Tuesday, May 27, 2008

RUSH- the Science Illiterate

Today, Rush Limbaugh waxed long and hard about Mars and the recent landing of the Phoenix and the fact Mars possessed an atmosphere of 95% carbon dioxide – and yet there was no global warming!

Fancy that! All that CO2 and little heat to show for it! Meanwhile, Earth doesn't even have a half of a percent CO2 and we are supposed to believe there's a connection to global warming!

Hello! Calling all dingbats! First, Mr. Limbaugh, Mars is more than 1.5 times further from the Sun than Earth. As any basic physics student knows, the intensity of radiation (including heat and light received) falls off as the inverse square of the distance.

Thus, relative to the Earth (1360 watts/ m^2 received), on Mars one would have:

(1360 W/m^2) x 1 / (1.5)^2 = 1360 W/ m^2/ 2.25 = 604 W/M^2

or less than half the intensity of radiation, heat.

This means that before CO2 even enters the picture Mars is much colder than Earth.

Added to that is the fact that the atmospheric pressure on Mars is barely 0.0056 of that on Earth. In other words, just over five thousandths of an atmosphere. This is less atmosphere than one would encounter on Everest.

The low density of atmosphere means that CO2 occurs in too low a density to matter, in terms of effecting any climate change or in this case – global warming.

By analogy, the higher one goes up a mountain on Earth, the less air there is to absorb heat.(What we call 'heat' is really energy associated with motion and positionsof molecules in a material. The conversion of radiant energy - say from the Sun- is really a conversion of large scale energy, e.g. in electro-magnetic waves- to internal or microscopic energy.

In effect, if air is thin, as it is at the top of a mountain (or on Mars), there isn't enough MASS present to enable or facilitate energy transfer to the medium. Hence, it feels 'cold' to the human observer.

The thermal capacity is defined by the quantity:

W = mc

where m is the mass and c, the specific heat capacity. It is a measure of how difficult it is to increase the temperature of a medium by one degree (e.g. 1K or 1 Kelvin).

Again, the higher one is above the Earth, the lower the atmospheric density & pressure, and the lower the thermal capacity of the medium – so the smaller the amount of heat that can be retained, or measured.The lower one goes in altitude, the greater the number of particles, and the greater retention of heat- especially if water vapor is also included (since water has a large specific heat capacity ~ 4200 Joules/ kg K).

The low atmospheric pressure combined with the distance and low solar insolation means the CO2 present on Mars affords no measure of countervailing forcing factor for warming, such as the presence of CO2 does on Earth. Which, despite its low percentage in the atmosphere (< 0.04%) harnesses much more forcing on account of the atmosphere being 178 times more dense, and the Earth 1.5 times closer to the Sun.

This is why CO2 plays a vastly more critical and important role in controlling Earth’s climate, as opposed to Mars’.

Limbaugh finished his Mars’ piece by huffing to the effect: “Take that, you global warming idiots!”

But he’d do better to look at himself in a mirror when he babbles similar codswallop in the future.

Perhaps, he'd do even better by removing the penchant for "chaos" he is seeking to fulminate in the real world.

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