Cyanogen Gas in Comets: Threat Or Menace?

We may have known a lot – science wise – about comets since Halley’s Comet’s scheduled return back in 1910, but can anything we don’t know about comets actually endanger humanity? 

By: Ringo Bones 

Science-wise, comets pose a real threat to mankind when on very rare occasions it manages to collide with our planet releasing vast amounts of kinetic energy. Like the Tunguska, Siberia incident of 1908 or the suspected comet that hit us 65-million years ago that wiped out the dinosaurs. Besides kinetic energy impacts, are there other “esoteric” threats posed by comets to humanity and all life on Earth? 

A “comet scare” occurred back in 1910 when Halley’s Comet’s scheduled return flyby will make the planet Earth pass through its tail stream. And during the time, it was just recently discovered via spectroscopic analysis that Halley’s Comet contains vast amounts of cyanogen gas that could poison all oxygen-breathing life on Earth. By the way, cyanogen gas is a colorless, flammable poisonous gas that behaves as a univalent radical that is also present in simple and complex cyanide compounds. 

Back in 1910, insurance companies issued a somewhat hastily formulated comet insurance that was primarily aimed to compensate any loss of human life and / or livestock in an event of mass cyanogen gas poisoning. But when planet Earth passed through Halley’s Comet’s tail with no ill effects back in May 13, 1910 – the idea of comet insurance with cyanogen gas poisoning coverage was relegated to the more esoteric footnote of history. But does the cyanogen gas “scare” posed by Halley’s Comet scientifically valid? 

During the first decade of the 20^th Century, the science of spectroscopy was significantly way more advanced compared to when Isaac Newton experimented with its fundamental processes back in 1666. When Newton discovered that the white light from the Sun was dispersed into a colored spectrum by passage through a prism. 

In Germany in 1814, J. Fraunhofer extended Newton’s discovery by observing that the Sun’s spectrum, when sufficiently dispersed, was crossed by a large number of fine dark lines, later known as Fraunhofer Lines. Terrestrial sources, such as flames, were found to emit bright lines which were characteristic of the chemical elements in the flame. 

Focault – the French physicist – observed in 1848 that a flame containing sodium would absorb the yellow light emitted by a strong arc placed behind it. These facts were brought together in 1855 by G. Kirchoff in his famous law: That the ratio between the powers of emission and the powers of absorption for rays of the same wavelength is constant for all bodies at the same temperature. 

Kirchoff explained that the Fraunhofer Lines in the Sun’s spectrum were caused by action of chemical elements in the cooler part of the sun’s atmosphere in absorbing the continuous spectrum emitted by the hotter interior of the Sun. Analysis of the Sun’s atmosphere thus became possible. The method was extended later to stellar spectra and constitutes our only means – for a time before sample-return robotic spacecraft were invented – of studying the chemical elements occurring in the stars and other heavenly bodies. 

The observation and interpretation of the light emitted by physical objects – more especially, the interpretation of the light emitted by excited atoms and molecules in their states might have provided data to astronomers in the first decade of the 20^th Century that Halley’s Comet is chock full of cyanogen gas. It didn’t, however, predicted that planet earth could pass through Halley’s Comet’s tail with no ill effects whatsoever. 

  

Transit of Venus: Once-In-A-Lifetime Astronomical Event?

Though it’s been cloudy for three days straight in my neck of the woods, does the June 6, 2012 transit of the planet Venus across the face of the Sun really the once-in-the-lifetime astronomical event it was touted to be?

By: Ringo Bones

I just caught the one back in 2004 using an improvised welder’s protective glass as an ad hoc filter for my trusty-but-rusty Celestron. And comparing one view via the “protected” naked eye observations, all I can say that the transit of Venus across the face of the Sun would seem rather “abstract” to the astronomically uninitiated; But why the fuss across the global astronomical community?

 First of all - transit is an astronomical term defined by the passage of a celestial body across a line or region in the sky. A star in transit when on the celestial meridian; the planets Mercury and Venus appear as dark spots when the transit across the disc or face of the Sun; a moon or a natural satellite is in transit when it crosses the disc of the primary planet such as Jupiter. Transits that are visible to the (protected if necessary) naked eye are extremely rare astronomical events.

The transit of Venus across the Sun’s disc only happens every 105 years, and they usually last about seven hours. The first recorded viewing of the phenomena was back in 1639 Jeremiah Horrocks and William Crabtree. Another reason why the astronomical community makes a big deal about it is that transits are a very reliable method of confirming the existence of planets orbiting in other star systems / solar systems. In other words, they are a very useful method in finding extra-solar planets tens or even hundreds of light-years away.

Affordable CCD Cameras: Amateur Astronomy’s Weakest Link?

Given that quite a number of amateur astronomers now use “affordable” CCD cameras to capture what their telescope sees for posting on the web, does ultimate CCD camera performance still matters?


By: Ringo Bones


Once upon a time – or at least back in the 1970s and very early 1990s from my perspective – amateur astronomers used to rely on their handy film-based cameras with selectable exposure times to capture wonderful photos of what their home-based astronomy telescope set-up had seen. Then, digital Charged-Coupled Device cameras (CCD cameras) became low enough in retail price to pose serious competition to the humble film-based camera with selectable exposure times. As of late, given that CCD cameras capture what they “see” in digital form – as in format – quite a number of amateur astronomers had been busy posting / uploading what their astronomical telescope had seen on the web and / or their respective social network accounts – i.e. Facebook. But does the ultimate quality of your “affordable” CCD camera currently connected to you backyard telescope really matters?

The plain truth is, the quality of your imaging system – i.e. your backyard astronomical telescope and affordable CCD camera set-up – is fundamental to the quality of your results. Since the proliferation of back-illuminated grade one CCD cameras on the market aimed at amateur astronomers, the issue of quantum efficiency has more than ever became the selling point in the entry-level price point of CCD cameras for astronomical telescope use. But why is quantum efficiency so important by the way?

Quantum efficiency or QE is a measure of how much light gathered – typically by the front-end optics of your astronomical telescope – actually gets converted to charge in a typical CCD chip of a CCD camera. If your CCD camera has a rated peak QE of 85%, then it means that 85 out of every 100 photons striking the CCD get counted.

In practice, typical front-illuminated CCD cameras have a much lesser quantum efficiency than back-illuminated CCD cameras. Front-illuminated CCD cameras have a typical quantum efficiency of around 25% to 45%. And front-illuminated CCD cameras are also quite inefficient in the blue end of the visible spectrum where their quantum efficiency falls to a mere 5%, while a typical back-illuminated CCD camera only falls off to 70%.

During the latter half of the 1980s, mechanical sophistication – i.e. the expensive bits of your backyard astronomical telescope set up like optics and the related support systems – can already be replaced by relatively low-cost electronics, thus bringing enormous cost savings resulting in reduced exposure times brought about by a CCD camera with much higher quantum efficiency can be a boon for the amateur astronomer on a budget.

A shorter exposure time means lesser reliance on your astronomical telescope’s rather expensive mechanical systems – i.e. low-cost telescopes usually use low-cost mechanical systems. Better sensitivity via use of CCD cameras with higher QE means a smaller aperture can now accomplish what a larger – and pricier – telescope would before. Using a CCD camera with higher quantum efficiencies also allows you to image fainter objects in a shorter time, allowing you to image more objects per night using the backyard astronomy telescope set-up that you currently have. So buy the best-performing CCD camera for your astronomical telescope that you can comfortably afford to attain amateur astronomy bliss.

Phobos: Fermi Paradox Buster?

Its “strange” orbit had been intriguing astronomers for 133 years since its discovery, but is there a chance that the Martian moon Phobos is a product of an alien civilization?


By: Ringo Bones


Anyone in the know will readily admit that there is something strange with the Martian moon called Phobos. Inexplicably, everything strange about the planet Mars was discovered in 1877. From the “discovery” of straight, geometrically patterned channels – or canali – by the Italian astronomer named Giovanni Schiaparelli to the two tiny satellites – called Phobos and Deimos - discovered by the American astronomer named Asaph Hall. The first generation of robotic spacecraft launched to explore Mars during the 1960s has since proved that Sciaparelli’s “canals” as nothing more than an optical illusion, but the “mystery” behind the Marian moons managed to “survive” space-probe scrutiny.

The small size and proximity of Deimos and Phobos to their parent planet make them unique in the Solar System. Both are too small to gain enough hydrostatic equilibrium to acquire a spherical shape. Deimos is about 7.5 miles in diameter and orbits about 15,000 miles from the surface of Mars. Phobos, 13.7 miles in diameter, orbits much closer at 5,800 miles and has enough “intriguing” characteristics – including recently discovered ones – that had acquired the interest of generations of astronomers over the years.

The most remarkable thing about Phobos, according to some observations, is that its period of revolution appears to be decreasing slowly but perceptibly. The only plausible explanation is that the slight drag of the Martian atmosphere is taking energy from it, thus making it move closer to Mars and follow a shorter and faster orbit. The Martian atmosphere is so thin than a satellite the size of Phobos affected this way must have extremely low density. If these observations are correct, then Phobos must be lighter than any known solid substance.

The Russian astronomer Iosif S. Shklovsky has supplied a novel answer to this puzzle. He believes that Phobos is hollow and artificial and the work of highly civilized Martians of hundreds of millions of years ago. According to Shklovsky, when the Martians discovered that they would soon became extinct, they constructed one or two extraordinarily spacious satellites to serve as libraries and museums as a way to preserve their culture for future explorers as a testament to the glorious history and achievements of their doomed civilization - a sort of mother-of-all-time-capsules.

Few scientists – Shklovsky included – actually count on finding any such rather “convenient” repositories of ancient learning, and discovering any sort of intelligent, civilized life flourishing is considered extremely unlikely. But future prospective explorers of Mars will certainly look for archaeological evidence of long dead civilizations. Maybe Iosif S. Shklovsky had a big beef with what is now called the Fermi Paradox – the inexplicable lack of even the most basic archaeological remains proving the existence of extraterrestrial biological beings as smart as – or smarter – than the human race.

Our current knowledge suggests that the beginning of life on a planet and its evolution toward higher forms has no fixed timetable. Life may have started early on Mars and evolved faster, reaching climax hundreds of millions of years ago. Even if nothing nearly as spectacular is found on Mars – even recent ones like the monkey-like humanoid face on Mars later turned out to be nothing more than an optical illusion – the exploration of the “red planet” will be an event unmatched in all of humanity’s history.

So will Phobos be the Fermi Paradox buster every believer in extraterrestrial life is waiting for? Maybe too soon to tell, but more recent images of Phobos taken by the Mars Reconnaissance Orbiter did show a blue patch near the rim of a deep crater on an otherwise reddish surface. A contrast that’s rarely seen on a body supposedly a captured asteroid turned into a moon. Some astronomers say the blue is recently exposed terrain that hasn’t yet weathered to red; others think it is a wholly different material poking out from the interior. Russia already has plans to send a lander to Phobos to gather samples – and perhaps clues to this Martian moon mystery. Maybe Iosif S. Shklovsky was right all along.

Can the Phases of the Moon Affect Precipitation?

Often dismissed as an old superstition, but does the changing phases of the Moon affect when it would rain or snow?


By: Ringo Bones


I don’t know how many heard of it, but I first heard this supposedly old superstition back in 1989 that goes: Wet weather follows the new Moon and the full Moon. Dry weather follows the first quarter Moon and the last quarter Moon. Strangely enough, a correlation was indeed found out at that time using U.S. Weather Bureau precipitation records showing that there is indeed a better than average chance of rain or snow in the week after a full Moon and the week after new Moon. While the driest periods tend to occur the week after the first quarter Moon and the week after the last quarter Moon. Unfortunately at the time, no clear-cut explanation was provided behind the phenomena after the study was published showing a correlation between occurrence of precipitation and the phases of the Moon. Will a renewed study ever shed light on the validity of this old superstition?

My hypothesis on the matter is that probably during the week after the full Moon and the week after the new Moon, the gravitational effects between the Earth and the Moon during these periods probably allowed higher than average amounts of meteoric and cometary dust to fall into our atmosphere. These comet and meteorite sourced material probably acted as nuclei via the Bergeron-Findeisen Theory of Rain / Precipitation thus causing rainfall and snowfall frequency to increase a week after the full Moon and the new Moon. But is this explanation really satisfactory?

Swedish meteorologist Tor Bergeron first proposed the nuclei theory of precipitation around the mid-1930s, which was later elaborated by German physicist Walter Findeisen and is now widely accepted as the Bergeron-Findeisen Theory Rain. This theory was later applied as the working principle behind cloud seeding. Artificial seeding of rain clouds to induce precipitation during times of drought was developed in 1946 by General Electric’s Vincent J. Schaefer and Irving Langmuir. They used both silver iodide and dry ice as cloud seeding material.

Silver iodide, whose crystalline structure is similar to that of natural ice and therefore provides hospitable nuclei on which ice crystals readily form. Solid carbon dioxide or dry ice – another good cloud seeding agent - is so cold that it causes water vapor to solidify into enormous numbers of tiny ice crystals. In either case, precipitation should follow, according to the Bergeron-Findeisen Theory. Pellets of dry ice are usually sown into a cloud from airplanes while silver iodide is released as smoke, sometimes from an airplane, sometimes from the ground. Meteoric and cometary dust could act as a cloud seeding nuclei, increasing chances of rain or snow – depending on the season – during the week after full Moon and the week after new Moon.

Johannes Hevelius: Father of Selenology?

Given the existing technology at the time, did Johannes Hevelius (1611-1687) able to know more about the Moon in comparison to his astronomy contemporaries?


By: Ringo Bones


Some astronomers think that we only managed to know more about the Moon than Johannes Hevelius did when we had the ability to send robotic spacecraft and manned exploration of the Moon, but is there some truth to this? Even though it was Galileo who first documented the Moon’s topography as seen from his first telescope back in 1610. It was Johannes Hevelius, a notable Polish astronomer born in January 28, 1611 that from his crowded rooftop in Danzig laden with his custom built telescopes – where he gained the fame as the pioneer of Lunar topography a few years later. Hevelius also studied distant celestial objects, but learned little because of dust and other disturbances in the atmosphere over Poland despite using an aerial telescope of his own design that’s 150 feet (46-meter) long – equal to the height of a modern 12-story building.

In collaboration with his wife Elizabeth, they charted the Lunar landscape then published their descriptions in Selenographia back in 1647. During his extensive studies of the Moon, Hevelius got curious of the fact that 59% of the Moon’s surface visible from Earth. During his time, the period between new Moons was already measured with a fair degree of accuracy. And the fact that the same face is always turned toward the Earth with only minor wobbling – the extra 9% of the Moon’s surface seen from Earth – was noted although not explained. The modern explanation is in part that the Moon is not a perfectly symmetrical spheroid. The Moon has a massive bulge, which the Earth’s gravitation attracts like a plumb bob, thus keeping the same hemisphere towards the Earth. With such detailed observations of the Moon, Johannes Hevelus’ contribution to modern selenology was indeed indispensable.

During his lifetime, Johannes Hevelius was also credited for discovering four comets and was noted for his suggestion that the comets revolved around the Sun in a parabola. And his observations on comets were published in Prodromus Commeticus in 1665 and Cometographia in 1688. Hevelius also listed 1,564 stars and in 1661 became the second person on Earth to witness the transit of Mercury – i.e. the planet Mercury moving across the face of the Sun as seen from Earth. Coincidentally, he passed away during his birthday on 1687.

Aperture Synthesis: Making Radio Telescopes “See”?

Developed by Sir Martin Ryle back in 1952, can aperture synthesis be used to make radio telescopes finally “see” celestial objects when before it can only “hear” them?


By: Ringo Bones


When the Rayleigh Criterion is taken into account, radio telescopes seem to “hear” rather than actually “see” the celestial objects of interest they are aimed at due to the much longer wavelengths of the radio spectrum in comparison to the optical / visible light part of the electromagnetic spectrum. This is the reason why RADAR or radio wave-based imagery of the universe has always been inferior in resolution terms in comparison to optical astronomy. The most obvious solution is to make ever-larger radio telescope dish antennas so that their resolution capabilities would equal that of optical telescopes, but that presents its own problems. Even the 1,000-foot diameter RADAR dish in Arecibo, Puerto Rico - in imaging terms - still cannot match the detail resolution of the human eye, and making ever bigger dishes presents its own problems.

Since radio astronomy began, astronomers had been constructing ever-larger dish antennas in an attempt to detect radio emissions from objects millions of light years away from Earth where the optical portion of the electromagnetic spectrum – i.e. visible light – cannot be picked up by optical telescopes. Radio astronomers knew, however, that to “see” into more distant objects would require the construction of antennas several miles wide. And it had taken awhile for radio astronomy to rival that of its optical sibling in resolution terms.

Ever since Albert A. Michelson used his interferometer in optical astronomy to bypass the inherent Rayleigh Criterion limitations of reflecting telescope with finite-sized mirrors, radio astronomers have adopted this technique in radio astronomy. The simplest kind of radio interferometer is based on the Michelson interferometer – which consists of two small reflectors. Radio waves arriving at an angle to the baseline of the reflectors reach each other slightly before the other, producing a multi-lobed antenna pattern similar to the fringe pattern in optical interferometers. The farther apart the reflectors, the narrower the width of the lobes – or beams – of the antenna’s radiation pattern, thus greatly increasing the radio telescope’s resolution.

A very example of this type of radio telescope is the California Institute of Technology twin-element interferometer, which consists of two 90-foot steel-mesh parabolic antennas. The antennas are mounted on special vehicles that move along special railroad tracks that can be separated by up to 1,600 feet in either east-west or north-south direction. With a beam-width or acceptance angle as narrow as 0.03 degrees, the telescope is used to record the 960-MHz radio noise in our Milky Way galaxy.

Another type of radio interferometer consists two linear arrays at right angles to each other that electronically compares the fan-shaped beams of the two arrays that result in a single pencil beam being produced that can accurately pinpoint radio sources. Developed in the early 1950s by the Australian radio astronomers W. N. Christiansen and B. Y. Mills. Each array may consist of many dipole antennas (Mills cross), parabolic antennas (Christiansen cross), or a parabolic cylinder.

The Mills cross near Sydney Australia was completed in 1952 and has legs 1,500 feet in length. Later upgraded to a version in 1957 with 3,500-foot legs, and a 1.6-kilometer version. The cross antenna at Stanford University consists of 16 steerable 10-foot parabolic reflectors in a row 375 feet long bisected by a similar row at right angles to it. This antenna is roughly equivalent to a single paraboloidal antenna 375 feet in diameter. Other cross radio telescopes include the Soviet Union’s 0.62-mile (1-kilometer) cross consisting of two parabolic cylinders, while a similar instrument is also found in the University of Bologna in Italy.

Radio interferometer resolution further improved when British astronomer Sir Martin Ryle developed a more effective method called aperture synthesis. He discovered that if he periodically varied the distances between a number of small radio telescopes, they would yield the resolving power of a single mammoth-sized radio telescope. Aperture synthesis was developed over two decades starting in 1952. This technique revolutionized radio astronomy by allowing radio astronomers to achieve an accuracy and resolution rivaling that of optical science. Together with Antony Hewish, Ryle won the Nobel Prize in physics in 1974. The first ever given to astronomers since it began in 1901. In fact, the long time-exposure of Ryle’s telescopes allow “viewing” with a definition so sharp that in the words of the Nobel selection committee: “it corresponds to an observer on Earth being able to see details of a postage stamp on the Moon.”

Years later, aperture synthesis even influenced the development of the US Navy’s Synthetic Aperture RADAR technology that allows their ship and plane based radar systems to achieve the same capabilities to that of the Distant Early Warning (DEW) Line base in Thule, Greenland. Many pundits claim that Synthetic Aperture RADAR is the main technology that made Operation Desert Storm a success in 1991.