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Moment in the Sun

By Dan Gordon '85

Published Jan 1, 2018 8:00 AM

With the help of a UCLA space physicist professor, we are going closer to the sun than ever before.

Artist’s concept of the Parker Solar Probe spacecraft approaching the sun. At closest approach, Parker Solar Probe will be hurtling around the sun at approximately 450,000 miles per hour — that’s fast enough to get from Philadelphia to Washington, D.C., in one second. Closest approach will be 3.83 million miles.

Whether you're plotting an idyllic summer retreat or simply taking your mind on a journey far from the daily grind, your vision of paradise, like our planet, almost certainly revolves around the sun. Now, NASA’s Parker Solar Probe, which will depart on its own years-long journey next summer, is taking sun worshipping to an extreme.

In what the space agency bills as humanity’s first visit to a star, the 10-foot-long probe will hurtle through the sun’s atmosphere, moving well within the orbit of Mercury to a mere 3.9 million miles from our star’s surface on the closest of its 24 flybys (Earth’s average distance from the sun, in case you’ve forgotten, is 93 million miles). It will be a scorcher, with temperatures expected to approach 2,500 degrees Fahrenheit. To withstand the brutal conditions, Parker Solar Probe will use the gravity of Venus during the flybys to gradually bring its orbit closer to the sun. A 4.5-inch-thick, carbon-composite shield will protect the spacecraft and its measuring instruments from the extreme heat. The Probe was the result of the MegaSIMS lab, which is part of the The Earth Planetary and Space Sciences Department and is where the research for the project is carried out.

Under the scientific leadership of Marco Velli, UCLA professor of space physics, those instruments will be employed for research aiming to revolutionize our understanding of the sun — and, by proxy, stars throughout the universe. Among the key questions the mission scientists hope to answer: How do energy and heat move through the solar corona (the sun’s outer atmosphere, which is far hotter than the solar surface)? What accounts for the origin and acceleration of solar wind?

“We’re immersed in this high-temperature wind, and we don’t know the details of what produces this supersonic flow,” Velli says. “Trying to understand it by observing it from the Earth is like trying to understand what’s going on in the engine of an airplane by looking at the exhaust. The only way is to fly into the region where it’s happening.”

The questions have important earthly implications. Solar wind disturbances and other conditions near our planet, referred to as space weather, can alter Earth’s magnetic field, potentially wreaking havoc on the satellites upon which we increasingly depend. Learning what causes space weather, and potentially how to predict it, could protectEarth from a catastrophic solar event. Understanding the space environment is also vital to the safety of spacecraft and astronauts on increasingly faraway excursions.

By the time of its launch, Parker Solar Probe will have been 15 years in the making. Velli, who was part of the probe’s initial science team as an employee at Pasadena’s Jet Propulsion Laboratory, notes that the data collected from the spacecraft will be available to UCLA Ph.D. students for their studies. “This is cutting-edge physics, with cutting-edge technology; it’s very exciting,” he says. “It will allow us to answer questions we couldn’t have previously answered, and could show us things that are happening that we haven’t predicted.”