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It seems to me that the character(s) who produced the YouTube video that has caused so much religious fulmination in the sandy parts of the world ought to be parachuted into Cairo to answer for their actions. Surely they can give the best explanation of what their movie represents.
Another thing has occured to me. Perhaps we should make a minor adjustment to the Drake Equation which describes the number of civilizations in our galaxy with which communication might be possible. The equation can be found at this link. The L factor defines the length of time a civilization releases detectable [radio] signals into space. Given the self destructive behaviours of beings capable of generating radio signals on at least one planet, maybe it is time to define L*.
L* = L(1 – P*/P) where P = average number of intelligent inhabitants of a planet and P* = average number of intelligent inhabitants willing to die/kill for their magical or political beliefs.
Perhaps the reader has a better modification. Here is the Drake equation copied straight from Wikipedia:
- N = the number of civilizations in our galaxy with which communication might be possible;
- R* = the average rate of star formation per year in our galaxy
- fp = the fraction of those stars that have planets
- ne = the average number of planets that can potentially support life per star that has planets
- fℓ = the fraction of the above that actually go on to develop life at some point
- fi = the fraction of the above that actually go on to develop intelligent life
- fc = the fraction of civilizations that develop a technology that releases detectable signs of their existence into space
- L = the length of time for which such civilizations release detectable signals into space
Photo of Curiosity during descent phase, taken from orbit. This shot is amazing all by itself.
Curiosity is powered by a Pu-238 oxide thermoelectric generator. The Multi-Mission Radiosiotope Thermoelectric Generator, MMRTG, has an output of 2000 watts thermal and 100-120 watts electric. The MMRTG unit sits in the aft end of the rover enclosed by a finned heat exchanger.
I hope folks out there had a chance to view the transit of Venus across the solar disk yesterday. I was lucky enough to see it through a 6 inch refractor and a Coronado H-alpha solar telescope. It’s always fun to see celestial mechanics in operation.
NASA has a video of the transit acrosst the sun taken at various wavelengths. Evidence of sunspot activity is much more pronounced at these wavelengths.
I’m always a little skeptical when I hear astronomers talking about specific compositions of matter out in the universe. The recent gushing press release from Reuters about a diamond planet orbiting a neutron star just adds to my burden of disbelief.
I truly hope there is more evidence than that revealed in the press release. That is, the assignment of the diamond allotrope of carbon based on density (3.53 g/cm3). The report seems to express amazement that the planet is “so dense”. A specific gravity of 3.53 is not that high. Many other compositions are possible. Perhaps Reuters should look at high density objects closer to home.
Last Saturday the local chapter of the EAA held a fly-in at Vance Brand Airport in Longmont, Colorado. We got there late, so we missed most of the show. Did see some good aerobatics though. This is the airport where yours truly learned to fly.
What is most interesting about attending an EAA fly-in is the variety of airplanes that are on display. But the show was a bit lean this year. Only one warbird was there. Usually there is more action with the relics.
Vance Brand used to have excellent air shows, but A**en built a pharmaceutical plant adjacent to the airport and caused the airspace to be unsuitable for aerial displays. To add insult to injury, certain products were black boxed a few years back with the result that good people have been let go and much of the production hit the skids. So, what was a rich culture of aviation at this field has been chased away by a marginal pharma plant that can’t seem to either thrive or shut down. It’s pathetic, but it’s what happens when you build a business plan on technology that is as complex as what they were trying to do. Pharma companies- never in doubt but frequently wrong.
The French air safety authority, the BEA, is beginning to put together the picture of what happened to AF447 enroute from Rio de Janeiro to Paris. Key parts of the wreckage have been found, including the flight data recorder. The BEA website contains links directing the reader to a more detailed view of many aspects of the investigation.
What has been so unnerving about this particular crash is the lack of detailed understanding of how it initiated and propagated. We know how it terminated. In particular, the flight is an example of in-flight loss of control of the aircraft. By all accounts, the airplane was in good working order and well equipped for transoceanic flight. It had a crew that, by prevailing standards, was well qualified to operate the aircraft. How could there possibly be a loss of control that could confound this well equipped machine with expereienced crew?
The aircraft had more than one crew on board as well as a highly automated flight control system comprised of advanced navigation and communications, auto pilot, and auto throttle systems with the usual redundancies. Yet with all of the human resources and automation, and with a century of aircraft design knowledge behind it, this passenger aircraft managed to take an excursion into uncontrolled flight and impact the ocean.
The BEA has disclosed a timeline of events in the cockpit as well as a description of the flight attitude of the aircraft. What I find interesting are the control inputs made by the PF (pilot flying). In the face of indications of a stall, the PF primarily tried to pull the nose up. This is the wrong control input for a stalled airplane. What makes the incident worthy of note is the interaction of the crew with the automation and sensors. Aviation Week and Space Technology has a good article worth reading on this very topic.
SpaceX has announced their Falcon Heavy lift rocket. It consists of two liquid fuel rockets astride a longer center rocket. Each of the three rockets has 9 Merlin rocket engines. SpaceX claims it will lift 53 metric tons into low earth orbit- twice the payload of the Space Shuttle and more than twice that of the Delta IV. Depending on configuration a launch will cost between $80 and $125 million.
This seems to be real progress for the space business.
My day job requires that I can practice the art of calorimetry with some reasonable extent of expertise, so in that vein I have been cracking open some of my dusty p-chem texts and revisiting basic thermo.
The other day while on an excursion to a bricks and mortar bookstore to pick up some of my favorite periodicals (Kitplanes and Vanity Fair), I happened upon a copy Elements of Chemical Thermodynamics by Leonard K. Nash (1970, Dover, $12.95). Feeling bad for Borders and their current run of poor luck, I bought the book as though it would make some difference.
Figure 2 on p 5 (below) shows a schematic of a ice calorimeter. An ice calorimeter uses a thermally isolated enclosed space M completely filled with liquid and solid water immersed in an insulated tank of ice and water B. The internal, thermally isolated, working volume of water has two important features- it has a small volume sample container R protruding into it and it has a calibrated small inside-diameter expansion capillary C.
A sample in container R is in thermal contact with reservoir M. Heat absorbed in M melts some ice and results in the loss of low density ice and the formation of higher density liquid water. The net volume of the contents then decreases and is registered as a column height change in capillary C.
Given the volume change and knowing the density and heat of fusion of water at 0 C, one can calculate the heat absorbed by the reservoir.
So, what about Saturn’s moon Enceladus? The moon is thought to be covered by water ice with liquid water underneath. It’s reasonable to assume that if some volume of water below the ice transitions to the solid phase then the collective volume for liquid water is decreased resulting in an uptick in pressure.
If this happens, it could provide a mechanism for the geyser phenomenon witnessed by the Cassini probe. The geyers could simply be a result of PV work energized by gravity and radiative cooling of the surface and subsequent thickening of the surface ice into the underlying liquid phase.
I’m sure the boys and girls at Cassini have thought of this, but since I’m not tied into the literature I have not heard anybody express it.
Air France Flight 447 crashed in the Atlantic 400-odd miles outbound from Brazil to Paris after its evening departure from Rio de Janeiro on May 31st, 2009. While the flight data recorder has not been recovered, 24 fault messages were relayed to the AF headquarters via satellite. From these messages, and from forensic evidence found floating in the area of the crash site, a picture of the event is beginning to emerge. Spiegel Online has published an analysis of the disaster based on what is presently known.
The evidence collected so far suggests that the aircraft impacted the water on its belly with a 5 degree nose up pitch attitude. The calculated impact force based on certain kinds of material strength data is 36 g. The aircraft departed just under max gross takeoff weight with 70 tons of kerosene fuel on board. Abnormalities did not begin to appear until the aircraft was ostensibly at cruising altitude of ca 35,000 ft. There was a suspicious uptick in the OAT reading (outside air temperature) of a few degrees. Investigators believe that this is an indication of icing on the OAT sensor and pitot tube.
The aircraft may have been attempting to penetrate an area of thunderstorms in the inter-tropical convergence zone. This is a band of atmosphere on either side of the equator where northward and southward flows from the respective hemispheres meet and produce vertical air movement. The convergence of these flows can result in moisture laden air being lifted. Together with the natural buoyancy of warm humid air, vigorous convection cells can be kick-started into severe thunderstorms. The cloud tops in this zone can be substantially higher than those at the mid latitudes. At altitude, storm cells commonly produce icing conditions.
Out in the midocean spaces at night, airline pilots have only on-board radar and the moonlight, and perhaps a few pilot reports by others who have just been in the area, to estimate the areas of high storm intensity ahead. Flight through the intertropical convergence zone can produce bumpy rides to the point of violent turbulence. What most passengers don’t understand is that passenger jets are build to absorb considerable abuse before a structural failure occurs due to turbulence.
The upshot of the report is that the pitot tube that senses the airspeed of the aircraft failed due to icing. This failure basically causes the computerized flight control system to shut down owing to lack of input of this key airspeed data. In flight control, airspeed is one of the very critical pieces of information necessary to sustain controlled flight.
Without airspeed information, and without computer assistance in the control of the various flight control surfaces, the modern passenger jet becomes very difficult to handle manually. The is especially true if the aircraft is under instrument conditions with low/no visibility and in high turbulence.
A complex and aerodynamically clean aircraft being jostled along all three axes at a high mach number presents a large workload for the pilots. At a mach number (o.85 or so) as typically attained in high altitude cruise, a sharp pitch down in the nose can lead to transonic flow over the control surfaces and in the engine inlet. This can lead to engine instability and loss of flight control. Sonic flows over ordinary flight surfaces can lead to flow separation and loss of control. This lesson was learned the hard way in the early days of high speed aviation. Pilots typically throttle back after penetrating turbulent air.
The investigators of AF 447 have all but concluded that the aircraft crashed owing to loss of critical airspeed information and subsequent departure from stable flight. While the Spiegel article states that investigators are confident in this analysis, recovery of the flight data recorder will undoubtedly provide important details for refinement of the investitgation.