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Maunder Minimum

The Maunder Minimum was a prolonged period of exceptionally low solar activity, characterized by a drastic reduction in sunspot numbers and nearly absent cyclic variations, spanning from approximately 1645 to 1715.^[1] This grand solar minimum, the only one directly observed through telescopic records, was noted in 1894 by British astronomer Edward Walter Maunder, who analyzed historical sunspot observations from the 17th and early 18th centuries and presented his findings to the Royal Astronomical Society.^[2] Building on earlier work by German astronomer Gustav Spörer, Maunder noted that sunspots were exceedingly rare during this interval, with annual group sunspot numbers often below 5, compared to typical values of 50–100 in modern cycles.^[2]^[1] The event's significance lies in its insights into solar dynamo behavior, revealing a mode where magnetic activity is suppressed for decades, as evidenced by corroborating data from cosmogenic isotopes like carbon-14 in tree rings and beryllium-10 in ice cores, which indicate a reduction in total solar irradiance of approximately 2–3 W/m² compared to modern values.^[1]^[3]^[4] It coincided with the Little Ice Age, a cooler climatic phase in the Northern Hemisphere from roughly 1300 to 1850, particularly evident in Europe through harsher winters and Thames River freezes, though reconstructions show the cooling began before 1645 and was more strongly influenced by volcanic eruptions than solar forcing alone.^[3] Fewer auroral sightings and weakened geomagnetic activity during this time further underscore the diminished heliospheric output.^[1] Modern studies, including those using sunspot group reconstructions from diaries and eclipse drawings, confirm the Maunder Minimum as a benchmark for understanding rare grand minima, which occur about once every 400–500 years based on Holocene records, with implications for space weather forecasting and long-term solar variability. Recent 2025 studies further indicate that a similar minimum would not substantially offset modern global warming.^[1]^[3]^[5]

Historical Background

Discovery and Naming

The period of anomalously low solar activity spanning much of the 17th century was first systematically identified by German astronomer Gustav Spörer in 1887, based on his compilation and analysis of historical sunspot observations from 1618 to 1874. Spörer's work revealed a striking scarcity of recorded sunspots during this interval, contrasting sharply with more active periods before and after, and he published his findings in the Vierteljahrsschrift der Astronomischen Gesellschaft. This analysis drew on fragmentary records from early telescopic observers, highlighting the unusual nature of the phenomenon without yet attributing a specific name to it. Building on Spörer's insights, English astronomer Edward Walter Maunder further compiled and popularized the discovery in 1890 through his paper "Professor Spörer's Researches on Sun-Spots," published in the Monthly Notices of the Royal Astronomical Society. Maunder integrated data from prominent 17th-century astronomers such as Johann Hevelius, who observed from 1642 to 1679, and Christoph Scheiner, whose records covered 1611 to 1631, to demonstrate the prolonged dearth of sunspots. His efforts emphasized the global consistency of the low activity across European observations, solidifying the historical significance of the event.^[6] In 1894, Maunder extended this work with a detailed discussion of the prolonged sunspot minimum, published in Knowledge. The era of diminished sunspot activity was formally termed the "Maunder Minimum" in 1976 by American astronomer John A. Eddy, in recognition of Edward Maunder's pivotal role in its documentation and analysis, distinguishing it from the earlier Spörer Minimum (circa 1460–1550), which Spörer had also delineated through similar historical scrutiny. This naming honors the late-19th-century efforts that brought the phenomenon to scientific prominence. Overall sunspot numbers during the period remained exceptionally low, often near zero for extended years.

Time Frame and Definition

The Maunder Minimum encompasses a period of exceptionally low solar activity spanning approximately 1645 to 1715, a duration of about 70 years. This interval is recognized as a grand solar minimum, defined by the prolonged and severe suppression of the Sun's approximately 11-year activity cycle, during which sunspot formation was dramatically reduced due to a special dynamical state of the solar magnetic field.^[1] In contrast to typical solar cycles, the Maunder Minimum featured an amplitude reduction approaching zero, yet evidence indicates the persistence of weak underlying cyclic variations, distinguishing it as an anomalous regime rather than a mere temporary lull.^[1]^[7] Sunspot records from this era reveal the extent of the suppression: over the entire period, annual group sunspot numbers rarely exceeded 5 to 15, far below the levels observed in modern cycles where such numbers often reach hundreds per year.^[1] Notably, during the core low-activity phase from 1672 to 1699—a 28-year span—fewer than 50 sunspots were documented in total, compared to the 40,000 to 50,000 sunspots that occur across equivalent durations in contemporary solar cycles.^[8] This near-absence of sunspots underscores the grand minimum's classification, as it represents a global diminishment in magnetic activity rather than localized or short-term fluctuations.^[1] The Minimum unfolded in distinct sub-phases, beginning with a gradual onset around 1645, preceded by lengthened solar cycles that signaled the transition to diminished activity.^[9] The deepest suppression occurred from the 1670s to the 1690s, aligning with the aforementioned core period of minimal sunspot visibility, before a progressive recovery commenced around 1700, culminating in the restoration of more typical cycle amplitudes by 1715.^[1]^[10] This phased progression highlights the Minimum's character as a sustained dynamo irregularity, with the weak cycles maintaining a subdued rhythm throughout.^[7]

Observations of Solar Activity

Sunspot Records

The Maunder Minimum was characterized by direct telescopic observations of sunspots that revealed an extraordinarily low level of solar activity, with records indicating that during the 28-year period 1672–1699 within the minimum, observations revealed fewer than 50 sunspots.^[11] Key observers included Johann Hevelius in Danzig, who documented sunspots intermittently from 1653 to 1684, recording 19 groups.^[12] Jean Picard in Paris provided extensive observations from 1653 to 1659 over 2,352 days, mostly reporting no sunspots, while Giovanni Cassini, also based in Paris, contributed detailed drawings in 1671 and 1701 that captured rare complex spot structures.^[1] These efforts, among a handful of European astronomers, formed the primary dataset, as systematic monitoring was limited to a few dedicated sites. Despite the overall scarcity, faint remnants of the typical 11-year solar cycle persisted, with weak maxima identified around the 1650s (notably 1657), 1676–1677, 1684, and 1705, followed by near-zero minima that suppressed activity to negligible levels.^[13] Annual sunspot numbers during the core phase (roughly 1645–1700) averaged less than 1, contrasting sharply with modern cycle averages of 40–100, and specific tallies from 1672 to 1703 ranged from 0 to 5 per year.^[12] Group sunspot numbers, a proxy for activity, remained below 5 annually in conservative estimates, underscoring the anomalously quiet solar surface.^[1] Historical records faced significant challenges that contributed to inconsistencies, including the aftermath of the Thirty Years' War (1618–1648), which caused political instability and disrupted scientific continuity across Europe, particularly in German-speaking regions.^[14] Additionally, early 17th-century telescopes had resolution limits that hindered detection of small or faint sunspots, leading to potential underreporting, as evidenced by gaps when observers like Picard and Cassini noted none while others sporadically did.^[12] These factors, combined with irregular observation schedules, highlight the fragmentary nature of the data but confirm the period's profound solar quiescence through the surviving accounts.^[1]

Eclipse and Coronal Observations

During the Maunder Minimum, total solar eclipses provided rare opportunities to observe the Sun's corona, revealing characteristics consistent with suppressed solar activity. The total eclipse of May 12, 1706, observed from multiple sites in Europe including Nürnberg, Zürich, and Montpellier, showed a faint, structureless halo-shaped corona lacking prominent streamers or radial features.^[10] Drawings by observers such as Maria Clara Eimmart, Johann Meyer, and Johann Melchior Füssly depicted a uniform pale glow extending to about 0.5 solar radii, interpreted as dominated by the featureless F-corona due to minimal K-corona scattering from a weakened magnetic field.^[10] Accounts from Montpellier by Jean de Clapiès and Louis de Plantade similarly described a dim, amorphous luminous ring without detectable structure, aligning with the low sunspot numbers recorded around this time.^[10] The total eclipse of May 3, 1715, visible across England, offered further evidence of evolving but still subdued coronal activity. Edmond Halley, observing from London, noted a pearly white corona of subdued intensity, while sketches by Roger Cotes from Cambridge illustrated a luminous ring with irregular cross-like extensions, suggesting the emergence of weak streamer structures amid overall dimness.^[10] These features extended to 0.24–0.28 solar radii and appeared asymmetric, contrasting with the entirely uniform appearance of 1706 but still far less pronounced than in periods of normal solar activity.^[10] Historical records from the Maunder Minimum indicate fewer detailed reports of total eclipses, partly due to limited observations, but those available consistently highlight reduced prominence and streamer activity in the corona. A modern analysis of these accounts, including graphical records, confirms the corona's faint and amorphous nature, with no evidence of the extended, dynamic structures typical of active solar phases.^[10] This points to suppressed dynamics in the solar atmosphere, driven by low magnetic activity and reduced solar wind, as the open magnetic flux remained exceptionally weak throughout the period.^[10]

Broader Astronomical Evidence

Proxy Data from Cosmogenic Isotopes

Proxy data from cosmogenic isotopes provide indirect evidence for the low solar activity during the Maunder Minimum (approximately 1645–1715) by recording increased galactic cosmic ray (GCR) flux reaching Earth's atmosphere. During periods of reduced solar magnetic activity, the heliospheric magnetic field weakens, allowing more GCRs to penetrate and interact with atmospheric constituents, thereby enhancing the production of isotopes such as carbon-14 (¹⁴C) and beryllium-10 (¹⁰Be). These isotopes are archived in tree rings and polar ice cores, respectively, offering a long-term record that complements sparse direct observations like sunspot counts.^[15] Elevated ¹⁴C levels in annual tree rings, measured via accelerator mass spectrometry, show a peak during 1650–1710, with an increase of approximately 0.5–1% above baseline values, anti-correlating with reconstructed solar activity. This signature arises because ¹⁴C, produced primarily by neutron capture on nitrogen-14 in the upper atmosphere, has a longer effective lifetime (about 1,000 years due to carbon cycle mixing), damping short-term production changes into a smoother record. Studies of cedar and pine samples from Japan and Europe confirm this elevation, demonstrating persistence of solar modulation even during the minimum.^[16]^[15] Similarly, ¹⁰Be concentrations in ice cores from Greenland (e.g., Dye-3, GRIP) and Antarctica (e.g., Dome C) exhibit fluxes up to 20% higher than modern baselines during the same interval, reflecting a more direct response to GCR intensity due to ¹⁰Be's short atmospheric residence time (1–2 years). This isotope forms through spallation of oxygen and nitrogen by high-energy protons and is deposited via precipitation, with minimal post-depositional alteration in polar regions. The ¹⁰Be signal aligns closely with the ¹⁴C record, supporting a consistent picture of enhanced cosmic ray influx.^[17] These proxy records have been calibrated against historical sunspot data from the late 17th century, where available, and extend the evidence for the Maunder Minimum's grand minimum status beyond the era of telescopic observations, revealing residual 11- and 22-year cycles in isotope production. Cross-verification between ¹⁴C and ¹⁰Be datasets, accounting for minor climate influences on deposition, strengthens their reliability as indicators of heliospheric field strength.^[16]^[15]

Auroral and Geomagnetic Records

During the Maunder Minimum, historical records of auroral activity indicate a marked reduction in frequency and intensity of aurorae borealis visible in Europe, consistent with diminished solar-terrestrial interactions driven by weakened solar magnetic output.^[18] Observations from mid-latitudes, such as those compiled by de Mairan, document only about 60 auroral events between 1645 and 1698, far fewer than expected during periods of typical solar activity.^[19] This scarcity persisted notably in the 1670s through 1690s, with astronomers like Cassini reporting rare and feeble sightings, such as a dim event in 1687, despite favorable viewing conditions at sub-auroral latitudes.^[19] Key European annals further underscore this trend, particularly from Scandinavian sources where auroral visibility is typically high. Danish records, summarized by Anderson in 1746, describe aurorae as uncommon prior to 1730, with sparse mentions during the 1650–1700 interval.^[19] Similarly, Swedish chronicles, including early 18th-century notes by Celsius, highlight the rarity of displays before a post-1716 resurgence, aligning with broader Nordic accounts of diminished northern lights over the period.^[19] These observations reflect reduced geomagnetic disturbances linked to lower solar wind pressure, as inferred from proxy reconstructions of heliospheric conditions.^[20] Geomagnetic records from the era, derived from early compass variations and historical magnetometer precursors, reveal correspondingly subdued activity. Sunspot-correlated magnetic storms were infrequent, with overall variability estimated at approximately 28% of modern levels, indicating a profound quieting of Earth's magnetosphere.^[20] This reduced geomagnetic response underscores the era's overall solar magnetic field weakness, which limited particle influx to polar regions.^[20] Despite the general suppression, isolated instances of more prominent aurorae occurred, suggesting incomplete diminishment of solar activity. For example, a vivid display in 1707, noted by the astronomer Kirch, exhibited characteristics typical of moderate solar wind events, providing a contrast to the prevailing scarcity.^[19]

Climate Connections

Association with the Little Ice Age

The Little Ice Age was a period of regional cooling that extended from approximately 1300 to 1850, during which Northern Hemisphere temperatures were about 0.5–1°C below the long-term average.^[21] This cooling episode featured multiple phases of colder conditions, with the most pronounced lows occurring between 1650 and 1710, coinciding precisely with the Maunder Minimum. The temporal alignment suggests a possible link between reduced solar activity and the intensified chill of this era's final, most severe stage.^[21] During the Maunder Minimum, total solar irradiance is estimated to have decreased by about 0.24%, equivalent to roughly 0.82 W/m² lower when averaged over Earth's surface.^[22] This reduction in incoming solar energy is thought to have contributed to a global cooling of 0.1–0.3°C, providing a modest but sustained forcing amid the broader Little Ice Age dynamics. Regional climate records underscore this impact; for instance, the Central England Temperature series indicates some of the lowest readings of the period in the 1690s, with annual means dropping below 8°C during several harsh winters. Similarly, severe frosts enabled frost fairs on the River Thames in London during the winters of 1683–1684 and 1707–1709, events that highlighted the exceptional cold gripping Europe.^[23] While solar variability offered a consistent driver over decades, the Little Ice Age cooling was multifaceted, overlapping with clusters of volcanic eruptions in the 1690s that injected aerosols into the atmosphere and amplified short-term temperature drops.^[24] Nonetheless, the prolonged low solar output during the Maunder Minimum likely played a key role in sustaining the colder conditions across this phase.^[3]

Debates on Causal Links

The debate over causal links between the Maunder Minimum and Little Ice Age (LIA) cooling centers on whether reduced solar activity was a primary driver or merely a contributing factor amid other influences. Proponents of strong solar influence argue that the period's diminished total solar irradiance (TSI), estimated at about 0.3 W/m² below levels a century later, directly lowered global temperatures by altering atmospheric heating.^[25] Additionally, the Svensmark hypothesis posits that low solar activity weakened the heliosphere, allowing more galactic cosmic rays to penetrate Earth's atmosphere, ionize air particles, and form cloud condensation nuclei, thereby increasing low-level cloud cover and enhancing albedo-induced cooling—potentially amplifying the TSI effect by up to 1–2 W/m² in radiative forcing during the Maunder era. Counterarguments, as outlined in the IPCC's Fifth Assessment Report (AR5), emphasize that solar forcing during the Maunder Minimum was too weak—contributing only about 10–20% of the total natural radiative forcing—to account for the observed LIA cooling, with primary drivers being explosive volcanism and internal climate variability such as ocean-atmosphere oscillations.^[26] Climate model simulations support this view, showing that solar forcing alone produces only modest Northern Hemisphere cooling of 0.1–0.2 K, insufficient to match proxy-reconstructed amplitudes of 0.5–1 K, whereas combining solar reductions with volcanic aerosol injections explains approximately 0.4 K of the drop through enhanced shortwave reflection.^[3] These models, including the CESM Last Millennium Ensemble, further indicate that LIA cooling began before the Maunder Minimum's onset around 1645, underscoring the role of pre-existing volcanic clusters in initiating the trend.^[3] Societal impacts attributed to this cooling period include widespread droughts and crop failures in 17th-century Europe, where harsh winters and wet summers from 1640–1700 led to harvest shortfalls, famine, and population declines in regions like Silesia and Estonia, though political instability from the Thirty Years' War compounded these effects.^[14] In China, the Ming Dynasty faced similar crises, with prolonged droughts in the 1640s triggering rice crop failures, social unrest, and contributing to the dynasty's collapse in 1644, intertwined with governance failures and military pressures.^[27] Attribution remains mixed, as historical records suggest that while climatic extremes exacerbated vulnerabilities, human factors like poor agricultural policies often determined the severity of outcomes.^[27]

Theoretical Explanations

Solar Dynamo Irregularities

The solar dynamo operates through the interaction between the tachocline—a thin shear layer at the base of the convection zone—and convective motions in the overlying convection zone, where differential rotation shears poloidal magnetic fields into toroidal ones (the omega effect), while helical convection regenerates poloidal fields from toroidal ones (the alpha effect).^[28] This alpha-omega dynamo mechanism sustains the roughly 11-year solar cycle of magnetic activity.^[28] During grand minima like the Maunder Minimum, irregularities in this process lead to suppressed activity, characterized by a weakened conversion of poloidal to toroidal fields, which causes the amplitude of the magnetic cycle to collapse. In flux-transport dynamo models, such suppression can arise from reduced poloidal field generation or a slowdown in meridional circulation, which normally transports the poloidal field poleward and aids cycle regeneration; a weakened meridional flow allows greater diffusive decay of the poloidal field, preventing recovery to normal amplitudes.^[29] These intrinsic dynamo failures result in prolonged low-activity states, consistent with the near-absence of sunspots observed during the Maunder Minimum.^[30] Solar cycle anomalies during the Maunder Minimum included both lengthened and shortened periods, reflecting dynamo instability. Reconstructions indicate cycles extended to approximately 14 years, linked to slowed meridional circulation that delays field advection and regeneration.^[9] Conversely, auroral records reveal evidence of shortened cycles averaging about 8 years, possibly due to accelerated meridional flows or enhanced diffusion altering wave propagation speeds in the dynamo.^[7] Alpha-omega dynamo models simulate these as phases of grand minima, where stochastic perturbations push the system into low-activity regimes lasting decades.^[31] The mathematical framework for these irregularities builds on Parker's dynamo equations, which describe the evolution of mean magnetic fields through coupled partial differential equations for poloidal (A) and toroidal (B) components:

\frac{\partial A}{\partial t} = \alpha B + \eta \nabla^2 A,

\frac{\partial B}{\partial t} = \beta \frac{\partial A}{\partial \theta} + \eta \nabla^2 B,

where \alpha is the alpha effect, \beta relates to differential rotation, \eta is magnetic diffusivity, and \theta is latitude; adaptations incorporate stochastic fluctuations in \alpha or meridional flow speeds, leading to intermittent dynamo wave quenching.^[31] Such models predict a low probability for entering grand minima states over typical cycle timescales, aligning with the rarity of events like the Maunder Minimum in solar history.^[32]

Proposed Triggers and Mechanisms

Several hypotheses have been proposed for the initiation and sustenance of the Maunder Minimum, focusing on internal solar dynamo processes and potential external influences. Internal triggers often involve stochastic fluctuations in the dynamo mechanism, such as noise in the poloidal field generation that can push the system into a sub-critical regime, leading to suppressed activity over multiple cycles.^[33] Hemispheric asymmetries, where sunspot activity is predominantly confined to one solar hemisphere with imbalanced polarity strengths, have been identified as a key feature during the event, particularly evident from the 1670s onward when observations showed a clear trend of asymmetry that may have contributed to the prolonged low state.^[30] For instance, dynamo models incorporating Babcock-Leighton flux transport demonstrate that random variations in active region tilt angles can spontaneously produce grand minima-like episodes characterized by such asymmetries.^[34] External factors, while more controversial, include potential influences from planetary tidal forces. Reconstructions of planetary alignments during the Maunder Minimum suggest that combined gravitational perturbations from Jupiter and Saturn could have modulated solar activity, possibly by altering convection patterns in the tachocline.^[35] Studies of tidal effects from Venus, Earth, and Jupiter have indicated correlations with solar cycle variations, supporting the idea that these forces might synchronize or amplify dynamo irregularities, though this remains debated as a primary driver.^[36] Other proposed external mechanisms, such as interference from the interstellar magnetic field weakening the heliospheric shield, have been hypothesized to exacerbate low-activity states but lack strong observational consensus.^[37] The recovery from the Maunder Minimum is attributed to the inherent memory of the solar dynamo, where residual polar fields gradually rebuild through diffusive processes and stochastic forcing, allowing the system to transition back to normal cycles. A 2025 study using stochastically forced dynamo simulations estimates recovery timescales from similar grand minima at approximately 50–100 years, independent of the onset rate and tied to achieving a critical polar flux threshold.^[38] Despite these models, no consensus exists on the exact onset trigger for the Maunder Minimum, with simulations indicating it likely required a rare alignment of multiple factors, including amplified stochastic noise and hemispheric imbalances, to sustain the grand minimum state.^[39]

Contemporary Research

Recent Reconstructions

Recent advancements in proxy data have refined our understanding of the Maunder Minimum's onset and internal dynamics. A 2021 study utilizing high-precision radiocarbon (¹⁴C) measurements from tree rings demonstrated a gradual lengthening of the 11-year solar cycles in the decades prior to the minimum's start around 1645 CE, indicating a progressive decline in solar activity rather than an abrupt shift.^[9] Similarly, analysis of historical equatorial aurora records in 2023 provided evidence for an 8-year solar cycle persisting during the Maunder Minimum, linked to sporadic sunspot activity near the solar equator, challenging earlier assumptions of complete cycle suppression.^[7] Simulations incorporating these updated proxies have explored the minimum's broader environmental effects. A 2025 study in National Science Review reconstructed rainfall patterns in East Asia during the period, revealing a prolonged drought lasting nearly a century, with cascading societal impacts in the Joseon dynasty, attributed to reduced solar forcing.^[40] Meanwhile, Phase 4 of the Paleoclimate Modelling Intercomparison Project (PMIP4) has integrated solar irradiance reductions with volcanic aerosol forcings in last-millennium simulations, showing that combined external forcings amplified cooling during the Maunder Minimum by modulating global temperature responses beyond solar effects alone.^[41] Efforts to identify stellar analogs have expanded using large spectroscopic surveys. In 2025, researchers analyzed RAVE (Radial Velocity Experiment) spectra to search for Sun-like stars exhibiting Maunder Minimum-like low activity states, identifying several candidates with suppressed chromospheric emission indicative of grand minima phases.^[42] Methodological innovations have enhanced data accessibility and precision. Machine learning techniques, combining convolutional and recurrent neural networks, have been applied to digitize handwritten historical solar observation records, facilitating more accurate catalogs of sunspot occurrences during low-activity epochs like the Maunder Minimum.^[43] Refined total solar irradiance (TSI) reconstructions, drawing on these digitized datasets and proxy integrations, estimate variability of 0.1–0.4% during the minimum relative to modern levels, providing benchmarks for model validations.^[44]

Implications for Modern Climate and Solar Predictions

Studies of the Maunder Minimum provide critical insights into the potential for grand solar minima in the current Solar Cycle 25, which began in December 2019 and reached its smoothed maximum in October 2024 with a sunspot number of 160.9, indicating stronger than initially predicted activity.^[45]^[46] The unexpectedly robust Cycle 25 further supports the low risk of an imminent grand minimum. Dynamo models suggest the risk of a Maunder-like grand minimum occurring is low, on the order of 7% of solar cycles exhibiting conditions conducive to such events, or roughly 1 in 14 cycles, far from a frequent occurrence.^[47] The Maunder Minimum's historical cooling effects inform assessments of future solar minima's role in global climate, as outlined in the IPCC's Sixth Assessment Report (AR6), which emphasizes that variations in solar irradiance during grand minima contribute minimally to long-term climate trends compared to anthropogenic forcings.^[48] A simulated Maunder-like minimum with a 0.25% reduction in total solar irradiance could induce a global cooling of about 0.09°C by 2070, a modest offset against projected anthropogenic warming of 1–5°C by the end of the century.^[49] Ensemble dynamo simulations have advanced predictive capabilities for solar activity recovery following minima, incorporating data assimilation techniques like the Ensemble Kalman Filter to forecast Cycle 25's progression and subsequent cycles with reduced uncertainty. Recent 2025 research explores interactions between elevated CO₂ levels and solar minima, modeling scenarios where a prolonged low-activity period coincides with rising greenhouse gases, revealing amplified stratospheric cooling but limited surface temperature reversal in the Southern Hemisphere and select Northern Hemisphere regions.^[5] Beyond climate, the Maunder Minimum highlights space weather implications of grand minima, including reduced solar flares and coronal mass ejections, which could lower risks to satellites and power grids during such periods.^[1] Analogies to the Dalton Minimum (1790–1830), a shallower event with elevated cosmic ray fluxes compared to modern minima, aid in calibrating historical models for contemporary predictions, underscoring the variability in minimum depth and duration.^[50]

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Modern Grand Solar Minimum will lead to terrestrial cooling - PMC
Aug 4, 2020 · The most recent grand solar minimum occurred during Maunder Minimum (1645–1710), which led to reduction of solar irradiance by 0.22% from the ...
[37]
Recovery of the Solar Cycle from Maunder-like Grand Minima ... - arXiv
May 13, 2025 · We find that the duration of a grand minimum is independent of the onset rate and does not affect the recovery rate. Our results suggest a ...Missing: dynamics 50-100
[38]
Models for the long-term variations of solar activity
Jun 26, 2023 · Grand minima are the extended episodes of considerably lower magnetic activity than the normal one. The best example of these is the Maunder ...
[39]
Cascading impacts of the Maunder Minimum on rainfall and society ...
Jul 12, 2025 · Here we quantitatively reconstruct the rainfall patterns, revealing a rare, nearly century-long drought around the MM, accompanied by decadal ...
[40]
A search for Maunder-minimum candidate stars
RAVE fluxes appear higher than the STELLA and PEPSI fluxes by on average 19% for IRT-1, 21% for IRT-2, and 25% for IRT-3 due to their lower spectral resolution.
[41]
Machine learning for digitization of historical records of solar activity
We present a machine-learning model based on a combination of convolutional and recurrent neural networks (CRNN) trained to recognize sequential textual data ( ...Missing: Minimum | Show results with:Minimum
[42]
Magnitudes and timescales of total solar irradiance variability
Jul 25, 2016 · Note that TSI fluctuations of approximately 0.1% are in phase with activity over the 11-year solar cycle, as indicated by sunspot numbers.
[43]
Solar Cycle Progression - Space Weather Prediction Center - NOAA
The Prediction Panel predicted Cycle 25 to reach a maximum of 115 occurring in July, 2025. The error bars on this prediction mean the panel expects the cycle ...
[44]
Origin of Grand Minima in Sunspot Cycles | Phys. Rev. Lett.
Oct 25, 2012 · This period is known as the Maunder minimum [1] . Although reliable sunspot data did not exist before 1610, the solar activity at earlier ...Missing: frame | Show results with:frame
[45]
Could a future “Grand Solar Minimum” like the Maunder Minimum ...
Mar 18, 2013 · [1] A future Maunder Minimum type grand solar minimum, with total solar irradiance reduced by 0.25% over a 50 year period from 2020 to 2070, ...
[46]
Would the occurrence of a Maunder-like solar minimum reverse the ...
Jan 1, 2025 · This study examines a scenario combining a prolonged solar minimum, like the historical Maunder Minimum, with the increased CO2 emissions ...
[47]
Comparison of the extended solar minimum of 2006–2009 with the ...
Mar 19, 2014 · The inferred cosmic ray intensities during the Spoerer, Maunder, and Dalton Grand Minima were significantly greater than those during 2006–2009.