NASA’s Solar Dynamics Observatory captured a stunning image of a rare phenomenon which some scientists say is a sure sign of the oncoming solar minimum. The solar minimum is a regularly-occurring phase of the solar cycle which marks a low point in solar activity. That means solar flares and sunspots reach their lowest point, causing all sorts of changes to weather patterns and even a decline in auroras. SpaceWeather.com has published NASA’s images of the bizarre-looking blank sun, noting that this is the thirty-first day of a Sun with no spots. The image might look like nothing like a computer-generated yellowish circle, but it is actually a white-light image of the sun.
The increasing occurrence of blank sons has some astronomers suspecting that we might even currently be experiencing a solar minimum. Determining the exact dates of a solar minimum can be tricky because identifying a minimum requires a longitudinal study of average solar activity. In other words, we might not know for sure that a solar minimum has occurred until months after it ends.
Aside from decreased aurora activity and sunspots, the solar minimum can lead to dangerous levels of radiation in the Earth’s atmosphere, potentially posing a threat to frequent airline travelers. A recent study by University of Colorado astrophysicists noted that this particular solar cycle appears to be one of the weakest since the dawn of the aviation age, meaning any possible effects on air travelers is still unknown:
[...] Perhaps the most important to aircrews and over-the-pole frequent flyers, we are entering a phase of the solar cycle (solar minimum) when solar activity naturally calms, allowing GCRs [(galactic cosmic rays)] easy access to Earth. Since the Sun has recently been less active than in previous solar cycles the upcoming solar minimum is expected to be deep [...] With the forecast for reduced solar magnetic activity in the near term, frequent flyers can expect an uptick in radiation exposure.
The Earth and Sun might each be over 4.5 billion years old, but humankind has only been taking scientific measurements of the interactions between the two for a few hundred years, if that. We have extrapolated data based on radiation levels of geologic samples, but there is still much we don't know about the Sun's activity.
Already, scientists and astronomers have found evidence of solar anomalies deep in the Earth’s past which allowed high levels of radiation to bombard the planet. Another period of irregularly-low solar activity could mean bad news for your smartphone and maybe even marine animals, which some studies have found to die in large numbers whenever solar activity reaches low points. It sure is a mysterious universe.