On the 12th of August 2018, following technical problems and delays, the Parker solar probe finally started its record-breaking mission towards the sun. Named after the astrophysicist Eugene Parker, the solar probe is programmed to fly into the sun’s corona (an aura of plasma surrounding the star) and ultimately come within 6.1 km of the sun’s surface. Travelling at around 724,000 kph, the probe will hitchhike on Venus’ gravitational orbit seven times to come closer and closer to the sun.
Several measures have been put in place to protect the probe and its equipment from the scorching temperatures. The spacecraft will be protected by a state-of-the-art carbon heat shield, and has built-in sensors to rapidly compensate in case it turns and exposes its equipment to the full heat of the sun. Although the plasma that makes up the corona reaches well into the millions of degrees Centigrade, the probe will only be exposed to a breezy 1,400°C due to the very thin structure of the corona, which means that the probe won’t actually touch that many of the superheated plasma particles; “think of putting your oven on and you set it at 400 degrees, and you can put your hand inside your oven and you won’t get burned unless you actually touch a surface”, explains Nicola Fox, a solar scientist at Johns Hopkins University and part of the Parker probe team.
Through this ground-breaking mission, scientists hope to solve some of the sun’s best-kept secrets, for example; why is the corona so much hotter than the surface of the sun? And what lies behind the solar wind, the term coined in the 1950s by Eugene Parker to describe the gas that speeds away from the sun at over a million miles per hour? When Parker first proposed this idea, he was scorned by the scientific community. But in time, research came to vindicate him, and we now know that such a wind does indeed exist and has a significant impact on the solar system. “We’ve had to wait so long for our technology to catch up with our dreams,” says Fox. “It’s incredible to be standing here today.” Parker himself is rather more prosaic: “I’ll bet you 10 bucks it works”.
Applicants for Physics, Natural Sciences, or Engineering might be interested in learning more about the solar probe’s mission and the research and questions that lie behind the mission. Those particularly interested in astrophysics may wish to read Eugene Parker’s 1958 paper on solar wind.