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## Comment Re:You know the cops are going to want it .. (Score 3, Interesting)138

Not to be pedantic, but lasers most certainly have drop. In fact, the photons in a pulse of laser light fall towards the center of the Earth at exactly the same rate of acceleration as bullets do (namely 32 ft per second per second). It's just that they travel so fast, the transverse velocity they develop (v=gt) and distance off target that they move (d=1/d g t^2) during their short time of flight (t) are negligible.

## Comment Re:Earth not _turning_ slower, but already is slow (Score 2)289

Most of the depleting rotational energy of the Earth goes into the orbital energy of the moon, which means the moon will be boosted in its orbit and recede from Earth until the Earth is slowed down enough that the same side of the Earth faces the moon as it orbits ("tidally locked"). Which, by the way, is why the man in the moon always faces us (i.e. tidal locking happened long ago on the moon). At that point, a day and Earth an an orbit on the Moon would both last about 47 days. Estimates for when this would occur are around 50 billion years, by which time the sun will have swollen up in its death throes and consumed the Earth. There is some heat generated due to friction from tides and distortions of the Earth's crust, but the rotational-orbital exchange is much more significant.

## Comment I Am an Astrophysicist (but you do not salute me) (Score 4, Insightful)234

Here's your best and most direct path: use your IT skills to leverage an engineering job in the field. I have seen many technically inclined IT engineers and programmers take this route. Step-by-step:
• Immediately: take an introductory astronomy course at a local community college or continuing education program at your local university to demonstrate your interest,
• Then: assess your IT skills, and apply them directly to the support of an upcoming large ground- or space-based observatory. This is an especially sensible route if you do any database related work. The future of astronomy is big data and massive virtual observatories which collect together and make useful petabytes of information from a wide variety of facilities.
• Check the job listings at the American Astronomical Society, looking in particular for IT support positions where your domain knowledge would outrank that of PhD-trained astronomers (who learn to program "on the job" and rarely master grittier back-end systems). Realize that almost all existing and (especially) new astronomical facilities have substantial IT/engineering staff, and that your skills do not exist among traditional PhD scientists. Example: the LSST will produce 30 TB of data per night, which needs to be processed in semi-real time. Example #2: the incredibly successful Sloan Digital Sky Survey partnered with Microsoft database engineers to build its (at the time) state-of-the-art public-facing data archive. The late Jim Gray was instrumental in building the Sloan backend, and said his favorite thing about astronomical data is that it was "worthless" (by which he meant the usual access control layers were not necessary, freeing him to focus on much more rewarding and useful tools).
• Relocate to a mission control or operations center for the facility. These are often located at major research universities, or equivalent national facilities like the Space Telescope Science Institute in Baltimore, the National Radio Observatory in Charlottesville, VA, the Gemini Observatories (Hawaii/Tucson/Chile), etc. Advantage? You will very likely be immediately mixed in with groups of professional astronomers. You will be strongly encouraged to learn to speak their language, and to become more involved in the scientific aspects of the project. You will learn a great deal just through osmosis. You will likely be able to attend seminars, sit in on classes, bend the ear of willing faculty, etc. And the most significant advantage? You could be contributing directly to the forefront of astrophysics research within 3-5 years. Disadvantages: the pay might be somewhat less than similar background applied in the financial or health industries. Often the intellectual rewards bring talented engineers anyway. Also, may projects are time limited, so you positions are typically not permanent (but new projects are coming online all the time).

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

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

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 need... (Score 2, Informative)378

Uhhh.. you mean like their "More Search Tools -> Fewer Shopping Sites" option?

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

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

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

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:Basic thermodynamics... (Score 1)484

Because the bulk of the energy hitting that snow, at optical and ultraviolet wavelengths, is reflected back into space?

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

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

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.