Chris Lintott, a Professor of Astrophysics at the University of Oxford, invites listeners to explore the sun's intriguing nature as a swirling mass of plasma and magnetic activity. He discusses groundbreaking insights from NASA's Parker Solar Probe and ESA's Solar Orbiter, shedding light on the sun's dynamic surface and the prolonged journey of sunlight. Lintott also delves into the historical significance of sunspots and the complexities of the sun's magnetic field, emphasizing its profound effects on Earth and humanity.
The Parker Solar Probe has revolutionized our understanding of the sun by revealing its complex layers and dynamics through unprecedented close observations.
Solar activity, influenced by the sun's magnetic field, significantly impacts Earth, affecting satellite communications and creating beautiful auroras in our atmosphere.
Deep dives
The Complexity of the Sun
The sun is often perceived as a familiar and simple celestial body, yet it possesses a complex structure that reveals itself when studied closely. Unlike distant stars that seem simple points of light, the sun's proximity allows scientists to observe its intricate dynamics and phenomena. For example, the Parker Solar Probe, which recently flew closer to the sun than any other craft, has provided unprecedented insights into solar activity, moving at an astonishing speed of 430,000 miles per hour. Such close study has unveiled the sun's various layers, from its hot core to the convective zone, emphasizing the importance of technological advancements in solar research.
Mass and Energy of the Sun
The mass of the sun is a staggering 333,000 times that of Earth, and its vastness is complemented by its temperatures, estimated at around 6,000 degrees Celsius on the surface. Early scientists debated theories about the sun's energy source, culminating in the revolutionary idea of nuclear fusion proposed by Arthur Eddington. This fusion occurs at the sun's core, where hydrogen atoms combine to form helium, releasing an immense amount of energy in the process. Advanced methods, including direct measurement of solar neutrinos, have confirmed this process as a primary energy source, which sustains the sun for approximately 10 billion years.
Solar Flares and Magnetic Fields
Solar activity is highly influenced by the sun's magnetic field, leading to phenomena such as sunspots and solar flares. These sunspots are cooler areas on the sun's surface caused by magnetic field disturbances that inhibit heat flow. Over an 11-year cycle, sunspots wax and wane in activity, forming patterns observed since the 18th century. These dynamic changes in solar behavior have profound effects on the solar system, including disrupting satellite communications and powering stunning auroras on Earth.
The Interstellar Boundary and Future Research
As spacecraft like Voyager 1 and Voyager 2 venture beyond the solar system, they encounter the heliopause, which marks the boundary where solar influence diminishes. The exploration of this region has shown that the transition from solar to interstellar space is not a simple one, as the boundary exhibits a complex structure formed by solar emissions. Current initiatives, including missions proposed in the recent Decadal Study, aim to delve deeper into solar science, including understanding solar siblings—other stars formed in the same vicinity as the sun. As technology advances, researchers hope to unravel the mysteries of our sun and its interactions with the broader galactic environment.
Despite its familiarity, the Sun is a very different presence from the friendly yellow circle in children's paintings. Our star is a broiling mass of plasma, with its powerful magnetic fields, twisted by its rotation, capable of producing dramatic events of spectacular beauty and power. Using results from NASA's Parker Solar Probe - the fastest moving human-made object ever - and ESA's Solar Orbiter, this spectacular lecture takes a new look at the mysteries of the Sun, and its effects on the Earth.
This lecture was recorded by Chris Lintott on 15th January 2024 at Conway Hall, London
Chris is Gresham Professor of Astronomy.
He is also a Professor of Astrophysics at the University of Oxford, and a Research Fellow at New College.
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