NASA's Curious Universe: The Sun, Corona Mysteries, and Parker Solar Probe

Podcast overview

In this episode of NASA's Curious Universe, the sun is introduced as our closest star and a powerful driver of space weather. Guests explain the Sun’s multi-layer structure, the mysterious corona heating problem, and how solar activity affects Earth, from auroras to GPS signals. The Parker Solar Probe mission is highlighted as it journeys closer to the Sun than ever before to shed light on these questions.

• The Sun is a hot plasma with core, radiative and convective zones, and observable layers such as the photosphere, chromosphere, and corona.
• The corona is incredibly hot, averaging around 2 million degrees, hotter than the solar surface, and its heating mechanism remains a long-standing mystery.
• Solar activity creates space weather that can drive auroras but also disrupt satellites and GPS on Earth.
• The Parker Solar Probe is venturing into the Sun's outer atmosphere to study how energy moves and why the corona stays so hot.

Overview

NASA's Curious Universe invites listeners to explore the Sun, our neighborhood star, and the dynamic space environment it creates. The episode emphasizes that understanding the Sun is fundamental to understanding broader stellar processes and the space around us. Katie Atkinson introduces the topic while experts such as Patti Boyd, Nicky Fox, and Aleyda Higginson explain why the Sun matters, not just as a bright object in the sky but as a physicist's laboratory and a driver of space weather that directly impacts Earth.

Sun structure and atmospheric layers

The podcasters break down the Sun into a non‑solid core where nuclear fusion power resides, surrounded by a radiative zone and a convective zone that transport energy outward. Above these layers lies the photosphere, which is what we perceive with the naked eye. Beyond the photosphere are the chromosphere and the corona, two hazy outer layers that are visible only during a total solar eclipse when the Moon blocks the Sun’s bright disk. The corona, though faint, is crucial for understanding how solar energy propagates into the solar system and interacts with planetary environments.

The corona is paradoxically the hottest part of the Sun, with average temperatures around 2 million kelvin, vastly hotter than the Sun's surface at about 6,000 kelvin. This striking temperature increase moving away from the surface is described as the coronal heating mystery, a central question heliophysicists have chased for more than a century. The episode discusses how scientists study the Sun from multiple wavelengths and how the corona shapes space weather that travels through the heliosphere and influences planets, satellites, and human spaceflight.

Space weather and Earth

The Sun continuously emits a stream of plasma that forms space weather. While these solar outbursts create beautiful auroras, they can also disrupt satellite electronics and GPS reception. The Sun’s activity thus functions as a protective bubble around the solar system, but its boundary is dynamic and responsive to solar activity, constantly challenging scientists to forecast and mitigate disruptions on Earth.

Parker Solar Probe and heliophysics

In 2018, NASA launched the Parker Solar Probe, a mission designed to fly into the Sun’s corona and skim the outer solar atmosphere with unprecedented closeness. The probe has already begun returning data as it approaches regions where the corona transitions into the solar wind, seeking to answer why the corona is so hot and how energy and particles travel from the solar surface to the broader solar system. Parker Solar Probe is described as one of the most ambitious efforts to study star physics up close and has far-reaching implications for physics and space weather understanding.

Discipline and outlook

The program emphasizes heliophysics as a field that connects solar physics, space weather, and astrophysical plasma physics. It is portrayed as both a traditional and foundational science—an “original discipline of science”—because humanity has always looked to the Sun to explain its world. The episode closes with a sense of ongoing discovery: there are billions of stars like the Sun, and each new measurement from missions like Parker Solar Probe brings scientists a little closer to unraveling the Sun’s enduring mysteries.