U.S. #5602
2021 55¢ Sun Science – Plasma Blast
Issue Date: June 18, 2021
First Day City: Greenbelt, MD
Type of Stamp: Commemorative
Printed by: Banknote Corporation of America
Printing Method: Flexographic, Foil Stamping
Format: Pane of 20
Self-Adhesive
Quantity Printed: 18,000,000
Most of the time, people describe the Sun as a massive ball of hot gas. While this isn't entirely incorrect, it is more accurate to say the Sun is a massive ball of hot plasma.
In school, we were all taught the three states of matter: solid, liquid, and gas. However, there is also a fourth state, known as plasma. Plasma comes from the ancient Greek word for "moldable substance" and was first studied in the 1920s. Plasma occurs when a gas with a neutral electrical charge is superheated or exposed to a very strong electromagnetic field. At this point, the gas becomes "ionized" and known as plasma. This state of matter is highly conductive and is easily influenced by electric or magnetic fields – even at great distances.
Plasma can be a bit confusing to understand, but looking at real-life examples can help. For instance, lightning, neon signs, and, of course, the Sun are all forms of plasma. In fact, plasma is actually the most abundant type of ordinary matter in the universe! As you can probably tell from these examples, plasma is often extremely hot and gives off quite a bit of light. The Sun's plasma is generated by the intense nuclear fusion reactions occurring within its core.
Sun science is a bit technical, but it's still fun to learn about the star at the center of our solar system!