Benchmarks: May 6, 1852: Edward Sabine links the geomagnetic and sunspot cycles

At the beginning of the 19th century, little was understood about Earth’s magnetic field, but interest in its workings had begun to grow, especially in Europe. That the magnetic field exists had long been recognized, and magnetic compasses had aided in navigation for centuries, particularly at sea where fixed landmarks are hard to come by. Not surprisingly, the increased attention emerging around the turn of the century came from naval and shipping interests, which recognized that an accurate understanding of the field’s behavior would be a boon to their fleets.

By this time, the underlying physical explanation for the magnetic field had also become a major source of scientific curiosity. In the preceding two centuries, observers had measured differences in the field’s intensity, inclination and declination — the angle between magnetic and true north — between locations, as well as changes in those properties at the same location, both over varying lengths of time. Others had noted the synchronized occurrence of colorful atmospheric auroras with widespread disturbances in the magnetic field, termed magnetic storms.

It was clear the planet’s magnetic field was an inconstant and complex phenomenon, and many eminent scientists saw it as the next great natural mystery to unravel.

13 May 2014

Precise to a fault: How GPS revolutionized seismic research

Conceived in the 1960s to provide precise time and position for the U.S. military, GPS was soon embraced by geodesists and earth scientists. Today, it is an essential tool for geoscience research that extends far below — and above — Earth's surface.

30 Apr 2014

A new tool for atmospheric studies

Scientists are putting GPS to work in some unexpected new ways, including in atmospheric research.

30 Apr 2014

A truly global system

Like the GPS navigation system in your car or smartphone, a high-precision GPS receiver uses signals from satellites to determine the distance from the receiver to the satellite. But that’s where the similarities end. 

30 Apr 2014

Observing a plate boundary

The U.S. Plate Boundary Observatory (PBO), a component of EarthScope, includes more than a thousand continuous GPS stations arrayed across the western United States and Alaska. 

30 Apr 2014

Bare Earth Elements: Mars rocks wear manganese coats

Several rocks on the surface of Mars are coated with distinctive dark-colored surface layers enriched in manganese that, while sharing similarities with manganese-rich rock varnish found on Earth, do not appear to be varnish themselves based on differences in trace element levels, according to new research presented Wednesday by Nina Lanza of Los Alamos National Laboratory at the Lunar and Planetary Science Conference (LPSC) in The Woodlands, Texas.

19 Mar 2014

Comet ISON still intrigues and inspires, even after its demise

Comet ISON is dead, but its memory will live on." That eulogy for the much-discussed “comet of the century" was delivered today by Karl Battams of the Naval Research Laboratory in Washington, D.C., during a series of reports presented at the annual meeting of the American Geophysical Union (AGU) in San Francisco, Calif.

11 Dec 2013

Juno salutes its home planet and heads to Jupiter

Thanks to orbital mechanics, a spacecraft heading to Jupiter must go most of the way there, then loop around the sun, zoom back close to Earth, and finally head out again on its mission to the largest planet in the solar system. That's the story of Juno, launched by NASA on Aug. 5, 2011, and due to arrive at Jupiter on July 4, 2016. Its journey required a boost in velocity, relative to the sun, which it received when it flew as close as 559  kilometers above Earth on Oct. 9, 2013.

11 Dec 2013

In or Out? Has Voyager left the solar system?

San Francisco - There is a possibility that Voyager, the U.S. spacecraft launched in 1977, which is thought to have left the heliosphere and entered interstellar space last year, could still be "inside," said Ed Stone, Voyager project chief scientist, today at the annual meeting of the American Geophysical Union in San Francisco.

09 Dec 2013

How strong was the Carrington Event?

NASA has described the magnetic field of the coronal mass ejection (CME) associated with the 1859 Carrington Event, the largest solar storm ever detected, as “extremely intense” relative to other CMEs. The amount of plasma it ejected is difficult to estimate, but more important in determining its strength is how fast it arrived.

21 Jan 2013