Alexandra Witze

Alexandra Witze is a science journalist in Boulder, Colorado.

Known as the “Potsdam Gravity Potato,” this visualization of variations in Earth’s gravity field is produced by Germany’s GFZ Earth science research center based on satellite and surface data. Gravity “highs” are red, “lows” are blue. The differences are due mostly to the different density of materials above or below the Earth’s surface.

How Satellites and Telescopes are Tracking the Effects of Global Change, Down to the Millimeter

NASA and other research agencies bring are bringing new tools to the science of geodesy.

Using aircraft and satellites, scientists have recently begun to measure the rate at which Greenland’s glaciers, left, are losing mass as the ice melts and slides into the sea.

As the Earth Melts

Scientists try to fathom what remains beneath the tip of the iceberg.

The Gulfstream V operated by the National Center for Atmospheric Research will spend four minutes under totality by flying along the eclipse path.

Chasing the Eclipse at 45,000 Feet

Researchers aboard a Gulfstream V will study the sun’s rarely-seen outer atmosphere.

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California’s Snow Sentinel

When all your water is in the snowpack, you better keep your eyes on the mountaintops.

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