Science

rocket-lab-entered-“hero-mode”-to-finish-mars-probes—now-it’s-up-to-blue-origin

Rocket Lab entered “hero mode” to finish Mars probes—now it’s up to Blue Origin

blue origin, Commercial space, escapade, heliophysics, launch, Mars, new glenn, rocket lab, Science, Space / /
The two spacecraft for NASA's ESCAPADE mission at Rocket Lab's factory in Long Beach, California.

Enlarge / The two spacecraft for NASA’s ESCAPADE mission at Rocket Lab’s factory in Long Beach, California.

Two NASA spacecraft built by Rocket Lab are on the road from California to Florida this weekend to begin preparations for launch on Blue Origin’s first New Glenn rocket.

These two science probes must launch between late September and mid-October to take advantage of a planetary alignment between Earth and Mars that only happens once every 26 months. NASA tapped Blue Origin, Jeff Bezos’ space company, to launch the Escape and Plasma Acceleration and Dynamics Explorers (ESCAPADE) mission with a $20 million contract.

Last November, the space agency confirmed the $79 million ESCAPADE mission will launch on the inaugural flight of Blue Origin’s New Glenn rocket. With this piece of information, the opaque schedule for Blue Origin’s long-delayed first New Glenn mission suddenly became more clear.

The launch period opens on September 29. The two identical Mars-bound spacecraft for the ESCAPADE mission, nicknamed Blue and Gold, are now complete. Rocket Lab announced Friday that its manufacturing team packed the satellites and shipped them from their factory in Long Beach, California. Over the weekend, they arrived at a clean room facility just outside the gates of NASA’s Kennedy Space Center in Florida, where technicians will perform final checkups and load hydrazine fuel into both spacecraft, each a little more than a half-ton in mass.

Then, if Blue Origin is ready, ground teams will connect the ESCAPADE spacecraft with the New Glenn’s launch adapter, encapsulate the probes inside the payload fairing, and mount them on top of the rocket.

“There’s a whole bunch of checking and tests to make sure everything’s OK, and then we move into fueling, and then we integrate with the launch vehicle. So it’s a big milestone,” said Rob Lillis, the mission’s lead scientist from the University of California Berkeley’s Space Science Laboratory. “There have been some challenges along the way. This wasn’t easy to make happen on this schedule and for this cost. So we’re very happy to be where we are.”

Racing to the finish line

But there’s a lot for Blue Origin to accomplish in the next couple of months if the New Glenn rocket is going to be ready to send the ESCAPADE mission toward Mars in this year’s launch period. Blue Origin has not fully exercised a New Glenn rocket during a launch countdown, hasn’t pumped a full load of cryogenic propellants into the launch vehicle, and hasn’t test-fired a full complement of first stage or second stage engines.

These activities typically take place months before the first launch of a large new orbital-class rocket. For comparison, SpaceX test-fired its first fully assembled Falcon 9 rocket on the launch pad about three months before its first flight in 2010. United Launch Alliance completed a hot-fire test of its new Vulcan rocket on the launch pad last year, about seven months before its inaugural flight.

However, Blue Origin is making visible progress toward the first flight of New Glenn, after years of speculation and few outward signs of advancement. Earlier this year, the company raised a full-scale, 320-foot-tall (98-meter) New Glenn rocket on its launch pad at Cape Canaveral Space Force Station and loaded it with liquid nitrogen, a cryogenic substitute for the methane and liquid hydrogen fuel it will burn in flight.

Rocket Lab entered “hero mode” to finish Mars probes—now it’s up to Blue Origin Read More »

meteorites-give-the-moon-its-extremely-thin-atmosphere

Meteorites give the Moon its extremely thin atmosphere

astronomy, atmosphere, Impacts, meteors, planetary science, Science, the Moon / /

The exosphere gets the vapors —

Impacts that vaporize bits of the lunar surface maintain the Moon’s thin atmosphere.

–

Graphic of a spacecraft above a grey planetary body, with a distant sun in the background.

Enlarge / Artist’s rendition of the LADEE mission above the lunar surface.

The Moon may not have much of an atmosphere, mostly because of its weak gravitational field (whether it had a substantial atmosphere billions of years ago is debatable). But it is thought to presently be maintaining its tenuous atmosphere—also known as an exosphere—because of meteorite impacts.

Space rocks have been bombarding the Moon for its 4.5-billion-year existence. Researchers from MIT and the University of Chicago have now found that lunar soil samples collected by astronauts during the Apollo era show evidence that meteorites, from hulking meteors to micrometeoroids no bigger than specks of dust, have launched a steady flow of atoms into the exosphere.

Though some of these atoms escape into space and others fall back to the surface, those that do remain above the Moon create a thin atmosphere that keeps being replenished as more meteorites crash into the surface.

“Over long timescales, micrometeorite impact vaporization is the primary source of atoms in the lunar atmosphere,” the researchers said in a study recently published in Science Advances.

Ready for launch

When NASA sent its orbiter LADEE (Lunar Atmosphere and Dust Environment Explorer) to the Moon in 2013, the mission was intended to find out the origins of the Moon’s atmosphere. LADEE observed more atoms in the atmosphere during meteor showers, which suggested impacts had something to do with the atmosphere. However, it left questions about the mechanism that converts impact energy into a diffuse atmosphere.

To find these answers, a team of MIT and University of Chicago researchers, led by professor Nicole Nie of MIT’s Department of Earth, Atmospheric and Planetary Sciences, needed to analyze the isotopes of elements in lunar soil that are most susceptible to the effects of micrometeoroid impacts. They chose potassium and rubidium.

Potassium and rubidium ions are especially prone to two processes: impact vaporization and ion sputtering.

Impact vaporization results from particles colliding at high speeds and generating extreme amounts of heat that excite atoms enough to vaporize the material they are in and send them flying. Ion sputtering involves high-energy impacts that set atoms free without vaporization. Atoms that are released by ion sputtering tend to have more energy and move faster than those released by impact vaporization.

Either of these can create and maintain the lunar atmosphere in the wake of meteorite impacts.

So, if atoms sent into the atmosphere by ion sputtering have an energy advantage, then why did the researchers find that most atoms in the atmosphere actually come from impact vaporization?

Touching back down

Since the lunar soil samples provided by NASA had previously had their lighter and heavier isotopes of potassium and rubidium quantified, Lie’s team used calculations to determine which collision process is more likely to keep different isotopes from fleeing the atmosphere.

The researchers found that atoms transferred to the atmosphere by ion sputtering are sent zooming at such high energies that they often reach escape velocity—the minimum velocity needed to escape the Moon’s already feeble gravity—and continue to travel out into space. Atoms that end up in the atmosphere can also be lost from the atmosphere, after all.

The fraction of atoms that reach escape velocity after impact vaporization depends on the temperature of those atoms. Lower energy levels associated with impact vaporization result in lower temperatures, which give atoms a lower chance of escape.

“Impact vaporization is the dominant long-term source of the lunar atmosphere, likely contributing more than 65 percent of atmospheric [potassium] atoms, with ion sputtering accounting for the rest,” Lie and her team said in the same study.

There are other ways atoms are lost from the lunar atmosphere. It is mostly lighter ions that tend to stick around in the exosphere, with ions falling back to the surface if they’re too heavy. Others are photoionized by electromagnetic radiation from the solar wind and often carried off into space by solar wind particles.

What we’ve learned about the lunar atmosphere through lunar soil could influence studies of other bodies. Impact vaporization has already been found to launch atoms into the exosphere of Mercury, which is thinner than the Moon’s. Studying Martian soil, which may land on Earth with sample return missions in the future, could also give more insight into how meteorite impacts affect its atmosphere.

As we approach a new era of manned lunar missions, the Moon may have more to tell us about where its atmosphere comes from—and where it goes.

Science Advances, 2024.  DOI: 10.1126/sciadv.adm7074

Meteorites give the Moon its extremely thin atmosphere Read More »

passing-part-of-a-medical-licensing-exam-doesn’t-make-chatgpt-a-good-doctor

Passing part of a medical licensing exam doesn’t make ChatGPT a good doctor

AI, chatgpt, diagnosis, medicine, Science / /
Smiling doctor discussing medical results with a woman.

Enlarge / For now, “you should see a doctor” remains good advice.

ChatGPT was able to pass some of the United States Medical Licensing Exam (USMLE) tests in a study done in 2022. This year, a team of Canadian medical professionals checked to see if it’s any good at actual doctoring. And it’s not.

ChatGPT vs. Medscape

“Our source for medical questions was the Medscape questions bank,” said Amrit Kirpalani, a medical educator at the Western University in Ontario, Canada, who led the new research into ChatGPT’s performance as a diagnostic tool. The USMLE contained mostly multiple-choice test questions; Medscape has full medical cases based on real-world patients, complete with physical examination findings, laboratory test results, and so on.

The idea behind it is to make those cases challenging for medical practitioners due to complications like multiple comorbidities, where two or more diseases are present at the same time, and various diagnostic dilemmas that make the correct answers less obvious. Kirpalani’s team turned 150 of those Medscape cases into prompts that ChatGPT could understand and process.

This was a bit of a challenge because OpenAI, the company that made ChatGPT, has a restriction against using it for medical advice, so a prompt to straight-up diagnose the case didn’t work. This was easily bypassed, though, by telling the AI that diagnoses were needed for an academic research paper the team was writing. The team then fed it various possible answers, copy/pasted all the case info available at Medscape, and asked ChatGPT to provide the rationale behind its chosen answers.

It turned out that in 76 out of 150 cases, ChatGPT was wrong. But the chatbot was supposed to be good at diagnosing, wasn’t it?

Special-purpose tools

At the beginning of 2024. Google published a study on the Articulate Medical Intelligence Explorer (AMIE), a large language model purpose-built to diagnose diseases based on conversations with patients. AMIE outperformed human doctors in diagnosing 303 cases sourced from New England Journal of Medicine and ClinicoPathologic Conferences. And AMIE is not an outlier; during the last year, there was hardly a week without published research showcasing an AI performing amazingly well in diagnosing cancer and diabetes, and even predicting male infertility based on blood test results.

The difference between such specialized medical AIs and ChatGPT, though, lies in the data they have been trained on. “Such AIs may have been trained on tons of medical literature and may even have been trained on similar complex cases as well,” Kirpalani explained. “These may be tailored to understand medical terminology, interpret diagnostic tests, and recognize patterns in medical data that are relevant to specific diseases or conditions. In contrast, general-purpose LLMs like ChatGPT are trained on a wide range of topics and lack the deep domain expertise required for medical diagnosis.”

Passing part of a medical licensing exam doesn’t make ChatGPT a good doctor Read More »

rocket-report:-ula-is-losing-engineers;-spacex-is-launching-every-two-days

Rocket Report: ULA is losing engineers; SpaceX is launching every two days

falcon 9, Federal Aviation Administration, launch, NASA, rocket lab, rocket report, russia, Science, Space, starship, stoke space, united launch alliance / /

Every other day —

The first missions of Stoke Space’s reusable Nova rocket will fly in expendable mode.

–

A Falcon 9 booster returns to landing at Cape Canaveral Space Force Station following a launch Thursday with two WorldView Earth observation satellites for Maxar.

Enlarge / A Falcon 9 booster returns to landing at Cape Canaveral Space Force Station following a launch Thursday with two WorldView Earth observation satellites for Maxar.

Welcome to Edition 7.07 of the Rocket Report! SpaceX has not missed a beat since the Federal Aviation Administration gave the company a green light to resume Falcon 9 launches after a failure last month. In 19 days, SpaceX has launched 10 flights of the Falcon 9 rocket, taking advantage of all three of its Falcon 9 launch pads. This is a remarkable cadence in its own right, but even though it’s a small sample size, it is especially impressive right out of the gate after the rocket’s grounding.

As always, we welcome reader submissions. If you don’t want to miss an issue, please subscribe using the box below (the form will not appear on AMP-enabled versions of the site). Each report will include information on small-, medium-, and heavy-lift rockets as well as a quick look ahead at the next three launches on the calendar.

A quick turnaround for Rocket Lab. Rocket Lab launched its 52nd Electron rocket on August 11 from its private spaceport on Mahia Peninsula in New Zealand, Space News reports. The company’s light-class Electron rocket deployed a small radar imaging satellite into a mid-inclination orbit for Capella Space. This was the shortest turnaround between two Rocket Lab missions from its primary launch base in New Zealand, coming less than nine days after an Electron rocket took off from the same pad with a radar imaging satellite for the Japanese company Synspective. Capella’s Acadia 3 satellite was originally supposed to launch in July, but Capella requested a delay to perform more testing of its spacecraft. Rocket Lab swapped its place in the Electron launch sequence and launched the Synspective mission first.

Now, silence at the launch pad … Rocket Lab hailed the swap as an example of the flexibility provided by Electron, as well as the ability to deliver payloads to specific orbits that are not feasible with rideshare missions, according to Space News. For this tailored launch service, Rocket Lab charges a premium launch price over the price of launching a small payload on a SpaceX rideshare mission. However, SpaceX’s rideshare launches gobble up the lion’s share of small satellites within Rocket Lab’s addressable market. On Friday, a Falcon 9 rocket is slated to launch 116 small payloads into polar orbit. Rocket Lab, meanwhile, projects just one more launch before the end of September and expects to perform 15 to 18 Electron launches this year, a record for the company but well short of the 22 it forecasted earlier in the year. Rocket Lab says customer readiness is the reason it will be far short of projections.

The easiest way to keep up with Eric Berger’s space reporting is to sign up for his newsletter, we’ll collect his stories in your inbox.

Defense contractors teaming up on solid rockets. Lockheed Martin and General Dynamics are joining forces to kickstart solid rocket motor production, announcing a strategic teaming agreement today that could see new motors roll off the line as early as 2025, Breaking Defense reports. The new agreement could position a third vendor to enter into the ailing solid rocket motor industrial base, which currently only includes L3Harris subsidiary Aerojet Rocketdyne and Northrop Grumman in the United States. Both companies have struggled to meet demands from weapons makers like Lockheed and RTX, which are in desperate need of solid rocket motors for products such as Javelin or the PAC-3 missiles used by the Patriot missile defense system.

Pressure from startups … Demand for solid rocket motors has skyrocketed since Russia’s invasion of Ukraine as the United States and its partners sought to backfill stocks of weapons like Javelin and Stinger, as well as provide motors to meet growing needs in the space domain. Although General Dynamics has kept its interest in the solid rocket motor market quiet until now, several defense tech startups, such as Ursa Major Technologies, Anduril, and X-Bow Systems, have announced plans to enter the market. (submitted by Ken the Bin)

Going polar with crew. SpaceX will fly the first human spaceflight over the Earth’s poles, possibly before the end of this year, Ars reports. The private Crew Dragon mission will be led by a Chinese-born cryptocurrency entrepreneur named Chun Wang, and he will be joined by a polar explorer, a roboticist, and a filmmaker whom he has befriended in recent years. The “Fram2” mission, named after the Norwegian research ship Fram, will launch into a polar corridor from SpaceX’s launch facilities in Florida and fly directly over the north and south poles. The three- to five-day mission is being timed to fly over Antarctica near the summer solstice in the Southern Hemisphere, to afford maximum lighting.

Wang’s inclination is Wang’s prerogative … Wang told Ars he wanted to try something new, and flying a polar mission aligned with his interests in cold places on Earth. He’s paying the way on a commercial basis, and SpaceX in recent years has demonstrated it can launch satellites into polar orbit from Cape Canaveral, Florida, something no one had done in more than 50 years. The highest-inclination flight ever by a human spacecraft was the Soviet Vostok 6 mission in 1963 when Valentina Tereshkova’s spacecraft reached 65.1 degrees. Now, Fram2 will fly repeatedly and directly over the poles.

Rocket Report: ULA is losing engineers; SpaceX is launching every two days Read More »

explosion-of-cicada-eating-mites-has-the-state-of-illinois-scratching

Explosion of cicada-eating mites has the state of Illinois scratching

CDC, cicadas, health, itch mites, mites, outbreak, rash, Science / /

Attack of the mites —

The good news: There’s little risk beyond the rash. The bad: The rash is awful.

–

A cicada from a 17-year cicada brood clings to a tree on May 29, 2024, in Park Ridge, Illinois. The state experienced an emergence of cicadas from Brood XIII and Brood XIX simultaneously. This rare occurrence hasn't taken place since 1803.

Enlarge / A cicada from a 17-year cicada brood clings to a tree on May 29, 2024, in Park Ridge, Illinois. The state experienced an emergence of cicadas from Brood XIII and Brood XIX simultaneously. This rare occurrence hasn’t taken place since 1803.

A plague of parasitic mites has descended upon Illinois in the wake of this year’s historic crop of cicadas, leaving residents with raging rashes and incessant itching.

The mighty attack follows the overlapping emergence of the 17-year Brood XIII and the 13-year Brood XIX this past spring, a specific co-emergence that only occurs every 221 years. The cacophonous boom in cicadas sparked an explosion of mites, which can feast on various insects, including the developing eggs of periodical cicadas. But, when the mites’ food source fizzles out, the mites bite any humans in their midst in hopes of finding their next meal. While the mites cannot live on humans, their biting leads to scratching. The mite, Pyemotes herfsi, is aptly dubbed the “itch mite.”

“You can’t see them, you can’t feel them, they’re always here,” Jennifer Rydzewski, an ecologist for the Forest Preserve District of DuPage County, told Chicago outlet The Daily Herald. “But because of the cicadas, they have a food source [and] their population has exploded.”

The mites are around 0.2 millimeters in length and very difficult to see with the naked eye, according to agriculture experts at Pennsylvania State University. They have four pairs of legs and are tan with a reddish tinge. Female itch mites can produce up to 250 offspring, which emerge from her abdomen as adults. Emerged adult offspring quickly mate, with the males then dying off and the newly fertilized females dispersing to find their own food source.

Itchy outbreak

Besides “itch mites” these parasites have also been called the “oak leaf itch mite” or “oak leaf gall mite,” because they have often been found feasting on the larvae of oak gall midges. These midges are a type of fly that lays eggs on oak trees. The resulting larvae feast on the tree, spurring the formation of unusual growths (galls) around the larvae.

The first known outbreak of itch mites in the US occurred in Kansas in August 2004. The Kansas Department of Health and Environment had called in the Centers for Disease Control and Prevention to help investigate a puzzling outbreak of rashes in Crawford County. At the start, 300 residents in the small city of Pittsburg reported extremely itchy rashes, primarily on the limbs, neck, and face. The rashes looked similar to those from insect bites, but few of the affected people recalled being bitten by anything.

With the help of entomologists, outbreak investigators pinned the rashes to the itch mites. The area had experienced a mild winter and cooler summer temps, leading to an explosion of oak gall midges and subsequent infestation of oak galls. A detailed investigation determined that county residents were nearly four times more likely to have an itchy rash if they had a pin oak tree on their property. Once the itch mites invade a gall-infected oak tree, more than 16,000 mites can emerge from the galls on a single leaf. The mites can then drop from trees and are even small enough to be carried by the wind, giving them ample opportunity to find their way onto humans.

By the end of the outbreak, investigators estimated that 54 percent of the roughly 38,000 residents in Crawford County—that is, around 20,500 people—had been bitten by the mites.

Profuse parasites

But oak gall midges are far from the only insect the itch mites feed upon. In 2007, the emergence of a particularly prolific brood of cicadas led to an outbreak of itch mites in the Chicago area. The Illinois Department of Public Health noted that the “proposed common name ‘oak leaf itch mite’ for P. herfsi is misleading and contributed to the delay in identifying the causative agent of the 2007 Illinois outbreak.” The department noted that at least five insect orders and nine insect families are prey to the mites.

In the US, cases of itch mite rashes have been documented in at least Illinois, Nebraska, Ohio, Oklahoma, Pennsylvania, Missouri, Tennessee, and Texas.

If bitten, humans develop an itchy red rash, typically with pimple-like bumps, which can stick around for up to two weeks. The rash develops between 10 to 16 hours after exposure, which can make it difficult to identify the source. But, the mites typically don’t produce groupings of bite marks like bedbugs or burrowing like scabies.

To try to avoid rashes, experts recommend wearing protective clothing when outside—including gloves while gardening or doing yard work—and washing clothes and showering after a potential exposure. The insect repellent DEET is often recommended, but anecdotal reports indicate DEET may not be entirely effective. If you already have a rash, the only thing to do is treat the symptoms with things like ice packs, soothing lotions (like calamine), oral antihistamines, over-the-counter hydrocortisone creams, and, if needed, prescription topical steroids. The good news is that the mites will not live on you and are not known to spread any diseases.

Explosion of cicada-eating mites has the state of Illinois scratching Read More »

big-name-drugs-see-price-drops-in-first-round-of-medicare-negotiations

Big-name drugs see price drops in first round of Medicare negotiations

Big pharma, drug prices, health, medicare, Pharmaceutical industry, PhRMA, price negotiations, Science / /

price cut —

If the prices were set in 2023, Medicare would have saved $6 billion.

–

Prescription drugs are displayed at NYC Discount Pharmacy in Manhattan on July 23, 2024.

Enlarge / Prescription drugs are displayed at NYC Discount Pharmacy in Manhattan on July 23, 2024.

In the first round of direct price negotiations between Medicare and drug manufacturers, prices for 10 expensive and commonly used drugs saw price cuts between 38 percent to 79 percent compared to their 2023 list prices, the White House and the US Department of Health and Human Services (HHS) announced Thursday. The new negotiated prices will take effect on January 1, 2026.

The 10 drugs that were up for negotiations are used to treat various conditions, from diabetes, psoriasis, blood clots, heart failure, and chronic kidney disease to blood cancers. About 9 million people with Medicare use at least one of the drugs on the list. In 2023, the 10 drugs accounted for $56.2 billion in total Medicare spending, or about 20 percent of total gross spending by Medicare Part D prescription drug coverage. But in 2018, spending on the 10 drugs was just about $20 billion, rising to 46 billion in 2022—a 134 percent rise. In 2022, Medicare enrollees collectively paid $3.4 billion in out-of-pocket costs for these drugs.

The 10 drugs as well as their use, 2023 costs, negotiated prices, and savings.

Enlarge / The 10 drugs as well as their use, 2023 costs, negotiated prices, and savings.

For now, it’s unclear how much the newly set prices will actually save those who have Medicare enrollees in 2026. Overall costs and out-of-pocket costs will depend on each member’s coverage plans and other drug spending. Additionally, in 2025, Medicare Part D enrollees will have their out-of-pocket drug costs capped at $2,000, which alone could significantly lower costs for some beneficiaries before the negotiated prices take effect.

If the newly negotiated prices took effect in 2023, HHS estimates it would have saved Medicare $6 billion. HHS also estimates that the prices will save Medicare enrollees $1.5 billion in out-of-pocket costs in 2026.

The price negotiations have been ongoing since last August when HHS announced the first 10 drugs up for negotiation. Medicare said it held three meetings with each of the drug manufacturers since then. For five drugs, the process of offers and counteroffers resulted in an agreed-upon price, with Medicare accepting revised counteroffers from drugmakers for four of the drugs. For the other five drugs, Medicare made final written offers on prices that were eventually accepted. If a drugmaker had rejected the offer, it would have either had to pay large fees or pull its drug from Medicare plans.

“The negotiations were comprehensive. They were intense. It took both sides to reach a good deal,” HHS Secretary Xavier Becerra told reporters Wednesday night.

“Price-setting scheme”

Both the price negotiations and the $2,000 cap are provisions in the Inflation Reduction Act (IRA), signed into law by President Biden in 2022. In a statement Thursday, Biden highlighted that Vice President Kamala Harris cast the tie-breaking vote to pass the legislation along party lines and that they are both committed to fighting Big Pharma. “[T]he Vice President and I are not backing down,” Biden said. “We will continue the fight to make sure all Americans can pay less for prescription drugs and to give more breathing room for American families.”

“Today’s announcement will be lifechanging for so many of our loved ones across the nation,” Harris said in her own statement, “and we are not stopping here.” She noted that the list of drugs up for Medicare negotiation will increase in each year, with an additional 15 drugs added in 2025.

In a scathing response to the negotiated prices, Steve Ubl—president of the industry group Pharmaceutical Research and Manufacturers of America (PhRMA)—called the negotiations a “price-setting scheme” and warned that patients would be disappointed. “There are no assurances patients will see lower out-of-pocket costs because the [IRA] did nothing to rein in abuses by insurance companies and PBMs who ultimately decide what medicines are covered and what patients pay at the pharmacy,” Ubl said. He went on to warn that IRA “fundamentally alters” the incentives for drug development and, as such, fewer drugs will be developed to treat cancer and many other conditions.

In a December 2023 report, the Congressional Budget Office estimated that “over the next 30 years, 13 fewer new drugs (of 1,300 estimated new drugs) will come to market as a result of the law.”

The pharmaceutical industry has unleashed a bevy of legal challenges to the negotiations, claiming they are unconstitutional. So far, it has lost every ruling.

Big-name drugs see price drops in first round of Medicare negotiations Read More »

an-asteroid-wiped-out-the-dinosaurs,-not-a-comet,-new-study-finds

An asteroid wiped out the dinosaurs, not a comet, new study finds

asteroids, Chicxulub impact, Science / /

It came from outer space —

Analysis of ruthenium isotopes showed the impactor was a carbonaceous-type asteroid.

–

Artist impression of a large asteroid impacting on Earth such as the Chicxulub event that caused the end-Cretaceous mass extinction, 66 million years ago.

Enlarge / Artist impression of a large asteroid impacting on Earth, such as the Chicxulub event that caused the end-Cretaceous mass extinction 66 million years ago.

Mark Garlick

Some 66 million years ago, an errant asteroid wiped out three-quarters of all plant and animal species on Earth, most notably taking down the dinosaurs. That has long been the scientific consensus. However, three years ago, Harvard astronomers offered an alternative hypothesis: The culprit may have been a fragment of a comet thrown off-course by Jupiter’s gravity and ripped apart by the Sun.

Now an international team of scientists have reaffirmed the original hypothesis, according to a new paper published in the journal Science. They analyzed ruthenium isotopes from the Chicxulub impact crater and concluded the impact was due to a carbonaceous-type asteroid, likely hailing from beyond Jupiter.

As previously reported, the most widely accepted explanation for what triggered that catastrophic mass extinction is known as the “Alvarez hypothesis,” after the late physicist Luis Alvarez and his geologist son, Walter. In 1980, they proposed that the extinction event may have been caused by a massive asteroid or comet hitting the Earth. They based this conclusion on their analysis of sedimentary layers at the Cretaceous-Paleogene boundary (the K-Pg boundary, formerly known as the K-T boundary) found all over the world, which included unusually high concentrations of iridium—a metal more commonly found in asteroids than on Earth. (That same year, Dutch geophysicist Jan Smit independently arrived at a similar conclusion.)

The 66-million-year-old Cretaceous-Paleogene (K-Pg) boundary layer at Stevns Klint in Denmark.

Enlarge / The 66-million-year-old Cretaceous-Paleogene (K-Pg) boundary layer at Stevns Klint in Denmark.

Philippe Claeys

Since then, scientists have identified a likely impact site: a large crater in Chicxulub, Mexico, in the Yucatan Peninsula, first discovered by geophysicists in the late 1970s. The impactor that created it was sufficiently large (between 11 and 81 kilometers, or 7 to 50 miles) to melt, shock, and eject granite from deep inside the Earth, probably causing a megatsunami and ejecting vaporized rock and sulfates into the atmosphere.

This in turn had a devastating effect on the global climate, leading to mass extinction. In 2022, scientists suggested that one reason so many species perished while others survived may have been because the impact occurred in the spring (at least in the Northern Hemisphere), thereby interrupting the annual reproductive cycles of many species.

In 2016, a scientific drilling project led by the International Ocean Discovery Program took core samples from the crater’s peak ring, confirming that the rock had been subjected to immense pressure over a period of minutes. A 2020 paper concluded that the impactor struck at the worst possible angle and caused maximum damage. It has been estimated that the impact would have released energy over a billion times higher than the atomic bombs dropped on Hiroshima and Nagasaki in 1945.

Asteroid or comet?

Harvard’s Avi Loeb and his then-undergraduate student Amir Siraj challenged the asteroid-as-impactor hypothesis in a 2021 paper, proposing instead that the impact was caused by a special kind of comet—originating from a field of debris at the edge of our solar system known as the Oort cloud—that was thrown off course by Jupiter’s gravity toward the Sun. The Sun’s powerful tidal forces then ripped off pieces off the comet—akin to what happened to the comet Shoemaker-Levy 9 when it crashed into Jupiter in 1994—and one of the larger fragments of this “cometary shrapnel” eventually collided with Earth.

Loeb and Siraj’s analysis was based on numerical simulations to calculate the flux of long-period comets in our solar system. They found that events like the one described above should happen frequently enough and produce enough sufficiently large fragments to result in a significantly higher impact rate of Chicxulub-sized impactors than the background comet or asteroid populations. They argued that their comet hypothesis would also explain the Chicxulub impactor’s unusual composition of carbonaceous chondrite—rare for asteroids but more common for long-period comets—which is consistent with an Oort cloud origin rather than the main asteroid belt.

This latest paper addresses that latter point in particular. Mario Fischer-Gödde of the University of Cologne in Germany and his co-authors took samples from the K-Pg boundary layer from a site at Stevns Klint in Denmark and analyzed the ruthenium isotopes via plasma mass spectrometry. They did the same for samples taken from the sites of five other known asteroid impacts over the last 541 million years, as well as ancient Archean samples (between 3.5 to 3.2 billion years old).

Fischer-Gödde et al. concluded that the ruthenium signatures in the K-Pg samples were a close match to asteroids known as carbonaceous chondrites, so the impact most likely resulted from a C-type asteroid that hailed from the outer Solar System. They were able to rule out the possibility of a comet impactor proposed by Loeb and Siraj since the ruthenium data was inconsistent with that hypothesis. Most of the other samples had ruthenium isotope signatures consistent with salicaceous (S-type) asteroids from the inner Solar System, although the ancient Archean samples were also consist with a C-type asteroid.

Science, 2024. DOI: 10.1126/science.adk4868  (About DOIs).

An asteroid wiped out the dinosaurs, not a comet, new study finds Read More »

facing-“financial-crisis,”-russia-on-pace-for-lowest-launch-total-in-6-decades

Facing “financial crisis,” Russia on pace for lowest launch total in 6 decades

roscosmos, russian space program, Science, Space / /

SMO fallout —

“This forces us to build a new economy in severe conditions.”

–

A Soyuz 2.1b rocket booster with a Frigate upper stage block, the Meteor-M 2-1 meteorological satellite, and 18 small satellites launched from the Vostochny Cosmodrome.

Enlarge / A Soyuz 2.1b rocket booster with a Frigate upper stage block, the Meteor-M 2-1 meteorological satellite, and 18 small satellites launched from the Vostochny Cosmodrome.

Yuri Smityuk/TASS

A Progress cargo supply spacecraft launched from the Baikonur Cosmodrome in Kazakhstan early on Thursday, local time. The mission was successful, and Russia has launched hundreds of these spacecraft before. So it wasn’t all that big of a deal, except for one small detail: This was just Russia’s ninth orbital launch of the year.

At this pace, it appears that the country’s space program is on pace for the fewest number of Russian or Soviet space launches in a year since 1961. That was when Yuri Gagarin went to space at the dawn of the human spaceflight era.

There are myriad reasons for this, including a decision by Western space powers to distance themselves from the Russian space corporation, Roscosmos, after the invasion of Ukraine. This has had disastrous effects on the Russian space program, but only recently have we gotten any insight into how deep those impacts have cut.

In recent weeks, the first deputy director of Roscosmos, Andrei Yelchaninov, has given a series of interviews to Russian news outlets. (Most Russian media are state-owned or state-controlled, so none of this information can be independently verified, but it is interesting nonetheless.) One of the most revealing of these interviews was given to national news agency Interfax. It was translated for Ars by Rob Mitchell and provides perspective on Russia’s space crisis and how the country will seek to rebound.

A financial crisis

“We are in an ongoing process of emerging from financial crisis, and it’s complicated,” Yelchaninov told Interfax. “I would remind you that contract cancellations by unfriendly contacts cost Roscosmos 180 billion rubles ($2.1 billion US). This forces us to build a new economy in severe conditions.”

As a result of this, Russia’s space industry has been operating at a loss in recent years and may not begin to break even until 2025. Russia’s invasion of Ukraine also came as United Launch Alliance finally ended its practice of purchasing RD-180 rocket engines, manufactured by NPO Energomash. This fact, in concert with decreased commercial demand for Russia’s Proton and Soyuz rockets, has forced the Russian government to subsidize these elements of Roscosmos.

These companies “are currently in a financial revitalization procedure and have received State subsidies several years ago in order to maintain viability, and are now seeking new sales markets and additional workload,” Yelchaninov said. Asked about possibly selling more Russian-made engines to the United States, Yelchaninov replied, “That issue is not on the agenda.”

Russia had to look to new sales markets after what Yelchaninov euphemistically refers to as the “special military operation,” which is Russia’s term of art for its war against Ukraine. “After the beginning of the SMO we were forced to shift from our traditional partners in Europe and the US, with whom we had many years of interaction, for new international directions including the countries in Africa, the Mideast, and Southeast Asia,” he said.

During the interview, Yelchaninov confirmed that Russia has committed to participating in the International Space Station program until “at least” 2028. NASA is pushing to extend the operational lifetime of the station to 2030, at which point the United States plans to de-orbit the aging laboratory using a modified Crew Dragon spacecraft.

Rather than working with the United States in space, Yelchaninov said that Russia’s space program would focus on cooperation with China rather than competition there. “The key project of our bilateral cooperation is creating an International Lunar Station to which we are jointly striving to attract additional international partners,” he said.

Big plans, big delays?

In addition, Russia is also continuing the development of its oft-delayed “Russian Orbital Station,” or ROS. The current plans call for the launch of a scientific and power module in 2027, with the core of the station (four modules) to be launched into orbit by 2030. Further expansions will take place in the early 2030s. It should be noted, however, that these dates can charitably be described as aspirational.

Even more speculatively, Yelchaninov mentioned several future rocket projects, including the Amur-LNG vehicle and the Corona rocket.

In 2020, Russia aimed to debut the methane-powered Amur rocket with a reusable first stage by 2026. This vehicle was developed to be cost-competitive with SpaceX’s Falcon 9 rocket. Yelchaninov now said Roscosmos intends to develop first-stage reuse in two phases. In the first of these, a Grasshopper-like program would test landing technologies before moving to experiments with a complete booster. But don’t expect to see Amur any time soon. Yelchaninov revealed that Russian and Kazakh officials are still in the design phase of a launch site at Baikonur, rather than actively building anything.

Yelchaninov also said Roscosmos would like to develop a single-stage-to-orbit rocket named Corona in the future. This appears to be an updated take on a Russian rocket design that is more than three decades old.

“We have already studied whether or not a new booster of this type will be in demand,” Yelchaninov said. “The answer is obvious—we are reducing the cost of access to space by more than an order of magnitude and discovering entirely new opportunities for super-operational delivery of cargo, and we are moving toward an ideology of space as a service.”

I would not hold my breath on seeing Corona fly.

Facing “financial crisis,” Russia on pace for lowest launch total in 6 decades Read More »

mpox-outbreak-is-an-international-health-emergency,-who-declares

Mpox outbreak is an international health emergency, WHO declares

africa, CDC, health, Infectious disease, mpox, outbreak, Science, WHO / /

PHEIC —

The declaration is “the highest level of alarm under international health law.”

–

A negative stain electron micrograph of a mpox virus virion in human vesicular fluid.

Enlarge / A negative stain electron micrograph of a mpox virus virion in human vesicular fluid.

The World Health Organization on Wednesday declared an international health emergency over a large and rapidly expanding outbreak of mpox that is spilling out of the Democratic Republic of the Congo.

It is the second time in about two years that mpox’s spread has spurred the WHO to declare a public health emergency of international concern (PHEIC), the highest level of alarm for the United Nations health agency. In July 2022, the WHO declared a PHEIC after mpox cases had spread across the globe, with the epicenter of the outbreak in Europe, primarily in men who have sex with men. The outbreak was caused by clade II mpox viruses, which, between the two mpox clades that exist, is the relatively mild one, causing far fewer deaths. As awareness, precautions, and vaccination increased, the outbreak subsided and was declared over in May 2023.

Unlike the 2022–2023 outbreak, the current mpox outbreak is driven by the clade II virus, the more dangerous version that causes more severe disease and more deaths. Also, while the clade I virus in the previous outbreak unexpectedly spread via sexual contact in adults, this clade II outbreak is spreading in more classic contact patterns, mostly through skin contact of household members and health care workers. A large proportion of those infected have been children.

To date, Democratic Republic of the Congo (DRC), where the virus is endemic, has reported more than 22,000 suspect mpox cases and more than 1,200 deaths since the start of January 2023. In recent months, the outbreak has spilled out into multiple neighboring countries, including Burundi, Central African Republic, Republic of the Congo, Rwanda, Kenya, and Uganda.

Earlier on Wednesday, the WHO convened an emergency committee to review the situation, in which experts from affected countries presented data to independent international experts. The committee concluded that the outbreak constituted a PHEIC, and WHO Director-General Dr. Tedros Adhanom Ghebreyesus followed their recommendation.

“The emergence of a new clade of mpox, its rapid spread in eastern DRC, and the reporting of cases in several neighboring countries are very worrying,” Tedros said in a statement announcing the PHEIC. “On top of outbreaks of other mpox clades in DRC and other countries in Africa, it’s clear that a coordinated international response is needed to stop these outbreaks and save lives.”

On Tuesday, the Africa Centers for Disease Control and Prevention declared a similar emergency. Africa CDC Director General Dr. Jean Kaseya said the declaration will “mobilize our institutions, our collective will, and our resources to act—swiftly and decisively. This empowers us to forge new partnerships, strengthen our health systems, educate our communities, and deliver life-saving interventions where they are needed most.”

For now, the US Centers for Disease Control and Prevention assess the risk to the US public to be “very low,” given that there is limited and no direct travel between the US and the epicenter of the outbreak. So far, no clade I cases have been detected outside of central and eastern Africa.

Mpox outbreak is an international health emergency, WHO declares Read More »

nasa-shuts-down-asteroid-hunting-telescope,-but-a-better-one-is-on-the-way

NASA shuts down asteroid-hunting telescope, but a better one is on the way

asteroids, jet propulsion laboratory, NASA, near earth object, NEOWISE, Science, Space / /

Prolific —

The NEOWISE spacecraft is on a course to fall out of orbit in the next few months.

–

Artist's illustration of NASA's Wide-field Infrared Survey Explorer spacecraft.

Enlarge / Artist’s illustration of NASA’s Wide-field Infrared Survey Explorer spacecraft.

Last week, NASA decommissioned a nearly 15-year-old spacecraft that discovered 400 near-Earth asteroids and comets, closing an important chapter in the agency’s planetary defense program.

From its position in low-Earth orbit, the spacecraft’s infrared telescope scanned the entire sky 23 times and captured millions of images, initially searching for infrared emissions from galaxies, stars, and asteroids before focusing solely on objects within the Solar System.

Wising up to NEOs

The Wide-field Infrared Survey Explorer, or WISE, spacecraft launched in December 2009 on a mission originally designed to last seven months. After WISE completed checkouts and ended its primary all-sky astronomical survey, NASA put the spacecraft into hibernation in 2011 after its supply of frozen hydrogen coolant ran out, reducing the sensitivity of its infrared detectors. But astronomers saw that the telescope could still detect objects closer to Earth, and NASA reactivated the mission in 2013 for another decade of observations.

The reborn mission was known as NEOWISE (Near-Earth Object Wide-field Infrared Survey Explorer). Its purpose was to use the spacecraft’s infrared vision to detect faint asteroids and comets on trajectories that bring them close to Earth.

“We never thought it would last this long,” said Amy Mainzer, NEOWISE’s principal investigator from the University of Arizona and UCLA.

Ground controllers at NASA’s Jet Propulsion Laboratory in California sent the final command to the NEOWISE spacecraft on August 8. The spacecraft, currently at an altitude of about 217 miles (350 kilometers), is falling out of orbit as atmospheric drag slows it down. NASA expects the spacecraft will reenter the atmosphere and burn up before the end of this year, a few months earlier than expected, due to higher levels of solar activity, which causes expansion in the upper atmosphere. The satellite doesn’t have its own propulsion to boost itself into a higher orbit.

“The Sun’s just been incredibly quiet for many years now, but it’s picking back up, and it was the right time to let it go,” Mainzer told Ars.

Astronomers have used ground-based telescopes to discover most of the near-Earth objects detected so far. But there’s an advantage to using a space-based telescope, because Earth’s atmosphere absorbs most of the infrared energy coming from faint objects like asteroids.

With ground-based telescopes, astronomers are “predominantly seeing sunlight reflecting off the surfaces of the objects,” Mainzer said. NEOWISE measures thermal emissions from the asteroids, giving scientists information about their sizes. “We can actually get pretty good measurements of size with relatively few infrared measurements,” she said.

The telescope on NEOWISE was relatively modest in size, with a 16-inch (40-centimeter) primary mirror, more than 16 times smaller than the mirror on the James Webb Space Telescope. But its wide field of view allowed NEOWISE to scour the sky for infrared light sources, making it well-suited for studying large populations of objects. One of the mission’s most famous discoveries was a comet officially named C/2020 F3, more commonly known as Comet NEOWISE, which became visible to the naked eye in 2020. As the comet moved closer to Earth, large telescopes like Hubble were able to take a closer look.

“The NEOWISE mission has been an extraordinary success story as it helped us better understand our place in the universe by tracking asteroids and comets that could be hazardous for us on Earth,” said Nicola Fox, associate administrator of NASA’s science mission directorate.

What’s out there?

The original mission of WISE and the extended survey of NEOWISE combined to discover 366 near-Earth asteroids and 34 comets, according to the Center for Near-Earth Object Studies. Of these, 64 were classified as potentially hazardous asteroids, meaning they come within 4.65 million miles (7.48 million kilometers) of Earth and are at least 500 feet (140 meters) in diameter. These are the objects astronomers want to find and track in order to predict if they pose a risk of colliding with Earth.

There are roughly 2,400 known potentially hazardous asteroids, but there are more lurking out there. Another advantage of using space-based telescopes to search for these asteroids is that they can observe 24 hours a day, while telescopes on the ground are limited to nighttime surveys. Some hazardous asteroids, such as the house-sized object that exploded in the atmosphere over Chelyabinsk, Russia, in 2013, approach Earth from the direction of the Sun. A space telescope has a better chance of finding these kinds of asteroids.

WISE, and then the extended mission of NEOWISE, helped scientists estimate there are approximately 25,000 near-Earth objects.

“The objects (NEOWISE) did discover tended to be overwhelmingly just dark, [and] these are the objects that are much more likely to be missed by the ground-based telescopes,” Mainzer said. “So that, in turn, gives us a much better idea of how many are really out there.”

NASA shuts down asteroid-hunting telescope, but a better one is on the way Read More »

scientists-solved-mysterious-origin-of-stonehenge’s-altar-stone:-scotland

Scientists solved mysterious origin of Stonehenge’s Altar Stone: Scotland

Archaeology, Science, stonehenge / /
The Altar Stone at Stonehenge.

Enlarge / The Altar Stone at Stonehenge weighs roughly 6 tons and was probably transported by land—or possibly by sea.

English Heritage

The largest of the “bluestones” that comprise the inner circle at Stonehenge is known as the Altar Stone. Like its neighbors, scientists previously thought the stone had originated in western Wales and been transported some 125 miles to the famous monument that still stands on the Salisbury Plain in Wiltshire, England. But a new paper published in the journal Nature came to a different conclusion based on fresh analysis of its chemical composition: The Altar Stone actually hails from the very northeast corner of Scotland.

“Our analysis found specific mineral grains in the Altar Stone are mostly between 1,000 to 2,000 million years old, while other minerals are around 450 million years old,” said co-author Anthony Clarke, a graduate student at Curtin University in Australia, who grew up in Mynydd Preseli in Wales—origin of most of the bluestones—and first visited the monument when he was just a year old. “This provides a distinct chemical fingerprint suggesting the stone came from rocks in the Orcadian Basin, Scotland, at least 750 kilometers [450 miles] away from Stonehenge.”

As previously reported, Stonehenge consists of an outer circle of vertical sandstone slabs (sarsen stones), connected on top by horizontal lintel stones. There is also an inner ring of smaller bluestones and, within that ring, several free-standing trilithons (larger sarsens joined by one lintel). Radiocarbon dating indicates that the inner ring of bluestones was set in place between 2400 and 2200 BCE. But the standing arrangement of sarsen stones wasn’t erected until around 500 years after the bluestones.

No contemporary written records exist concerning the monument’s construction, and scholars have pondered its likely use and cultural significance for centuries. Stonehenge’s form (and maybe its purpose) changed several times over the centuries, and archaeologists are still trying to piece together the details of its story and the stories of the people who built it and gathered in its circles.

In 2019, Parker Pearson and several colleagues reported the results of their investigation into the quarry source for the bluestones. They found that the 42 bluestones came all the way from western Wales. Chemical analysis has even matched some of them to two particular quarries on the northern slopes of the Preseli Hills.

One quarry, an outcrop called Carn Goedog, seems to have supplied most of the bluish-gray, white-speckled dolerite at Stonehenge. And another outcrop in the valley below, Craig Rhos-y-felin, supplied most of the rhyolite. When another group of archaeologists studied the chemical isotope ratios in the cremated remains of people once buried beneath the bluestones, those researchers found that many of those people may have come from the same part of Wales between 3100 and 2400 BCE.

But the sarsen stones hail from much closer to home. Since the 1500s, most Stonehenge scholars have assumed the sarsen stones came from nearby Marlborough Downs, an area of round, grassy hills 25 to 30km (17 miles) north of Stonehenge, which has the largest concentration of sarsen in the UK. A 2020 study by University of Brighton archaeologist David Nash and colleagues confirmed that.

The arrangement of stones at Stonehenge, color-coded to show where they came from.

Enlarge / The arrangement of stones at Stonehenge, color-coded to show where they came from.

English Heritage/Curtin University

Fifty of the sarsens shared very similar chemical fingerprints, which means they probably all came from the same place, most likely one site in the southeastern Marlborough Downs: West Woods, about 25 km (16 miles) north of Stonehenge and just 3 km (2 miles) south of where most earlier studies had looked for Neolithic sarsen quarries. The other two surviving sarsens came from two different places, which archaeologists haven’t pinpointed yet.

Scientists solved mysterious origin of Stonehenge’s Altar Stone: Scotland Read More »

the-fish-with-the-genome-30-times-larger-than-ours-gets-sequenced

The fish with the genome 30 times larger than ours gets sequenced

Biology, evolution, Genetics, Genomics, lungfish, Science, tetrapods / /
Image of the front half of a fish, with a brown and cream pattern and long fins.

Enlarge / The African Lungfish, showing it’s thin, wispy fins.

When it was first discovered, the coelacanth caused a lot of excitement. It was a living example of a group of fish that was thought to only exist as fossils. And not just any group of fish. With their long, stalk-like fins, coelacanths and their kin are thought to include the ancestors of all vertebrates that aren’t fish—the tetrapods, or vertebrates with four limbs. Meaning, among a lot of other things, us.

Since then, however, evidence has piled up that we’re more closely related to lungfish, which live in freshwater and are found in Africa, Australia, and South America. But lungfish are a bit weird. The African and South American species have seen the limb-like fins of their ancestors reduced to thin, floppy strands. And getting some perspective on their evolutionary history has proven difficult because they have the largest genomes known in animals, with the South American lungfish genome containing over 90 billion base pairs. That’s 30 times the amount of DNA we have.

But new sequencing technology has made tackling that sort of challenge manageable, and an international collaboration has now completed the largest genome ever, one where all but one chromosome carry more DNA than is found in the human genome. The work points to a history where the South American lungfish has been adding 3 billion extra bases of DNA every 10 million years for the last 200 million years, all without adding a significant number of new genes. Instead, it seems to have lost the ability to keep junk DNA in check.

Going long

The work was enabled by a technology generically termed “long-read sequencing.” Most of the genomes that were completed were done using short reads, typically in the area of 100–200 base pairs long. The secret was to do enough sequencing that, on average, every base in the genome should be sequenced multiple times. Given that, a cleverly designed computer program could figure out where two bits of sequence overlapped and register that as a single, longer piece of sequence, repeating the process until the computer spit out long strings of contiguous bases.

The problem is that most non-microbial species have stretches of repeated sequence (think hundreds of copies of the bases G and A in a row) that were longer than a few hundred bases long—and nearly identical sequences that show up in multiple locations of the genome. These would be impossible to match to a unique location, and so the output of the genome assembly software would have lots of gaps of unknown length and sequence.

This creates extreme difficulty for genomes like that of the lungfish, which is filled with non-functional “junk” DNA, all of which is typically repetitive. The software tends to produce a genome that’s more gap than sequence.

Long-read technology gets around that by doing exactly what its name implies. Rather than being able to sequence fragments of 200 bases or so, it can generate sequences that are thousands of base pairs long, easily covering the entire repeat that would have otherwise created a gap. One early version of long-read technology involved stuffing long DNA molecules through pores and watching for different voltage changes across the pore as different bases passed through it. Another had a DNA copying enzyme make a duplicate of a long strand and watch for fluorescence changes as different bases were added. These early versions tended to be a bit error-prone but have since been improved, and several newer competing technologies are now on the market.

Back in 2021, researchers used this technology to complete the genome of the Australian lungfish—the one that maintains the limb-like fins of the ancestors that gave rise to tetrapods. Now they’re back with the genomes from African and South American species. These species seem to have gone their separate ways during the breakup of the supercontinent Gondwana, a process that started nearly 200 million years ago. And having the genomes of all three should give us some perspective on the features that are common to all lungfish species, and thus are more likely to have been shared with the distant ancestors that gave rise to tetrapods.

The fish with the genome 30 times larger than ours gets sequenced Read More »