During a routine data calibration meeting in 2020, scientists working with NASA's Parker Solar Probe spotted something unexpected. Visualizations of solar wind particles revealed a bizarre, flattened shape resembling a hammerhead, rather than the typical rounded proton distribution.
The discovery challenges conventional models of how energy moves through the solar wind. These "proton sharks" may help explain why the Sun's outer atmosphere, the corona, is millions of degrees hotter than its surface—a long-standing puzzle in heliophysics.
Researchers were initially skeptical, suspecting an artifact from the probe's instruments. However, further analysis confirmed the structures were real, appearing in multiple datasets as the spacecraft made its close approaches to the Sun.
The Parker Solar Probe continues to dive deeper into the corona, gathering data that could refine theories of plasma heating. This finding suggests that complex, non-uniform processes govern the solar wind's behavior, with implications for space weather prediction.
Decoding how these hammerheads form may ultimately reveal the missing piece in the coronal heating puzzle. The team plans to trace the structures across different solar distances to understand their evolution.