Researchers have identified a giant planet orbiting Tabby’s Star, offering a natural explanation for the erratic dimming that previously suggested an alien megastructure.
Tabby’s Star mystery solved
For years, the strange light patterns of KIC 8462852 sparked speculation about a massive solar energy plant, or Dyson sphere, orbiting the star. Scientists now believe a large planet passing in front of the star from Earth’s perspective accounts for these events.
While reviewing data from NASA’s Transiting Exoplanet Survey Satellite, the team found a single unreported transit event on 3 September 2019. This event lasted 21 hours and hints at a giant planet roughly ten times as massive as Jupiter.
“No transiting companion has ever been detected around this well-known star, so the potential evidence of a candidate presented in this work is significant,” said researchers led by Cristina Madurga-Favieres of the University of Warwick.
The strongest theory suggests that a group of exocomets or planetesimal fragments are responsible for the irregular dips. The presence of a companion would explain why these bodies are driven toward the star, breaking up as orbital perturbations push them inward.
In other words, the huge planet may be gravitationally pulling a flock of smaller bodies into orbit around the star, producing the dimming events. While not quite as sensational as a colossal alien power plant, it may help resolve the decade-long mystery of this strange star.
Hannibal’s alpine crossing
Scientists have calculated the energy costs of various routes Hannibal Barca might have taken over the Alps in 218 BC.
The Carthaginian general marched an army of 46,000 men and 37 war elephants to threaten Rome. Although this advance became one of the most legendary military moves of all time, Hannibal was ultimately unsuccessful in his attempt to sack the city.
Experts have generally considered a route called the Col du Clapier to be the most likely. New results suggest an alternate route known as the Col de la Traversette would have exacted less energy from the advancing army, which might have boosted its odds as Hannibal’s choice of crossing.
“Most of the discussions concerning Hannibal’s crossing were guided by philological and geological considerations, which tend to ignore the biology of the men and animals,” said authors Emilio Berti of Halle-Jena-Leipzig and Fritz Vollrath of the University of Oxford.
Compared to choosing the Col de la Traversette, the routes via the Col de Montgenèvre, Col du Clapier, and Col du Mont Cenis would have required 11%, 16%, and 19% more energy, respectively, for the army as a whole.
While this study does not resolve the question of exactly where Hannibal hauled his troops over the Alps, it sheds new light on the immense costs of this ancient act of bravado. Berti and Vollrath estimated that even if the army took the path of least resistance—the Col de la Traversette—the elephants would have lost 4% of their body fat reserves, horses 11%, and men 19%.
Considering that half of Hannibal’s troops died during the crossing, this diet is not recommended.
High-altitude survival
The Andean leaf-eared mouse lives more than four miles above sea level, making it by far the highest-dwelling mammal on Earth.
The mouse has surpassed the known elevational range limits of all other terrestrial vertebrates. These areas were previously thought to be uninhabitable by mammals owing to severe hypoxia and frigid temperatures.
To understand how this unassuming mouse survives up in the clouds, scientists analyzed the genomes of 167 leaf-eared mice collected across their range. The results revealed that the mountain mice have evolved a unique set of adaptations that are distinct from many other alpine animals, including the ability to metabolize toxic plants.
“The world’s highest-dwelling mammal has adapted to habitats at both the low- and high-elevation limits of its range, and much of the elevation-related selection relates to previously unappreciated aspects of feeding ecology,” the team concluded.
Oldest evidence of handedness
Paleontologists have discovered the oldest potential evidence of a right-handed animal. The 550-million-year-old seacrawler in question does not actually have hands.
Spriggina floundersi, an inch-long creature that lived in the Ediacaran period, has long fascinated scientists because it appears to be one of the first animals in the fossil record capable of locomotion.
When scientists took a closer look at more than 100 exquisite Spriggina fossils from South Australia, they discovered that about twice as many of them seemed bent to the left compared to the right. This suggests the animal had a preferred direction of motion, or handedness. In this case, it was right-handed because the fossils are preserved in negative hyporelief, meaning that they are mirror images of the animal.
“A significant number of fossil specimens are bent to the left (right in life),” said researchers led by Scott D. Evans of the American Museum of Natural History. “The nature of these bends does not match expectations of anatomical asymmetry and instead constitutes the oldest described evidence of behavioural handedness.”
What it means
These findings shift the focus from exotic explanations to natural phenomena. The dimming of Tabby’s Star is likely caused by a planetary system rather than artificial structures. Similarly, the energy constraints of ancient armies and the biological adaptations of high-altitude mammals provide concrete data on how physical limits shape history and evolution.
