Transit of Venus, 2012

Today, starting at 6:04 pm, you will have a chance to witness an event that will not happen again for more than a century. Venus will pass directly between us and the Sun, an event called a “transit.” If you can safely view the Sun (more on that in a minute), you will see a tiny black dot slowly move across its face. It will continue to transit well after the Sun has set. Alaska and Hawaii are the only U.S. states that will witness the entire event.

Time lapse photographs of the June 8, 2004 transit taken from a solar observatory in the Canary Islands. The black spots are Venus as it transited the Sun. Courtesy, the National Solar Observatory. 

Even though Venus is in an orbit closer to the Sun than the Earth’s, its orbit is tilted ever so slightly so that it’s usually never directly between us and the Sun. But every century or so, our orbital planes line up and we have a chance to witness two transits, eight years apart. Then we have to wait another century or so to see it again. The last Venus transit happened in 2004, and could be seen in progress at sunrise. I was lucky enough to see it. If you missed it, you have another chance today.

You might think that this event is interesting but otherwise useless. Until this century, though, countries spent enormous amounts of money and risked ships and lives to see and precisely record the transit. Why? Because it enabled us to measure the distance of the Earth to the Sun, what astronomers call the Astronomical Unit (A.U.). This distance, 93 million miles (150 million kilometers), is the ruler we use to measure all other distances in the solar system. Without it, we couldn’t send astronauts to the Moon or rovers to Mars.

Johannes Kepler first predicted that a transit would occur in 1631, but it wasn’t until the second 1639 event (eight years later) that Jeremiah Horrocks and William Crabtree actually witnessed one. Edmund Halley, of Halley’s Comet fame, suggested that by placing observers at different points on the Earth and carefully timing the event, one could triangulate and calculate the distance to Venus and the Sun. In response, all of the major European powers sent observers to the far corners of the Earth to record the 1761 and 1769 events and later, the 1874 and 1882 events. The travels and trials of these scientists as they went off to Siberia, Newfoundland, Madagascar, and other exotic locations are the stuff of adventure novels. You may recognize at least two names in the annals of this history – Captain James Cook observed the 1769 transit from Tahiti, and Charles Mason and Jeremiah Dixon (who later surveyed PA’s southern border, the Mason-Dixon Line) went to Cape Town, South Africa for the 1761 transit. At least one play, appropriately titled “The Transit of Venus” by Maureen Hunter, loosely documents the decade-long adventure of Guillaume Le Gentil, who lost his wife and home and was declared dead before returning from his expedition!

 Jeremiah Horrocks making the first observation of a transit of Venus in 1639. By Eyre Crowe. Courtesy Wikipedia.

How can you see this marvelous event? The safest way is to watch a broadcast from a solar telescope. There is an excellent educational website, http://www.transitofvenus.org/, that has loads of interesting information about the event and will broadcast live pictures. IF it’s clear, a 50-50 prospect around here in June, there are a few safe ways to view the event and I will again point you to that website for the best and safest ways. You must remember though, accidents while attempting to view the Sun with telescopes or binoculars often result in permanent damage or blindness. You cannot blink fast enough to protect your eyes. Sunglasses will not protect you. Black film (negatives) will not protect you. Even welding glass may not protect you because some wavelengths you cannot see may penetrate and still cause damage. Your retina has no pain sensors, so you wouldn’t know it was burning it until it was too late.

So be safe and enjoy the show! The next feature won’t start until December, 2117.


Originally published in the Bloomsburg Press Enterprise on June 5, 2012.

Helium

It was a spring evening in early May when hundreds of people descended on a landing field in Lakehurst, New Jersey for their first glimpse of a trans-Atlantic airship. There had been storms earlier in the day, but by 7 p.m., the storms had passed and the weather was deemed suitable for the landing of the Hindenburg, a German zeppelin – a sausage-shaped balloon filled with lighter-than-air hydrogen gas. The airship approached and circled before hovering about 400 feet over the landing site. Ropes were dropped to moor the zeppelin and pull it closer for passengers to disembark. Shortly after the ropes were dropped, a fire started near the rear of the airship. The outer skin of the zeppelin was breached and the hydrogen began to escape and mix with oxygen in the air, making an explosive mixture. The zeppelin quickly exploded in flames. Thirty-six passengers and crew were killed, and newsreel footage of this disaster has become iconic.

The Zeppelin LZ 129 Hindenburg explosion, May 6, 1937 in Lakehurst, NJ. Public domain image, courtesy Wikipedia.

Hydrogen is highly explosive, so why did the German’s use it instead of non-explosive helium in their zeppelins? Because at that time, the U.S. was the world’s main source of helium and tensions with the Nazi government led to an embargo of that critical resource. The U.S. is still the world’s leading source of helium, but you may have seen news reports about a possible shortage in the near future with rapidly increasing prices. Where do we get this gas and why is it so important?

Modern blimps use helium instead of hydrogen for safety reasons. Courtesy, D. Jensen and Wikipedia.

Helium, element #2 on the Periodic Table, is the second most abundant material in the universe, just after hydrogen. But it is rare on the Earth because it is so light, and once it escapes into the atmosphere, it quickly leaves the Earth forever. It is therefore a non-renewable resource, like oil. Almost all of the Earth’s helium supply was slowly produced by the radioactive decay of uranium and thorium, both present in small amounts in crustal rocks. Because it is a gas, it tends to be trapped where natural gas is also trapped, so most of our helium is taken from natural gas wells in the Midwest (Oklahoma, Texas, Kansas) where it makes up a few percent of all the gas coming from the wells. Back in the 1920’s, the U.S. built plants, pipeline, and underground storage facilities near Amarillo, Texas to extract and store the helium, thus establishing the National Helium Reserve (NHR).

Helium has many unique properties that make it valuable. It stays liquid even near temperatures of absolute zero and, for this reason, is used for deep cooling of superconducting magnets like those used in MRI machines, super-colliders, and high-speed bullet trains. It is used in the manufacturing of computer chips and optical fibers. One of its biggest uses is in arc welding and high-tech plasma coating applications where its main job is to keep more chemically reactive air away from the surfaces being welded or coated. In sum, helium is a critical resource for many of our highest tech industries and scientific research.

MRI machines are the largest single user of helium in the world today. Courtesy, KasugaHuang and Wikipedia.

By 1995, the U.S. had huge reserves of helium stored in the NRH, but it was more than a billion dollars in debt. So Congress passed a law in 1996 directing the liquidation and sale of the reserve to private industry by 2014 to recoup the costs. This law was controversial at the time, but has become more so because it was discovered that the formula used to sell the helium was well below market price and encouraged waste. By 2014, the NRH will be out of money, and whatever helium remains in the storage reservoir will not be accessible. This sudden disruption in the supply of a critical resource will likely lead to price spikes; in anticipation, prices have already jumped significantly. The U.S. Senate is now considering a bill (S.2374) to maintain the reserve for an additional 15 years to ease the transition to private suppliers. Other countries have started to look for their own supplies.

Out of curiosity, I checked to see if helium was present in the Marcellus shale gas being produced locally. I could find nothing definitive, but if helium prices do spike, you can expect to see it becoming a bigger issue.

Originally published in the Bloomsburg Press Enterprise on May 22, 2012.

Silver and Socks

I sing a song of silver. It began when I was shopping for athletic socks, and a friend told me about new ones that incorporate silver in the threads to reduce their smell. What? How does that work? I had to do some digging.

Next to gold, silver is the best known “precious” metal. In astrology, the Sun is gold, but the Moon is silver and its pale light rules the shade. Silver crosses repel vampires; silver bullets kill werewolves. Why not gold crosses or bullets? It may be because silver is associated with the power of night, or because its whitish color suggests purity. But a more interesting possibility is because of silver’s reported medical uses.

Crystalline silver. Courtesy, Wikipedia.

First a disclaimer. As I searched, I found many reported claims of silver used for medicinal purposes in antiquity, but I could not find the original sources. Such are the dangers of Internet research. A claim is posted on one site without reference, and that claim is cited by another site as evidence, not realizing (or caring) that the first is little more than hearsay. Even my favorite go-to site, Wikipedia, is not without this fault.

So, with that caution, I found claims that the Phoenicians would store water and wine in silver vessels where it would keep for years. Hippocrates is said to have written about silver’s healing properties. Some say that American pioneers would put silver dollars in water casks to purify the water. These may all be true, and in hindsight, all look to be based on sound science. But just to keep the proper perspective, others in the past have praised the healing powers of mercury, arsenic, and radium. They were sadly, and sometimes fatally, mistaken.

It is a known fact that many metals, including silver, mercury, and lead, will kill bacteria. This phenomenon even has a name – the oligodynamic effect. We still don’t know what causes it, but one hypothesis is that these metals bind with and change enzymes – chemicals that control reactions in cells – and render them useless. Without these enzymes, the bacteria die. Any of these metals will do that but, unfortunately, most of them are toxic. If you store water in a lead-lined jar, the lead will kill the bacteria, but it will also slowly poison whoever drinks from it. Silver, though, isn’t so toxic.

Silver has a number of modern health and medical applications. It’s used to kill bacteria in water purification systems. Catheters are coated with it to reduce urinary infections. Silver nitrate eye drops were once given to newborns to prevent eye infections. Silver sulfadiazine cream is still used on burns, also to prevent infections. And silver impregnated bandages are now sold to reduce bacterial and fungal contamination of healing wounds. It’s even made it into socks to kill the bacteria associated with smelly feet.

Like most good things, there is the potential for abuse. One product being sold as a nutritional supplement is “colloidal silver,” a suspension of micro-scale particles of silver in a liquid. So far, medical science can find no evidence that eating silver will help in any way. And there are some significant side effects, including a condition called argyria – a permanent bluish discoloration of the skin, nails, and gums. It may also interfere with the absorption of other medicines taken at the same time, including antibiotics and drugs for thyroid problems or rheumatoid arthritis (you can read more here http://nccam.nih.gov/health/silver).

A patient suffering from argyria. Courtesy, Wikipedia.

Some may claim that these warnings are hogwash and medical science doesn’t know everything. That’s true – at least the last part. But the history of untested nutritional supplements is littered with terrible mistakes. In the 1920’s, the tonic of choice was radium. You could buy pre-mixed radium water, or make your own by letting water sit overnight in a radium-lined crock. It was promoted to restore vigor and treat a host of diseases, including arthritis, cancer, and high blood pressure. Instead, you got radiation poisoning.

So until there is some overwhelming evidence that ingesting silver is healthy, I’ll just keep it jingling in my pocket or imbedded in my new stinky-proof socks.

Originally published in the Bloomsburg Press Enterprise on May 8, 2012