In the year 1610, it was commonly believed that the Earth was the center of the Universe, that all bodies rotated around the perfect planet, placed by god with the heavens around it. Galileo Galilei dealt a major blow to this idea, by using an early telescope to improve his vision and look up at some surprising dots. These dots formed a line that went straight through the bright planet Jupiter. As Galileo looked again and again, night after night, he noticed that they not only persisted, they moved. Their motion was predictable, and Galileo realized that they were orbiting Jupiter, just...
Even after a decade of interloping among the Saturnian system, the Cassini spacecraft is still doing great science. It helps that there are lots of places to visit, since Saturn has 62 moons and the largest ring system of the gas giants. Arguably the best science has come from Saturn’s largest moon Titan, second largest moon in the solar system (behind Ganymede) and the only moon known to have an atmosphere. Since Cassini has been in orbit around Saturn and it’s system of moons, it’s been revealed that over 1.6 million square kilometers of Titan’s surface are covered in liquid...
I feel like I’ve been covering a lot of stories on magnetic fields over the past few months. Fields around the Earth, the Sun, Mars, Jupiter’s Moons, and exoplanets are just some of the places in the universe where we are looking at magnetic field behaviour. The intention is to use our understanding of magnetism to figure out what is inside these worlds, and how they interact with their space environment. You would expect us to understand the Earth’s magnetic field and interior very well, after all, we are stuck here. But it turns out it’s very difficult to study the interior of...
When we see the Earth’s only Moon up in the sky, we often think about how small it is. It’s only about 1/4 the diameter of the Earth, and at a distance of 384,000 Km, it looks small in the sky. But often size is entirely a matter of perspective. What we compare something to, that’s what determines it’s size. When the Moon is high in the sky we easily compare it to the size of the window we are looking through, or to a nearby tree, or our outstretched hand. All of this can make the Moon seem pretty tiny....
Auroras on Earth are caused by the ionization of atoms high in the atmosphere near the north and south magnetic poles. The solar wind flies toward the Earth and this harmful radiation is blocked and funnelled by our magnetic field, creating harmless, beautiful glows that remind us how close we came to total destruction, but were saved by our planet. Do other planets have auroras? Certainly! Jupiter and Saturn do, and even moons like Ganymede can have auroral activity. It really depends on the magnetic field. So how does a planet like Mars, with no magnetic field, have auroras? This...
For a long time, the scientific community has been hopeful for a mission to some of the most interesting moons of the solar system. Europa, Enceladus, and Ganymede all have subsurface oceans and will give substantial insights into the formation and evolution of life in the solar system and beyond. The only problem is that it costs an astronomical (literally) amount of money to get there. A bare bones mission to Europa would cost over 600 Million dollars, and if we are spending that much we had better be sure it will work. Money aside, the technology to get appropriate...
Our Solar System is so much more than just the eight planets that inhabit it. One of the things I learned a bit later in my career as an astronomer (my teenage years; been doing this for awhile) is how unique and diverse the natural satellites are. Our own moon seems somewhat tame, and it’s easy to think the same of all moons. Many of them are boring quiescent rocks with little more scientific value than asteroids, but the largest hide deep and profound secrets that we are just starting to unlock. Four moons in our solar system are larger...
About a year ago I had an idea for a music video. I wanted to take a concept in science and put it to music, making it funny, catchy, memorable, and educational. I wrote out the majority of the lyrics but left it alone for a few months, until I connected with the right friend. My good friend Bob Wegner is a very talented guitarist and audio engineer, and as we spoke about the idea he wanted to be the guy to record it. We spent an afternoon doing the vocals and guitars, and he cleaned it up and made...
With all the talk of the large geomagnetic storm of the past few days, it’s important to understand that other worlds have beautiful auroral activity as well. Being on Earth and seeing the gorgeous displays that result from our magnetic field protecting us from harmful solar radiation, the best views come from Earth. But there are several other places in our own solar system that have aurora. Jupiter has a massive magnetic field, and its gigantic aurora are visible here. Jupiter’s moon Ganymede is the only moon in the solar system that has auroral activity. Saturn has its own, discovered...
After reaching a deeper understanding of the subsurface ocean of Enceladus just yesterday, a stunning discovery has just been made about the largest Moon in the solar system. The largest moon of Jupiter, Ganymede, contains a subsurface ocean of it’s own. The discovery was made with the Hubble space telescope and a careful study of aurora on the giant moon. That’s right Ganymede has auroral activity. This is because it is the only moon in the solar system with a magnetic field. The magnetic field funnels radiation from the Sun toward the north and south poles, where it ionizes molecules...
