NASA – The Sun Is Slowly Waking Up: After Decades Of Quiet, Solar Activity Is On The Rise.

After decades of decline, the Sun is showing clear signs of increasing activity. A new NASA study, published in The Astrophysical Journal Letters in September 2025, reports that several solar indicators, such as solar wind strength, sunspot counts, coronal mass ejections (CMEs), and magnetic field measures, have been climbing steadily since about 2008. This reversal from a long lull has surprised many in the solar physics community and carries implications for space weather, technological infrastructure, and astronaut safety.

The Long Decline: What Was Expected.

From the 1980s through to 2008, a broad contraction in solar activity was observed. Sunspots, flares, the solar wind, and many metrics seemed to be trending downward. In 2008, solar activity reached what was, at that time, the weakest level on record, leading many scientists to believe that the Sun might be heading into a prolonged, historic minimum, perhaps one like the Maunder Minimum of the 17th-18th centuries.

The notion of a “grand minimum” was not unreasonable: solar cycles are known to fluctuate on ~11-year cycles, but additional longer-term patterns exist, too. Expectations, formed in part by observations of the drop in solar output, magnetic field strength, and sunspot activity, leaned toward continued quiet.

The Reversal: What Has Changed Since 2008.

The recent research by Jamie Jasinski (NASA’s Jet Propulsion Laboratory) and Marco Velli indicates that the decline ended around 2008, and since then, many indicators have increased:

• Solar wind velocity has increased by about 6%.
• Solar wind density has increased by ~26%.
• Solar wind temperature is up by about 29%.
• The strength of the interplanetary magnetic field carried by the solar wind has jumped by ~31%.

These are not just minor fluctuations; the increasing trend is persistent over multiple solar cycles. Jasinski commented: “All signs were pointing to the Sun going into a prolonged phase of low activity. So it was a surprise to see that trend reversed. The Sun is slowly waking up.”

What This Means: Solar Cycle 25, Solar Maximum, And Beyond.

We are currently in Solar Cycle 25, which officially started in December 2019.

• The peak of solar maximum in this cycle has been marked by more sunspots than early predictions anticipated.
• In May 2024, the Earth experienced one of its strongest geomagnetic storms in over 20 years. Several large flares, including multiple X-class flares, produced spectacular aurorae visible at unusually low latitudes.
• NOAA and NASA have identified that while we may have entered the active (maximum) phase of this solar cycle, determining its exact peak may take more months or even years.

The NASA study’s longer-term findings suggest that this upward trend in solar activity may persist for decades, meaning more frequent space weather events could become the “status quo.”

Potential Impacts: Technology, Space Travel, Earth.

As solar activity increases, so do potential risks from space weather:

• Satellites and spacecraft are vulnerable to damage or malfunction from increased radiation, charged particles, and magnetic disturbances.
• Astronaut safety, particularly for missions beyond low Earth orbit (e.g., Artemis program), is more challenging as exposure to solar energetic particles and cosmic rays can increase significantly.
• Power grids, radio communications, GPS systems, and satellite navigation can be disrupted by geomagnetic storms and unusual solar emissions.
• Auroras and other natural phenomena (e.g. atmospheric heating in the upper layers) are more likely to be visible at lower latitudes.

What Scientists Don’t Yet Understand:

While the evidence for increasing activity is growing, several big questions remain:

• Why did the previously declining trend reverse? The triggers for the reversal are not fully understood. The new NASA study acknowledges the long-term trends are “a lot less predictable and are something we don’t completely understand yet.”
• How strong will the upcoming cycles be? Will Solar Cycle 26 (expected sometime between 2029 and 2032) continue the upward trend or settle into a new plateau? How high will the solar maximum reach?
• What are the long-term implications for climate vs. space weather? While solar variability influences Earth’s upper atmosphere and space environment, the role of solar output in ongoing climate trends is small compared to anthropogenic greenhouse gas forcing. NASA and other scientific bodies continue to stress that solar changes, while real, are not the main driver of current global warming.

Quotes And Expert Voices:

• Jamie Jasinski, NASA Jet Propulsion Laboratory (study lead):
  “All signs were pointing to the Sun going into a prolonged phase of low activity. So it was a surprise to see that trend reversed. The Sun is slowly waking up.”
• Elsayed Talaat, NOAA’s Director of Space Weather Operations, commenting on Solar Cycle 25’s peak period, said:
  “This announcement doesn’t mean that this is the peak of solar activity we’ll see this solar cycle … While the Sun has reached the solar maximum period, the month that solar activity peaks on the Sun will not be identified for months or years.”
• Lisa Upton, heliophysicist at the Southwest Research Institute, in Scientific American on stronger cycles:
  “Solar storms — it’s a probabilistic thing, so sometimes they don’t always do what you would expect.”Also, a warning that the coming cycles may be more eventful than predictions made earlier.

Latest Developments & Missions:

To better monitor and understand these changes, agencies are rolling out or planning additional missions:

• NASA’s Solar Dynamics Observatory (SDO) continues to provide detailed imaging of sunspots, flares, and the solar atmosphere.
• NOAA and NASA’s prediction centres are refining their forecasts for the current and next solar cycles.
• Missions such as Parker Solar Probe (already flying) are giving us close-in observations of solar activity and the solar wind.

Implications & Takeaways:

• The idea that we were entering a “grand minimum” of solar activity now seems less likely; instead, an era of elevated or at least resurgent solar activity may be underway.
• Planning for space weather is more urgent, both for technological infrastructure on Earth and for human spaceflight.
• While solar activity does affect Earth, its impact on climate is modest compared to human emissions, but its effects on satellites, navigation, power grids, and astronaut health are very real and increasing.

Conclusion:

In short: after decades of decreasing activity and a deep solar minimum around 2008, the Sun has begun to “wake up.” Multiple indicators, solar wind, magnetic fields, and sunspot counts, are rising. The current Solar Cycle 25 is more vigorous than many predicted. Dawn of Solar Cycle 26 remains in the future, but taken together, the evidence suggests we may be entering a period of heightened solar activity, with associated risks for space weather. Scientists are watching closely, but many of the underlying mechanisms, especially what caused the reversal and how extreme future cycles will be, remain uncertain.