full_frontal_occlusion

Partially correct but not the excess energy bit: The white light is a band spread of energy of differing quanta levels. The laser light is coherent because electrons drop from an outer to lower shell at a specific quantum of energy determined by the gas used. The gas loses energy when photons are produced. The excess energy is needed to raise electrons from inner shells to outer shells in the gas molecules from where they can then drop giving up their energy as a photon. The amplitude of the light is simply the number of photons created and their density at any given time. i.e. The amplitude of the laser light is a function of how much energy the gas is losing in a given time. See my previous response to laserguy. ffO.

Lets see if we can make this more coherent: So far so good Falling between higher to a lower level is random and will occur only for a proportion of electrons and as you correctly identify, this is called spontaneous emission. Because the electrons can change shells only at specific quanta of energy and the wavelength of light is directly proportional to energy, the photons will all be at the same wavelength characteristic of the gases used. The concept of stimulated emission (very different from spontaneous) now needs to be introduced: When a photon of sufficent energy passes an electron in an outer shell, it can cause that electron to drop an energy level i.e. from an outer to a lower shell. In the process giving off another photon. Critically, the new photon is the same wavelength as the first and propagating in the same direction. We now have two photons of the same wavelength travelling in the same direction. You can now see that the external light is used as a catalyst to not only promote stimulated emission, but to also provide the energy to allow electrons to jump from a lower energy level to a higher level. In which case, the external energy would need to all come from the applied light source making the process quite inefficient. The electric current provides a continuous supply of electrons as well as removing electrons from the outer shell of the gas atoms and providing energy for electrons to jump from lower shells to higher energy levels. In this way electrons are constantly replaced, changing shells and therefore providing the excess power needed to sustain an efficient process. OK Incorrect, see previous para. From my previous explanation, the laws of thermodynamics are maintained. The photons generated through both spontaneous and stimulated emission get their original energy from the gas initially in its steady state but then from the external electric current and external light source. ffO.

This is kind of scary, bit like giving yur kids a hand gun! http://www.youtube.com/watch?v=YaLCUGUsLq4

Think of all the fun you could have with a class IV laser at a petrol station or creating black tulips or practicing distance depilation. The possibilities are endless.

Don't want to be a killjoy, but Magpies warning should not be taken lightly. Not for no-good reason then that the legal use of lasers for pointing devices in the UK is limited to Class II <1mW power. Legally, all lasers must be classified according to the danger presented to vision. Unfortunately, imported lasers very often exceed these safety limits and therefore classification by the manufacturer is no guarantee of safety. Beware imported products. The power limit above which visual damage will result is defined by DIN std EN60825-1 at 25W/m2 on the retina. Even at <1mW power, depending on the spot size, these lasers can exceed 4000W/m2 at 5 feet on the retina! Far worse than staring directly at the sun. For many years I worked as a designer in the aerospace industry where lasers were used for target designation, ranging etc. Very strict health and safety legislation meant rigorous training in their safe use and 6 monthly comprehensive eye tests were mandatory. Just a polite warning that if you misuse a laser pointer, this is the kind of grief you can find yourself facing. These are UK specific laws: By shining a laser at an aircraft, you are committing an offence under the "Safety of air navigation act". If convicted you face up to 6 months imprisonment AND £100,000 fine. By using your laser outside i.e. not private property you are violating HS(G)95. The Health & Safety Executive rules on public use of lasers. Basically an un-authorised display. The HSE can implement £UNLIMITED fines. If your actions result in property damage you are liable for criminal damage. If you injure someone you are looking at GBH. Up yo 5 years prison. If you kill someone its Manslaughter. 20 YEARS. Have fun but please take care and be responsible. Sermon over. ffO.

Thanks CB. I will read them and reply shortly. This debate has raged for quite some time, indeed when I first joined NW now three years ago, there was an AGW thread that regularly ran to hundreds of posts, lengthy tomes, more references than an IPCC report and with a 10,000+ hit count. Stratospheric will remember it as will Penguin, John Holmes, Paul, Roo and several others I'm sure. It played out somewhat mirroring the current IPCC vs layman arguments, with on the one hand pro-AGW supporters representing the scientific community and on the other, the sceptics, represented by primarily two antipodeans namely Stockman70 and Ken Ring. The former a retired ranch owner and the later, a new-age / alternative life-style maths teacher cum weather forecaster, whose unorthodox methodology relied on lunar, solar and planetary barycentric cycles topredict globalweather patterns. Ken had quite a following especially in New Zealand, where he appealed to a large contingent - probably because of his disdain for orthodoxy and organised social convention. Stockman appealed to the layman with his no-nonsense robust outdoors 'Marlboro County' style. The discussions were heated, highly charged and at times descended into downright mud-slingng. Not the sort of discussion that would get past the censors these days (eh OON!), but immense fun all the same. One had to have a thick skin though! And these in the days before Gore, Crichton et al, and two years before the fourth IPCC report hit the streets and four years after the third report - it was still vigorously refuted, defended and refuted again. No conclusion was drawn at that time. I guess people decided to wait for the next IPCC report. What I can say is the arguments have not changed. Same dogma on both sides, just different names and some new styles. It's human nature to be competetive and argumentative. In the west and now increasingly in the east, self interest and meglomania leaves little room for altruism. Indeed, benevolence from rich western nations towards historically poor third world countries is waning as we now see (through loss of jobs, erosion of our previous world status, projection of military power, explosion of the surveillance culture etc) them as a big threat. Our distrust of corporate giants has grown in proportion, we see a growing new educated Proletariat who (rightly IMHO) equate business with government. Government has become adept at spin, gloss and rhetoric able to manipulate previously independent institutions through market forces. So exactly who can we trust? Which is precisely why we cannot agree until that question is resolved. If we are to trust, then the IPCC should be as unfettered by government as the judicial sysytem. That means the access by public enquiry to ensure freedom and fairness, to publish without editing by any government or corporation and the funding ring fenced and unhindered to spend without needing a return on investment. If AGW is a real and present danger, Stratospherics oft quoted tragedy of the commons is one outcome. If not, then we are left with an awful feeling of manipulation. ffO.

Quote from end of article: "The writer is an international business consultant specializing in the investigation of scientific frauds". No axe to grind then eh? B) If you really want to play games: http://www.guardian.co.uk/science/story/0,,1947245,00.html ffO.

I think its suggesting our solar system is the product of our sun going supernova 5 billion years ago and that our sun now has a collapsed neutron dense supernova type core.It suggests, evidence is gleaned from analysis of the composition of solar system chemistry, nuclear decay products, overabundance of light elements in the solar wind and photosphere, the barycentric orbital cycle of the solar system inducing a gravitational torque on the sun which in turn coincides with the sunspot cycle (it stops short of saying its the reason why there are sunspot cycles) and hence induced climatic variation on earth. mmmm. Tenuous methinks. ffO.

For a more accurate estimate of timings from your location try www.heavens-above.com I use this website and it is accurate to within seconds and gives a full sky map wih track plots for ease of location. Best visibilty should be 12 December onwards when the ISS assembly will be one of the brightest objects in the night sky. Just for info, the ISS is now in an orbital plane allowing the Space Shuttle mission STS-122 to rendezvous. STS-122 will deliver to the ISS, the European Space Agency built Columbus laboratory and thereby extend the scientific experimental capability and crew capacity of the station considerably. No new solar panels will be deployed during the sts-122 mission, although an extension to the mission may allow inspection of one of the solar panel arrays suffering partial malfunction due to unexpected debris within the solar tracking mechanism. As of tonight (1800 GMT), STS-122 is delayed at launch as a result of faulty fuel cut-off sensors or associated systems. For a time during the journey of STS-122 to the ISS, it may be possible to see both the ISS and the shuttle on the same path a few seconds apart, as the shuttle closes the distance to the station. Ccheck www.heavens-above.com for both. Yo can follow the launch of STS-122 and the full live coverage of the mission at http://www.nasa.gov/multimedia/nasatv/ or if you have Vista, there is a nasa tv gadget. Cheers, ffO. http://www.nasa.gov/mission_pages/shuttle/main/index.html

I can't take credit for this but Glacier Point on the model discussion thread gets full marks, this is now etched on my brain! 'What we have here I think is an expansion of the polar westerlies, aided by Rossby Wave distribution, leading to an exageration of the twin tropospheric vortices allowing a downward deflection of warmth at the stratosphere into the tropopausal depths resulting in that very particular Arctic High and ridge into Alaska.' Thanks again GP. ffO.

A voice of sense and reasoning. Thank you John. ffO.

QUOTE: 'mortality rate that would trim 1.5 Billion from the world population' An awful lot of cremations and burials, creating more CO2 and methane. Seems a shame to waste all that energy! <_< No disrespect intended. ffO

Paradoxically, western democracy enshrined in the constitutional and institutional laws of 'egalite, fraternite, liberte' are exactly those which conspire to prevent governments from unilaterally taking action to curb emissions. No government will risk alienating its populous for fear of losing office. This sets up a very cautious route maps and long term targets that nobody will blink at because as others state, there is no immediate perceived risk to lifestyles. Brinkmanship then ensues for succsesive politicians and their respective political parties, no one wants to be the harbinger of unpopular policy: Poll tax, prohibition, Patriot act? Democratic goverments will act if it can be shown that the population demands action. Anything else is viewed as control and subversion. At the 11th hour, rich nations will dig into their deep pockets to protect themselves, poor nations continue at others mercy. ffO.

The STS main boosters each use 500 tons of ammonium perchlorate composite fuel - a mixture of ammonium perchlorate, aluminium, iron oxide and a binding polymer. This produces at maximum some 1500 tons of thrust each with combustion products comprising 4 parts aluminium oxide (why the smoke looks white), 12 parts water vapour, 3 parts nitrogen and 3 parts chlorine. The main engines burn some 730 tons of propellant comprising liquid hydrogen and liquid oxygen as the oxydiser. producing water vapour as the combustion by-product. The Orbital Maneuvering thrusters burn about 20 tons of hydrazine compound and reactant producing 9 parts nitrogen, 12 parts water vapour and 3 parts carbon dioxide. From a GW perspective, a space shuttle mission produces less greenhouse gases than say the average UK family in a few months. ffO.

OMG up to the middle of last year it was......wait for it.......32 tonnes! Shameful. Admittedly a household of four including 2 teenage girls, er make that 3 teenage girls including mrs ffO. Since she ran off with the guy from the video rental store (I kid you not) my CO2 footprint is now a more respectable 5.5 tonnes and nost of that was from a holiday abroad. Still I'd rather have the 32 tonnes and my old life back. Penguin, Stratos and others - sorry guys, one of the reasons I have not been too sociable on NW in the past year or so. ffO.

February 1999 - Arlberg region in the Austrian Alps My party were headed for St Anton but never made it as the whole region was cut off by massive snowfalls, drifts and avalanches. Over 60cm of snow fell that night (23rd) and nearly three metres had fallen in a few short weeks. Galtur in the next valley had suffered an avalance which had buried a hotel causing scores of fatalities. We were diverted to a hotel in Ischgl overlooking the fated valley and watched the rescue operation in the distance, with helicopters flying in and out of Galtur as the only workable method of rescue and access. The snow was so deep, drifting had built snow to half way up the balconies on windward rooms on the first floor of our surrogate hotel. Other guests did not realise they were actually living on the first floor and panic set in when a chap (probably drunk) stepped off his balcony and disappeared in the snow. Frantic digging by hotel staff saved the day and he was taken to hospital, cold and shaken and lucky to be alive. The night we arrived, a section of the St Anton road tunnel collapsed under the weight of snow and sealed the valley for several days. Essentially we were trapped until the transport links could be established again about five days later. The locals were in a state of shock but did their utmost to make the best of a tragic situation. Until then snow was harmeless and something to be excited about - it's now treated with the greatest respect. ffO.

Wait till next week when the temperatures plummet. Expect to go from daytime high in the 20's this week to -20's overnight by middle of next! ffO

Taken from Ontarioweather outlook for this weekend: Yeeehaaaah! LG QUATRE - LAFORGE AND FONTANGES. SATURDAY..SUNNY. LOW MINUS 28. HIGH MINUS 23. SUNDAY..SUNNY. LOW MINUS 29. HIGH MINUS 20. NORMALS FOR THE PERIOD..LOW MINUS 29. HIGH MINUS 18. ffO

Lets try this one again Avian! The thing is to think about what's happening with individual atoms / molecules at the micro scale, then once that's in your head, try and imagine what it would look like at the macro - weather system scale. Atomic scale: Atoms of gas (Oxygen, Nitrogen, Hydrogen etc.), and molecules (Carbon Dioxide, Water Vapour etc.) all have very different masses and are very small in comparison to the distances between the atoms. They rush around at very high speeds colliding with each other or the ground and any objects in their path. Each time a collision between individual atoms occurs, the atoms exert a force and deflect each other changing speed and direction in the process. Very similar to billiard balls on a table. Some atoms colliding head on will bounce off each other and head off in the direction from which they came. Others will glance off each other, rebounding at different angles. All speed up or slow down depending on the relative mass / velocities of the atoms involved in each collision. Other forces are also acting on individual atoms; namely the pull of gravity, and the induced Coriolis force (see description later on) due to the Earths rotation imparting a constant change in direction as atoms collide with the surface objects of the Earth. At this point, introduce the concept of pressure. Pressure, is just a way of describing the collective force imparted by all the atomic collisions happening over a given area. Gravity pulls the atoms down towards the Earths centre of mass so that many more atoms congregate close to the surface than do higher up. As a result of this gravitational pull, more collisions between atoms occur since there are many more atoms to collide with - hence the higher pressure at the Earths surface than high up in the atmosphere. Temperature also affects pressure in that the individual atoms speed up with higher temperatures. This means that more collisions between atoms/molecules happen over the same time span than for a cooler gas. With greater numbers of collisions, the force exerted collectively has increased and hence the pressure within the gas is higher. Because of the sheer number of atoms in the atmosphere, no atom will make the journey from one side of a weather system to the other (not impossible, just highly improbable) without soon colliding with another atom. However, momentum can be exchanged between individual atoms and therefore energy propagates throughout the weather system because of the fundamental physical law of conservation of energy. This effect is observed every time a drop of water hits the surface of a pond - the drop soon vanishes into the water but the momentum imparted ripples outwards in concentric waves. Note however that the waves propagate at a certain finite speed. Macro scale: As previously explained (last post) at the collision boundary between the different pressure air masses (weather front) momentum between atoms is constantly exchanged and ripples through both systems (as described above) at finite speed because of the sheer number of atoms involved even though individual atoms do not make the journey from one side of a system to the other. The higher pressure system comprises on average, higher momentum atoms than the low pressure system and so collisions at the weather front will tend to ripple further and more quickly into the low pressure system than into the high. However, because at the atomic scale momentum is conserved, the original 'bias' of the bulk atoms of each weather system must also be conserved. The collisions at the weather front imparts a new bulk 'bias' as they ripple throughout the weather system. But so many collisions are happening, it's impossible to pick out one ripple from the next. It's the NET effect that's important because this is what we observe and comprehend at the human scale. At the atomic level, mingling and exchange of momentum between atoms occurs constantly at the weather front - with exchanges of energy rippling throughout both weather systems. The intial momentum conservation (rotation etc) as observed at the bulk level is also maintained and therefore 'appears' as if the air masses are skirting around each other. ffO

Hi Avain. The 'membrain' as you put it, is exactly where the mixing is taking place:- The key point to remember is that both pressure systems have enormous mass and therefore corresponding inertia. Like two colliding cars, the mixing takes place at the point of collision until the energy difference between them is equalised when no further mixing takes place. The boundary between the contrasting air masses is the 'front' where literally collisions between the different velocity air molecules is taking place. This is a sharp demarcation with air on either side of the contrasting air masses experiencing mixing over the length of the front and height extending to tens of thousands of feet. The rate of mixing is determined by the air pressure gradient between the air masses i.e. the pressure difference between the high and low pressure systems. The bigger the difference, the higher the wind speeds generated. The colder heavier air associated with the high pressure air mass sinks below the lighter warmer air associated with the low pressure air at the boundary (Heat rises, cold sinks). Because the low is advancing in relation to the receding high, the front is formed at an angle rising above and towards the centre of the low. Warm air with a high moisture content (picked up over the oceans) is forced to rise at the front, and in so doing the moisture condenses into clouds and then rain in a relatively narrow but long band. All this to say that mixing occurs over a large surface area at the point of collision between the different pressure air masses. Because of intertia, the low pressure air behind the collision front is deflected (think of billiard balls glancing off each other). The higher energy content of the high pressure system winning out and thus forces the warmer low pressure air to change direction. i.e. cars never win an argument with a tank. Keep in mind though, that all the while mixing is taking place at the frontal boundary. Eventually the energy difference and exchange between the two systems is equalised - the low pressure system increases in pressure fed with energy from the high, whilst the high pressure system weakens somewhat sapped by the low. When that happens, the pressure gradient eases and the winds drop - mixing and deflection has stopped. Hope this helps. ffO

Shadowcat.jpg Things to come..... ffO

One way of getting around the import problems is to ask trusted family or friends residing in the US or Canada to purchase the item on your behalf (assuming you know someone suibtable). They then ship you the item as a 'gift' whilst you arrange transfer of the monies. Best not to do this too often though. ffO

Renewed activity? http://www.dcs.lancs.ac.uk/iono/aurorawatch/rt_activity/ Could be building to something this evening? ffO

Vorticity The measure of rotation of a finite air packet i.e the packet spins as it moves along its path with the axis of rotation extending in any direction. Meteoriologically, the rotational motion of the air about an axis is primarily perpendicular to the earth's surface. No spin = zero vorticity. In the Northern Hemisphere, +ve vorticity is anticlockwise (cyclonic). Relative Vorticity The sum of the rotation of an air packet about the axis of the pressure system together with the rotation of the packet about its own axis. Vertical Velocity Applied to vorticity is the perpendicular velocity (rate of change of distance) of the air packet relative to the plane parallel with the earths surface. The maths gets complex requirig a knowledge of div, grad and curl. Hope this helps! ffO

Good morning everyone. I’ve waited patiently on the sidelines for a long while, observing the game and itching to play but always had to refrain. Work somehow keeps getting in the way. And a warm hello to you Penguin after such a long while. Hockey sticks may not look impressive, but wait till one whacks you on the shin. I predict you will exhibit one of three behaviours: Carry on playing with impunity (shin pads or perhaps thick-skin will absorb the impact); stop and remonstrate for foul play (the ref’ will either concede a penalty or force play-on); become volatile, throw down your hockey stick, walk over to me and punch my nose. If you are a particularly nasty cad, you will most likely hit me with said hockey stick! The latter instance probably represents game over. That the Earths ecology, atmospheric composition and climate are all complex and intricately linked is, I hope, beyond question. All are in critical balance but highly responsive to (albeit on a timescale far exceeding mere human lifetimes) the incident energy received from the Sun. This incident energy changes with factors such as Milankovitch cycles, solar fluctuations, rotational precession etc. There are many more variables but these are probably the main influences. Humans are an adaptive species. Our perception of ‘change’ is based on comparison to the present and within our own time reference. i.e. human lifetimes. Over a longer period, our ability and adaptation to change is almost imperceptible, with the Earth appearing to be in a state of constant equilibrium. The interesting factor with the hockey stick is therefore not limited to the size of the blade, but the rate at which the blade is growing. (rate of change). Equilibrium will be reached – it always does – the resultant instability while it does so may exceed the ability of humans, and far more, other species to adapt and survive. ffO.