I Have Two Pieces of News for You

I have two pieces of news for you. The first. The age of sharks is determined by the annual rings on their vertebrae. Sharks have a cartilaginous skeleton, but the vertebrae are mineralised with enough calcium to lay down visible annual layers. In a cross-section of a vertebra, concentric rings can be seen under the microscope. The pale, broad ones correspond to the season of active feeding, the dark and narrow ones to a period of slowing down, and a pair of bands corresponds to one year of life.

The second piece of news. Scientists have learned to determine age from the chemical composition of the annual rings rather than by visual counting, as before. The method reads the ratios of strontium, calcium and potassium isotopes and links them with regional records of precipitation and water geochemistry, in effect reconstructing the biography of each individual.

The old microscopy technique produced errors for older individuals, in which the annual rings cease to grow, and took up to two days. For a third of shark species, hammerheads and rays, which are under threat of extinction, this is a critical change: an exact age is needed to calculate reproductive age and catch quotas

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At the close of the Strugatskys' "Roadside Picnic" the Golden Sphere is asked for this: "Happiness for everybody, free, and let nobody go away unsatisfied!" I do not promise to leave no one aggrieved, but the digest really does come free

At the close of the Strugatskys' "Roadside Picnic" the Golden Sphere is asked for this: "Happiness for everybody, free, and let nobody go away unsatisfied!" I do not promise to leave no one aggrieved, but the digest really does come free. So, here is the

Frederic Leighton

Frederic Leighton. “Daedalus and Icarus”, 1869 Daedalus warns his son not to climb too high: the heat of the sun may melt the wax, but Icarus is already gazing into the distance, and the lamentations of a foolish old man interest him not in the least

I Have Two Pieces of News for You

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At the close of the Strugatskys' "Roadside Picnic" the Golden Sphere is asked for this: "Happiness for everybody, free, and let nobody go away unsatisfied!" I do not promise to leave no one aggrieved, but the digest really does come free

Frederic Leighton

Attempts to resolve the problems of many years of uncontrolled mass migration

Characters from Gogol's "Petersburg Tales" on the pedestal of the monument to Nikolai Gogol on Nikitsky Boulevard, photograph of the 1960s