7 Science Lessons In The Stunning Astronaut Earth Photo

By the time you read this article, the Artemis II crew will be much closer to the moon than Earth. As they journey around it, they will conduct tests in preparation for future lunar missions. They will also see parts of the moon humans have never seen before. While cruising towards the moon, astronaut Reid Wiseman snapped the iconic photo above from the Orion spacecraft. We are all sitting on that planet right. That should bring you pause. It reminds me of all of the things to be thankful for on a day many people around the world celebrate Easter. It also inspired me to dig into this photo to reveal seven hidden science lessons. Two Aurora Present It is hard to see at first, but the photo captured an aurora near each Pole, respectively. To reveal the aurora at the North Pole, I zoomed in on the region in the image above. Do you see the faint greenish feature seemingly wrapping Earth like an onion skin? That's aurora borealis or northern lights. "Auroras are colorful, dynamic, and often visually delicate displays of an intricate dance of particles and magnetism between the Sun and Earth called space weather," wrote NASA's website. If you look closely at the original image, you also see aurora australis near the South Pole. The Earth Atmosphere Is Really Thin As an atmospheric scientist, I think about the atmosphere quite a bit. We live within it, and it's the source for our weather. The stratosphere also protects us from harmful ultraviolet radiation coming from the sun. When we look up at the sky or fly on an airplane, the atmosphere can seem quite thick relative to our human perspective. In reality, the atmosphere is very thin compared to the size of the planet. "The Earth is a sphere with a roughly 8000 mile diameter; the thickness of the atmosphere is about 60 miles," according to NASA. The space agency website went on to say, "If the Earth were the size of a basketball, the thickness of the atmosphere could be modeled by a thin sheet of plastic wrapped around the ball." That thin sliver of atmosphere is tethered to the Earth by gravity and is a fluid. The changes in that fluid in space and time govern our weather processes. Several weather and cloud processes are evident in the photo. Zodiacal Light I also see zodiacal light in the photo. What's that? NASA described it as a, "Pyramid of ghostly light a couple of hours after sunset around the spring equinox, or a couple of hours before dawn around the autumnal equinox." It is often referred to as "false dawn." From the surface, it may take on a pyramid or cone shape, but it is evident in the bottom right of the Earth photo as a haze of faint light. It is caused by sunlight being scattered by interplanetary dust. The Earth Is Moonlit If you notice illumination of the Earth, you might assume that it is the sun. Katie Mack, a cosmologist at the Perimeter Institute, told Alan Boyle that the planet is actually moonlit. "The sun is entirely behind Earth, which makes it a kind of solar eclipse, but with Earth doing the eclipsing instead of the moon," said Mack in Boyle's CosmicLog blog. If you look really closely, you can actually see city lights on the Iberian Peninsula. Nighttime lights imagery is commonly produced from low-earth orbiting satellites using moonlight. Earth Is A Water Planet The Earth is a very watery place. I am having visions of the movie Waterworld, but I digress. In fact, roughly 71 percent of the Earth's surface is covered with water. The oceans of the world hold about 97 percent of it, and that is quite evident in Wiseman's photo. Unfortunately, most of that water is salty. We primarily survive from the tiny percentage of available freshwater found in rivers, lakes, ground sources, ice caps, glaciers and permafrost. Another Planet Is In The Picture Too The bright dot in the lower right part of the picture also might catch your eye. That's Venus "photobombing" Earth. Venus is generally the closest planet to us, but its distance varies between roughly 24 million to 162 million miles depending on the orbits. Is Earth Upside Down? At first glance, you may think you are looking at Australia and Oceania, the name of the collection of islands in the Pacific Ocean. However, the Earth, relative to how we look at a static map, is upside down in the photo. You are actually seeing the western Sahara region of Africa and the Iberian peninsula. Brad Johnson is a geography professor and meteorologist at Florida State University. "Not sure why this jumps out to me, but the Saharan dust is a distinctive feature of our planet like the red spot on Jupiter.... Our own personal flare," said Johnson in a message to me. This is a stunning image, but as a former NASA Earth scientist it is important to remind everyone that there is a fleet of Earth-observing satellites that are producing images like this daily. Many of the instruments on those satellites are providing critical data to understand Earth. As we rightfully set our sights on the moon, Mars, and beyond, we must continue to invest in science and technology to understand Earth too. You know why? Most of us are not going anywhere, and there is no "plan B planet" within immediate reach.