NASA's Parker Solar Probe
What is the issue ?
- NASA's Parker Solar Probe will be the first ever mission to probe the Sun's atmosphere.
- It is set for a July 2018 launch.
Aim of the mission :
- To develop a better understanding of the Sun, which has been a key top priority for the NASA scientists for decades.
- The primary goal of the mission would be to trace how energy and heat move through the solar corona and to explore what accelerates the solar wind as well as solar energetic particles.
Phenomena that will be looked into :
- Solar wind
- Explosion of magnetic field and plasma
About the Sun's atmosphere : Can be broadly divided into 3 parts
1. Photosphere :
The lowest layer of the sun's atmosphere is the photosphere. It is about 300 miles (500 kilometers) thick.
This layer is where the sun's energy is released as light. Because of the distance between the Earth and sun, light reaches our planet in about eight minutes.
The photosphere is marked by bright, bubbling granules of plasma and darker, cooler sunspots, which emerge when the sun's magnetic field breaks through the surface.
The photosphere is also the source of solar flares: tongues of fire that extend hundreds of thousands of miles above the sun's surface.
Solar flares produce bursts of X-rays, ultraviolet radiation, electromagnetic radiation and radio waves.
2. Chromosphere :
The next layer is the chromosphere. The chromosphere emits a reddish glow as super-heated hydrogen burns off.
But the red rim can only be seen during a total solar eclipse. At other times, light from the chromosphere is usually too weak to be seen against the brighter photosphere.
3. Corona :
The third layer of the sun's atmosphere is the corona. It can only be seen during a total solar eclipse as well. It appears as white streamers or plumes of ionized gas that flow outward into space.
Temperature's in the sun's corona can get as high as 3.5 million degrees Fahrenheit (2 million degrees Celsius). As the gases cool, they become the solar wind.
Why the corona is upto 300 times hotter than the photosphere, despite being farther from the solar core, has remained a long-term mystery.