You are currently browsing the category archive for the ‘Astronomy and Aerospace’ category.

A recent paper (free) in Geophysical Research Letters reports the discovery of long anticipated ionospheric disturbances caused by the passing of the moon’s shadow over the earth during an eclipse. The paper, submitted by the MIT’s Haystack Observatory, reports the occurrence of ionospheric bow waves associated with the shadow ground-track of the August, 2017, North American eclipse.  The online source, MIT News, summarized the discovery.



I found myself up north in Casper, Wyoming, with friends for the 8/21/17 solar eclipse. We were modestly equipped for the spectacle. A member of our small group brought a Celestron 8″ Cassegrain telescope with solar filter and clock drive. We set up in an uncrowded neighborhood and began the wait.

Knowing that Casper would be crowded I had arrived 2 days early to explore some of the local geology. Jeez- I guess that makes me a geotourist. This activity gives a person a mission to complete. Pick some locations to visit and go do it within your time constraints. There is a beginning, a middle, and an end. Success consists of finding the location of interest, getting samples and photographs of unique rocks, stata and general landforms.

I’ve had good luck with the Roadside Geology series of books by Mountain Press Publishing. In the case of the eclipse trip, I secured a copy of the Roadside Geology of Wyoming ahead of time at a local Barnes and Noble. These books are quite well written and illustrated, especially important if you’re not packing a degree in geology.

The unique value of the Roadside Geology books is that the content is divided into state regions then subdivided into stretches of highway that you can drive along. Commonly along the highway can be seen many large scale features described in the book. Even better, photographs and diagrams of road cuts are frequently highlighted. In hilly or mountainous regions there are many road cuts that allow you to view underground features.

Lately I’ve taken to wearing a yellow reflective vest along the roadside while taking a close look at the exposed formation. People don’t expect to see some yay-hoo walking along the road with a  hammer and a notebook as they careen around the curves on a mountain road. Best not to surprise drivers.

Teapot Rock north of Casper, Wyoming.

There is a bit of interesting US history attached to the geology of the Casper area. The Teapot Dome scandal erupted during President Warren G. Harding’s administration in 1922. Harding’s Secretary of the Interior, Albert Bacon Fall, was caught taking bribes in exchange for awarding oil rights to a subsidiary of the Sinclair Oil Company.  The oil field was within the Navy Petroleum Reserve north of Casper.

“Teapot” Dome takes its name from Teapot Rock– a formation that, at the time, had a feature that resembled a spout. This feature is no longer there. “Dome” comes from an anticline fold in the oil bearing stata below. It is part of the larger Salt Creek Oil Field.

The seeing in Casper was good right up to the back third of the eclipse. The Celestron was rigged to throw an image onto a white screen. A chain of sunspots were visible early in the eclipse. As I was equipped with only my Samsung 6 for photography, I did not manage to get great pictures, nor was it really my intent. Sometimes you have to put the camera down and look. Just before totality we saw Baily’s Beads and the diamond ring. The autofocus of the Samsung was unable to produce a sharp image of the beads on the projection owing to the low light level.

Close-up of sunspots early in the eclipse.

When totality arrives you can look at it directly with the naked eye. It’s best to view it without the distraction of equipment. During totality it became noticeably cooler. The eclipsed sun had a wispy corona around it, reaching into space. Around the horizon back on the ground was a beautiful 360 degree sunset. People in the neighborhood were cheering. What a thing to see.


Pinhole projection using aluminum foil and a cereal box.


Here you can see some knucklehead trying to get a view through a pinhole projector cleverly disguised as a box of corn flakes. He commented that the image was only slightly better than nothing. In fact the image projecting through a colander onto the pavement was superior (below).






Multiple images of eclipse as projected through a colander.


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 = R^{\ast} \cdot f_p \cdot n_e \cdot f_{\ell} \cdot f_i \cdot f_c \cdot L


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
f = 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 in descent phase. Photo taken by NASA’s Mars Reconnaissance Orbiter. Credit: NASA/JPL-Caltech/Univ. of Arizona.

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.

On the tie-down ramp at Vance Brand, June 25, 2011.

 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.


Blog Stats

  • 520,692 hits