Dark winters 'led to bigger human brains'

Humans living at high latitude have bigger eyes and bigger brains to cope with poor light during long winters and cloudy days, UK scientists have said.
The Oxford University team said bigger brains did not make people smarter. Larger vision processing areas fill the extra capacity, they write in the Royal Society's Biology Letters journal.
The scientists measured the eye sockets and brain volumes of 55 skulls from 12 populations across the world, and plotted the results against latitude. Lead author Eiluned Pearce told "We found a positive relationship between absolute latitude and both eye socket size and cranial capacity."
Eiluned Pearce said: "Both the amount of light hitting the Earth's surface and winter day-lengths get shorter as you go further north or south from the equator.
"We found that as light levels decrease, humans are getting bigger eye sockets, which suggests that their eyeballs are getting bigger.
"They are also getting bigger brains, because we found this increase in cranial capacity as well.
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"In the paper, we argue that having bigger brains doesn't mean that high-latitude humans are necessarily smarter. It's just they need bigger eyes and brains to be able to see well where they live."
The work indicates that humans are subject to the same evolutionary trends that give relatively large eyes to birds that sing first during the dawn chorus, or species such as owls that forage at night.
The team, from the Institute of Cognitive and Evolutionary Anthropology, used skulls dating from the 1800s kept at museums in Oxford and Cambridge.
The skulls were from indigenous populations ranging from Scandinavia to Australia, Micronesia and North America.
The largest brain cavities came from Scandinavia, while the smallest were from Micronesia.
Co author Prof Robin Durbar said: "Humans have only lived at high latitudes in Europe and Asia for a few tens of thousands of years, yet they seem to have adapted their visual systems surprisingly rapidly to the cloudy skies, dull weather and long winters we experience at these latitudes."

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Tempest-from-hell seen on Saturn

  shows an image of Saturn taken in 2010 by the Cassini camera, …

Imagine being caught in a thunderstorm as wide as the Earth with discharges of lightning 10,000 times more powerful than normal, flashing 10 times per second at its peak.


Now imagine that this storm is still unfolding, eight months later.

One of the most violent weather events in the Solar System began to erupt on Saturn last December and is still enthralling astronomers.

Two studies draw on observations by professional and amateur astronomers using a broad range of gear, from relatively small ground-based telescopes to NASA's magnificent scoutcraft, Cassini.

Saturn, like Jupiter, is no stranger to convective storms.

It too is a "gas giant," or planet comprising layers of thick, roiling gases rather than a rock, like Earth, Mars, Venus and Mercury.

The difference, though, is that jovian mega-storms tend to erupt unexpectedly, but the lord of the rings gives birth to a monster almost periodically.

It occurs on average once every Saturnian year -- nearly 29.5 Earth years -- and appears to be linked to the summer solstice, when the planet's orbit brings it a bit closer to the Sun and its atmosphere warms a little.

The event is known as the "Great White Spot" (a counterpart to the swirling "Great Red Spot" on Jupiter) because of the mass of brilliant white storm clouds that erupt in the upper atmosphere.

The show is so big that it can be visible by telescopes from distant Earth. Five have been observed in the last 130 years. The last occurred in 1990.

But the current Great White Spot is proving to be a dazzling spectacle, revealed by an unprecedented array of observational power at hand.

Events began at 2105 GMT on December 5, when ground-based telescopes detected a "barely visible white point" on a normally unblemished and hazy part of Saturn's northern hemisphere, at around latitude 35 degrees north.
At the same time, Cassini turned its "ears" towards the target, listening in to radio emissions from the storm via an onboard plasma-wave instrument.
These signals are the telltales of lightning. Lightning cannot be seen visually on Saturn at night because of interference from sunlight scattered from the planet's ring system, which comprises billions of shiny particles.
Within a few weeks, the point had ballooned into a storm system that was some 10,000 kilometers (6,000 miles) across, roughly comparable with the diameter of the Earth, and after two months the clouds had almost encircled the entire planet.
Analysis of the data suggests that the "spot" is in fact a cluster of super-storms, produced by upwelling of heat, moisture and ammonia from water clouds from lower down in the Saturnian atmosphere, where the pressure is high.

As this mix rises into a cooler atmospheric layer called the tropopause, bright, white clouds of ammonia start to spread horizontally into a tail, sculpted by eastward jets of wind.

Astronomers are especially intrigued by the current Great White Spot.

The observational history of this phenomenon is sketchy. But evidence suggests the present spot is exceptionally intense and rather premature, for it was still spring on Saturn when the storm brewed.

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