RESOURCES: The Other Sunscreen

See allHide authors and affiliations

Science  09 Aug 2002:
Vol. 297, Issue 5583, pp. 903
DOI: 10.1126/science.297.5583.903d

Much as the ozone layer fends off DNA-scarring ultraviolet radiation, Earth's magnetic field shelters us from the solar wind—a gale of charged particles blowing from the sun that can addle satellites and even knock out power grids. Keeping tabs on the field, which comes mostly from the motion of molten iron within Earth's core, is this site from the U.S. Geological Survey (USGS). The clearinghouse supplies data on short-term and long-term fluctuations of the magnetic field collected by satellites and earthbound instruments.

Fourteen observatories run by USGS provide current plots of the strength and direction of the magnetic field. Scientists mapping the field use the data to factor out daily variation. Focusing on longer term changes are global magnetic charts and an online calculator that computes characteristics of the field as it has evolved over the past 4 centuries. You can also download results of modeling studies that use magnetic data to peek into Earth's interior. For example, this candy-striped image depicts the flow of liquid rock at the junction between the core and the mantle.

Stay Connected to Science

Navigate This Article