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  Night Sky
 

Enjoy the starry night skies
Be a considerate neighbor. Reduce nighttime glare.
Shield your outside lights downward.
Let the stars light up the night.

June 2016 night sky

—Charlie Christmann

With SpaceX looking to send the first private, unmanned spacecraft to Mars in 2018, the prospects of humans walking on the Red Planet may soon be a reality. The question is, whether the ship will be from a country’s space organization or a private company.

 There are many perils on any trip to Mars; only about half of the missions have had any success. The U.S.S.R. began early in the space age, attempting several missions in the 1960s. The first Mars mission launched in October of 1960 and failed to reach Earth’s orbit. Six more Soviet missions were attempted through November of 1964—all failures. The United States’ first mission was also a failure in November 1964. Mariner 4, a U.S. mission, made the first successful flyby, making its closest approach in July of 1965.

The 2000s have been much kinder to Mars missions with only a couple of failures. The U.S. and the European Space Agency have seven operational missions either in orbit or on the surface with two more E.S.A. missions en route. There are a couple of intriguing questions about Mars they are trying to answer: did Mars ever have liquid, flowing water on its surface, and what happened to its atmosphere? If humans are to ever call Mars home with any hope of not wearing a space suit to wander outside, these questions need an answer, and NASA may have the answers.

All of Mars’s topographical features scream water. Water seems to have eroded the landscape into lakes, rivers, and oceans, yet Mars today seems very dry. We do know there is some water trapped in the polar ice caps, but Mars must have had much more water at some time in its past.

The Mars Resonance Rover has recently found evidence of water seeping down the sides of canyons. When temperatures exceed ten degrees Fahrenheit, streaks of hydrated minerals appear. Hydrates indicate water attached to a mineral. So, it appears some water is still present on Mars, it may be very salty, but there is water below the surface.

Now, we need to know what happened to the atmosphere. If there was water in the past, there must have been a thick blanket around the planet to keep the water liquid. If we ever want to live there, we will need to recreate that atmosphere, and keep it.

Four billion years ago, Mars and Earth were like twins. There was carbon dioxide, oxygen, methane and even clouds. Today, the air pressure on the surface of Mars is equivalent to one hundred thousand feet altitude, at best, on Earth. NASA’s the Mars Atmosphere and Volatile Evolution (MAVEN) spacecraft has been dipping in and out of the Red Planet’s upper atmosphere. It discovered wisps of Mars’s air escaping at the rate of about 3.5 ounces per second. Even though the gravity there is enough to hold the thick atmosphere, the sun’s charged particles, over the millennia, have stripped away the gas and water vapor. Solar storms only make the process worse; twenty times more air is lost during those solar events.

Mars’s magnetic field disappeared not long after it was created and the molten core froze. Without the protection of the magnetic field, the charged particles spewing from the sun will continue to strip away any atmosphere on Mars.

Earth, fortunately, has a magnetic field to deflect the charged solar particles around us, or funnels them into the Polar Regions, where we see them as the aurora. But, recent measurements by earth-based instruments and satellites in orbit show our magnetic field is weakening. The north magnetic pole is moving toward Asia. The South Atlantic Anomaly, an area of unusually weak magnetism, is getting weaker and moving, now covering most of South America. Spacecraft see an increased amount of radiation as they pass over the area.

Measurements show field strength over the U.S. has decreased 3.5 percent since 1999 while increasing by two percent over Asia. Some think this may indicate a pole reversal here on Earth. The north and south poles will change places. The question is what happens during the process. Does our magnetic shield disappear? For how long? Reversals in the past have affected life, not usually for the best.

Not having experienced a pole reversal in 780,000 years (they have occurred on average every 250,000 years), scientists have not experienced an event. The geologic record does not contain many details of the process. Who knows, perhaps you will wake up one morning to find your compass pointing in the opposite direction.


 
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