In the spring of 1944, amidst the chaos of World War II, Tokyo residents faced frequent aerial assaults from Allied bombers. Air raid sirens blared, urging citizens to seek shelter, and the city was plunged into strategic blackouts. However, for 28-year-old Hisako Koyama, these blackouts presented unique opportunities. Shielded by a futon, Koyama would peer into the night sky, observing various astronomical phenomena. Her latest endeavor, however, required the light of day.
Koyama ingeniously angled her telescope towards the sun, projecting its light onto a sheet of paper. This setup allowed her to sketch the sun’s ever-changing surface. Over weeks, she meticulously tracked and recorded these changes. Unbeknownst to her, these drawings would become one of the most significant records of solar activity in history.
To comprehend Koyama’s observations, one must first understand the sun’s internal dynamics. Every second, trillions of hydrogen atoms undergo nuclear fusion, transforming into helium and maintaining the sun’s core temperature at a staggering 15 million degrees Celsius. This immense energy converts gas into swirling pools of plasma, which consist of charged particles generating powerful magnetic fields. Unlike the stable magnetic fields on Earth, the sun’s plasma is in constant motion, disrupting and amplifying its magnetic field.
This dynamic activity leads to temporary concentrations of magnetic energy, inhibiting molecular movement and reducing heat in those areas. Consequently, regions with the strongest magnetic fields appear as dark spots, known as sunspots, scattered across the sun’s surface. These sunspots are in perpetual motion due to the plasma’s swirling and the sun’s rotation. Accurately counting and tracking sunspots is challenging, relying heavily on the observer’s perception and judgment.
Despite lacking formal astronomical training, Koyama’s observations and sketches were remarkably precise. Her dedication earned her a commendation from the Oriental Astronomical Association. With their support, she accessed a superior telescope at the Tokyo Museum of Science, where she eventually joined the staff as a professional observer. Over the next 40 years, Koyama produced over 10,000 drawings of the sun’s surface.
Researchers were aware of the sun’s 11-year magnetic cycle, which moved sunspots in a butterfly-shaped path. However, Koyama’s detailed records allowed scientists to track specific sunspots and clusters with unprecedented precision. This data provided real-time insights into the sun’s magnetic activity, enabling the prediction of solar phenomena, including solar flares. These flares, originating near sunspots, can reach Earth’s atmosphere, causing geomagnetic storms that disrupt communications and power grids. They also pose significant risks to satellites and space stations, making their prediction crucial.
In a 1964 interview, Koyama expressed regret that her 17 years of observation had yielded only a single butterfly record of the solar cycle. Yet, by the end of her career, she had documented three and a half cycles, creating one of the longest records ever. The consistency of her drawings allowed researchers to reconstruct 400 years of sunspot activity from historical sources, extending her legacy far beyond her lifetime.
Koyama’s work exemplifies that science is not solely about groundbreaking discoveries but also about meticulous observation of the world around us. Her contributions have provided invaluable insights into solar activity, underscoring the importance of careful and sustained scientific inquiry.
Using simple materials like a cardboard box, aluminum foil, and a pin, create a pinhole projector to safely observe the sun. Track and sketch the sunspots you see over a week. Compare your sketches with those of Hisako Koyama and discuss the similarities and differences.
Research the 11-year sunspot cycle and create a timeline that includes key events and discoveries related to sunspots. Highlight Hisako Koyama’s contributions and how her work fits into the broader understanding of solar activity.
Conduct an experiment to visualize magnetic fields using iron filings and a magnet. Relate your observations to the sun’s magnetic fields and how they create sunspots. Write a short report explaining the connection between your experiment and Koyama’s observations.
Pair up with a classmate and simulate an interview with Hisako Koyama. One student plays the role of Koyama, and the other is a journalist. Prepare questions and answers based on her life, work, and contributions to solar science. Present your interview to the class.
Investigate how solar flares affect Earth’s technology and daily life. Create a presentation that explains the risks posed by solar flares to satellites, power grids, and communication systems. Include how Koyama’s work helps in predicting these events.
Hisako – A name that may refer to a person, often used in Japanese culture. – Hisako was fascinated by the stars and wanted to become an astronomer when she grew up.
Koyama – A surname that can be found in Japan, often associated with notable individuals. – Koyama’s research on solar flares helped scientists understand more about the sun’s behavior.
Sun – The star at the center of our solar system that provides light and heat to Earth. – The sun rises in the east and sets in the west, creating day and night.
Solar – Relating to the sun. – Solar panels convert sunlight into electricity for homes and schools.
Sunspots – Dark spots on the surface of the sun caused by magnetic activity. – Scientists study sunspots to learn more about the sun’s magnetic field and its cycles.
Plasma – A state of matter where gas is heated to the point that it becomes ionized. – The sun is made mostly of plasma, which is why it can produce so much energy.
Magnetic – Relating to magnets or magnetic fields. – The Earth’s magnetic field protects us from harmful solar radiation.
Observations – The act of watching and recording information about something. – Astronomers make careful observations of stars and planets to gather data for their research.
Science – The study of the natural world through observation and experimentation. – Science helps us understand the universe and our place in it.
Energy – The ability to do work or cause change; it comes in many forms, including light and heat. – The energy from the sun is essential for life on Earth, powering plants and warming the planet.
