Monday, September 10, 2012

We Must Ride the Lightning

Lightning_by_Stock_by_KaiWe Must Ride the Lightning and Ride it well…

A quote from Robert Heinlein, he was referring to technology and warfare in the atomic age but I am going to discuss lightning.   Lightning is pretty common, we’ve all observed it, and some of us have even had the opportunity misfortune of being its conductor.  Odds that a person in the United States will “ride the lightning” once in their lifetime (naturally, not as ordered by the state) is approximately 1 in 3,000.  Lightning here within our terrestrial amphitheater, with all of its truly awe inspiring power and might still seems fairly mundane because it is a fairly common occurrence.  In this article we are going to discuss extraterrestrial lightning.  But first, what is lightning?

What is lightning?
Many of you may know what lightning is, but it bears repeating for those who may not.  Lightning is a large electrostatic discharge caused by a differential in electrical charge within the atmosphere.  Simply put, ground discharge lightning occurs when the ground and atmosphere have a difference in charge that is so great that difference discharges in the form of a large spark. Lightning is similar to when a person shuffles their feet along the ground and gets a shock when touching a door knob.  That is all fine and good, but other planets have lightning?
Artist's Depiction of a Venusian Storm


Earth is not the only planet that has an atmospheres so it stands to reason that other planets may have atmospheric conditions leading to lightning strikes.  The first recorded lightning strike was recorded by the Russian Venera 12 space probe, these results were later called into question in 1999 when the Cassini space orbiter flew by and detected no signs of lightning.  However in 2005 the ESA launched the Venus Express orbiter which was able to confirm that lightning does occur in the Venusian atmosphere.  One fact that makes Venus’ lightning unique and interesting when compared with other planets, is that the Venusian clouds are comprised of sulfuric acid rather than water. This means the mechanics of rain drops falling and rubbing amongst each other causing the charges to build also occurs with other chemicals.  This could mean that on Titan with its methane seas, and methane rain most likely also experiences lightning.  If this is the case we may be able to peek into an environment somewhat similar to Earth’s own primordial state currently taking place on the surface of Titan.


Jupiter Storm
In 2007 the New Horizons mission, a very exciting mission in its own right, used Jupiter for a gravity assist on its way to Pluto (still a planet at the time and still a planet in our hearts) was able to record lightning strikes near the Jupiter’s North and South poles.  Some of the bolts were up to 10 times as powerful as any lightning strikes recorded on earth.  During both the Galileo mission in the 90s and voyager probe in 1979 lightning was recorded nearer the equator.  Similar to storms that occur on Earth water vapor rises and ice particles form, then fall colliding on their way down towards the surface, building electrical charge which then discharges as lightning.  Jovian storms not only have extremely energetic lightning, but due to the incredible gravity rain falls faster causing the charges to build quickly.  Jupiter’s storms are often larger than the entire Earth, and along with gravity, and an extremely dry atmosphere, an atmosphere made up almost entirely of hydrogen and helium, the rain can fall very fast.  All of these things culminate into the…perfect…storm.


Saturn Lightning
Daytime lightning had not been observed until March 6, 2011.  The Cassini spacecraft was able to visually observe a lightning strike in a very large storm.  Scientists have calculated that the bolt Cassini saw was about 3 billion watts and lasted for one second.  The flash was approximately 100 miles in diameter and exited the top of the cloud surface. 

The very fact that other planets exhibit and experience atmospheric conditions similar to those found on Earth helps shape our perception of the planets around us.  They are different from ours and we may not be able to live on them, for now, but they are more similar than one would first suppose.  Of course we would not have been able to learn about these weather patterns if NASA, the ESA and the Russian Space programs had not sent space vehicles to explore them.  The insight we gain by observing weather on other planets may help us to understand the weather here on the planet we call home.


The following quite is taken from a memo that Robert Heinlein wrote to for the Naval Air Material Command in 1945 it is a bit of a pessimistic viewpoint for humanity, but this was not an uncommon view held by many scientists at the time.   None the less it is where I derived the title of this posting and they are still the words of Heinlein.

This question needs to be approached with humility and with real desire to serve rather than simply with the idea of preserving a particular bureaucratic institution as a going concern. It may be conclusively assumed that, while war may possibly be successfully outlawed through the use or the threat of the use of the atomic bomb, the atomic bomb itself may no more be outlawed than sex or the silent stars. It’s here, we’ve got it. It is a fait accompli. We must at all times be ready and willing to use it. If our culture is to survive we must contain that power with sober judgment and humanity. It is a simple fact that (1) we can not afford a war ever again, (2) the atomic bomb cannot be abolished, nor can it be indefinitely kept from other peoples. We must ride the lightning and ride it well. I conceive the atomic bomb as being the force behind the police power for a planetary peace. Perhaps the custodian will be called the “Armed Forces of the U.S.” or perhaps the “Peace Forces of