Almost 60 years ago an astrophysicist named Eugene Parker published a paper describing what he believed to be high speed matter and magnetism emanating from the sun. For just as long, scientists have sought to learn the mechanisms behind this far-reaching phenomenon, which we know today as solar winds. NASA says advances in technology have now made it possible to get some answers, and it will next year launch a probe to enter orbit around our star in an effort to unlock some of its long-held secrets.
Solar winds are streams of subatomic particles that escape from the sun and take its magnetic field along for the ride. They move with such force – at supersonic speeds – that they can travel billions of miles and affect our planet, along with the rest of the solar system.
In 2015, for example, data from NASA's MAVEN probe found that these winds are slowly stripping away Mars' atmosphere atom by atom. When the winds and magnetic field flow over Mars, it generates an electric field that in turn sends gas ions from the upper Martian atmosphere blowing into space. Closer to home, these winds smash into the Earth's own magnetic field and, while most are bounced back into space, charged particles can slip inside. These then heat the upper atmosphere, cause geomagnetic storms, trigger bright polar auroras and interfere with GPS signals.
The origins of these solar winds have intrigued scientists for decades, but going in for a closer look would involve sending a space probe through the sun's atmosphere, known as the corona, and into temperatures of nearly 2,500°F (1,377°C). But NASA says that this is now possible thanks to advances in thermal engineering, which can keep the spacecraft safe and its payload at near room temperature, thanks to a 4.5-inch-thick (114-mm) carbon composite plate.
While it was previously called the Solar Probe Plus, the craft is now named the Parker Solar Probe in Eugene's honor. It is around the size of a small car and will make seven flybys of Venus, using the planet's gravity over a seven-year journey, to pull itself closer to the sun. It will then fly through the sun's atmosphere as close as 3.7 million miles (6.27 million km) to its surface, around seven times closer than any spacecraft before it.
Here, while zipping around the sun at around 430,000 mph (700,000 km/h), the probe will travel through the birthplace of the highest-energy solar particles and the region where solar winds go from subsonic to supersonic speeds. It will be fitted out with four instrument suites intended to image the solar wind and study magnetic fields, plasma and energetic particles.
By gathering this imagery and in-situ measurements, it is hoped that we can learn more about how energy and heat travel through the sun's atmosphere and what is accelerating the solar winds. This could offer vital clues on other stars around the universe, how life on Earth developed, outer space as a whole and how we can protect our technologies like GPS and satellites from the destruction of solar winds.
The Parker Solar Probe will launch sometime in July or August 2018, aboard NASA's Delta IV Heavy rocket. The short video below offers an overview of the mission.