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Comment: Re:strange future tense (Score 1) 312

by floateyedumpi (#34973140) Attached to: Betelgeuse To Blow Up Soon — Or Not
That is our bias, an observer's bias. For example, "Supernova 1987a" occurred in the Large Magellanic Cloud, a small dwarf galaxy orbiting the Milky Way, which is close to 170,000 light years away. So this star actually blew up just as the first modern Homo Sapiens began wandering around East Africa. Yet we call it "1987a". And for good reason. Many of the supernova we routinely observe in the early universe are reaching us from across such great distances, that they happened well before the Sun and Earth even formed; many perhaps even before the Milky Way galaxy was meaningfully assembled.

Comment: Re:Why would you refuse a breathalyzer? (Score 1) 1219

by floateyedumpi (#34730208) Attached to: 'No Refusal' DUI Checkpoints Coming To Florida?
I worked a summer as an engineering intern at the largest US manufacturer of breath-alcohol systems. There were dozens of models made to accommodate the wildly varying requirements among states and nations regarding what false positive signals to "rule out". Basically, the systems were very simple infrared spectrometers, made to look for telltale absorption bands of the ethanol molecule in just a few (like 3-4) broad infrared wavelength bands (see e.g. here). The problem is, a large range of simple organic molecules absorb at similar wavelengths. So, for example, to rule out acetone (rotten fruit? nail polish remover?), you'd need to add one or more bands where the two molecules differed in absorption properties. And so on for other molecules with similar optical behavior. I believe the UK had the strongest requirements for ruling out false positives; something like a dozen channels were required (which increased cost, difficulty of calibration, and weight).

Comment: Re:what we could get? (Score 1) 209

by floateyedumpi (#33460572) Attached to: Canon Develops 8 X 8 Inch Digital CMOS Sensor
It's because implicit in this comparison is the statement "for a fixed field of view and resolution", which implies a focal length, and hence aperture size, which scale with with sensor size: See http://www.clarkvision.com/imagedetail/does.pixel.size.matter/#The_f_ratio_Myth. Large detectors are not intrinsically more sensitive, but for a given field of view and angular resolution, they collect more light than small sensors, going as the square of the its size.

Comment: I guess it depends on the scientists (Score 2, Informative) 508

by floateyedumpi (#31846906) Attached to: Neil Armstrong Criticizes Obama's Space Strategy

All the scientists I know (myself included) would correctly indicate that the sun will not grow cold, but will, after exhausting its core hydrogen fuel, vastly increase its luminosity, and swell in size past the Earth's orbit, essentially vaporizing it. All this, in roughly 5 billion years.

Modern humans as a species are 0.0002 billion years old. Yes, that's three zeroes to the right of the decimal. Do you really believe that we'll care about a couple thousand years worth of exemplars of humanity after we've evolved 25,000 times further than since we separated from proto-human homonids? Will we even be humans at that point? Are there any other conceivable disasters our species or its descendants could suffer during those billions of years, which colonizing space could not prevent?

Comment: Re:NOT first spectrum of planet's atmosphere (Score 5, Informative) 32

by floateyedumpi (#30791774) Attached to: Spectrum of Light Captured From Distant World

The article is wrong on many levels. The key word here is "direct". The 2002 transmission spectra you mention (and others like it) consist of light from the host star, passing through the atmosphere of the planet as it passes in front of it, which imprints spectral signatures of the planetary atmosphere on that stellar spectrum. So in this sense, its not a direct spectrum of the planet's own light, but of the star, modified by the planet in front of it.

The first spectrum of a planet, consisting only of planetary light, came from the Spitzer Space Telescope, which used a differencing technique:

planet + star [out of eclipse] - star [when planet eclipsed] = planet only

The star and planet could not be resolved (separated) by the telescope, but by using the known orbit of this eclipsing planetary system, and timing the observations carefully, a spectrum of the "planet's own light" was obtained.

The novelty of this latest result is that no differencing of this sort was required. Using adaptive optics to correct distortions due to Earth's atmosphere, the light from a star and the light from its associated giant planet where physically resolved, and a spectrum of the planet, all by itself, was obtained. Even with adaptive optics, however, very few systems have star-planet separations on the sky large enough to permit this technique.

Comment: Re:If you give up the inch, they'll take the mile (Score 1) 901

by floateyedumpi (#28454701) Attached to: NASA Sticking To Imperial Units For Shuttle Replacement
I am a scientist, and work primarily in metric units. I can think equally comfortably of a mile or km, and acknowledge the many benefits of calculations performed in metric, and of celsius (or it's relative, Kelvin) as a temperature scale in the laboratory. Yet I cannot endorse the Celsius temperature scale for everyday use over Fahrenheit.

From one viewpoint, there is no fundamental difference between them. They scale linearly between two temperature points, assigning values of 0 and 100:

  • Celsius: [freezing point of water, boiling point of water]
  • Fahrenheit: [a cold solution of brine, human body temperature (approx)]

I argue that degrees F offers a more suitable range, and better resolution, than degrees C for temperatures encountered in everyday life. The smallest temperature difference I can detect? Roughly 1 degree F. That's 0.55 degree C. It's also why you often see forecasts in fractional degrees C. A day so cold you have to protect skin? 0 degrees F. A day so hot that wind actually warms you up? 100 degrees F. The advantages of Celsius in the lab are clear. For weather? Not so much.

Comment: Re:Not many choices... (Score 1) 867

by floateyedumpi (#28432673) Attached to: Wind Could Provide 100% of World Energy Needs
You are close to correct. Some large number of joules of energy here on Earth arise from material leftover from supernova predating the sun: radioactive materials, which can be harvested directly in fission reactors, or indirectly through tapping the Earth's molten inner they help to heat. The Earth's internal heat also results not from the sun, but from the continued slow tapping of gravitational potential energy from the material from which the sun and its planets formed. This power source is roughly 40 TW, compared to the 100,000 TW of solar power reaching the Earth's surface. Still, several times the current worldwide energy consumption.

Comment: Re:Price (Score 1) 128

by floateyedumpi (#27243567) Attached to: The Lightning Hybrid and the Inizio EV

My car gets about 30 MPG and after a half hour 30 mile drive is thirsty for a gallon of gas. After a multi-hour 30 mile bike ride I am very hungry and can easily eat two pounds of food (and still lose weight, if it's salad and not eight quarter pounders with cheese and bacon). Anyway, that two pounds of food obviously takes twenty pounds of gasoline to grow and process and ship and cook. Now at 6 pounds of aviation gas per gallon (note I am not a pilot, but that is my fuzzy memory from wanting to be a pilot decades ago) that would make a bit over 3 gallons of gas to grow the food to bicycle 30 miles.

Your argument only works if you assume that otherwise you would not have consumed those 2lbs of food. Obesity-associated illness trends, in the USA at least, would indicate otherwise. By biking, you burn calories you would be eating anyway, improve your health, and save gas too.

Comment: Re:Don't want the bundle (Score 1) 538

by floateyedumpi (#26580195) Attached to: 2/3 of Americans Without Broadband Don't Want It
When I had comcast and they began this bundling business some 5 years back, it was actually $3 cheaper to get the basic TV service with your internet than no service at all. When I pointed out the inanity to the customer service rep, they kept saying: "It's a package deal, like at McDonalds". To which I replied: "Yes, but since when is the cheeseburger more expensive than the happy meal?"

Never underestimate the bandwidth of a station wagon full of tapes. -- Dr. Warren Jackson, Director, UTCS

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