The sun's atmosphere, which has an enormous effect on the solar system, is said to be much larger than scientists initially thought. Using NASA's Solar Terrestrial Relations Observatory, scientists have determined that the sun's atmosphere, called the corona, extends to about 5 million miles above the sun's surface—or the equivalent of 12 solar radii, NASA said.
The agency said this latest finding has implications for a future Solar Probe Plus mission in 2018, which is set to get closer to the sun than any manmade object before it has ever gone.
NASA scientists were able to determine the sun's atmosphere by measuring the inner and outer boundaries of the heliosphere, or the bubble that surrounds the sun and all the planets. Researchers took measurements through sound-like waves known as magnetesonic waves—they can't actually hear them in space, but they can see them ripple through the corona.
These magneto sonic waves, a derived from Alfven waves, are much different from the ones observed here on Earth; whereas sound waves on Earth oscillate several hundred times per second, these magnetosonic waves oscillate one every four hours—and NASA says they're about ten times the length of Earth.
So when NASA talks about giant solar storms or coronal mass ejections, the ripple effects are felt much farther out into the universe than researchers thought. With NASA's Solar Probe Plus mission, the agency is hoping to get within 4 million miles of the sun, giving scientists valuable information about the sun and its inner solar magnetic system.
"The mission will directly measure the density, velocity and magnetic field of the solar material there, allowing us to understand how motion and heat in the corona and solar wind are generated," said Marco Velli, a Solar Probe Plus scientist.
