Friday Headlines: 2-15-13

Friday Headlines, February 15, 2013

THE LATEST IN THE GEOSCIENCES

 

THIS JUST IN:

METEOR STRIKE INJURES HUNDREDS IN CENTRAL RUSSIA

A meteor hit in Russia’s Ural mountains at about 9:30 in the morning, local time. The following shock wave (whether from a sonic boom, or the impact itself) caused the shattering of windows and resulted in nearly 1000 injuries, mostly from broken glass. As yet, no fatalities have been reported. The videos and photographs of the event are astounding!

Update:

Neil deGrasse Tyson explains more about it here.

 

ASTEROID IMPACT THAT KILLED THE DINOSAURS: NEW EVIDENCE

A paper in the journal Science published last Friday provided more support that the asteroid impact that happened about ~65 million years ago near Chicxulub (along the Yucatan peninsula of Mexico) probably dealt the deathblow to the dinosaurs.

The new study shows that, within the measurement precision of age, the impact event occurred at the same time as the extinction of dinosaurs. The impact and the extinction occurred no more than 33,000 years apart. Previous studies have argued that there was a substantial time gap between the impact and the extinction.

This does not preclude the possibility that dinosaurs were already on their way out prior to the impact, but it gives more confidence that the impact itself marked the total demise of dinosaurs.

 

SALMON USES MAGNETIC FIELD TO GUIDE ITSELF BACK HOME

A fascinating topic in biology is how, exactly, to migrating organisms know where their going. How do birds know in what direction and how far to fly each winter? How do Monarch butterflies find their roosting sites in Mexico after being born in the United States? How do salmon find their way back to the streams where they hatched? New research had provided an answer to at least the last of these questions.

Many organisms have tiny bits of magnetite in their brains. Even the most primitive of organisms, bacteria, are known to possess magnetite, which they use to orient themselves to the Earth’s magnetic field, much like how a compass needle points North. Organisms can then orient themselves North to South.

At a first pass, it is easiest to think of the Earth’s magnetic field as a simple bar magnet inserted along the Earth’s axis of rotation. But the Earth’s magnetic field is much more complex than that, resulting in it actually being quite different and unique at every point on the Earth’s surface. These differences make every place magnetically unique, and with a sensitive enough magnetometer, one can tell where they are based only on the Earth’s magnetic field.

So a salmon, when it decides to spawn, uses the magnetic field to identify the place where it first swam from river to ocean. Once it’s there, the salmon just starts swimming upstream.