River Delta Schematic

River Delta: How It Forms

Streams carrying too much sediment clogs the entrance into the basin. As sediments dump in, water flow decelerates and widens the entrance forming a delta.

Earth Atmosphere Layers

What Are the Layers of the Atmosphere?

There are 4 primary layers of the atmosphere on Earth: troposphere, stratosphere, mesosphere and thermosphere. The ionosphere and exosphere are above those.

How Far Is Moon From Earth Lunar Distance

How Far Is the Moon?

If only there was a ruler long enough to reach the moon. Over the years, astronomers have used parallax, radar and laser ranging to measure lunar distance.

Earth Rotation

Earth Rotation: The Day-Night Boundary

As the Earth spins, the sun always shines on one side which gives it sunlight. When you’re facing the sun, it’s daytime. But when you’re not, it’s night.