Saturday, 20 October 2012

The bringer of jollity

OK...the penultimate Solar System video is here:


What can i say?  Jupiter is bloody massive of course, being two and a half times as massive as the rest of the planets in this solar system put together, but is also quite a bit smaller than various planets in other solar system.  It's even possible, though unlikely, that way out in the depths of the cloud of embryonic comets which surrounds the centre of the system lurks a planet provisionally named Tyche which is a whole lot bigger, orbiting a quarter of a light year from the Sun.

The largest known planet, incidentally, is HAT-P-32b, which is about twice the diameter of Jupiter but less massive than it, and is a "hot Jupiter" - a large planet orbiting near its sun.

Anyway, what to say about Jupiter?  Astrologically and herbally, Jupiter is the liver of the Solar System because it eliminates comets which might otherwise constantly bombard Earth (and when i say constantly i probably mean every few centuries), so like the liver, it clears our system of toxins in a sense.  It may also have helped this planet form in the right place for life.  The Solar System is said to consist of the Sun, Jupiter and assorted debris.  Given Jupiter's powerful gravitational pull, before the other planets formed, it's likely to have organised the rocks and gas into zones like the asteroid belt but much denser.  This is because an object which orbited, say, exactly twelve times for each Jovian year would be yanked at each time it was at its nearest to the planet, pulling it outwards slightly until the orbit no longer had that direct ratio.  This applies on both sides of Jupiter, but more so further in because it would happen more often - shorter years.  That would cause rocks and gas to clump together just outside those resonances, leading to more collisions and a greater tendency for things to turn into planets.  Jupiter orbits the Sun once every 11.86 years, so Earth is probably largely made of stuff which took 361 days to do so.

Near Jupiter, this effect is strong enough to prevent any real clumping at all, so there is an asteroid belt between Mars and Jupiter.  Jupiter takes 6.3 Martian years to circle the Sun, so this may mean early Martian history is turbulent, perhaps involving colliding with Earth to produce the Moon at some point.

Also, Jupiter and Mars, being near the asteroid belt, have managed to capture some.

Jupiter is turbulent and looks like it's boiling.  It's warm inside and cool outside, and has an unexplained long term storm, the Great Red Spot, which has been there for many centuries but sometimes disappears.

Right, these will form a playlist comprising a tour of the Solar System.  The next and last one will be on the inner planets.