Category: 7. Science

Scientists have mapped the human genome for a quarter century, yet millions of DNA letters are still unresolved. A new study now reports the most complete reference to date, covering those difficult sections.

The international team sequenced 65 ancestry diverse genomes and closed 92 percent of the gaps left by earlier projects, providing a resource that lets clinicians zoom all the way into regions long considered unreadable.

The project was led by Christine Beck of The Jackson Laboratory and the University of Connecticut Health Center (UConnHC).

Decoding critical DNA regions

Beck noted that the missing pieces often carry variants influencing digestion, immunity, and muscle control. Without them, risk models for many conditions have been blind to entire classes of DNA changes.

Clinicians felt that blindness whenever genetic tests ruled out mutations yet patients still developed disease. The new assemblies bring those stretches into view, letting variant calling software finally flag complex rearrangements that older methods skipped.

The most important areas that were finally decoded include a stretch of DNA related to spinal muscular atrophy, a serious genetic disease. Another key region is the major histocompatibility complex, a crowded section tied to over 100 different health conditions.

Refining the human genome

The team used a newer type of sequencing that reads much longer pieces of DNA than older methods. They combined two types of reads: one that’s very accurate and another that’s extra long, so they could capture big and tricky sections.

The experts stitched those reads together to build complete sets of DNA from each person, including both their mother’s and father’s versions.

This approach allowed the researchers to finish some chromosomes from end to end in about 4 out of every 10 cases, which is a major improvement over earlier attempts. They also shared their method so that other scientists can now do the same without having to start from scratch.

What the team found in the DNA

The researchers uncovered nearly 2,000 complicated DNA changes that were too hard to find before. They also identified over 12,000 pieces of jumping DNA, which are bits that can move around and change how genes work. 

On top of that, the team fully mapped more than 1,200 centromeres, which are the central parts of chromosomes that help them divide properly. Many of these turned out to have two possible “connection points” instead of one, something that may change how scientists understand genetic stability.

The researchers saw up to 30 fold differences in α satellite repeat length at centromere cores, variation that could affect fertility or cancer risk once paired with clinical records. Those comparisons were impossible before the gaps were filled.

The experts also mapped the notoriously variable amylase gene cluster, which influences how well people digest starch. Such detailed mapping lets anthropologists match genes with regional culinary traditions.

Diverse genomes improved the map

Earlier references were built mostly from European genomes, a limitation that has skewed risk scores and drug studies for decades. Clinicians in Africa, South America, and Asia have repeatedly reported mismatches between test results and patient outcomes.

Nearly 60 percent of the newly found insertions and 14 percent of deletions occur in fewer than one in 100 people, making them perfect markers for rare disease diagnosis.

Short read pipelines that once flagged tens of thousands of candidate changes can now shrink the list to a few hundred, speeding answers for families.

This inclusive strategy follows the draft pangenome published in 2023, which wove 47 genomes into a graph based reference. The new work extends that concept by adding depth as well as breadth, delivering a finished quality sequence where the pangenome merely outlined possibilities.

Sequencing complete genomes

“It’s only been in the last three years that technology finally got to the point where we can sequence complete genomes,” noted Charles Lee of the Jackson Laboratory for Genomic Medicine. He considers 65 complete genomes to be a starting point, not a finish line.

“There’s more and more realization that these sequences are not junk,” added Jan Korbel, interim head of EMBL Heidelberg, referring to the repetitive DNA now decoded. Korbel highlighted that the resource is open for anyone to explore.

Both scientists see the data as a launchpad for large health care projects, from newborn screening to predictive polygenic tools, that work equally well for every community. Those applications are already being piloted by regional health systems.

What’s next for the genome map

The consortium is already feeding its assemblies into graph based tools so routine short read data can benefit from the richer reference. Early tests push per genome variant detection past 26,000 structural changes, roughly double earlier counts.

Sequencing costs are falling so quickly that fully phased, telomere-to-telomere genomes may soon be routine in diagnostic labs, ending the era in which physicians worked with partial maps and educated guesses. A single clinical genome that once cost millions now slips below $10,000 in some centers.

According to Beck, understanding health requires the full genetic blueprint, and this study finally hands clinicians most of the missing pages. The remaining gaps may close as long-read sequencing becomes more common in everyday medicine.

The study is published in the journal Nature.

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One person’s junk is another’s treasure.

An international team of scientists have found that strings of “junk” DNA in the human genome that were previously written off as having no useful function are actually pretty important after all.

The work, published as a study in the journal Science Advances, focuses on transposable elements, a class of DNA sequences that can “jump,” via a biological copy-and-paste mechanism, to different locations in a genome. These “jumping genes” take up nearly 50 percent of human DNA; in other organisms, the proportion is even higher.

What the researchers from Japan, China, Canada, and the US found is that a particular family of these TEs, called MER11, can strongly influence gene expression and act like “genetic switches” — without actually changing the underlying DNA.

“Our genome was sequenced long ago, but the function of many of its parts remain unknown,” study coauthor Fumitaka Inoue from Kyoto University said in a statement about the work. 

MER11 sequences are what’s known as long terminal repeat (LTR) retrotransposons. Spookily, these are believed to have originated from an endogenous retrovirus (ERV) that infected a simian ancestor tens of millions of years ago, hijacking the DNA of the cells it invaded to produce copies of its genetic makeup that have never gone away, but have largely remained inert. Per the researchers, at least eight percent of the human genome comes from these retroviruses.

That, plus all the other TEs littering our genome, makes for a lot of puzzling clutter for human scientists to sift through. The authors argue that the current methods for classifying and annotating TEs are inaccurate, leading to DNA sequences being overlooked as genetic junk. This inspired them to test their own classification system. 

“The proper classification and annotation of LTR instances is critical to understanding their evolution, co-option and potential impact on the host,” the authors wrote in the study.

The researchers’ system classified MER11 sequences based on their evolutionary relationships and how well they were preserved in primate genomes, according to the researchers’ statement. Then, they divided MER11 into four separate subfamilies, MER11_G1 through G4, based on their age.

This allowed the team to compare the MER11 subfamilies to what are known as epigenetic marks: chemicals that can affect how important proteins function, and as a consequence affect gene activity. Crucially, epigenetic marks don’t have to physically alter a cell’s DNA to modify a cell’s behavior, such as silencing a gene that should be expressed. Accurately tying the MER11 subfamilies to the markers is a key step to revealing the extent of their impact on gene expression.

With that as a springboard, the team tested some 7,000 MER11 sequences from humans and primates, measured how much each one affected gene activity, and found that the youngest MER11 subfamily, G4, had a strong ability to influence gene expression — namely, by bearing its own DNA “motifs” that attract proteins called transcription factors that regulate what genes are switched on and off.

“Young MER11_G4 binds to a distinct set of transcription factors, indicating that this group gained different regulatory functions through sequence changes and contributes to speciation,” lead author Xun Chen from the Chinese Academy of Sciences said in the statement.

The implications are fascinating. Though these strands of DNA may have started as “junk,” they have gradually insinuated their way to playing a role in gene regulation today — suggesting a vast portion of unknown evolutionary history that we’re only scratching the surface of.

“Transposable elements are thought to play important roles in genome evolution, and their significance is expected to become clearer as research continues to advance,” Inoue said.

More on genetics: Elon Musk Using Eugenics Startup to Inspect DNA of Potential Babies for Intelligence

Most exoplanets are discovered as they transit, or move across, their parent stars. But a new study details the opposite scenario: As a giant planet crossed its host star, peculiarities in its transit signature revealed a new discovery about the star itself — in particular, a spot that occupies an enormous 7% of the star’s surface and has lasted at least seven years.

Nearly 6,000 exoplanets — planets beyond our solar system — have been confirmed to date. While many methods have helped amass this trove, the most successful has been the transit method. This technique, which has helped to reveal nearly 75% of known exoplanets, measures the transient, tiny decrease in a star’s brightness when an orbiting planet passes along the line of sight between the star and an observing telescope.

On Episode 170 of This Week In Space, Rod Pyle and Tariq Malik are joined by are joined by Dr. Robert O’Brien, director of the Center for Space Nuclear Research for the Universities Space Research Association, to discuss powering spacecraft by radioisotope thermoelectric generators (RTGs).

Powering spacecraft, especially out in the dark, cold outer solar system, is a huge challenge. There are limits to how large solar panels can be, and they are not very efficient in the weak sunlight beyond Mars.

A new group of Starlink satellites are circling the Earth after an early Saturday morning (July 26) launch from Florida.

A SpaceX Falcon 9 rocket lifted off at 5:01 a.m. EDT (0901 GMT) from Space Launch Complex 40 (SLC-40) at Cape Canaveral Space Force Station in Florida. The booster’s upper stage reached a preliminary orbit about nine minutes after leaving the ground.

The 28 broadband internet satellites (group 10-26) were released into low Earth orbit about an hour into the flight.

“Deployment of 28 Starlink satellites confirmed,” SpaceX confirmed on the social media network X.

The launch is the first of two Starlink missions planned for the day. SpaceX has scheduled a second launch with 24 satellites from Vandenberg Space Force Base in California at 8:55 p.m. PDT local (11:55 p.m. EDT or 0355 GMT on July 27).

Summers are not only a great season for some sweet treats but also for some sweet surprises. The best of these can be a night spent stargazing with your partner. Next week, you can enjoy not one but two such opportunities where the sky will be illuminated with about 25 shooting stars per hour.Two minor meteor showers, the Southern Delta Aquariids and Alpha Capricornids, will peak overnight on July 29-30, making the two nights the perfect time for some stargazing for astronomy lovers and romance lovers alike.

Southern Delta Aquariids: Areas, timing, and how to watch

The stronger of the two showers, the Southern Delta Aquariids is expected to shoot 20 meteors per hour at its peak. Active from July 18 to August 12, the shower is also known for its faint trails.The peak of the shower will be broad between July 24 and July 31 and will be best seen from the Southern Hemisphere. Those in the northern hemisphere are advised by NASA to catch a sight by “looking halfway between the horizon and the zenith, and 45 degrees from the constellation of Aquarius.” They can best be viewed in the pre-dawn hours, away from the city lights.

Alpha Capricornids: Areas, timing, and how to watch

The second meteor shower is the Alpha Capricornids, which has been in the skies since July 12 and will remain visible till August 22. While the speed of this one is relatively slow and rarely more than five meteorites will appear in a row, it is considerable for its fireballs that are dazzling and appear brighter than any single star.To view these fireballs, also known as meteorites, the American Meteorological Society suggested waiting until they reached their highest point in the night sky, around midnight to 1 o’clock and looking south. The peak here will be reached between 29 and 30 July.For best views, it is best to find a dark sky area with clear views towards the south. In terms of viewing areas, this shower is visible from both hemispheres.

What is a meteor shower?

While orbiting around the sun, many times a year, Earth passes through the debris left by comets and asteroids. When these fast-moving space rocks enter the Earth’s atmosphere, they encounter resistance and burn up, resulting in a glow and a fiery tail. While the Delta Aquariids are debris from the comet 96P/Machholz, the Alpha Capricornids originate from the comet 169P/NEAT.

Scientists from the Vienna University of Technology (TU Wien) studying the origin mystery of the Moon’s thin, gaseous exosphere have found that a key mechanism previously credited with much of its formation, called solar wind-driven sputtering, has likely been significantly overestimated in previous studies.

The authors of the new study caution that they did not remove solar wind-driven sputtering as a cause of the exosphere’s formation. However, the Tu Wien team did ultimately conclude that the calculations based on computer models simulating the moon’s surface material had neglected the rough and porous nature of real lunar regolith, resulting in an overestimation of its exosphere impact.

Solar Wind and the Lunar Exosphere

In a statement announcing the team’s research, Prof. Friedrich Aumayr from the Institute of Applied Physics at TU Wien explained that, unlike Earth, the Moon lacks a dense atmosphere of particles and gases. However, the Moon does have a thin envelope of individual atoms and molecules surrounding the planet called an exosphere. The professor said understanding the origin of this envelope of particles “remains one of the key questions in lunar science.”

The two most likely mechanisms identified by previous studies involve either particles being ejected by high-velocity micrometeorite impacts or the surface material’s interaction with the constant stream of protons, helium ions, and other highly charged particles emitted by the Sun, known as solar wind-driven sputtering. However, the team notes that very reliable experimental data on how much of the exosphere could be caused by these solar wind particles colliding with the moon’s surface “is lacking.”

Hoping to improve the sputtering models of previous efforts, the TU Wien team gained the access needed to perform high-precision experiments with real lunar regolith samples collected in the 1970s by NASA’s Apollo 16 mission. Johannes Brötzner, PhD student at TU Wien and lead author of the study, explained how access to this material, combined with state-of-the-art 3D modelling, was crucial in determining how much sputtering impacts the development of the moon’s exosphere.

“Using a specially developed quartz crystal microbalance, we were able to measure the mass loss of lunar material due to ion bombardment with extremely high accuracy,” Brötzner explained. “In parallel, we conducted large-scale 3D computer simulations on the Vienna Scientific Cluster, allowing us to incorporate the actual surface geometry and porosity of lunar regolith into our calculations.”

After comparing their results to previous estimations of the effects of solar wind-driven sputtering on lunar exosphere creation, the team found that the data from real regolith was markedly different from that used in models simulating regolith. According to the statement, the true yield of exospheric particles from this process “is up to an order of magnitude lower” than previously estimated.

A further analysis of the data revealed the likeliest cause for the differences between real and simulated regolith was the material’s surface structure. Unlike smoother models, the team found that the “porous, loosely bound layer of dust” that makes up the moon’s surface regolith dramatically mitigated the impact of the solar wind’s bombardment. Specifically, their real lunar regolith-based models showed that incoming ions often lose significant energy when bouncing around inside microscopic cavities in the porous surface rather than using that energy to eject atoms.

Findings Could Help Solve Another Lunar Mystery

Aumayr said that along with providing the first “realistic, experimentally validated sputtering yields for actual lunar rock,” the team’s findings could help solve another lunar mystery.

“A recent Science Advances study based on isotope analysis of Apollo samples concluded that, over geological timescales, micrometeorite impacts – not the solar wind – are the dominant source of the lunar exosphere,” he explained. “Our new experimental data independently confirms this conclusion from an entirely different perspective.”

Because NASA’s Artemis program involves a series of missions to the moon with an ultimate goal of establishing a permanent base, the study authors suggest that findings like this could help mission planners determine how to best utilize the moon’s natural processes to their advantage. The researchers also note that with both Artemis and the ESA and JAXA BepiColombo missions, the latter of which is preparing to deliver the first “in-situ” measurements of Mercury’s exosphere in the coming years, interpreting these types of data “will require a detailed understanding of the underlying surface erosion mechanisms – and that is precisely where TU Wien’s research makes a crucial contribution.”

The study “Solar wind erosion of lunar regolith is suppressed by surface morphology and regolith properties” was published in Communications Earth & Environment.

 Christopher Plain is a Science Fiction and Fantasy novelist and Head Science Writer at The Debrief. Follow and connect with him on X, learn about his books at plainfiction.com, or email him directly at christopher@thedebrief.org.

July 26 (UPI) — SpaceX early Saturday launched another 28 Starlink satellites into low-Earth orbit from Florida, days after a short service outage hit the space-based internet provider.

The Falcon 9 lifted off at 5:01 a.m. EDT from Cape Canaveral Space Force Station’s Pad 40.

The first-stage booster launched for the 22nd time, including Crew-6 and 17 previous Starlink missions.

About 8 minutes after liftoff, the booster landed on “A Shortfall of Gravitas” drone ship stationed in the Atlantic Ocean. It was the 119th touchdown on the droneship and the 480th to date for SpaceX in Florida and California.

This year, it was the 91st Falcon 9 launch, according to SpaceFlight Now.

There are more than 8,000 Starlink satellites in orbit, according to astronomer Jonathan McDowell.

On Thursday, Starlink users reported a rare full network outage of internet service. It began at 4 p.m. About 2 1/2 hours later, SpaceX announced most service had been restored. Then, 1 1/2 hours later, full service was back, Starlink reported.

“The outage was due to failure of key internal software services that operate the core network,” Michael Nicholls, vice president of Starlink Engineering at SpaceX wrote on X. “We apologize for the temporary disruption in our service; we are deeply committed to providing a highly reliable network, and will fully root cause this issue and ensure it does not occur again.”

There are more than 6 million Starlink customers worldwide, including 2 million in the United States after debuting in 2021.

The next SpaceX launch is scheduled for 8:55 p.m. PDT Saturday from Vandenbrug Space Force Station’s Pad 4E in California. An additional 24 Starlink satellites are scheduled for deployment.

Astronomers have observed what they believe to be a never-before-seen companion star orbiting Betelgeuse, a pulsating red supergiant star in the shoulder of the Orion constellation.

One of the best known and most luminous stars in the night sky, Betelgeuse has long intrigued anyone who has gazed up and seen its reddish tint, which is visible to the naked eye. What has most fascinated astronomers, however, is that its brightness has been known to change over time. Now, they think the newly detected celestial object may hold the key to understanding Betelgeuse’s varying brightness.

From late 2019 to the beginning of 2020, Betelgeuse dimmed so sharply that astronomers thought the star was on the brink of exploding in a supernova. Since the event, called the “Great Dimming,” teams of astronomers have determined that the star ejected a large dust cloud, which temporarily blocked some of its light from Earth’s perspective.

The Great Dimming led to an increased interest in solving longstanding mysteries about one of the cosmos’ most observed stars — such as why its brightness appears to fluctuate regularly over a six-year cycle and has for decades.

A team of astronomers has now discovered an explanation. Using an instrument on the Gemini North telescope in Hawaii, they employed an unusual imaging technique to get a glimpse of a suspected companion star, colloquially called “Betelbuddy,” that builds on a previous theory.

They suggest calling the star Siwarha, or “her bracelet,” an Arabic name befitting the companion to Betelgeuse, which means “Hand of the Giant.” (“Elgeuse” is also the historic Arabic name of the Orion constellation.)

Understanding more about the dynamic between Betelgeuse and its companion star, also referred to as Ori B in a new study published Thursday in The Astrophysical Journal Letters, could shed light on the entwined fate of both stars.

As a supergiant star, Betelgeuse is immense. Compared with our sun, it’s about 700 times the radius and contains 18 times as much mass, said lead study author Steve Howell, a senior research scientist at NASA Ames Research Center in California. If our sun were replaced with Betelgeuse, the star would not only engulf Earth and all the inner planets but reach past the orbit of Jupiter, according to NASA. It also shines 7,500 to 14,000 times as bright as the sun.

At 10 million years old, Betelgeuse is a fraction of the age of our sun, which is estimated to be 4.5 billion years old. However, Betelgeuse’s enormousness means it has already burned through all the hydrogen at its core, causing it to expand as it nears the end of its life.

Years of observations have shown that its luminosity varies periodically about every 416 days, growing fainter and then brighter. This pulsation is typical of red supergiant stars.

But Betelgeuse displays an unusual pattern on top of that. “It has been noted for decades that Betelgeuse also shows a much longer period (of variation) of about 2,170 days (about six years) which remained unexplained,” Howell wrote in an email.

Two independent groups of astronomers published papers in 2024 suggesting that an unseen companion star could cause the variability. The Hubble Space Telescope and NASA’s Chandra X-Ray Observatory, however, could see no evidence of such a star. Betelgeuse’s size and brightness have posed challenges to attempts to spot a companion.

To see both Betelgeuse and its companion, an image has to be both high-resolution and high-contrast, said Jared Goldberg, a research fellow at the Flatiron Institute’s Center for Computational Astrophysics. Goldberg authored a November study suggesting Betelgeuse may have a companion star, but he was not involved with the new research.

“Normally, the Earth’s atmosphere makes it hard to do this for the same reason that stars twinkle — the moving gas in the atmosphere scatters the starlight around,” Goldberg said.

Howell’s team decided to use a speckle imager called ‘Alopeke, which means “fox” in Hawaiian, to search for the companion.

“Speckle imaging is a technique that obtained many thousands of very short exposures of an astronomical object,” Howell said. “These images are so short that they do not look like stars or galaxies at all, but a blob of ‘speckles.’”

The speckles are due to distortions from Earth’s atmosphere. The thousands of brief images are processed in a way that removes the atmospheric blurring, resulting in a high-resolution telescope image, Howell said.

When members of Howell’s team observed Betelgeuse during the Great Dimming in 2020, they didn’t see anything; the companion was likely obscured behind Betelgeuse, according to Goldberg. But in December, they spied a faint blue glow exactly where Goldberg’s research — as well as another study authored by Morgan MacLeod at the Harvard-Smithsonian Center for Astrophysics — predicted the companion would be.

The speckle imaging revealed a young, bluish star that isn’t burning hydrogen at its core yet and only has a mass of 1.5 times that of the sun.

The companion star’s faintness — four-tenths of one percent as bright as Betelgeuse — is just one reason it’s been hard to spot, Howell said. The other is the stars’ proximity to one another — only about four times the distance between Earth and the sun separates them. On average, the Earth is about 93 million miles (150 million kilometers) away from the sun. The thing that allows the companion star to be seen, said Goldberg, is that it is a different hue than Betelgeuse.

“If the two headlights on a car represent the two stars, our view from Earth to Betelgeuse and its companion would be the same as trying to separate the two car headlights with your eye from a distance of 50,000 miles,” Howell said. “Our observations were aided by the fact that we can directly observe Betelgeuse using very short exposures (14 milliseconds each) so as to not saturate our cameras and the large mirror size of Gemini (8 meters) allows us to obtain very high angular resolutions in images of the sky, enough resolution to separate the two stars.”

It’s the first time a stellar companion has been detected orbiting a supergiant star so closely, the study authors said.

“I was surprised that the companion was so obvious immediately after our data was processed,” Howell said. “I was thinking it’d be hard to find, but boom, it was right there.”

MacLeod, a postdoctoral fellow in theoretical astrophysics and member of the Institute for Theory and Computation at the Harvard-Smithsonian Center for Astrophysics, worked on research published in December that collected historical measurements of Betelgeuse’s radial velocity, or motion toward or away from Earth, that began around 1896 on photographic glass plates. The team saw a repeating six-year pattern consistent with the tug of a smaller, orbiting companion star, MacLeod said.

“Putting these lines of evidence, collected from a century of astronomical measurements, together let us predict right where a companion ‘should be’ if it were real,” he said. “But we hadn’t seen it directly. Howell and his team made a pioneering observation in order to be able to make this initial detection.”

MacLeod, who was not involved with the new study, calls its finding “an amazing result … that shows that even the best-studied stars in our night sky have mysteries to reveal.”

“Because this was such a challenging detection to make, the observations are on the very edge of detection,” MacLeod said. “What pushed this over the edge is that the star appeared just where we expected when we pulled together the predictions of a century’s worth of astronomers.”

While the discovery of the companion aligns with Goldberg’s research predictions, future observations are still needed to confirm the detection. Speckle imaging is a hard measurement to make and isn’t always accurate, Goldberg said.

Given that the star was discovered near the limits of the instrument, its presence is probable but “not yet a slam dunk,” said Edward Guinan, professor of astronomy and astrophysics at Villanova University in Pennsylvania. Guinan has studied Betelgeuse but was not involved in the new research.

However, seeing the companion star track along its proposed six-year orbit would represent a definitive detection of the companion, Guinan said.

“Currently, we think the companion is moving away from us, and going behind Betelgeuse. So there is a clear path to confirm the new study’s results: Look again when we expect the companion to be fully behind Betelgeuse, and it will be gone. Look once more when it should be coming back around on the other side, and it should be there,” Goldberg said.

A new opportunity to confirm the companion’s presence with telescopes will occur in November 2027 when the star would be at its farthest distance from Betelgeuse, making it easier to spot.

Like MacLeod’s team, Goldberg and his colleagues also determined that Betelgeuse wobbles toward and away from Earth within the same six-year period due to the presence of a stellar companion. Still, questions remain about how exactly a companion star is contributing to Betelgeuse’s six-year variability, which appears to be connected to changes in dust around the star, Goldberg said.

“The dimmer phase happens when the companion is behind Betelgeuse, and the brighter phase is when the companion is in front of Betelgeuse,” Goldberg said by email. “This means it’s the opposite of an eclipse, so it seems most likely that Betelgeuse is producing its own dust and the companion is shaping it, rather than dragging it along.”

About 30% of pulsating red giant and supergiant stars show the same type of variability, and if that means a companion is present, “then many more stars harbor these little friends,” Goldberg added. “Understanding this stellar pair can help us understand the population of things like it. And understanding that population will teach us about star and planet formation in systems that are otherwise extremely hard to observe.”

Meanwhile, astronomers still wonder when Betelgeuse will explode, a catastrophic event that has been anticipated since the Great Dimming. While Betelgeuse and its companion star were likely born at the same time, the companion is still forming as a normal star, Howell said. But companion’s close orbit, within the outer layers of Betelgeuse’s atmosphere, will be its doom, he said.

One of two things will happen. The companion star’s orbit may cause it to drift slowly closer and plunge into Betelgeuse in about 10,000 years.

“At that point Betelgeuse and its companion will enter into an eternal hug,” Goldberg said. “If we can get decades of precise direct observations, we might be able to directly test that prediction by seeing if the orbit is shrinking, and if so how quickly.”

But if Betelgeuse explodes before that — “maybe tomorrow, maybe in 100 years” — then the companion star will be destroyed in the supernova, Howell said. “The future is not good for either star.”

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For wild animals, survival may come down to the split-second decision to bolt or stay put when danger appears. A new study traces that choice to a tiny cluster of neurons deep in the midbrain.

By comparing two closely related deer mouse species, the team showed that evolution simply tunes the sensitivity of this hub rather than rebuilding the whole defensive network.

Forest-dwelling Peromyscus maniculatus flee at the faintest hint of a hawk, while open field Peromyscus polionotus remain statues until the threat becomes overwhelming.

Study co-lead Felix Baier of Harvard University teamed up with Karl Farrow at the Vlaams Instituut voor Biotechnologie (VIB) in Leuven to identify the neurons involved in the brain’s survival switch.

Same senses, different instincts

Predators strike in milliseconds, yet landscapes differ. Animals can easily take cover in a brushy habitat, but not necessarily on the prairie.

As a result, deer mice have evolved opposite default settings, even though their eyes and ears register danger with equal fidelity.

Baier’s group confirmed this by showing identical activity in the optic tract and superior colliculus of both species during low intensity “shadow” stimuli. Only the behavior diverged, proving the sensory side was not the source of the split.

Survival switch controls fear response

Attention then turned to the dorsal periaqueductal gray (dPAG), a cigar shaped nucleus already known to initiate escape in laboratory mice.

Neuropixels probes – silicon shanks carrying hundreds of electrodes – recorded each spike while looming discs simulated an aerial predator attack.

In forest mice, a single loom sparked a volley in dPAG neurons that paralleled running speed. Open field cousins showed only a muted dPAG murmur even when their feet finally flew, meaning the threshold for firing was set far higher.

“We were surprised to find that evolution acted in a central brain region, downstream of peripheral sensory perception,” said Baier.

Survival switch in other animals

The dorsal periaqueductal gray (dPAG) has long been known as a key hub for defensive behavior in mammals.

In lab mice and rats, stimulating this region can trigger running, jumping, or even vocalizations. In humans, analogous brainstem structures help process intense fear and panic.

By focusing on the dPAG, the researchers tapped into a deeply conserved circuit. Yet the study shows that even hardwired regions like this one can be tweaked to meet local demands.

That finding challenges the assumption that core survival systems are biologically fixed across species.

Same midbrain, different reactions

Next, the team used optogenetics to nudge the hub. Flash activating excitatory cells in the forest species made them sprint even when the arena was calm.

The same light caused prairie mice to decelerate or halt, as though the stimulation felt more like a brake than a gas pedal.

When researchers used chemogenetics to dampen activity in the brain’s escape hub, forest mice began behaving like their prairie relatives – waiting longer and needing a stronger threat signal before reacting.

The reverse manipulation never flipped prairie mice into hyper skittish mode, highlighting their raised internal threshold.

Midbrain tweaks when to escape

Such fine grained tuning matches recent work showing that GABA rich neurons in dPAG set the “go/no go” point for escape.

In the new study, inhibitory cells lit up strongly in the forest species but stayed mostly quiet in the prairie species, hinting that evolution dialed inhibition rather than altering excitatory drive.

Other animals deploy similar tricks. In zebrafish, threat avoidance ensembles in the dPAG scale with distance from a predator. That parallel supports the idea that central thresholds, not peripheral sensitivity, often decide which hard wired action rolls out.

Habitat shapes the survival switch

The two mouse species occupy very different landscapes shaped by predation risk. In brushy forests, motion attracts less attention than freezing, since cover is nearby.

On open plains, stillness may be the best way to avoid being spotted by aerial predators. These constraints likely drove selection for divergent midbrain response thresholds.

Shifting the escape threshold in a central node like the dPAG may offer an efficient solution. Rather than overhauling sensory input or building a new circuit, evolution simply adjusts how soon a threat triggers action.

This flexibility may also explain why such neural adaptations can arise repeatedly in separate species facing similar pressures.

What it means for human fear

The findings add to a growing picture in which survival circuits come with built-in sliders that natural selection can nudge. That economy may explain why species thriving in wildly different niches still share a common neural architecture.

The findings also have medical relevance: overactive defensive circuits are linked to panic and anxiety disorders in humans.

Discovering that a single midbrain hub can adjust its sensitivity opens up potential strategies for recalibrating fear responses without dulling sensory perception.

The study is published in the journal Nature.

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