The Smithsonian’s Grand Tour of the Solar System, a three part Zoom lecture series, begins with the 4.5-billion-year-old star at the center of the solar system, the Sun. As the most massive object around, the sun’s gravity is the glue that holds the solar system together, keeping everything from the biggest planets to the smallest bits of debris in orbit around it. The sun’s activity, from powerful eruptions to the steady stream of charged particles it sends out, influences the nature of space throughout the solar system and provides a protective bubble that shields the planets from damaging galactic radiation. A hot, glowing ball of mostly hydrogen and helium, the Sun emits its own radiation—mainly visible, ultraviolet, x-ray, and infrared. It is the most important source of energy for life on Earth. George Mason University astrophysicist and cosmologist Hakeem Oluseyi shines a light on what astronomers already know about the sun and what they are still trying to understand.

Each lecture may be purchased separately for $25 (Smithsonian members) or $30 (nonmembers). The Sun will be discussed on April 18 at 6:45 pm Eastern. Future episodes are Mercury, Small but Mighty Interesting (May 9) and Venus, Shrouded in Clouds (May 30). Register at https://smithsonianassociates.org/ticketing/tickets/solar-system-sun