Taxonomy term

static administrative page

What powers U.S. transportation?

Consumption of U.S. energy
U.S. Energy Information Administration

 

01 Dec 2009

What consumes U.S. energy?

Consumption of U.S. energy
U.S. Energy Information Administration
01 Dec 2009

Geology 101: Reading the story in the rocks

David Harwood’s field geology course gives future teachers an introduction to several of geology’s most fundamental principles, including the stratigraphic basics described by Nicholas Steno in 1669. Go to the head of the class with this quick primer.

20 Oct 2009

The vital statistics

Ardipithecus ramidus was a hominid that lived in Ethiopia’s Afar region 4.4 million years ago. After spending more than a decade studying the species, scientists can now provide a sketch of what the hominid looked like:

Brain: Ardipithecus had a brain size similar to that of a female chimpanzee, about 300 to 350 cubic centimeters.

Stature: Standing 120 centimeters tall and weighing 50 kilograms, Ardipithecus was about the size of a chimpanzee.

01 Oct 2009

Not the oldest hominid

At 4.4 million years old, Ardipithecus ramidus is not the oldest known hominid. In 2002, scientists announced they had discovered a hominid skull from the Sahel region of Chad. Named Sahelanthropus tchadensis, the species dates to about 7 million years ago. And a few years earlier, scientists had announced the discovery of several hominid fossils, including a thigh bone, in Kenya that dated to about 6 million years ago. They named the species Orrorin tugenensis.

01 Oct 2009

The trailblazers

Volcanologists have long been assessing the impacts of volcanic ash and gases on the environment and human health. This effort began in earnest when volcanologists at the U.S. Geological Survey undertook extensive studies of the environmental characteristics of ash from the 1980 Mount St. Helens eruptions. These studies included water leach tests showing that rain falling onto fresh ash can be quite acidic due to the liberation of acidic gas species that condense onto ash particles in the eruption cloud.

01 Oct 2009

Musical magnetic reversals

Although Earth’s magnetic field currently points toward the North Pole, the planet’s magnetic dipole flips direction every few hundred thousand years or so. Engebretson tracked the last 85 million years of these magnetic reversals, with higher pitches representing shorter polarities (a period of time when the direction of the magnetic field stays the same), and lower pitches longer ones.

22 Sep 2009

Earth tides in A major

Earth experiences small, millimeter-sized tides, called Earth tides. Using a dataset from NASA’s Jet Propulsion Laboratory in California from A.D. 1600 to A.D. 2200, Engebretson calculated the net gravitational force of the sun and the moon at particular intervals and then mapped them onto the A major scale.

22 Sep 2009

Pages