Curious Kids is a series for children of all ages. If you have a question you’d like an expert to answer, send it to [email protected] do we see snow on mountaintops that are closer to the Sun but not near the ground? – Ms. Drews’ third grade class, Beechview Elementary School, Farmington Hills, MichiganThere’s not much better than a bluebird day in the mountains – a crisp, sunny day accompanied by a fresh blanket of snow. But why doesn’t the Sun quickly melt all that high altitude snow away?It all boils down to our atmosphere, which is what I research as a scientist in Colorado. Let’s dive in!Our atmosphere: Earth’s armorEarth’s atmosphere begins right at its surface and extends to outer space, and it is filled with a mixture of many different gases. Gases in the atmosphere include the oxygen we breathe and the water vapor that makes it rain and snow. They are essential to supporting life on Earth in several ways.AdvertisementAdvertisementOne of the most important jobs those gases have is to protect us from harmful things in space, including our closest star: the Sun.The Sun’s radiation provides heat to our planet, but too much of it can be a problem. If you’ve ever gotten a sunburn, then you’re already familiar with this idea.Gases in the atmosphere warm the Earth by trapping heat close to the planet’s surface. Too much of those greenhouse gases can cause global temperatures to rise beyond normal and stay high. Climate Central, CC BYSome of our atmospheric gases limit the amount of radiation from the Sun that can reach the Earth’s surface by absorbing some of it, which prevents temperatures from being way too warm in the daytime. At night, certain atmospheric gases also trap some of the heat that the Earth’s surface releases as it cools down, protecting us from unsurvivable cold.The way the atmosphere regulates Earth’s temperatures is known as the greenhouse effect. You’ll often hear this term used alongside climate change or global warming. That is because global warming is caused by enhancing the greenhouse effect: As people burn fossil fuels in cars and factories, the amount of greenhouse gases in the atmosphere increases. These extra gases allow the Earth’s atmosphere to trap more heat, causing an increase in temperatures.The atmosphere likes to stay groundedIf you were to compare the Earth’s atmosphere along a Caribbean beach to that surrounding the top of Mount Everest, it would look quite different.AdvertisementAdvertisementThat is because as you go higher up in the atmosphere, it gets “thinner,” meaning that there are less gases present at higher elevations and altitudes.[embedded content]Why? Blame it on gravity.More in ScienceIn the same way that gravity keeps people and objects from flying away to outer space, Earth’s gravitational force pulls on the gases in our atmosphere, trying to keep them as close to Earth as possible.As a result, there are fewer gas molecules in th …
