low Earth orbit constellation, the Space Development Agency is making supply chain security a high priority in the selection process, SDA Director Derek Tournear said Sept. 28 at the Space Sector Market Conference.
The prime contractors selected to build satellites for SDA’s Transport Layer Tranche 1 will be expected to protect the entire supply chain from cyber intrusions, counterfeiting and other threats.
“Obviously I’m concerned about supply chain provenance and interdiction, whether that be for counterfeit or nefarious purposes,” said Tournear. “That is something that we watch because we know we’re in a great power competition and we have to be careful,” he added. “We have to understand exactly what is going into these systems, even as we push to make them as affordable and commoditized as possible.”
Counterfeit parts are a problem in any industry and space is no exception, Tournear said. “We have processes in place that we’ve outlined in our request for proposals about how we plan on addressing those in Tranche 1, and we’re also planning on doing random parts testing, non destructive testing to make sure that the parts we’re using are the parts that we think they are.”
Research exploring how people forget things appears to have unintentionally stimulated better memory among its participants, a new study suggests.
The experiment was originally conducted in 2012 and was supposed to explore the role of the left dorsolateral prefrontal cortex (DLPFC) in voluntary forgetting.
While the 2012 experiment successfully demonstrated forgetting was something actively managed by the DLPFC, it turns out there was a bonus hidden inside its data.
A reanalysis has now shown that tickling this part of the brain with the right frequency of magnetic stimulation as we learn new material can also help us remember it.
"We were quite surprised when we saw these effects in the first study, which was designed to investigate a different question," says cognitive neuroscientist Simon Hanslmayr from the University of Glasgow.
To test if the results were more than just a fluke, researchers conducted a second experiment. In it, 24 healthy adults were presented with two lists of 10 words that they were asked to memorize. The two lists were shown separately a dozen times.
After a short task designed to distract the participants, the cohort was again asked to recall all the words from the two lists just presented.
While the words were being presented, half the group received a single hertz of slow repetitive transcranial magnetic stimulation (rTMS) to the prefrontal cortex. The other half received a hertz of rTMS to the top of the head.
Compared to participants in the control group, those who received magnetic stimulation to the DLPFC performed better on the memory recall task.
The stimulation didn't seem to help participants remember the order of the words any better, but it did help them remember each word independently.
The new study only included two dozen healthy adults, which means the findings need to be taken with a grain of salt. That said, the results don't stand completely on their own.
Not only do they support findings from the 2014 study, they also fall in line with similar studies exploring DLPFC and its role in memory formation.
Previous studies that have actively stimulated the DLPFC, for instance, have shown a reduction in memory performance. But rTMS is different. This slow type of stimulation seems to have an inhibitory effect on most of the cortex, not an excitatory one.
These inhibitory effects might even ripple outwards from the DLPFC to a closely connected area, known as the parietal cortex.
This part of the brain is involved in attention and perception, and in brain imaging studies, when activity here is reduced, our focus and memory performance tends to improve.
During the 2012 study, for instance, scientists measured a reduction in electrical activity within the parietal region of those undergoing brain stimulation.
"Our electrophysiological results suggest that frontal stimulation affects a wider network and improves memory formation by inhibiting parietal areas," says neuroscientist Mircea van der Plas from the University of Glasgow.
"These are complex but interesting effects that require further experiments to better understand their neural basis."
The results will need to be replicated among much larger cohorts before we can ascertain how widespread these effects might be.
Recently, however, noninvasive brain stimulation has begun to emerge as a promising new treatment for age-related memory loss and other neurological conditions that impact memory.
Neuroscientists are still trying to figure out which parts of the brain to stimulate and how for the best effects, but progression is slowly being made.
A brain imaging study in 2019, for instance, found multiple sessions of high-frequency magnetic stimulation to the hippocampus improved the neural hallmarks of age-related memory loss. At the same time, behavioral hallmarks of memory loss were also improved among older adults.
Another study in 2014, which targeted the right and not the left DLPFC, also found magnetic stimulation during memory encoding improved memory performance.
Far more research is needed to tease apart the intricacies of magnetic stimulation on memory, but re-analyzing previous datasets and replicating those results could be an important step to finding out more.
Space exploration requires all kinds of interesting solutions to complex problems. There is a branch of NASA designed to support the innovators trying to solve those problems – the Institute for Advanced Concepts (NIAC). They occasionally hand out grant funding to worthy projects trying to tackle some of these challenges.
The results from one of those grants are now in, and they are intriguing. A team from Masten Space Systems, supported by Honeybee Robotics, Texas A&M, and the University of Central Florida, came up with a way a lunar lander could deposit its own landing pad on the way down.
Lunar dust poses a significant problem to any powered landers on the surface. The retrograde rockets needed to land on the Moon's surface softly will also kick dust and rock up into the air, potentially damaging the lander itself or any surrounding human infrastructure.
A landing pad would lessen the impact of this dust and provide a more stable place for the landing itself.
Landing with and without the deposition system. (Masten Space Systems)
But constructing such a landing pad the traditional way would be prohibitively expensive. Current estimates put the cost of building a lunar landing pad using traditional materials at approximately US$120 million.
Any such mission also suffers from a chicken and egg problem. How to get the materials to build the landing pad land in place if there is no landing pad to begin with?
The technology Masten has developed is an ingenious solution to both of those problems.
Depositing a landing pad while descending would allow spacefarers to have a landing pad in place before a spacecraft ever touches down there. It would also cost much less to install as all that is needed is a relatively simple additive to the rocket exhaust already being blasted into the surface.
Masten's general idea is easy enough to understand.
Adding solid pellets into the rocket exhaust would allow that material to partially liquefy and deposit onto the exhaust's blast zone, potentially hardening it to a point where dust is no longer a factor as it is encapsulated in a hard external shell. Masten believed it could find the right material to add to rocket exhaust to do exactly that.
Success or failure would come down to the physical properties of the additive pellets. Any additive with too much heat tolerance wouldn't melt appropriately in the rocket exhaust, essentially bombarding the surface with tiny bullets.
On the other hand, any additive with too little heat tolerance could be completely melted by the rocket exhaust and vaporized into a useless cloud.
To find the perfect balance, Masten developed a two-tiered system, with relatively large (0.5 mm) alumina particles used to create a base layer of 1 mm of melted lunar surface combined with alumina.
Process of the FAST particle injector. (Masten Space Systems)
Then, as the lander got closer to the base layer, the additive would switch to a 0.024 mm alumina particle, which would deposit at 650 m/s onto the base layer and create a 6 m diameter landing pad that would cool in 2.5 seconds.
That all sounds like a pretty impressive idea, but it is still early days. Like many federal grants, the NIAC grant focused on developing this depositable landing pad idea takes a phased approach. Most of the Phase I, which has just been completed, focused on proving the idea is feasible, which Masten believes it is.
Feasible is not the same as functional, but that is precisely what NIAC grants are supposed to support – wild ideas that might just fundamentally change some aspect of space exploration.
If Masten is correct and the approach is possible and can be scaled up, landing pads might be seen cropping up all over the lunar surface. And eventually all over Mars as well.
Mary Ware Dennett wrote The Sex Side of Life in 1915as a teaching tool for her teenage sons. Photo illustration by Meilan Solly / Photos courtesy of Sharon Spaulding and Newspapers.com
Charged with violating the Comstock Act of 1873—one of a series of so-called chastity laws—Dennett, a reproductive rights activist, had written and illustrated the booklet in question for her own teenage sons, as well as for parents around the country looking for a new way to teach their children about sex.
Lawyer Morris Ernst filed an appeal, setting in motion a federal court case that signaled the beginning of the end of the country’s obscenity laws. The pair’s victory marked the zenith of Dennett’s life work, building on her previous efforts to publicize and increase access to contraception and sex education. (Prior to the trial, she was best known as the more conservative rival of Margaret Sanger, founder of Planned Parenthood.) Today, however, United States v. Dennett and its defendant are relatively unknown.
“One of the reasons the Dennett case hasn’t gotten the attention that it deserves is simply because it was an incremental victory, but one that took the crucial first step,” says Laura Weinrib, a constitutional historian and law scholar at Harvard University. “First steps are often overlooked. We tend to look at the culmination and miss the progression that got us there.”
Dennett wrote the offending pamphlet (in blue) for her two sons.
Sharon Spaulding / Dennett Family Archive
Dennett wrote the pamphlet in question, The Sex Side of Life: An Explanation for Young People, in 1915. Illustrated with anatomically correct drawings, it provided factual information, offered a discussion of human physiology and celebrated sex as a natural human act.
“[G]ive them the facts,” noted Dennett in the text, “... but also give them some conception of sex life as a vivifying joy, as a vital art, as a thing to be studied and developed with reverence for its big meaning, with understanding of its far-reaching reactions, psychologically and spiritually.”
After Dennett’s 14-year-old son approved the booklet, she circulated it among friends who, in turn, shared it with others. Eventually, The Sex Side of Life landed on the desk of editor Victor Robinson, who published it in his Medical Review of Reviewsin 1918. Calling the pamphlet “a splendid contribution,” Robinson added, “We know nothing that equals Mrs. Dennett’s brochure.” Dennett, for her part, received so many requests for copies that she had the booklet reprinted and began selling it for a quarter to anyone who wrote to her asking for one.
These transactions flew in the face of the Comstock Laws, federal and local anti-obscenity legislation that equated birth control with pornography and rendered all devices and information for the prevention of conception illegal. Doctors couldn’t discuss contraception with their patients, nor could parents discuss it with their children.
Dennett as a young woman
Sharon Spaulding / Dennett Family Archive
The Sex Side of Life offered no actionable advice regarding birth control. As Dennett acknowledged in the brochure, “At present, unfortunately, it is against the law to give people information as to how to manage their sex relations so that no baby will be created.” But the Comstock Act also stated that any printed material deemed “obscene, lewd or lascivious”—labels that could be applied to the illustrated pamphlet—was “non-mailable.” First-time offenders faced up to five years in prison or a maximum fine of $5,000.
In the same year that Dennett first wrote the brochure, she co-founded the National Birth Control League (NBCL), the first organization of its kind. The group’s goal was to change obscenity laws at a state level and unshackle the subject of sex from Victorian morality and misinformation.
By 1919, Dennett had adopted a new approach to the fight for women’s rights. A former secretary for state and national suffrage associations, she borrowed a page from the suffrage movement, tackling the issue on the federal level rather than state-by-state. She resigned from the NBCL and founded the Voluntary Parenthood League, whose mission was to pass legislation in Congress that would remove the words “preventing conception” from federal statutes, thereby uncoupling birth control from pornography.
Dennett soon found that the topic of sex education and contraception was too controversial for elected officials. Her lobbying efforts proved unsuccessful, so in 1921, she again changed tactics. Though the Comstock Laws prohibited the dissemination of obscene materials through the mail, they granted the postmaster general the power to determine what constituted obscenity. Dennett reasoned that if the Post Office lifted its ban on birth control materials, activists would win a partial victory and be able to offer widespread access to information.
Postmaster General William Hays, who had publicly stated that the Post Office should not function as a censorship organization, emerged as a potential ally. But Hays resigned his post in January 1922 without taking action. (Ironically, Hays later established what became known as the Hays Code, a set of self-imposed restrictions on profanity, sex and morality in the motion picture industry.) Dennett had hoped that the incoming postmaster general, Hubert Work, would fulfill his predecessor’s commitments. Instead, one of Work’s first official actions was to order copies of the Comstock Laws prominently displayed in every post office across America. He then declared The Sex Side of Life “unmailable” and “indecent.”
Mary Ware Dennett, pictured in the 1940s
Dennett Family Archive
Undaunted, Dennett redoubled her lobbying efforts in Congress and began pushing to have the postal ban on her booklet removed. She wrote to Work, pressing him to identify which section was obscene, but no response ever arrived. Dennett also asked Arthur Hays, chief counsel of the American Civil Liberties Union (ACLU), to challenge the ban in court. In letters preserved at Radcliffe College’s Schlesinger Library, Dennett argued that her booklet provided scientific and factual information. Though sympathetic, Hays declined, believing that the ACLU couldn’t win the case.
By 1925, Dennett—discouraged, broke and in poor health—had conceded defeat regarding her legislative efforts and semi-retired. But she couldn’t let the issue go entirely. She continued to mail The Sex Side of Life to those who requested copies and, in 1926, published a book titledBirth Control Laws: Shall We Keep Them, Change Them, or Abolish Them?
Publicly, Dennett’s mission was to make information about birth control legal; privately, however, her motivation was to protect other women from the physical and emotional suffering she had endured.
The activist wed in 1900 and gave birth to three children, two of whom survived, within five years. Although the specifics of her medical condition are unknown, she likely suffered from lacerations of the uterus or fistulas, which are sometimes caused by childbirth and can be life-threatening if one becomes pregnant again.
Without access to contraceptives, Dennett faced a terrible choice: refrain from sexual intercourse or risk death if she conceived. Within two years, her husband had left her for another woman.
Dennett obtained custody of her children, but her abandonment and lack of access to birth control continued to haunt her. Eventually, these experiences led her to conclude that winning the vote was only one step on the path to equality. Women, she believed, deserved more.
In 1928, Dennett again reached out to the ACLU, this time to lawyer Ernst, who agreed to challenge the postal ban on the Sex Side of Life in court. Dennett understood the risks and possible consequences to her reputation and privacy, but she declared herself ready to “take the gamble and be game.” As she knew from press coverage of her separation and divorce, newspaper headlines and stories could be sensational, even salacious. (The story was considered scandalous because Dennett’s husband wanted to leave her to form a commune with another family.)
Dennett cofounded the National Birth Control League, the first organization of its kind in the U.S., in 1915. Three years later, she launched the Voluntary Parenthood League, which lobbied Congress to change federal obscenity laws.
Sharon Spaulding / Dennett Family Archive
“Dennett believed that anyone who needed contraception should get it without undue burden or expense, without moralizing or gatekeeping by the medical establishment,” says Stephanie Gorton, author of Citizen Reporters: S.S. McClure, Ida Tarbell and the Magazine That Rewrote America. “Though she wasn't fond of publicity, she was willing to endure a federal obscenity trial so the next generation could have accurate sex education—and learn the facts of life without connecting them with shame or disgust.”
In January 1929, before Ernst had finalized his legal strategy, Dennett was indicted by the government. Almost overnight, the trial became national news, buoyed by The Sex Side of Life’s earlier endorsement by medical organizations, parents’ groups, colleges and churches. The case accomplished a significant piece of what Dennett had worked 15 years to achieve: Sex, censorship and reproductive rights were being debated across America.
During the trial, assistant U.S. attorney James E. Wilkinson called the Sex Side of Life “pure and simple smut.” Pointing at Dennett, he warned that she would “lead our children not only into the gutter, but below the gutter and into the sewer.”
None of Dennett’s expert witnesses were allowed to testify. The all-male jury took just 45 minutes to convict. Ernst filed an appeal.
In May, following Dennett’s conviction but prior to the appellate court’s ruling, an investigative reporter for the New York Telegram uncovered the source of the indictment. A postal inspector named C.E. Dunbar had been “ordered” to investigate a complaint about the pamphlet filed by an official with the Daughters of the American Revolution (DAR). Using the pseudonym Mrs. Carl Miles, Dunbar sent a decoy letter to Dennett requesting a copy of the pamphlet. Unsuspecting, Dennett mailed the copy, thereby setting in motion her indictment, arrest and trial. (Writing about the trial later, Dennett noted that the DAR official who allegedly made the complaint was never called as a witness or identified. The activist speculated, “Is she, perhaps, as mythical as Mrs. Miles?”)
Dennett’s is a name that deserves to be known.
When news of the undercover operation broke, Dennett wrote to her family that “support for the case is rolling up till it looks like a mountain range.” Leaders from the academic, religious, social and political sectors formed a national committee to raise money and awareness in support of Dennett; her name became synonymous with free speech and sex education.
In March 1930, an appellate court reversed Dennett’s conviction, setting a landmark precedent. It wasn’t the full victory Dennett had devoted much of her life to achieving, but it cracked the legal armor of censorship.
“Even though Mary Ware Dennett wasn’t a lawyer, she became an expert in obscenity law,” says constitutional historian Weinrib. “U.S. v. Dennett was influential in that it generated both public enthusiasm and money for the anti-censorship movement. It also had a tangible effect on the ACLU’s organizational policies, and it led the ACLU to enter the fight against all forms of what we call morality-based censorship.”
Ernst was back in court the following year. Citing U.S. v. Dennett, he won two lawsuits on behalf of British sex educator Marie Stopes and her previously banned books, Married Love and Contraception. Then, in 1933, Ernst expanded on arguments made in the Dennett case to encompass literature and the arts. He challenged the government’s ban on James Joyce’s Ulysses and won, in part because of the precedent set by Dennett’s case. Other important legal victories followed, each successively loosening the legal definition of obscenity. But it was only in 1970 that the Comstock Laws were fully struck down.
Ninety-two years after Dennett’s arrest, titles dealing with sex continue to top the list of the American Library Association’s most frequently challenged books. Sex education hasn’t fared much better. As of September 2021, only 18 states require sex education to be medically accurate, and only 30 states mandate sex education at all. The U.S. has one of the highestteen pregnancy rates of all developed nations.
What might Dennett think or do if she were alive today? Lauren MacIvor Thompson, a historian of early 20th-century women’s rights and public health at Kennesaw State University, takes the long view:
While it’s disheartening that we are fighting the same battles over sex and sex education today, I think that if Dennett were still alive, she’d be fighting with school boards to include medically and scientifically accurate, inclusive, and appropriate information in schools. ... She’d [also] be fighting to ensure fair contraceptive and abortion access, knowing that the three pillars of education, access and necessary medical care all go hand in hand.
At the time of Dennett’s death in 1947, The Sex Side of Life had been translated into 15 languages and printed in 23 editions. Until 1964, the activist’s family continued to mail the pamphlet to anyone who requested a copy.
“As a lodestar in the history of marginalized Americans claiming bodily autonomy and exercising their right to free speech in a cultural moment hostile to both principles,” says Gorton, “Dennett’s is a name that deserves to be known.”
WASHINGTON — Developers of satellite servicing technologies expect interest in refueling and life extension to come from customers in geostationary orbit and beyond, while low Earth orbit operators instead seek end-of-life disposal services.
In discussions at the Global Satellite Servicing Forum, a conference by the industry group Consortium for Execution of Rendezvous and Servicing Operations (CONFERS), companies and organizations working on various satellite servicing approaches said they expected LEO constellation operators to seek their services to keep their orbits clean.
“The economics really start to make sense when you have operators that have hundreds, if not thousands, of satellites orbiting in a very close regime, where they have a direct vested interest in protecting that,” said Harriet Brettle, head of business analysis at Astroscale, a company working on several satellite servicing and disposal technologies.
Constellation operators, she said, will seek out end-of-life satellite disposal services to free up those orbits for replacement satellites. “That’s really where you can see protecting operational service, ensuring that you have a robust and responsible use of that space,” she said. “If you’re looking at putting your next fleet up there, you want to make sure you’re doing that in a way that you can continue to operate safely and sustainably.”
Trevor Bennett, co-founder of Starfish Space, another satellite servicing company, agreed. “What we’re going to have to do is maintain specific orbits, so the pain is going to be felt most by constellations,” he said. “The paying customer is not the one that’s occasionally dodging a fleck of paint or a piece of debris there. It is the one who has tens of satellites in an orbit and finds value in maintaining that orbital shell or orbital plane.”
Besides constellations, Brettle predicted governments would be customers for debris removal services in LEO for “legacy” debris. The Japanese space agency JAXA, for example, awarded a contract to Astroscale to inspect a spent Japanese rocket stage left in orbit, with later plans to remove the stage.
“It’s really a combination of looking to governments to address that legacy debris issue that we see, but also looking for satellite operators to take responsibility for the future orbital environment,” she said.
However, LEO constellations are unlikely to be customers for satellite life extension or other servicing, another panelist predicted. “Refueling in LEO only makes sense under a limited circumstance,” said Karl Stolleis, lead for space robotics and logistics at the Air Force Research Laboratory’s Space Vehicles Directorate.
He argued that the economics for refueling “proliferated LEO” constellations didn’t make sense. “It’s cheaper to just build a new satellite and launch one, and dispose of the old one, than it is to actually try to refuel it,” he said.
The situation is different in GEO, he argued. One approach he suggested is for GEO satellites to launch with a design life of 15 to 20 years that is standard for such spacecraft today, but with only a few years’ worth of fuel on board, decreasing their mass. Those satellites could then be regularly refueled by satellite servicing vehicles, which would also dispose the satellite in a graveyard orbit at the end of its life. “I think the real strength is in the GEO market,” he said.
Joe Anderson, vice president of business development and operations at SpaceLogistics, said his company is looking beyond the satellite life extension services in GEO it provides with its existing Mission Extension Vehicles and future Mission Robotic Vehicle. The company, a subsidiary of Northrop Grumman, is already working on a third-generation vehicle capable of refueling GEO satellites and performing active debris removal.
“The first place we see a potential paying customer is in GEO,” he said of debris removal applications. “It’s going to be around high-value assets that are concerned about some other failed objects in the vicinity.”
Satellite servicing becomes “an interesting case” for cislunar missions, Stolleis added. He was particularly interested in using servicing vehicles for proper disposal of lunar spacecraft at the end of their missions, rather than crashing them into the moon as is typically done today.
“We don’t have a viable disposal orbit, like we have in GEO,” he said of lunar missions. “The moon should not be our universal garbage dump.”
Modern-day imaging technology is able to uncover ancient buildings and structures not visible on the surface, and we just got another excellent example: the discovery of a hidden neighborhood in one of the biggest historical Maya cities.
The city in question is Tikal, now in Guatemala. Thought to have been one of the most dominant settlements in the ancient Maya empire, particularly between 200-900 CE, at its peak it could have had as many as 90,000 people living there.
Using LIDAR scanning equipment, researchers found evidence of development under what was thought to be a natural area. What's more, the hidden ruins look to match the style of buildings in Teotihuacan – a sprawling metropolis established centuries before the rise of the Aztecs, built by a largely unknown culture.
The newly discovered structures match buildings in Teotihuacan. (Thomas Garrison/Pacunam)
That could give researchers some useful clues as to how these two cities interacted. Even though they were more than 1,000 kilometers (621 miles) away from each other, it's already known that traders traveled between the two urban centers.
"What we had taken to be natural hills actually were shown to be modified and conformed to the shape of the citadel – the area that was possibly the imperial palace – at Teotihuacan," says anthropologist Stephen Houston from Brown University in Rhode Island.
"Regardless of who built this smaller-scale replica and why, it shows without a doubt that there was a different level of interaction between Tikal and Teotihuacan than previously believed."
What makes the finding even more surprising is that Tikal has been extensively searched and explored since the 1950s – it's one of the ancient cities that we know most about. And all this time, there was part of it hidden from view.
Tikal is one of the most thoroughly studied archaeological sites in the world. (Stephen Houston)
Excavations were carried out after the scans to confirm the results and the presence of these buildings, with the discovery of these Teotihuacan-like structures opening up some fascinating possibilities. Tikal and Teotihuacan were different in many ways, including their overall size (Teotihuacan was much larger).
The researchers suggest that the buildings could have been a diplomatic embassy of some kind, or perhaps a military outpost. It seems to have been made by people from Teotihuacan, or locals under their control.
"It almost suggests that local builders were told to use an entirely non-local building technology while constructing this sprawling new building complex," says Houston.
"We've rarely seen evidence of anything but two-way interaction between the two civilizations, but here, we seem to be looking at foreigners who are moving aggressively into the area."
The excavations revealed that the Tikal buildings were made out of mud plaster rather than the traditional Maya limestone, suggesting some attempt to build replicas. They also matched the specific 15.5-degree east-of-north orientation of Teotihuacan's buildings.
Adding to the intrigue is the detail that Teotihuacan armies conquered Tikal in the late 4th century. It's clear that relationships ended badly between the two influential cities, but it's not certain what happened in the hundreds of years before that.
Another discovery was what looks like a burial site for a Teotihuacan warrior, matching up with similar sites in the larger metropolis over in Mexico. This is perhaps another clue as to how the two cities interacted with each other.
As well as helping historians dig deeper into the past, the new study is also an opportunity to explore one of the most discussed topics of the modern day: colonialism, and how dominant political and economic systems are felt further around the world. Meanwhile, research at Tikal continues.
"Exploring Teotihuacan's influence on Mesoamerica could be a way to explore the beginnings of colonialism and its oppressions and local collusions," says Houston.
An international collaboration including Oregon State University researcher Bev Law says the health of a terrestrial ecosystem can be largely determined by three variables: vegetations' ability to uptake carbon, its efficiency in using carbon and its efficiency in using water.
Findings, published in Nature, are important because scientists and policymakers need easier, faster and less expensive ways to determine how the ecosystems relied on by humans respond to climate and environmental changes, including impacts caused by people.
"We used these complex, continuous data to develop equations that can be applied with fewer measurements to monitor forest response to climate and other factors," Law said.
The team of researchers, led by the Max Planck Institute for Biogeochemistry in Jena, Germany, used satellite observations, mathematical models and multiple environmental data streams to determine that those three factors combine to represent more than 70% of total ecosystem function.
Put another way, if an ecosystem's carbon uptake, carbon-use efficiency and water-use efficiency are all strong, that means at least 70% of everything the ecosystem is supposed to do is being done well.
"Ecosystems on the Earth's land surface support multiple functions and services that are critical for society," said Law, professor emeritus in the OSU College of Forestry. "Those functions and services include biomass production, plants' efficiency in using sunlight and water, water retention, climate regulation and, ultimately, food security. Monitoring these key indicators allows for describing ecosystem function in a way that summarizes its ability to adapt, survive and thrive as the climate and environment change."
Water-and carbon-use efficiency are linked closely with climate and also with aridity, which suggests climate change will play a big role in shaping ecosystem function over the coming years, the scientists say.
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Among the building blocks of the current research are data from five semi-arid ponderosa pine sites where Law has been conducting research for 25 years.
Those sites are in the AmeriFlux network, a collection of locations in North, South and Central America managed by principal investigators like Law that measure ecosystem carbon dioxide, water and energy "fluxes," or exchanges with the atmosphere. AmeriFlux is part of the international FLUXNET project, and data from 203 FLUXNET sites representing a variety of climate zones and vegetation types were analyzed for the study.
Measuring ecosystem health has long been challenging given the complexities of ecosystem structure and how systems respond to environmental change, said Law, who has been researching the quantification of forest health for decades.
"In the 1980s, I was working on the development of indicators including similar carbon-use efficiency, and many of the measurements were incorporated in the Forest Service's Forest Health Monitoring plots," Law said. "The new flux paper shows how continuous data can be used to develop algorithms to apply in monitoring forest condition, and for evaluating and improving ecosystem models that are used in estimating the effects of climate on ecosystem carbon uptake and water use."
The water-use indicator is a combination of metrics that relate to an ecosystem's water-use efficiency, which is the carbon taken up per amount of water transpired by plants through their leaves. The carbon-use efficiency indicator compares the carbon that's respired versus carbon taken up; plant respiration means converting into energy the sugars produced during photosynthesis.
"Using three major factors, we can explain almost 72% of the variability within ecosystem functions," said Mirco Migliavacca, the study's lead author and a researcher at the Max Planck Institute for Biogeochemistry.
The three functional indicators depend heavily, Law said, on the structure of vegetation -- greenness, nitrogen content of leaves, vegetation height and biomass. That points to the importance of ecosystem structure, which can be altered by disturbances such as fire and also by forest management practices.
WASHINGTON — The Federal Aviation Administration said Sept. 29 that it completed its investigation into a problem on Virgin Galactic’s most recent SpaceShipTwo flight, allowing the company to resume flights of the suborbital spaceplane.
The FAA said it determined SpaceShipTwo deviated from its assigned airspace on its flight July 11 that took six people, including company founder Richard Branson, to an altitude of more than 80 kilometers. The company also failed to communicate that deviation with the FAA.
“The FAA required Virgin Galactic to implement changes on how it communicates to the FAA during flight operations to keep the public safe,” the FAA concluded in a brief statement. “Virgin Galactic has made the required changes and can return to flight operations.”
Asked about those changes, an FAA spokesperson referred to a separate statement from Virgin Galactic. The company said its corrective changes include new calculations to expand the protected airspace during SpaceShipTwo flights. “Designating a larger area will ensure that Virgin Galactic has ample protected airspace for a variety of possible flight trajectories during spaceflight missions,” the company stated.
Virgin Galactic also said that it would also make changes to its flight procedures “to ensure real-time mission notifications to FAA Air Traffic Control.”
“We appreciate the FAA’s thorough review of this inquiry,” Michael Colglazier, Virgin Galactic’s chief executive, said in a statement. “The updates to our airspace and real-time mission notification protocols will strengthen our preparations as we move closer to the commercial launch of our spaceflight experience.”
Neither the FAA nor Virgin Galactic elaborated on the issue during the July flight, known as “Unity 22” by the company, that triggered the investigation. The FAA announced the investigation Sept. 2, the day after an article in The New Yorker revealed that the vehicle’s pilots ignored an “entry glide cone” warning during its rocket-powered ascent, indicating that the vehicle was not climbing steeply enough. The warning meant that SpaceShipTwo was outside the volume of airspace where it could safely glide back to the runway at Spaceport America in New Mexico.
SpaceShipTwo did make it back to the runway without incident, and after the landing company officials didn’t mention that warning or any other problems with the flight. However, the vehicle flew outside of its designated airspace for a time during its descent, something the company acknowledged after The New Yorker article and blamed on high winds at upper altitudes.
Virgin Galactic said Sept. 10 it was postponing the next SpaceShipTwo flight, a research flight for the Italian Air Force called Unity 23, to no earlier than mid-October. The company didn’t update that schedule in its announcement about the end of the FAA investigation.
Unity 23 will be the last SpaceShipTwo flight until at least the latter half of 2022. Virgin Galactic said in August that, after Unity 23, it would start extensive maintenance on both SpaceShipTwo and its WhiteKnightTwo carrier aircraft to allow both to fly more frequently. The company expects that commercial flights of SpaceShipTwo will not resume until late in the third quarter of 2022.
A cave chamber sealed off by sand for some 40,000 years has been discovered in Vanguard Cave in Gibraltar – a finding that could reveal more about the Neanderthals who lived in the area around that time.
"Given that the sand sealing the chamber was [40,000] years old, and that the chamber was therefore older, it must have been Neanderthals," who lived in Eurasia from about 200,000 to 40,000 years ago and were likely using the cave, Clive Finlayson, director of the Gibraltar National Museum, told Live Science in an email.
While Finlayson's team was studying the cave last month, they discovered the hollow area. After climbing through it, they found it is 43 feet (13 meters) in length, with stalactites hanging like eerie icicles from the chamber ceiling.
Along the surface of the cave chamber, the researchers found the remains of lynx, hyenas, and griffon vultures, as well as a large whelk, a type of sea snail that was likely carried into the chamber by a Neanderthal, the archaeologists said in a statement.
The researchers are eager to see what they will find once they start excavating. One possibility is that the team will discover Neanderthal burials, Finlayson said.
"We found the milk tooth of a 4-year-old Neanderthal close to the chamber four years ago," he said. The tooth "was associated with hyenas, and we suspect the hyenas brought the child [who was likely dead] into the cave."
Researchers have discovered plenty of evidence of Neanderthals' presence in the cave system, called the Gorham's Cave Complex, including a carving that may have been early Neanderthal artwork.
In addition, findings have suggested that, at this cave system, our closest extinct relatives butchered seals, plucked feathers off birds of prey to wear as ornaments, and used tools, Live Science previously reported.
Scientists have speculated that this cave system may have been one of the last places Neanderthals lived before they went extinct around 40,000 years ago.
It may be dry as desert bones these days, but Mars was once so wet that entire landscapes were shaped by running water.
Wild floods thundered across the red ground, gouging chasms in the Martian surface and dumping vast quantities of sediment that changed the shape of the landscape. And, in contrast to such landscape-changing water movement on Earth, they happened quickly, on timescales of just a few weeks.
These floods were from overflowing lakes filling craters on the Mars surface, and were much more common than we thought, according to a newly published study.
"If we think about how sediment was being moved across the landscape on ancient Mars, lake breach floods were a really important process globally," says geoscientist Tim Goudge of the University of Texas at Austin.
"And this is a bit of a surprising result because they've been thought of as one-off anomalies for so long."
In comparison to Earth, Mars is pretty riddled with craters. That's because processes such as erosion and tectonic activity have erased a lot of the impact craters from Earth's surface; as a result, the two planets have very different surface profiles. On Mars, the profusion of ancient craters meant that, billions of years ago, when the red planet was still wet, crater lakes were very common.
We know that, when these lakes became too full, they would breach the crater walls and cause devastating floods in the surrounding landscapes. Previous research studying satellite imagery has revealed some of these breached craters, and the deep valleys their floods carved into the landscape nearby.
This time, Goudge and his team took a different approach. Rather than examining individual craters and their surrounds, their study includes 262 breached crater lakes, and how they shaped the surface of Mars globally.
We have a lot of detailed imagery covering the surface of Mars, thanks to years of satellites orbiting the red planet. From this, we have existing maps of river valleys across the globe. The researchers took these maps and placed the river valleys into two categories: those physically connected to a crater breach, and those that formed away from craters, suggesting a more gradual formation process.
In addition, they calculated the volumes of the eroded valleys based on depth and width measurements obtained by satellite measurements – and made a surprising finding.
The valley systems gouged out by crater breach floods only accounted for 3 percent of the length of the valleys eroded by water on the Martian surface. But this 3 percent was much, much deeper than the other river valleys – crater flood valleys had a median depth of 170.5 meters (559 feet) compared to the 77.5-meter (254 foot) median depth of the gradual valleys.
With all the figures added up, the crater flood valleys accounted for at least 24 percent of the volume of river valleys on Mars.
Because this effect was so sharp, the team found that it could have had a lasting impact on the surrounding landscape and river systems, despite the brief duration of the floods themselves. The deep valleys carved out by the floods would have dropped the local base level, establishing new lows for water flows. This would have a significant effect on pre-existing river systems.
All this could explain some features of the topography of Mars that are usually attributed to climate, such as convex fluvial valleys, the researchers said. This topography could instead be a response to disruptions to the base level caused by crater breach flooding.
It also highlights how important it is not to assume that processes here on Earth will occur the same way on other planets. Although the Solar System's rocky worlds have many similarities, their differences can be immense.
"When you fill [the craters] with water, it's a lot of stored energy there to be released," Goudge said. "It makes sense that Mars might tip, in this case, toward being shaped by catastrophism more than the Earth."
With powerful legs tipped by dagger-like talons, capable of eviscerating you with a single kick, cassowaries are the bird that most lives up to the moniker of a modern dinosaur.
But surprisingly, these strikingly unique avians may have been humanity's 'chickens' – long before we kept actual chickens.
Eggshell remnants suggest that as far back as 18,000 years ago, humans seemed to be collecting cassowary eggs for something other than just a tasty meal.
"This is not some small fowl, it is a huge, ornery, flightless bird that can eviscerate you," Penn state anthropologist Kristina Douglass explained.
These hefty fruit eaters maintain their rainforest homes in Australia and Papua New Guinea, with many plants relying on them for germination, dispersal and fertilization of their seeds.
Researchers studying how humans from the late Pleistocene to early Holocene managed their resources in Papua New Guinea's (PNG's) mountainous rainforests, discovered that these people harvested cassowary eggs far more than the adults of these birds. These were likely eggs from the dwarf cassowary, which weigh 20 kilograms (44 pounds) as adults.
Cassowaries use their feet as weapons. (Dezidor/Wikimedia Commons/CC BY 3.0)
Douglass and colleagues constructed a model of eggshell development using 3D microscopy of ostrich eggs, to identify key characteristics across time. After successful tests with other bird species they were then able to apply this model to more than 1,000 cassowary eggshell fragments from PNG's National Museum and Art Gallery, collected by New Zealand archeologist Susan Bulmer.
"A large majority of the eggshells were harvested during late stages," said Douglass, concluding with her team that these people were intentionally harvesting eggs at the stage the embryos had fully formed limbs, beaks, claws and feathers.
"The eggshells look very late; the pattern is not random. They were either into eating baluts or they were hatching chicks."
Baluts are a street food in Asia – embryonic chicks that are cooked and eaten from the shell. While there were signs that some of the eggs had indeed been cooked and eaten, they were eggs from earlier in development – their shells retained burn patterns. The shell fragments from eggs that were closer to hatching, however, were much less likely to contain traces of having been cooked.
"There are enough samples of late stage eggshells that do not show burning that we can say they were hatching and not eating them," said Douglass.
"This behavior that we are seeing is coming thousands of years before domestication of the chicken."
Chickens were domesticated around 9,500 years ago, according to genetic evidence. So while it's highly improbable that humans ever domesticated cassowaries, this is now the earliest known example of humans rearing birds.
"These findings might radically alter the known timelines and geographies of domestication that tend to be the most widely understood and taught," Hunter College archeologist Megan Hicks, who was not involved in the study, told The New York Times.
"Where mammals are the best-known early cases (dogs and bezoar ibex), we now know that we need to be paying closer attention to human interactions with avian species."
Cassowaries are generally quite shy and prefer to avoid humans, but they are territorial and very dangerous if they feel threatened. Despite this, people in PNG today still raise and trade the birds, making use of their meat, bones, feathers and eggs. There's also a long historical record of these birds being traded.
"Cassowary chicks imprint readily to humans and are easy to maintain and raise up to adult size," the team writes in their paper.
A modern day cassowary chick in PNG. (Andy Mack/Penn State University)
Humans reached this part of the world around 42,000 years ago; compared to the later impacts of farming, hunter-gatherers were thought to have had a relatively minimal impact on their environment. But this study suggests foraging communities did shape their environment in unexpected ways.
"Intergenerational knowledge of many Indigenous peoples, which indicates that traditional land owners and their ancestors have intentionally and intensively cultivated expansive landscapes, in some cases for millennia," the team writes.
Around the world, most ratites – the group of large flightless birds that also includes ostriches and elephant birds (Aepyornis maximus) – went extinct soon after humans arrived in their regions. Cassowaries are a rare exception.
The eggshell analysis used here has the potential to help us understand why many other large flightless birds did not make it, the team said.
For now, at least, cassowaries are still feasting on fruits in Australasian rainforests, making weird noises as they go.
The system produces short 'radar movies'. (DeepMind)
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