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Comment Mean and fluctuations (Score 2, Informative) 222

The climate has always been a highly fluctuating system where extreme temperatures oscillate over seasons and location by, say typically +/-20K (Kelvin), around a mean value around 287K, slowly growing. In some countries the fluctuations are larger, in some others smaller. All the discussion about the human-induced warming is about the effect of changing this mean value by a couple of K (now +0.5K, in the next century by +2-4K). So even in the most pessimistic scenarios the warming remains in amplitude a small fraction of the typical annual fluctuations. No wonder that it will be difficult to prove that any extreme fluctuations will result from the warming.

Comment Real advantage (Score 2) 108

One cannot escape the fact that bigger apperture telescopes can record fainter
stars, and/or perfom the photometry of bright stars with more precision than a simple camera.

To detect exoplanets one needs both large samples of stars recorded as continuously as
possible over several years and high precision photometry. Besides being cheap, the advantage
of a small camera is than the field is larger. But with a larger telescope in space like Kepler one
can target regions of the sky with density of stars optimal for the CCD/camera combination, and
observe continuously for months with the same instruments, which is crucial for differential
photometry. Thousands of amateurs worldwide detecting as many new exoplantes as Kepler
would face the problem of coordinating the analysis of huge amounts of heterogeneous and
incomplete data (due to day/night and weather interruptions in differently dark and transparent skies).

The real question is wether crowdsourcing planet detection is cheaper for global economy at equal scientific return than with state sponsored research. Perhaps the most important benefit of such an
activity is educational and promotional for research in general.

   

Comment Neutrino temperature (Score 5, Interesting) 80

The orginal article keeps quoting the temperature of 1.96K as the neutrino background temperature, as found in most textbooks on the topic. This is a relic of the time people were assuming massless neutrinos. The confusion is maintained by people using the temperature as a synonym of energy. Actually the non-zero rest mass energy must be subtracted, providing the real kinetic energy of these particles (moving now at 100-1000 km/s) that would be exchanged with a super large thermometer (in view of the tiny interaction cross section). The effective neutrino temperature would then be measured in the milliKelvin range.

 

Comment Re:He should get the Nobel Peace and War Prize (Score 1) 123

The so-called "Peace" prize is indeed badly named. Other famous war makers, H-bomb creator, mass killing authors and terrorists got it:

Yasser Arafat, Shimon Peres and Yitzhak Rabin (1994)
Mohamed Anwar al-Sadat and Menachem Begin (1978)
Andrei Dmitrievich Sakharov (1975)
Henry A. Kissinger and Le Duc Tho (1973)

So perhaps Edward Snowden and Laura Poitras have better not to be awarded
the Nobel.

Comment Re:Power density? (Score 1) 78

The total heat produced by radioactivity in Earth is 44.2 TW (Wikipedia).
The total solar power received by Earth by the upper atmosphere is 174 PW (Wikipedia).
This means 3937 more solar energy is received by Earth than produced by radioactivity in its interior.
Furthermore geothermal energy is high entropy energy in regard of solar energy since the temperature difference between
ground (~287K) and nearby space (>10K) (DT=277K) is much less than the temperature difference between
sunlight (5778K) and ground (DT=5491K).

In short the whole idea of converting Earth heat into electricity is completely inefficient in regard of solar energy.
The only way to use efficiently geothermal energy is to find hot spots where it is concentrated by thousands with respect to average.

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