Tag Archives: saturn

Neptune’s heart

Following on from yesterday’s post about orreries, I’ve decided to do a quick release with two changes.

First, the promised option to disable the click noise. I’ve also turned the volume down on it a bit, when it is enabled.

Secondly, rounding out the planets, as defined by science, Solar Explorer now has information about the core of Neptune, the other ice giant in our Solar System.

“Ice” is a counter-intuitive term used by planetologists to define the melting point of certain volatiles, whether they are in a solid, liquid or gaseous state.

Elements such as hydrogen and helium have a melting point below 100 degrees kelvin, so they are called gasses,while other elements such as methane and ammonia melt above 100 degrees kelvin, so they are called ices.

Because Uranus and Neptune have a lot of ammonia and methane, they are classed as ice giants even though the interior of these planets, where the “ices” are located, are under incredibly high pressures and temperatures, and these “ices” are in a liquid state.

Saturn and Jupiter on the other hand are almost entirely composed of hydrogen and helium, so they are gas giants.

Makes perfect sense.

To a planetologist.

Catching up with Cassini

Cassini has to considered to be the quiet achiever of space probes.

It left Earth in 1997, arriving at Saturn in 2004. After Huygens touched down on Titan, Cassini has largely been forgotten by the public while superstars like the Voyager twins set new distance and longevity records, and the Spirit and Opportunity rovers discover an ancient, wet Mars.

And yet, Cassini soldiers on, quietly studying the Saturnian system. In fact, it’s been doing such a good job (and is still in good working order) that it’s had it’s mission extended 2017.

I felt that it needed some recognition, so this week’s update for the Pro edition of Solar Explorer  features a detailed Cassini model.

A lot of work it was too.

Unlike Juno, Cassini has exposed instruments and struts all over it, which made it hard to convert to polygons. I’m getting the hang of spotting “shortcuts” now, so I was still able to come in well under my 2,000 polygon budget, to keep the speed up on all classes of Android devices, while keeping the model reasonably accurate.

My favourite feature of Cassini would have to be the sinister looking thermoelectric power generators that stick out around the base of the craft. Each of these produces electricity for the from heat generated by the radioactive decay of plutonium stored within the generator.

They kind of remind me of a Dalek’s gun from Dr. Who.

New Horizons, currently on it’s way to Pluto, got the Dalek ray gun treatment too, with a spare generator left over from Cassini bolted on.

There’s still lots more to come for Solar Explorer, but there’s only so many hours in a day…

It rains on Saturn?

Infrared photo of ice volcanoes erupting on EnceladusIn a previous post I commented that the Solar System is soaking wet.

Today we learned that there’s rain falling on Saturn.

OK, so it’s not exactly a downpour. The “rain” is water vapor that’s being sprayed into space by ice volcanoes on Enceladus, a tiny fraction of which ends up raining onto Saturn.

This discovery was made by the European Space Agency’s infra-red Herschel space telescope.

Salty geysers on Enceladus?

It looks like we might be able to add Saturn’s Enceladus to  to the growing list of moons that have the potential for liquid oceans under an outer crust of ice.

Instead of specifically mentioning which moons have possible oceans in Solar Explorer, I should probably just point out the ones that are dry. It’d be easier!