Alison C. Rohde


2010 Geminid Meteor Shower

The Geminid meteor shower, usually one of the best meteor displays of the year, returns to our December skies this year with the promise of a great show. At its peak on the night of December 13th through the early morning hours of the 14th, this year's display should reach rates upwards of 50 meteors per hour under clear skies.

What are the Geminids?

The Geminids are debris from 3200 Phaethon, an object which resembles an asteroid, yet has some orbital and compositional characteristics of a comet. Although many scientists disagree about what exactly 3200 Phaethon really is (asteroid? extinct comet? Captain Kirk's old coffee table?), it is technically classified as an Apollo asteroid, or an asteroid which has a near-Earth orbit. Whatever the true case may be, each year the Earth passes though a field of dust left behind by this mysterious space rock; when the debris collides with earth's atmosphere and ignites, we get the bright flashes of light we call shooting stars.

When and Where to Observe

This year the Geminds will start to reach maximum activity Monday night through Tuesday morning; at around 2 a.m., the rate of meteors should reach about one per minute.
The best way to observe the Geminids is under dark skies and looking toward the constellation Gemini, the apparent radiant of the shower. To really get the most out of the experience, allow your eyes 15-20 minutes to adjust to the darkness so that fainter meteors become much more visible to you.
This means setting aside at least an hour of pure, uninterrupted observing time; just grab a blanket, clear your mind, and enjoy one of the best shows the universe has to offer.



2010 Leonid Meteor Shower

The annual Leonid meteor shower will reach its peak this year on November 17th. For North America, the best time to see shooting stars will be in the early morning hours, when the moon has set and the sky is fully dark. Starting at around 2:30AM, look toward the constellation Leo, hanging near the Big Dipper on the eastern horizon. Although shooting stars will be visible all across the sky, many of the meteors will appear to be emanating from this constellation, therefore called the "radiant" and the namesake of the shower.

Probably the most well-known of meteor displays, the Leonids appear very regularly in the mid-November sky and sometimes last for many nights on either side of their peak. They are composed of tiny pieces of the comet Temple-Tuttle, which swings around the solar system every 33 years. During one of these close approaches, tiny pieces of the comet are shaken off; every year the earth passes through a field of these remnants, and as the ash and debris collide with our atmosphere, at an incredible speed of about 45 miles per second in the case of the Leonids, they produce the bright streaks of light we call shooting stars.

The best way to view the shower is with the naked eye under dark skies; a lawn chair, warm clothes, and maybe some hot cocoa are all you need.
This year's shower should produce about 15-20 meteors per hour; modest in comparison to years past, but still worth staying up for!


The Case for Organic Food

Today it seems as though purchasing organic, locally grown produce is the trendy thing to do. Many people feel they should purchase organic food because they have a vague idea that it may be better for them, but are often put off by higher prices. On average, organic products can cost about 20% more than their industrially produced counter parts. The question is: what are the true benefits of buying organic? Is it worth the extra cost?

Organic versus Factory Farming
Industrial farms today use methods which are harmful to our soil, air, and water. Fruits and vegetables are grown in fertilizers composed of synthetic chemicals and are sprayed with a variety of pesticides. These chemicals accumulate in the soil and are washed down into rivers and streams, where they may travel miles, affecting wide areas of aquatic life and drinking water. Pesticides may also cling to dust or be carried far away by the wind.

According to the Microbial Life Education Resources (MLER) project, which is funded by the National Science Foundation, there is a 7,000 square mile area (roughly the size of New Jersey) in the ocean near the Gulf of Mexico where much of the fragile ocean life inhabiting those waters has all but been wiped out. This large polluted area, known as a "dead zone," was caused by synthetic fertilizers containing nitrogen and phosphorous washing into the Mississippi river from industrial farmlands and then down into the sea. Part of the reason these polluted soils and fertilizers wash away so easily is that aggressive industrial farming tends to push the land to its limits; chemically saturated, overworked fields often become especially susceptible to soil erosion.

Animals on factory farms are fed a steady diet of growth hormones and antibiotics to make them grow larger and keep them from becoming ill due to living in very close quarters with one another. The grain and feed they consume often contains pesticides and inorganic materials. When you consume products from these animals, you are in turn ingesting a variety of drugs, hormones, and pesticides. A typical glass of milk from industrially farmed cows may contain excess amounts of pus, white blood cells, antibiotics, and bovine growth hormones (which have been linked to breast cancer).

Organic farms do not use synthetic pesticides or chemical fertilizers. Instead, they employ complicated soil rotation methods to keep weeds at bay and ensure that crops are grown in soil which is rich in natural nutrients. In this way the land is kept healthy and soil erosion is prevented. Any fertilizer used is completely natural, such as organic manure or compost.

Animals on organic farms are fed only organic grains, are not given growth hormones or antibiotics, and are not confined in tiny pens but allowed free range.

To keep pests away from fruits and vegetables, organic farmers encourage the presence of beneficial insects and birds and use mating disruption methods and traps to minimize populations of destructive creatures. In fact, unlike factory farms which drive away most wildlife, many organic farms become havens for native species, with birds, plants, and insects making homes for themselves and creating a diverse and thriving habitat.

Organic farms also tend to be run by families who rely on selling their produce locally to make a living. When you buy organic produce at a local farmer's market or grocery store, you are most likely supporting hardworking local farmers who are dedicated to providing safe, fresh, healthy food for you and your family.

Health risks of industrially farmed food
The synthetic pesticides used in intensive farming have been linked to various cancers, leukemia, birth defects, respiratory illnesses, and even Parkinson's disease. While pesticides can pose a risk to anyone who is exposed to them, people who live near farms and especially farm workers are the most affected. The hardworking people in the fields harvesting our food are at the highest risk for becoming seriously ill. Agriculture is considered the most dangerous industry, aside from construction, to work in. According to the EPA, 10,000-20,000 workers fall victim to pesticide poisoning every year. The true number may be much larger, given that many farm hands decline to report their sickness or have their symptoms (vomiting, dizziness, skin problems, eye irritations, headaches, etc.) misdiagnosed. On most industrial farms, clean water to drink and wash in is not available to workers, meaning they may unknowingly carry these poisons home on their skin and clothes, causing their husbands, wives, and children to become ill as well.

Unlike countries in the European Union, which err on the side of caution when it comes to the safety of pesticides, U.S. policies are a little less protective of our well being. Synthetic pesticides are allowed to go on the market with hardly any precautionary testing, and are never tested alongside other chemicals to ensure there will be no harmful interactions.

Expectant mothers are encouraged to completely avoid any exposure to these poisons. According to the American Pregnancy Association, pesticides may have detrimental effects on the nervous system of a developing fetus, especially during the first trimester. They advise that pregnant women living near agricultural areas relocate to avoid exposure to toxic pesticides. Other studies have shown that pregnant women living close to pesticide treated farmland had an increased chance of their baby being stillborn. Other studies have shown an increased risk of congenital defects and developmental disadvantages in the babies and children of women living near agricultural areas.

A typical commercially grown apple is covered with an average of about 30 different pesticides which remain on the apple even after a thorough washing. These poisons, which can kill or make people gravely ill, are a coating on the food we consume daily.

In addition to the cocktail of chemicals found in most produce, much of the non-organic food on the market (up to 75%) has been genetically modified to grow larger products faster and to protect against pests.

Genetic modification (GM) of food may seem attractive in light of a growing world population and an increased demand for food, but the alarming fact is that very little research has been done into just how safe these fruits and vegetables are to eat. In fact, there have been no studies on how these foods affect the human body, and only a handful on how they affect animals. One such recent study by the Committee of Independent Research and Information on Genetic Engineering looked at the long term effects of eating genetically modified corn grown by the Monsanto Corporation. The results of the study showed that rats who consumed the corn developed various types of serious organ disease. All three types of this GM corn were approved for sale and made widely available in the US, Europe, and elsewhere.

Instead of conducting more meaningful tests such as the one mentioned above, the industry claims GM foods are acceptable based on 'substantial equivalence'; the safety of these foods is judged based on how closely their compositions resemble that of the original, unmodified crop. If it looks similar to corn, then corn it is. This unscientific method exempts corporations from having to test their products or apply for a patent before introducing them to the market. These foods are therefore made available for consumption without going through any real vetting process.

Many scientists agree that there may be risks associated with GM foods. The insertions of genes into a genome can sometimes yield unexpected and random effects which may lead to the development of unforeseen allergens and toxins; GMs have been blamed for the dramatic increase in food allergies over the past few years. Recent studies have also linked them certain forms of cancer. Ultimately, no one knows what the long term effects of consuming genetically modified foods may be.

Does it really cost more to go organic?
When doing a superficial comparison at a typical grocery store, it may seem more affordable to buy traditional, industrially grown food. A more critical examination of the true value of buying organic food will reveal that, in the long term, it may cost you much less.

Organic foods do not have the worrisome health risks discussed earlier; they are real, un-tampered-with foods, grown in nutrient rich soil in a setting free of growth hormones, harmful pesticides, and chemicals. Studies have consistently shown that organic fruits and vegetables have much higher levels of important nutrients, vitamins, and antioxidants. To get the same nutritional value from industrially produced fare, you might have to purchase and consume about twice as much.

In the long run, people who eat organic foods will most likely be healthier; the higher concentrations of nutrients in organic foods boost immunity and ward off serious illnesses such as cancer and heart disease. Paying slightly more at the register today could save you heartache and thousands of dollars in medical bills down the road.

On a more tangible level, people who refrain from buying organic because of price often forget that many of the tax dollars they pay every year go the government's subsidizing of factory farms and also toward cleaning up and remediating areas polluted by industrial agriculture. It has been estimated that anywhere from $5 to $16 billion per year is spent on repairing damages such as water pollution, soil erosion, and destruction of wildlife and their habitats due to industrial agriculture. Just one such example is the Minnesota River, which over the years has become heavily polluted with runoff from surrounding farmland. So far, the state and federal governments have paid somewhere around $220 million in a partially successful effort of clean up the river.

Organic farms do not receive the same funding as factory farms, meaning that farmers must charge a little bit extra for their produce just to be able to stay in the game. Paying those few dollars extra at the register would add up to a sum much smaller than what we pay every year to support industrial farming. If the demand for organic food were to increase enough, the government might be forced to begin granting more funding to organic farms.

Some people are willing to pay a little extra for organic just because they say that to them it tastes much better; it reminds them of the sweet, juicy fruit and wholesome milk they remember from their childhood, which for many was before the time of genetic engineering and an overuse of pesticides.

When to buy organic
While it's ideal to make the switch to a completely organic diet, not everyone is willing or able to do so. It is widely agreed that dairy and meat products may be the most important items to buy organic, especially if you have young children. When it comes to produce, the Environmental Working Group has put together a useful guide to help you decide what fruits and vegetables you should try to buy organic. To download the guide to your computer or iphone, visit foodnews.org/walletguide.

A final analysis
Organic foods are healthier for us and for our planet. The well being of our land, water, animals, and fellow human beings is threatened by irresponsible farming practices. By making the choice to buy fresh, untainted foods, we are taking control and moving away from a world in which the things that should nurture us instead pose a risk to our health. We are looking out for our neighbors, ourselves, our children, and our environment. Isn't that worth paying a little extra for?



Disappearing Stars: the effect of light pollution on our health, happiness, and environment

9/16/10
A sky glowing with stars, the band of the Milky Way wheeling overhead, a glimpse into the heart of the universe.
A sight such as this can give hope, comfort, and the reassurance of eternity to those who view it.
Man has always looked to the heavens for guidance, observing the movements of the stars in a quest for understanding, on both a physical and spiritual level. Yet, with every passing generation, our dark, starry skies are fading away into a memory.

Today, due to excessive light pollution, many children will grow up without an awareness of the night sky, never having seen or understood the magnitude of one of the earth's greatest natural wonders.
The loss of the stars is a tragedy in itself, yet there are more subtle, serious risks associated with a brighter night.

What is light pollution?
Light pollution can be defined as misdirected or misused light. Examples of this are outdoor lights which tilt up or outward, or are improperly shielded, allowing light to spread out and up into the sky, and lights which are left on needlessly, sending their rays out into the night.
Drive down the street in almost any neighborhood and you will see homes with lights on in every room, flood lights illuminating entire lawns, empty office buildings glowing with unneeded lights, rows of street lights, and even supermarkets and drugstores which remain fully illuminated inside and out the whole night through.
All of this excess light creates sky glow, the term used to describe the bright halo often seen over towns and cities.

Wasted light means wasted resources
Over the past several years, concerns about wasted energy, global warming, and dwindling resources have been increasing across the nation and the planet.

When people hear the word 'conservation', they most often think of conserving forests, water sources, and open spaces. Energy conservation is right up there as well, but rarely does light itself come to the forefront as something to be conserved.

The energy produced to power our everyday electric lights is generated in power plants by fossil fuels, which take millions of years to form and are a limited resource. According to the US Department of Energy, 85% of all energy consumed in the US is generated by fossil fuels. Roughly 2/3 of the electricity used in this country is powered in this way. Clearly, humans are very dependant on this dwindling supply of fuel; it may be decades before the switch to green energy is completed and oil reserves are no longer a concern. Wasting fuel on unneeded lighting is a good way to speed up the depletion of this valuable resource, not to mention the well-known side effects; the gasses released by these burning fuels contribute to global warming, causing the melting of polar ice caps, rising temperatures and sea levels, and an increase in severe weather.

Effects on our health
The circadian rhythm of day and night, sleep and wakefulness is often disrupted by the availability of electric lighting. Because of our ability to light the night, many people do not have the benefit of sleeping in full darkness. Exposure to artificial light during the night has been linked to a range of health problems, from minor issues such as a lack of energy and a fuzzy head to an increased risk of cancer.

The central biological clock in humans, located in a section of the brain called the suprachiasmatic nucleus (SCN), regulates natural rhythms in the body such as thirst, sleep, hunger, blood pressure, body temperature, and hormone production. This circadian clock is regulated by the amount of light detected by photoreceptors in the retina. When it is dark, these receptors send a signal to the pineal gland of the brain, telling it to produce melatonin, a hormone which is thought to limit the production of reproductive hormones such as progesterone and estrogen. Numerous studies have shown that a decreased production of melatonin in the brain may increase the risk of cancers related to hormones, such as those of the breast and prostate2. A street lamp, a neighbor's security light, any other sources of light which commonly make their way into bedrooms, can disturb a person's sleep and cause melatonin production to drop.

A threat to wildlife
The behaviors and routines of animals are closely in tune with the cycle of day and night. Raccoons, foxes, tree frogs, and many others who feed and breed at night may wait until much later in the evening to go about their nightly business if their habitats are affected by excess lighting from cities or suburbs. This off-kilter nocturnal schedule may mean nighttime hunters find less food, ultimately lowering their chance for survival.

On a dark night in late June or early July, a grassy field or lawn filled with fireflies is quite something to see. The familiar greenish-yellow flashes produced by lightning bugs are courtship signals sent between males and females. In the presence of artificial outdoor lighting, these insects will not send out messages to each other, and therefore will not have the chance to meet, greet, and mate, ultimately resulting in a declining firefly population and the loss of a favorite summertime spectacle.

Around 450 species of birds migrate at night across North America, relying on the moon and stars for navigation. When the sky is lit with a halo of ambient light, they can lose their way or become distracted by the bright lights of buildings and broadcast towers. The disoriented birds will often circle endlessly above and around these lights until exhaustion gets the better of them and they drop to the ground. Occasionally, whole flocks are drawn in by the lights, leading to sometimes fatal collisions between birds3

The case of sea turtles along the shores of Florida is also reason to give pause and consider the effect man-made light has on the wild creatures which surround us. The eggs of these ancient reptiles hatch in the evening, following the light of the moon and stars to the safety of the waves. If the eggs are unlucky enough to hatch in a more developed area, the little turtles will often become confused and follow the beams of a street lamp or outdoor flood lights, meaning the young of this endangered creature will go the wrong way and never make it to the sea1.

What we can do to take back the sky
Here are a few tips for cutting down on excess lighting:
1. Train yourself to turn on only the lights you really need
2. If you have outdoor security lighting, make sure that the bulbs are pointed downward instead of at an angle; this will cut down on the amount of light escaping into the sky or a neighbor's yard, and will probably provide better illumination for the area you wish to light.
3. Replace outdoor and indoor lighting fixtures with dark sky-friendly alternatives. For a few ideas, visit StarryNightLights.com.
4. Swap out high powered bulbs for a lower wattage; you won't notice much difference in lighting quality, but you'll be using less energy.
5. Switch out timers for motion sensors; this ensures lights will only be on when they are needed.
6. Contact your local officials and encourage them to seek legislation for stricter lighting ordnances and more efficient town lighting. Visit the International Dark Sky Association website at darksky.org for ideas on how to start the ball rolling in your neighborhood.

Unlike many of the environmental problems we face today, light pollution is an easy fix; by doing just a few or all of the things listed above, we can make a significant difference in the health and well being of our towns, our cities, and our planet. It's not impossible to reverse the effects of all the excess light we see today; just by the flick of a switch, we can reclaim a truly dark night and a sky bright not with a halo of artificial light, but with millions of stars.

Notes:
1. "Deprived of Darkness; The Unnatural Ecology of Artificial Light at Night". Science News, April 2002 by Ben Harder.
2. "Circadian Disruption and Cancer: Making the Connection". New York Academy of Sciences, August 24, 2009. Reported by Megan Stephan.
3. "Light pollution taking its toll on wildlife, Eco groups say". National Geographic Today, 2003, by Sharon Guynup


A Closer Look: Going Supernova

12/18/09 A supernova is most often described as the explosion of a star in space. However, this definition is slightly inaccurate.
What actually happens during a supernova is better described not so much as an explosion, but as a massive ejection of the star's mass into outer space.
When a star can no longer withstand its own gravitational force due to either an accretion of too much mass, or the inability to continue nuclear fusion of its atoms, all the mass of the star collapses down, hits the core, and bounces back out in an enormous shockwave.
When it reaches maximum brightness, the supernova may even outshine the galaxy in which it resides.
There are two main types of supernovae, Type I and Type II. Type I supernovae take place in a binary system where two stars closely orbit each other. Over time, the gravitational force from the smaller star, called a white dwarf, will pull mass from its larger companion.
Eventually, the white dwarf will reach the Chandrasekhar limit, which is a mass of about 1.4 times that of the sun, at which point it collapses into itself and erupts into a supernova.
Type II supernovae occur when a single, very massive star dies. When the star begins to reache the end of its life, nuclear fusion slows down and then stops in its core, causing it to collapse. This collapse releases enormous amounts of energy in the form of neutrinos and electromagnetic radiation.
The force of this energy causes the outer layers of the star to shoot out into space in a bright "explosion".

Sometimes, the remnants of supernovae will form beautiful planetary nebulae or even a black hole.
In other cases, a very dense object called a neutron star may be left behind.


Last Chance to See Venus This Week

12/3/09 On March 27th of last year, the planet Venus once again became visible in the dawn skies as the morning star. For months it has danced along the horizon, moving closer to the sun. If you haven't yet enjoyed this spectacle, this week and the next may be your last chance for a good while. Over the next several days, Venus will drift too near the sun to be observed. Venus will not return to our skies until March of 2010, when it will reappear on the western horizon as an evening star.

Venus, often referred to as our sister planet because of the similarity in size to earth, is also the brightest object in our sky (excluding the sun, of course).When it is the evening star, it is the first object to appear in the sky after sunset. Conversely, it is the last celestial object visible before dawn. Because the orbit of Venus lies between Earth and the sun, it always appears to us to be either leading or following the sun very closely and has phases similar to those of the moon.

Right now, the phase of Venus is very close to full. Currently, Venus is traveling towards its superior conjunction on January 12, at which time it will be directly behind the sun from our vantage point.
After this point it will shrink in phase, reappearing from behind the sun in March and reaching its half-full phase in August. Between August and October, it will continue to wane until it reaches its crescent phase, which is an excellent time for telescope viewing.



How Dark are Your Skies?


12/3/09 On a dark, moonless night with perfectly clear skies, approximately 2,500 stars are visible to the naked eye. However, when factors such as city smog or ambient light are added into the equation, the number of visible stars can be greatly diminished.
In New York City for example, an average of only about 15 stars are visible in the night sky.

If you want to measure how dark your local skies are, look to the constellation Ursa Minor, also known as the Little Dipper. The two stars that form the side of the dipper are call Kochab and Pherkad. These are known as the "guardian stars" because they circle around Polaris, keeping watch over the North Star. These two are also brighter than the other stars which make up the dipper, with Kochab reaching a magnitude of 2 and Pherkad a magnitude of 3. The other stars have magnitudes of 4 and 5.
If your skies are dark, all the stars of the dipper should be visible.
If only the Guardians are visible, your sky can be considered fair to poor.

Light pollution is often defined as too much, or misdirected, light in an area. The primary sources of light pollution are uncovered lampposts, street lights, or outdoor lighting fixtures, such as flood or security lights. In wintertime, the lamps which illuminate ski slopes can have a significant negative effect on dark skies, creating a hazy glow of light which blots out a large portion of the stars.

Because of these interferences, most Americans will never experience a perfectly dark sky.

Although this may seem like a gloomy prediction, it's important to remember that this is a problem which can be helped. Each of us can do our part by turning off outdoor and any unnecessary lights and urging town officials to make smart lighting choices, such as covered lamps and street lights.


When I Heard the Learn'd Astronomer

WHEN I heard the learn'd astronomer,
When the proofs, the figures, were ranged in columns before me,
When I was shown the charts, the diagrams, to add, divide, and measure them,
When I sitting heard the learned astronomer where he lectured with much applause in the lecture room,
How soon unaccountable I became tired and sick,
Till rising and gliding out I wander'd off by myself,
In the mystical moist night-air, and from time to time,
Look'd up in perfect silence at the stars.

Walt Whitman (1865)


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