Jupiter’s Moons
Location: Suburban Sarver, Pennsylvania
Date / Time: September 20th, 2020 at 20:30
Telescope: Celestron Skymaster 15x70 Binoculars
Camera: Galaxy Note9 Camera, attached with Gosky Universal Cell Phone Adapter
So far I’ve only posted images taken with a medium-sized telescope, but I wanted to show you that you can explore our solar system without high-powered equipment. The binoculars I used to take this image are made for stargazing and are comparable to a low powered telescope. You can feed your curiosity without shelling out a lot of money!
When I first took this image, I thought there were only two of Jupiter’s moons visible. However, when I compared the image to Stellarium's representation of the same time, I realized that the dot to the right of Jupiter looks oval-shaped because it's actually Ganymede and Callisto appearing very close together. (I'd thought I just wasn't keeping the binoculars steady enough!) The dot to the left of Jupiter in this image is Io. Europa is also to the left, but it's hugging the planet very closely, making it harder to notice.
These are the four Galilean moons of Jupiter, named after Galileo Galilei (the first person to document these moons after seeing them through a telescope). Today, we know that:
Io, the closest Galilean moon to Jupiter, is the most volcanically active place in our solar system, spewing tremendous amounts of lava and sulfur. This intense volcanic activity is caused by Jupiter’s intense gravitational pull on Io. Io's orbit around Jupiter causes it to be "stretched" and "relaxed" so frequently that its interior gets hot enough to melt rock! This heat causes pressure to build up inside of Io, until molten rock blasts out of Io through volcanoes.
Europa is also volcanically active due to Jupiter’s gravity, but Europa's volcanoes don't spew molten rock -- they spew water and ice! This type of eruption is called “Cryo-volcanism”. Europa is an ice moon with liquid water under its icy exterior. It’s a prime target for astrobiologists because life (as we know it) can originate in water. And though Europa’s surface is far too cold for our kind of life to live on, ice is an excellent insulator. This means water under the ice could be warm enough (from Jupiter's gravity heating Europa in the same way it heats Io) to sustain life. We won’t know until we go there to find out!
Callisto and Ganymede are far enough away from Jupiter that they aren’t volcanically active like Io and Europa. But they're no less impressive! Ganymede is the largest moon in our solar system. Callisto is the third largest, but is similar in size to our solar system's smallest planet Mercury!
So don't wait to get top-notch equipment. Use whatever you have -- even if just your eyes -- to look towards the sky, and be curious about everything!
