I remember vividly my first astronomy class in university. Winter 2004, only months before the Cassini spacecraft was set to arrive at Saturn after a seven year journey. On several occasions in that class we talked about what we might see when Cassini reached it’s destination. The first dedicated mission to the jewel of the solar system, originally conceived right after the voyager flyby in 1982, would give us a chance to study more than just a planet, but an entire system of interaction between a planet and it’s moons. Beyond that, it included the Huygens probe, to land at...
Like lighthouse beacons in a dark ocean, stars act as tiny islands in the vast universe. Producing light at the atomic level from the powerful release of energy through fusion, they are the engines that drive the formation of new elements. But in the darkness there are plenty of other hidden objects that are cold and give off little to no light. Yet many of them are easily seen. Here’s Why! The first thing to think about is infrared light, the radiation given off by warm objects. Large planets and brown dwarf stars are very bright in infrared, much brighter...
One of the most surprising and intriguing finds during the decade-long Cassini mission has been the discovery of geysers on the Moon Enceladus. Originally spotted in 2005, scientists have spent the last decade trying to understand how they work. And now they finally have a working model. How does an eruption on a frigid Moon last so long? Eruptions on Earth are not long-lived, and if they are, they are very spread out. For Enceladus to have a ton of localized geysers in the South polar region, you need some pretty specific scenarios. Aside from the fact that a constant stream of material could clog...
You’ve seen the planets, now let’s look at some of the best moons to visit in the solar system, ala the romanticized art deco style! Ceres is like a gas station for that long trip to Jupiter, treated as an icy rock that is not the best tourist destination. Enceladus is a lot like the spacefarer’s version of Yellowstone park, with the southern hemisphere geysers being the appeal. My two favourites are Titan and Europa. Titan’s colour scheme and view of Saturn are gorgeous, but the best part is the paddle boats in the hydrocarbon seas. The most interesting visit...
Since 2004, the Cassini spacecraft has been orbiting Saturn, giving us unprecedented views of the rings and Moons, and sending back data that has helped us to understand the dynamic nature of the Saturnian system. The flexibility of such a craft allows for new science goals to be determined in an ongoing basis, since new discoveries often lead to new questions and new areas to focus our resources on. Yesterday, October 28th, Cassini focused its resources on the geysers of Enceladus, flying lower than ever before over the surface of the icy moon, in an attempt to sample some of...
For years there has been talk of a subsurface ocean present within Saturn’s icy moon Enceladus. Many have simply assumed it to be fact, but the reality is, something so complex on a world so far away is very difficult to prove conclusively. But now, using data from over a decade of observations by the Cassini spacecraft, mission scientists have shown conclusively that Enceladus must have a global ocean beneath a surface of ice. Previous data analysis suggested that there was a lens-shaped liquid ocean beneath the south polar region of the planet, giving a source for the observed plumes...
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...
Mercury, the smallest planet in the solar system, and closest to the Sun, is only a little bit bigger than Earth’s Moon. But the Moon is comparatively reflective object. Mercury is thought to be made of the same rock as the Moon, so what is the difference? Why do objects in our Solar system have different brightnesses? The key is in a property called albedo. It’s basically how much light an object reflects, measured as a fraction. For example, the Moon reflects 12% of the light the Sun shines on it, so it has an albedo of 0.12. The albedo...
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...
Some of the moons of gas giant planets have a unique property: They are worlds that have a source of heat other than the Sun. The huge tidal forces imparted by their host planet and fellow moons cause their crust to grow and shrink, creating huge friction and heating the rock. It means that even if these moons are far from the warmth of the Sun, they can still host liquid water. There are two moons in our own solar system that are especially enticing: Jupiter’s second moon Europa, and the icy moon of Saturn known as Enceladus. Each host...
