Kelly McSweeney

May 25th 2023

The Sun’s Heartbeat: A Solar Radio Burst


Researchers have discovered a solar radio burst with a signal pattern comparable to the Sun’s heartbeat. What does cardiology have to do with astronomy? The familiar lub-dub sound of a heart is a rhythmic pattern caused by electrical signals stimulating the heart muscle to contract. Similarly, the radio bursts feature a signal pattern reminiscent of a heartbeat.

An Electromagnetic Discovery

The electromagnetic (EM) spectrum is a range of wavelengths of EM radiation covering a wide spectrum from short gamma- and X-rays to longer waves, such as infrared, radio and microwaves. The human eye can only see a small portion of the spectrum (visible light), but scientific instruments, such as the James Webb Space Telescope, can capture invisible radiation that astronomers use to understand the universe.

An international team of researchers from institutions in China, Germany, the United Kingdom and New Jersey detected the solar radio burst by studying microwave imaging observations from a telescope in California called the Expanded Owens Valley Solar Array. They reported their findings in Nature Communications.

The study describes a solar radio burst, an intense burst of radio waves from the Sun. These bursts can feature signals with repeating patterns, and the signal pattern comes from within a solar flare more than 5,000 kilometers (~3,107 miles) above the Sun’s surface.

What Is a Solar Flare?

Solar flares are a type of powerful explosion from the surface of the Sun. According to Live Science, solar flares are intense bursts of EM radiation generated in the layers of sparse, hot gas that comprise the Sun’s atmosphere.

The researchers have labeled this particular solar flare as a C5.9 class, which is a medium-sized explosion on the immense scale of the universe. For context, the most powerful solar flares are equivalent to the energy of a billion hydrogen bombs, which is enough energy to power the world for 20,000 years, according to NASA.

What Causes Solar Flares?

The big yellow ball in the sky is a mixture of hydrogen and helium held together by the force of gravity. But there is another fundamental force at work: electromagnetism, which involves the interaction of electric currents and magnetic fields. This force causes matter to behave in certain ways, and when it comes to the Sun, magnetic energy sometimes builds up in the atmosphere and is suddenly released as a solar flare.

Most of the energy released by solar flares is in the ultraviolet and X-ray part of the EM spectrum at shorter wavelengths and higher energies than visible light. These events are not unusual. The Sun’s magnetic field drives a solar cycle, which is a period of solar activity that lasts approximately 11 years, according to

How Solar Flares Affect Earth

The recent discovery of “the Sun’s heartbeat” can help astronomers understand more about electromagnetism and how it affects activity in the universe and space weather in general.

“The discovery is unexpected,” said Sijie Yu, the study’s corresponding author and astronomer affiliated with the New Jersey Institute of Technology Center for Solar-Terrestrial Research. “This beating pattern is important for understanding how energy is released and is dissipated in the Sun’s atmosphere during these incredibly powerful explosions on the Sun. However, the origin of these repetitive patterns, also called quasi-periodic pulsations, has long been a mystery and a source of debate among solar physicists.”

Fortunately, Earth’s atmosphere protects our bodies from solar flares and similar solar activity. However, these events can affect technology on Earth because they can inhibit radio communications and GPS navigation. They can reach Earth in just about eight minutes — the amount of time it takes light to travel from the Sun to our planet — so the more we understand about solar flares, the better we can prepare.

As NASA and other space agencies prepare to send crews into space, a deeper understanding of solar activity will be crucial for safety as astronauts travel without the atmosphere’s protection.

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