Archive for July, 2016
we are here to worship you and seek wisdom. After forty plus years of flirting with the supreme deity of Zeus, aka planet Jupiter, yesterday NASA put a spacecraft, Juno, into orbit around the planet for the ultimate research project which will, hopefully, unlock the secrets of the origins of our solar system and our own creation. Powerful stuff when you get a computerised audience with the supreme deity of humanity’s ancient cultures.
Since the 70’s we have sent nine space missions up that way; it is the best part of 600 million kilometres away, or in more manageable terms, from Dunedin to Oamaru and back again once a day, every day for 7,000 years and when you say it like that it doesn’t seem so bad.
In 1995 Galileo actually entered Jupiter’s orbit and stayed there until 2003 and observed Jupiter. Juno’s mission is to get to the very core of Jupiter and get answers to some fundamental questions about the creation of our solar system, and of us. Juno will orbit in a path that passes over Jupiter’s poles and will measure microwave emissions, the gravity field and the magnetic field, which apparently is how the scientists will gain the vital clues into the formation of our solar system.
Don’t ask me to explain how all that works, I was bewildered just watching a real estate agent hovering a camera drone over the house next door. But if you ever wondered why Zeus (Greek)/ Thor (Norse) / Taranis (Celtic)/ Jupiter (Roman) was associated with the lightning, hammer and shield wielding warrior deity, considered the chief of the planet-gods in their mythologies, you might be interested to know that Jupiter is in fact a protector of earth. The massive energy of magnetic field and gravity of the gaseous giant has either deflected comets back out of our solar system or taken one for the team when its gravitational pull has dragged asteroids and comets to their death and preventing them turning their attention to earth. Such impacts are noted regularly and there is calculation that Jupiter’s size and gravitational pull drag in up to six asteroids/ comets per year. But some of the comets and asteroid strikes that our astronomers have actually observed have been real monsters.
Back in the eighteenth century there was a comet that appeared in our skies known as Lexell’s Comet, named after the astronomer Anders Johan Lexell who first calculated its orbit. He showed that the comet had made a close approach to earth of just 2.2 million kilometers. That was the closest a comet has ever been witnessed to approach the Earth and, in astronomical terms, it was a very near miss. Lexell worked out that with the speed the comet orbited around the Sun, we would see it again in 12 years, possibly a lot closer to earth and, if in an attack formation, would actually smash earth. In 1782, however, the comet was nowhere in sight.
The French mathematician Pierre Simon-Laplace then calculated that the comet had experienced a set of encounters with the giant planet Jupiter. After the 1770 sighting from earth, the second encounter with Jupiter modified the comet’s orbit, ejecting it from the Solar System altogether and removing it as a potential hazard.
A very serious comet in more recent times was named Shoemaker-Levy 9. The comet had orbited the Sun for billions of years but, in the 1960s or 1970s, it changed orbit and made a close pass at Jupiter and the giant planet captured it and it orbited Jupiter on a highly elongated path. On July 7, 1992, it passed so close to Jupiter that the planet’s mighty tides (hammer/ magic belt?) tore the comet apart. When it was re-discovered a year or so the comet had a squashed look due to having been smashed into fragments.
By observing the orbit of the comet, the astronomers calculated that it would collide with Jupiter in July of 1994. Having broken up the comet into bite-size chunks, the first piece of the comet that was pulled onto the planet’s surface was about 2 kilometres in diameter and hit with the equivalent of over a million one-megaton nuclear bombs exploding at the same time. It was probably Zeus’ version of having a really good curry, I imagine. That, however, was not the largest chunk which was fragment G. As illustrated, it made quite a bang.
More recently again in 2009 an asteroid impact, from a rock some 500 metres long, created a created a surface dent the size of the Pacific Ocean. Jupiter is just like our great big personal bodyguard. And the latest asteroid strike to be captured on camera was in fact on St Patrick’s day this year.
So if Jupiter is the mighty protector deity of earth then that explains why, as a planet, it was so respected and revered by ancient cultures as the warrior hero-god. In Norse Mythology, Thor (Jupiter) rode through the skies during a thunderstorm to kill the giants, the enemies of the gods (planets), and to kill the mighty serpent that flies through the skies with the lightning from his hammer and his magical ‘belt’ that doubles his strength.
In Greek mythology, Zeus, the presiding deity of the universe, ruler of the skies and the earth, was the god-master of all natural phenomena in the heavens. The personification of the laws of nature; the ruler of the state; and finally, the father of gods and men. At his command, mighty thunders would flash and lightnings would roll; he represented the grand laws of unchanging and harmonious order, by which both the natural and the spiritual world were governed.
Just how the ancients had any knowledge from which to create such myths about Jupiter performing such god-like protection roles is a matter of speculation, but the reality is, they did. But whatever the ancients thought, this is the moment when we finally have the technology to approach this chief planet deity that can unlock the secrets of the solar system and finally ask ‘what’s it all about, Alfie?’