The combination of a blue sky, dark overhead, lighter near the horizon, along with a reddened Sun at either sunrise or sunset, can all be explained scientifically, along with the blue color of the oceans as an independent phenomenon. Here’s the science of how it works. (Credit: ssxss/pixabay)

Why is the sky blue? Why is the ocean blue? The answers aren’t the same.

The sky is blue. The oceans are blue. While science can explain them both, the reasons for each are entirely different.

If you’ve ever been curious about the world you live in, you’ve probably wondered why the sky is blue. The incorrect answers that people often give in response include:

• that sunlight has a blue tint,
• that oxygen itself is a blue-colored gas,
• or that the sky reflects the oceans.

While none of those answers are correct, that last attempt brings up a related question that people often wonder about: why are the oceans blue?

As seen from space, planet Earth is often described as a pale blue dot, but it’s only the liquid bodies of water ⁠ — dominated by Earth’s oceans ⁠ — that appear blue-hued. The continents, clouds, and ice caps don’t appear blue at all; it’s the oceans, not the atmosphere, that give our planet its overall complexion. For thousands of years, humanity had to simply accept these properties of our world as facts. But with the advances of modern science, we understand why both the skies and oceans are blue.