Background: NASA’s Solar Parker Probe launched in Aug 2018 and has completed 3 of its scheduled 24 trips around the Sun. With each loop around the Sun, the craft is getting closer to the sun’s surface. The probe is carrying instruments to investigate the sun’s hot atmosphere – the corona and to understand the origin of the solar wind.
News: The probe has beamed back its first measurements from the sun’s fiery atmosphere. It has measured several never-before-seen events so small that all trace of them is lost before they reach Earth.
What do we know about the Sun?
The Sun is a ball of Helium and Hydrogen. The yellow disk or the surface of the sun that we see in the sky is about 10,000 degrees Fahrenheit. Wow, that is blazing hot, but cool compared with what lies above. The thin atmosphere of the Sun known as the corona is 300 times hotter.
Though the disc might look calm from millions of miles away it is extremely active. It constantly exhales streams of fast energetic particles and a magnetic field is known as the solar wind. The solar wind travels through space and impacts weather in space, satellites, astronauts, and electronics on Earth.
The first batch of data from the Solar Parker Probe has led to some unexpected findings.
Space is full of cosmic dust. One can see the space dust on earth as it reflects sunlight. The Parker probe displayed evidence that the dust stops 3.5 million miles from the sun. The sun vapourises the dust generated by the residue of planets and asteroids and creates a dust-free zone surrounding the sun.
The probe also observed that the Sun lets out sudden, violent bursts of particles, unlike the uniformly streaming solar wind we see by the earth. The speed of the particles is so powerful that the magnetic field flowing out from the sun flips in a whip-like motion. These streams will sometimes do a 180-degree flip, only to flip back to their original direction anywhere from a few seconds to several hours later. These flips release lots of energy that acts upon the solar wind, expediting it out into the solar system.
Scientists are not yet able to explain what’s causing these flips, although they may be related to the plasma spurts that sometimes erupt off the surface of the sun.
This accelerated release of energy from the sun’s center to its atmosphere could also help explain why the corona is hotter than the solar surface.
Scientists observed that the solar wind had two main parts: a “fast” one that comes from large coronal holes in the sun’s polar region; and a “slow” wind whose origin is unknown. Coronal holes are cooler, less dense regions, through which magnetic fields stream out into space, acting as channels for the charged particles to flow along. The Parker probe traced the slow wind back to small coronal holes scattered around the sun’s equator – solar formations that weren’t known before.
NASA’s mission to the Sun is a daring mission and extraordinary engineering effort. As it continues its loop around the sun we hope the data will help us understand our star better and in the future help predict solar storms, which could affect artificial satellites and astronauts.