If you’re like us, you’re not a huge fan of the sun going down at 5:30 in the afternoon. Well, we’ve got good news: the Winter Solstice is coming up on Saturday, marking the shortest day of the year, but also the beginning of the Earth’s journey back into longer, warmer days. In recognition of the Solstice, today we’re talking about seasonal fun facts and astronomy!
Why Does Daylight Vary Across the Year?
Variable daylight occurs at certain latitudes due to the Earth’s axis being slightly off-set. The axis is at a roughly 23-degree angle when compared to its orbit around the sun, meaning that the planet gets illuminated unevenly everywhere except for the equator.
For this reason, locations near the equator get roughly the same about of daylight year-round. Conversely, very far north or south points on the globe can go for months without any sunlight, as the Earth’s axis tilt takes them completely out of view of the Sun.
This Is Why Seasons Exist
Since the Earth’s axis tilt remains somewhat constant in relation to background stars, we experience seasons. As the planet orbits the Sun, regions further from the Equator get angled closer to, or farther from, the Sun’s rays. This, in turn, causes the uneven heating that results in weather patterns and seasons as we know them.
What Would Happen if Earth’s Axis Wasn’t Tilted?
Earth would look very different without seasons. Humans would not survive at higher latitudes, as they would be living in a perpetual winter, much like Antarctica today. The habitable band would be relegated to the tropical regions of Earth, and humans wouldn’t fare much better there, but for very different reasons.
Farming as we know it exists thanks to seasons. Without seasons, you don’t get crops like wheat, barley, rice, or corn. That means no bread, no fermentation, and, bluntly, no human settlements or civilizations. Humans would likely live in scattered dwellings, fighting off huge tropical insect swarms, disease, and large predator animals.
In short, while we may hate the shortest days of the year, we’re lucky that the Earth rotates through seasons, both to keep bugs in check and to give us the crops that make civilization possible!