To mix things up and make it interesting for me as I pore through satellite databases, I thought I’d give myself a challenge for the next several posts: find “geometric shapes” visible from space. By “geometric shapes”, I mean definable, recognizable and simple shapes such as circles, triangles and rectangles.
When I look around my room these shapes are ubiquitous in the furniture and other processed objects we as humans surround ourselves with: windows, paper, books, lighting fixtures, bed frames, etc. Outside, it’s a bit harder to find these forms. There are circular river stones and tree knobs, pyramidal crystals in the local bedrock, and hexagonal snowflakes. When it rains, which it seems like it always does here, the flooded ground is covered in expanding circular ripples from every raindrop.
It seems that when I observe my surroundings on a small scale, these geometric shapes are relatively easy to find. But increase scale from small natural objects to the size of mountain ranges and forests, and everything is even more chaotic and organic. Trying to apply these basic shapes to large objects would seem silly to anyone who has ever gone outside: there simply aren’t cubic clouds or perfectly linear (natural) rivers. Coastlines, mountains, lakes, and everything else at these sizes all subscribe to the random, fractal, organic nature of the world.
(Interestingly, scale up even more, and suddenly geometry becomes relatively clear again. The Earth is spherical—technically, it’s a geoid—the sun is also spherical, and orbits are elliptical—nearly circular. Meanwhile, it’s the smaller objects that are highly irregular in shape: asteroids, Pluto, the moons of Mars…)
But back to Earth. Now I’ve made it seem like it’s impossible to find geometric shapes on the surface of the Earth. But I can still try: for this post I will focus on satellite imagery that contains “circles”: two of the following images are unique geological structures and phenomena while one is the result of human intervention in the landscape. You can be the judge of how circular these objects really are.
Lac Manicouagan (shown here on a wintery day on March 9, 2020) is a massive impact crater lake located in a remote part of Quebec. The frozen water-filled ring spans nearly 70km, formed by a 5km wide meteor. I’ve written about this stunning feature in a previous post here.
Taranaki Maunga is a stratovolcano located on the North Island of New Zealand. Located within Egmont National Park, the contrast between dairy farms and old growth forest is clearly visible along the 12 mile radius defining the park boundaries (October 18, 2018).
Around 30 miles in diameter, this unusual formation is located among the Erg Oudane sand dunes in a remote part of the Sahara. Geologists are still somewhat puzzled with regards to how this formed (perhaps a highly eroded dome), but have ruled out a meteor impact.
Landsat 8 data gathered from NASA/USGS Earth Explorer.