Cassini Science: Ring Propellors

As I was watching the grand finale of Cassini and listening to the mission team talk about the accomplishments of the mission, I learned a little bit about propellors.  Not your typical airplane propellor, but the name used to describe this fascinating feature in Saturn’s rings. Seeing Saturn’s rings from afar, or even relatively close with Cassini, we see the rings as perfect.  How do we end up with strange features and imperfections like this one?  Looking elsewhere in the rings, we can find clues. The first clue is the namesake of the mission itself.  The Cassini spacecraft was named for...

Cassini – A Fond Farewell

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...

A Surprising Pan

You’d think I would have learned my lesson by now.  Every time I think I’ve seen it all, that I’ve seen every strange phenomenon in space, every unique planet, moon, star, galaxy, every variation, I’m proven wrong.  I expect that the order has been established and everything newly discovered will fall into a category with no more unique variation. But here we are again.  The close up view of Pan. Pan was photographed only a few days ago by the Cassini spacecraft as it carries out the final months of it’s mission to Saturn.  It was revealed to be a...

Reflection in a Dark Universe

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...

Mars in the Spotlight

On May 22nd, Mars will be at opposition.  It’s the astronomical term for when Mars and the Sun are on opposite sides of the Earth.  This makes the face of Mars fully illuminated from Earth, and also brings the Earth to it’s closest approach of Mars, at 75 Million Km.  Hubble images the red planet to celebrate the occasion. So get your telescopes out and be ready to take some pictures, because Mars is smiling! Mars will rise in the East at sunset, since they are on opposite sides of the Earth.  It will appear bright with a rusty hue, and...

The How and Why of Planet Nine

It hasn’t been found yet – let me make that clear.  But with evidence that it should exist, astronomers are looking more closely at the proposed planet nine and how it might have formed, and how it could have ended up in such a distant orbit. When you start to think about how a planet ten times the mass of Earth could have ended up more than ten times as far from the Sun as Neptune, a few scenarios pop into mind: It was formed in the inner solar system, where interactions with gas giants or another star pulled it out It formed...

Titanic Methane Seas

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...

Mercury Surprises

One of the most fascinating things happens whenever I show someone the planet Mercury in the sky. Their first reaction is to be surprised at how bright it is.  Most people think of Mercury as a faraway planet, too close to the Sun to see at all. But in reality, Mercury is close to Earth, and when the angles are just right, it’s not hard to find. Mercury is 57 million kilometers from the Sun, more than a third of the way to Earth.  We are also much closer to Mercury than we are to Jupiter and Saturn. When we see the...

Saturn Double Shot 2/2: Enceladus Eruptions Explained

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...

Saturn Double Shot 1/2: Less-Than-Ancient Moons

It’s always funny explaining astronomical time to a non-scientist.  I often get the craziest looks when I mention a million years as being a ‘blip on the radar.’  Perhaps there is some immortal alien race out there who would understand how nothing much happens on the scale of the universe in a million years.  To humanity and our ever-accelerating advancement, a million years is thrice the age of our entire species.  But I guess Einstein was right when he said that ‘it’s all relative.’ This brings us to Saturn, a planet as ancient as the solar system.  Moderately old in...