Blame it on the sun
Mercury is the closest planet to the sun, which means the sun’s heat and radiation are much stronger than on any other planet. On Mercury’s day side, temperatures soar to about 800 º Fahrenheit, but on the dark night side, they fall to about -300º F. Because of its location, Mercury is also affected by the solar wind.Office 2007 makes life great!
The solar wind is like a high-energy stream — in this case, a stream of plasma — that blasts away from the sun in all directions at about one million miles per hour. That’s fast enough to get from the Earth to the moon in about 15 minutes. When the solar wind hits Earth, we barely notice because Earth’s powerful magnetic field protects everything on the planet.
But Mercury’s magnetic field is weak, so the solar wind can do some damage.
The solar wind is an example of space weather. On Earth, understanding the weather means measuring such things as rainfall, temperature and humidity. Understanding space weather means measuring powerful forces — energy from the sun — that can blast through space and affect even distant planets or other stars. To understand space weather on Mercury, scientists study electricity and magnetism.Office 2007 download is on sale now!
Red arrows indicate the direction of fast solar wind streams leaving the sun. Yellow lines show magnetic fields in the sun’s atmosphere.European Space Agency, NASAThe high-energy particles in the solar wind are a natural source of electric charges. Scientists have known for centuries that electricity is closely related to magnetism. A moving magnetic field can generate electricity, and moving electric charges can form a magnetic field.
When the electric particles of the solar wind plow into Mercury, they’re also carrying a powerful magnetic field. In other words, Mercury’s puny magnetic field gets hammered by the one in the solar wind. As the solar wind blows toward Mercury, its magnetic field presses down on Mercury’s magnetosphere in some places and pulls it up in others. As these two magnetic fields tangle high above the planet’s surface, the magnetic fields twist together and grow — and a magnetic tornado is born. (Among themselves, scientists call these tornadoes “magnetic flux transfer events.”)Office 2010 key is for you now!
“When one of these magnetic tornadoes forms at Mercury, it directly links the surface of the planet to the solar wind,” Slavin says. “It punches a hole in Mercury’s magnetic field.” And through that hole, he says, the solar wind can spiral down, down, down — all the way to the surface.