Mercury is beginning its swing behind the sun and cannot be seen this month.
Venus continues as the ''Evening Star'' in the northwest evening twilight this month but it sinks lower in the sky each night. By the end of May, it disappears into the solar glare as it passes between Earth and the sun. Venus is the brightest object in our sky except for the sun and moon and its orbit is more nearly circular than that of any other planet.
As darkness falls, the reddish glow of Mars can be seen high in the southwestern sky. Most of the time, the Red Planet is a difficult target for even large amateur telescopes because of its small size. However, for the three to four months each Martian year that Mars and Earth come relatively close to each other, a medium to large amateur telescope will display some surface features.
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Jupiter is behind the sun in relation to Earth and is not visible during May.
Saturn appears in the southern evening sky, above and to the left of the blue giant star, Spica. On May 4, Spica and Saturn form a triangle with the moon. On May 31, Spica, Saturn and the moon align in a straight line.
Weather permitting, and if you have an unobstructed view of the western horizon, you may be able to glimpse a very small part of an annular solar eclipse on May 20 just as the sun is setting. The moon will appear to take a tiny bite out of the solar disk as the sun slips below the horizon. Look only through a piece of No. 14 welder's glass or an aluminized mylar film to avoid severe eye damage. Do not look through binoculars or a telescope without the proper solar filters.
INDISPENSABLE WATER
''All the water that will ever be is, right now.'' - National Geographic, October 1993
Nearly colorless, odorless and tasteless, pure water is vital for all forms of life on Earth. We can live for about a month without food, but dehydration and death will occur within about a week without water. Here are some interesting facts about this incredible commodity:
Water is the only substance found naturally on Earth in three forms: liquid, gas and solid.
Ice floats because it is 9 percent lighter than water, the only compound in which the liquid state is heavier than the solid.
Less than 1 percent of Earth's water supply can be used as drinking water.
Nearly two billion people do not have access to clean water. By the year 2025, it is estimated that 5.3 billion people, two thirds of the world's population, will suffer from water shortages.
Less than 1 percent of the water treated by public water systems is used for drinking and cooking.
Bottled water may not be as safe as tap water, although it can be more than 1,000 times more expensive. The reason bottled water often contains more bacteria and impurities than tap water is because the EPA regulates municipal water systems more stringently than the FDA regulates bottled water.
90 percent of wastewater in developing countries is discharged into rivers and streams without any treatment.
It takes about 6 gallons of water to produce a single serving of lettuce but more than 2,600 gallons are required to produce one serving of steak.
Water is the most common natural substance on Earth, covering nearly three-quarters of our planet's surface.
The recent increase in high pressure hydrofracking in shale gas formations in many parts of our country poses a serious threat to aquifers and surface drinking water. The amount of fluid used in fracking just one well can easily exceed one million gallons. Usually, these fluids used in the process of hydrofracking contain toxic chemicals, such as benzene.
More than 100 pharmaceuticals have been identified in water samples from rivers, lakes and coastal waters throughout Europe and the US.
Over 90% of the cost of a bottle of water is for the label, cap, and bottle. An estimated 1.5 million barrels of crude oil are used each year to produce the plastic used to bottle water. In the U.S. it is estimated that less than 20% of these bottles are recycled.
The world's first municipal water filtration plant opened in Paisley, Scotland, in 1804. Today, there are nearly 60,000 community water systems treating public water supplies in the U.S. In 1974, Congress passed the Safe Drinking Water Act which requires public water systems to monitor and treat drinking water for safety.
The rainiest city in the world is Cherrapunji, India, with an average rainfall of 498 inches each year.
The driest place on Earth is a region called the Dry Valleys in Antarctica. There has been no precipitation in this area for hundreds of thousands of years.
The longest river in the world is the Nile, at 4,132 miles.
Three quarters of all Americans live within 10 miles of polluted water.
Farming and ranching account for 70 percent of America's freshwater use.
Nearly one million miles of aqueducts and pipelines transport water in the U.S. and Canada.
Almost one half of the world's current population fails to receive the level of water services available 2,000 years ago to the citizens of ancient Rome.
A full 80 percent of the diseases in the developing world are caused by contaminated water.
Water is a $400 billion global industry, the third largest behind electricity and oil.
In the last few decades, 20 percent of freshwater fish species have been pushed to the edge of extinction from contaminated water.
The water we drink today is the same water the dinosaurs drank. There is no new water; it is simply recycled.
A large oak tree can evaporate 105 gallons of water in one day.
According to the EPA, residue from antidepressants, birth control pills and antibiotics is found in 80 percent of U.S. waterways and groundwater. Worldwide, two million tons of human, industrial and agricultural waste are discharged into rivers and lakes every day.
In 2010, an estimated 1.5 million children under age 5 died as a result of water- and sanitation-related diseases.
Editor's note: This monthly guide to the stars is from the Marshall Martz Memorial Astronomical Association, the Southern Tier Astronomy Recreation Society, and The Post-Journal. For further information, contact the M.M.M.A.A. at www.martzobservatory.org or S.T.A.R.S. at www.UpStateAstro.org/stars/stars.html.