The solar wind is a gas plasma blown off the surface of our sun at a million miles per hour. It is the outer atmosphere of the sun expanding out into space in all directions all the time. It effectively forms a shield around our solar system like a bubble that is called the heliosphere that tends to reflect harmful cosmic rays originating from other star systems, basically pushing away the rest of the galaxy from our solar system. This outward flow of particles is constant and creates outbound pressure referred to as a wind, a solar wind.

Sometimes it is stronger than at other times. Apparently, it is also sometimes weaker, as new data suggest.

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An image of the sun taken Sept 25 using the SOHO observatory’s Extreme ultraviolet Imaging Telescope at 304 Angstrom. SOHO, NASA/ESA

This is perplexing. The strength of the wind forms a pressure barrier that repels the intergalactic cosmic radiation, which is quite harmful to life, especially life floating around in space, space stations and spacecraft. Earth is protected by its magnetosphere and by its atmosphere for two additional tiers of protection. Spacecraft orbiting the Earth would also be protected by its magnetosphere. Spacecraft en route to the moon would have minimal protection.

The spacecraft Ulysses launched in October 1990, is a mission out of the plane of the planets orbiting the polar regions of the sun. Ulysses has detected a gradual decrease in the solar wind over the last 15 years equal to nearly 25%.

A segment today on Science Friday, talks to David McComas, Principal Investigator for Solar Wind Observations over the Poles of the Sun (SWOOPS) Experiment, about the solar wind and the findings by the spacecraft Ulysses. The archived podcast should be available later today here.

The Ulyssess/SWOOPS web site is here: http://swoops.lanl.gov/ .

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Science Friday http://www.sciencefriday.com/ has an excellent update on the Mars science program and planned projects for Mars. They also discuss possible missions in the next 5 to 10 years. The podcast should be available later today here: http://www.sciencefriday.com/feeds/about/.

Here’s the description of the segment from their web site:

In this segment, we’ll get the big picture on science on the planet Mars. From orbiting observatories to roving rovers to the ditch-digging Phoenix — what have planetary scientists learned about Mars, and what remains to be discovered?


The most recent visitor to the Red Planet is NASA’s Phoenix Mars Lander, which launched in August 2007 as the first mission in NASA’s Scout Program. Phoenix is designed to study the history of water and habitability potential in the Martian arctic’s ice-rich soil. So far, the lander has identified water ice in soil samples, and has detected the chemical perchlorate in the soil, a sign of the presence of liquid water in the past.


The Phoenix Mars Lander joins the twin rovers of the Mars Exploration Rover project, Spirit and Opportunity, which have been in operation since 2004. Now running years past their planned lifetime on Mars, the rovers are still exploring the surface. Rover Opportunity recently exited the Victoria Crater after several months on the crater floor.


Several orbiting observatories, including Mars Odyssey, Mars Express, and Mars Reconnaissance Orbiter are examining the different aspects of the planet from above. The orbiting platforms have studied the planet’s atmosphere, mapped its surface, and are also supporting the ground-based exploration missions.


We’re broadcasting this week from Tucson, Arizona, home base for NASA’s Phoenix Mars Lander, as guests of Arizona Public Media.”

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Image: NASA’s Mars Exploration Rover Opportunity climbed out of “Victoria Crater” following the tracks it had made when it descended into the half-mile-diameter bowl nearly a year earlier.