Solar maximum is approaching. Here’s where and how to see the Northern Lights
Strings of aurora borealis stretch across the sky over Whitehorse, YT, on August 31, 2012. Photograph: David Cartier Sr/NASA Goddard
The green aurora is produced by oxygen molecules 100 to 300 kilometers above the Earth’s surface. Red aurora is the result of collisions with free oxygen atoms at altitudes of 300 to 400 kilometers. The pink or dark red color that appears along the lower edge of the green aurora is due to the action of nitrogen molecules during periods of particularly strong aurora activity. Nitrogen can also produce a blue aurora above, which often appears purple when combined with the red color produced by atomic oxygen. The blue and purple aurora are also attributed to hydrogen and helium atoms being impacted during these events.
Even when solar activity is minimal, letting only the solar wind affect us, we still see the aurora circumnavigating the north and south poles on a fairly regular basis.
However, the most intense and widespread aurora tend to occur when solar activity is at its peak.
Our active sun
The progress of solar cycle 24, from 2008 to 2019, is shown in this graph of sunspot counts, revealing how their numbers increased during the first half of the cycle, reaching a double peak between 2011 and 2014, and then diminishing again to a minimum. In the background, eleven different views of the Sun are shown throughout the cycle, captured by the SWAP Extreme Ultraviolet Imager on the PROBA2 satellite in Europe. Credits: NOAA SWPC chart, background image courtesy of Dan Seaton/European Space Agency/NOAA/JPL-Caltech
The solar wind is the most persistent form of “space weather” produced by the Sun. However, as an active star, the Sun also undergoes cycles of activity, each approximately 11 years long and following a similar pattern. At first, solar activity starts out relatively quiet. Over the next 5-6 years, activity peaks, with the appearance of more sunspots, and frequent and more intense solar flares. Then, while we can still see some fairly intense events during the second half of the cycle, the overall frequency and intensity of activity gradually decreases to a minimum again.
However, each solar cycle is unique. Solar cycle 24, which lasted from 2008 to 2019, was the weakest since the 19th century. The current cycle, Solar Cycle 25, was initially expected to reach a similar or even weaker maximum in 2025. However, activity so far has already exceeded those expectations, says the National Oceanic and Atmospheric Administration’s (NOAA) Space Weather Prediction Center The cycle will likely peak in 2024, a year ahead of schedule. Much stronger than originally expected. This means that there will likely be more intense and increased solar activity in the coming months.
This image of the Sun in extreme ultraviolet light was captured by the Solar Dynamics Observatory on March 30, 2022. Several examples of solar activity have been cataloged, including a powerful solar flare that exploded that day. Image credit: Scott Sutherland/NASA SDO
The most obvious signs of increased solar activity are sunspots and solar flares. Sunspots are cooler, darker areas of the Sun’s surface exposed to space by entangled magnetic fields. When these entanglements suddenly break apart, they cause an intense burst of energy, ultraviolet radiation, and X-rays that we call a solar flare. Typically, the more severe the entanglements, the more intense the resulting glow.
(tags for translation) Space