Earth & The Planet

Earth & The Planet

How Earth’s Magnetic Field Reverses

Ancient rocks record changes in magnetic polarity. Reversals reflect the changing geodynamo deep inside Earth, not the planet physically turning upside down.

Sep 30, 2026 • 4 min read

Earth & The Planet

How Sinkholes Form Beneath Solid Ground

Sinkholes develop when underground material is removed and the surface subsides or collapses. Soluble rock, sediment and groundwater changes shape how—and how quickly—they appear.

Sep 30, 2026 • 3 min read

Climate Systems

How Aquifers Store and Release Groundwater

Aquifers store groundwater in pores and fractures and transmit it through connected pathways. Recharge, pressure and pumping determine how that water becomes available.

Sep 30, 2026 • 3 min read

Earth & The Planet

How River Deltas Build Land—and Why They Sink

Deltas grow when rivers deposit sediment faster than waves, currents and sinking remove it, but dams, extraction and rising seas can upset that balance.

Sep 29, 2026 • 12 min read

Earth & The Planet

Why Is the Ocean Blue?

The ocean usually looks blue because water absorbs longer red, orange and yellow wavelengths more strongly while blue light penetrates farther and is scattered…

Sep 29, 2026 • 14 min read

Climate & Weather

How Glaciers Record Past Climates in Layers of Ice

Snow compressed into glacier ice can preserve bubbles, dust, isotopes and chemicals that allow researchers to reconstruct parts of Earth’s atmospheric and climate history.

Sep 28, 2026 • 12 min read

Earth & The Planet

How Ocean Upwelling Feeds Some of Earth’s Richest Ecosystems

Coastal winds and Earth’s rotation can move surface water away from shore, allowing colder, nutrient-rich water to rise and fuel highly productive marine food…

Sep 28, 2026 • 12 min read

Earth & The Planet

How Rivers Create Meanders, Cutoffs and Oxbow Lakes

Flow moves faster along the outside of a river bend and more slowly along the inside, encouraging erosion, deposition and gradual migration that can…

Sep 28, 2026 • 12 min read

Earth & The Planet

What Causes Earthquakes?

Most earthquakes occur when stress built up by tectonic motion overcomes friction on a fault, causing rocks on either side to slip suddenly. The…

Sep 26, 2026 • 13 min read

Earth & The Planet

What Causes Ocean Tides?

Ocean tides are long-period changes in sea level driven mainly by differences in the Moon’s gravitational pull across Earth, with an important contribution from…

Sep 25, 2026 • 14 min read