Tag: solar cycle

Scientists: Neptune’s clouds appear to ebb and grow in conjunction with sunspot cycle

9:24 am

Graph showing correlation between Neptune's clouds and the sunspot cycle

Scientists have now discovered what appears to be a link between the coming and going of clouds on Neptune to the Sun’s 11-year-long sunspot cycle, despite Neptune receiving only 1/900th the sunlight of the Earth.

To monitor the evolution of Neptune’s appearance, Chavez and her team analyzed images taken from 1994 to 2022 using Keck Observatory’s second generation Near-Infrared Camera (NIRC2) paired with its adaptive optics system (since 2002), as well as observations from Lick Observatory (2018-2019) and the Hubble Space Telescope (since 1994). In recent years the Keck Observatory observations have been complemented by images taken as part of Keck Observatory’s Twilight Observing Program and by Hubble Space Telescope images taken as part of the Outer Planet Atmospheres Legacy (OPAL) program.

The data revealed an intriguing pattern between changes in Neptune’s cloud cover and the solar cycle – the period when the Sun’s magnetic field flips every 11 years, causing levels of solar radiation to fluctuate. When the Sun emits more intense ultraviolet (UV) light, specifically the strong hydrogen Lyman-alpha emission, more clouds appear on Neptune about two years later. The team further found a positive correlation between the number of clouds and the ice giant’s brightness from the sunlight reflecting off it.

“These remarkable data give us the strongest evidence yet that Neptune’s cloud cover correlates with the Sun’s cycle,” said de Pater. “Our findings support the theory that the Sun’s UV rays, when strong enough, may be triggering a photochemical reaction that produces Neptune’s clouds.”

The graph to the right shows the correlation between the clouds and the sunspot cycle. The paper is available here.

This conclusion remains uncertain because of the overall sparseness of the data. Yet, it is intriguing, and also underlines the importance of the Sun on the Earth’s climate. If the solar cycle can impact Neptune’s climate so significantly from 2.8 billion miles away, it certainly must have a major impact on the Earth’s climate at only 100 million miles distance.

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Sunspot update: In July the Sun continued its high sunspot activity

5:05 pm

Today NOAA released its monthly update of its graph that tracks the number of sunspots on the Sun’s Earth-facing hemisphere. As I have done every month for the entire thirteen years I have been doing this website, I have posted that updated graph below, adding to it some extra details to provide some context.

Though the sunspot count in July was slightly less than the very high numbers in June (the highest seen in more than two decades), the decline was almost inconsequential. Except for June’s activity, the activity in July was still the highest sunspot count in a month since September 2002, when the Sun was just beginning its ramp down after its solar maximum that reached its peak in late 2001. From that time until the last two months, the Sun had been in a very prolonged quiet period, with two solar minimums that were overly long and a single solar maximum that was very weak with a extended double peak lasting almost four years.
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Sunspot update: June saw the most sunspots in more than two decades

8:47 pm

Time for our monthly sunspot update, based on NOAA’s monthly graph that tracks the number of sunspots on the Sun’s Earth-facing hemisphere. I have posted that graph below, but have added some extra details to provide some context.

June saw the highest sunspot count in a month since September 2002, when the Sun was just beginning its ramp down after its solar maximum that reached its peak in late 2001. From that time until now, the Sun has been in a very prolonged quiet period, with two solar minimums that were overly long and a single solar maximum that was very weak with a extended double peak lasting almost four years.
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Sunspot update: May activity once again far above prediction

5:06 pm

With the start of the month it is time once again for our monthly sunspot update, based on the new data that NOAA today added to its own monthly graph that tracks the number of sunspots on the Sun’s Earth-facing hemisphere. I have posted that graph below, but have added some extra details to provide some context.

In May the number of sunspots zipped upward again, ending up at the second highest monthly count during this ramp up to solar maximum, and the second highest count since the last solar maximum in 2014.
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Sunspot update: April activity drops steeply

2:19 pm

NOAA this week once again published an update of its monthly graph that tracks the number of sunspots on the Sun’s Earth-facing hemisphere. As I do every month, I have posted this graph below, with some additional details included to provide some context.

In April the number of sunspots dropped again, for the second time in the past three months. The high activity previously had suggested that the solar maximum was going to be much higher than predicted, or possibly would come sooner than expected. The drop however now suggests that the fast rise in sunspot activity that we have seen since the beginning of the ramp up to solar maximum in 2020 might finally be abating.
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Scientists predict solar maximum to arrive one year early

9:39 am

The scientists whose prediction of a more active upcoming solar maximum that has so far turned out more accurate than the consensus prediction have now updated their prediction, lowering it somewhat but also predicting the maximum will occur one year early, in 2024 instead of 2025.

The team’s finalized forecast for the current cycle expects it to peak in late 2024, one year earlier than NASA and NOAA had predicted. The cycle, the team thinks, will reach about 185 monthly sunspots during its maximum and thus be somewhat milder than what the team originally forecasted. This peak intensity will place this cycle at about the average compared to the historical record.

In other words, now that we are about halfway to maximum, they have concluded that while NOAA’s prediction was too low, their prediction was too high. They have now adjusted their expectations to be closer to what they now think will happen.

A short solar cycle however has historically corresponded to much higher sunspot activity. If this new prediction is correct (a short cycle with a mild maximum), it will mean that the Sun is still behaving in ways that the solar science community does not understand, or can predict.

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Sunspot update: Activity remained high in March

12:35 pm

It is time for my monthly sunspot update. NOAA this week updated its graph that tracks the number of sunspots on the Sun’s Earth-facing hemisphere. This graph is posted below, with some additional details included to provide some context.

Last month the number of sunspots dipped slightly after a gigantic leap of activity in January. This month showed a small rise in activity, but not enough to bring levels back to the January’s levels. Nonetheless, activity remains the highest seen since 2014. when the last solar maximum was approaching its end, and continues to exceed significantly the 2020 prediction by NOAA’s panel of solar scientists.
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Sunspot update: After going through the roof last month, sunspots drop into the attic this month

11:05 am

With the start of another month NOAA this week updated its graph that tracks the number of sunspots on the Sun’s Earth-facing hemisphere. As I do every month, I have posted that updated graph below, adding some additional details to provide some context.

Last month the number of sunspots rocketed upward to the highest seen since 2014, and only the second time since November 2002 that the Sun was that active. In February those high numbers dropped, though the sunspot activity during the month remained well above the 2020 prediction by NOAA’s panel of solar scientists.

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Sunspot update: The most sunspots since 2014

9:26 am

Time for my monthly sunspot update, based on NOAA’s monthly graph that tracks the number of sunspots on the Sun’s Earth-facing hemisphere. The newest graph, with December’s numbers added to the timeline, is below. As always, I have added some additional details to provide context.

In December the half-year pause in the ramp up to solar maximum ceased, with the Sun seeing the most sunspots since September 2014. This high activity far exceeded the predicted sunspot count for December 2023, almost doubling it. In fact, December’s sunspot count almost equaled the predicted peak for the upcoming solar maximum, which is not supposed to happen until sometime in 2025.

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Sunspot update: The Sun’s unprecedented pause to maximum continues

9:44 am

It is the beginning of the month, and NOAA has once again published its update of its monthly graph that tracks the number of sunspots on the Sun’s Earth-facing hemisphere. Below is the newest graph, adding November’s numbers to the timeline and annotated by me with some additional details added to provide context.

Sunspot activity dropped in November, though still remained significantly higher than the prediction, a sunspot number of 77.6 compared to the predicted number of 57.4. At 77.6, the Sun continues the pause that began in June in the ramp up to solar maximum. For the past half year the Sun’s sunspot output has essentially stalled at approximately the same level.

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Sunspot update: The pause in the ramp up to solar maximum continues

11:34 am

NOAA has once again published its monthly update of its monthly graph that tracks the number of sunspots on the Sun’s Earth-facing hemisphere. Below is that November graph, annotated by me with some additional details added to provide context.

Though sunspot number continued to be much higher than the prediction (almost double), October saw almost exactly the same number of sunspots as seen in September, which is why this new graph seems almost identical to last month’s.

In other words, the pause in the ramp up to solar maximum, first noted in August, continues.
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Sunspot update: Activity again exceeds prediction but ramp up pauses

11:29 pm

NOAA this weekend published, as it does at the start of every month, its October update of its monthly graph that tracks the number of sunspots on the Sun’s Earth-facing hemisphere. As I have done since I started this website in 2011, I have published that graph below, with some additional details added to provide context.

An increase in sunspot activity in September wiped out the decline seen in August, so that the sunspot number in September once again matched or exceeded the numbers seen during the middle of the previous solar maximum from 2012 to 2014, a low period of activity between that maximum’s two peaks. Activity also continued to exceed the predictions of the panel of government solar scientists put together by NOAA.

At the same time, since May the ramp up to maximum has stalled, something I noted last month and has now become more evident.
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Sunspot update: Solar activity continues to exceed sunspot predictions

3:50 pm

It is the beginning of September and time to post another update on the Sun’s ongoing solar cycle. Below is NOAA’s monthly graph tracking the number of sunspots on the Sun’s Earth-facing hemisphere, with the activity in August now added. I have also added some additional details to the graph to give the numbers a larger context.

Though sunspot activity dropped in August it remained significantly above the predictions of the panel of government solar scientists put together by NOAA. The predicted sunspot number for August, as indicated by the red curve, was supposed to be about 48. The actual number was 75.

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Sunspot update: Activity recovers mostly from last month’s decline

9:04 pm

It is the start of the month, and thus time to post NOAA’s monthly update of its graph tracking the number of sunspots on the Sun’s Earth-facing hemisphere. That graph is below, with some additional details added by me to provide a larger context.

After the first real decline in sunspot activity in June, the Sun recovered that decline almost completely in July. Though the ramp up to solar maximum has stalled somewhat in the last two months, the trend continues to point to a very active maximum, much higher than predicted as well as much stronger than the last very weak maximum in 2020.

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Sunspot update: For the first time in 2022, sunspot activity eases

3:58 pm

With the year half over, the Sun in June did something it had not done since the start of the year: The number of sunspots seen daily on the Sun’s visible hemisphere actually declined from the month before.

I know this because, as I do every month, I have posted below NOAA’s monthly update of its graph tracking the number of sunspots on the Sun’s Earth-facing hemisphere, with some addition details added to provide a larger context.

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Sunspot update: In May we had sunspots, sunspots, and more sunspots!

10:31 am

It is time for another sunspot update! On June 1 NOAA released its monthly update of its graph tracking the number of sunspots on the Sun’s Earth-facing hemisphere. As I do every month, I have posted it below, having added some addition details to provide a larger context.

In May the sunspot activity on the Sun almost literally exploded, producing some of the strongest solar flares in years as well as the most sunspots since the previous solar maximum in 2014. On several days there were as many as eight sunspot groups on the Sun, with one so large that it was visible to the naked eye on Earth (if viewed properly with a protective filter).
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Astronomers discover a solar twin whose sunspot cycle changed into a grand minimum

9:19 am

Astronomers studying the sunspot cycle of several dozen stars that are twins of our Sun have identified for the first time a star whose 17-year cycle suddenly ceased, going into an extended grand minimum.

Comparing these stars to the Sun enables astronomers to better determine how typical – or not – the Sun is as a star. The Sun’s magnetic activity is defined by its 11-year sunspot cycle. Of the 59 stars that Baum’s team surveyed, 29 appeared to also have starspot cycles, and the period of those cycles could be measured for 14 of them.

“Of these 14 stars, the average length of their cycle is just under 10 years, which is similar to the Sun’s 11-year cycle,” Baum tells Physics World. However, not all the stars adhered to this time frame. One star that was surveyed has a cycle lasting less than four years, while another star, HD 166620, had a cycle 17 years long.

Note the past tense. Sometime between 1995 and 2004, HD 166620’s starspot cycle simply stopped.

When or if the star’s sunspot activity resume is unknown. The Sun’s last grand minimum, dubbed the Maunder Minimum, lasted 70 years during the 1600s.

No one yet understands why stars do this. This discovery however now shows that the Sun is not unique in this behavior.

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Sunspot update: Sunspot activity continues to outpace predictions

3:23 pm

It is the first of the month, and NOAA has once again updated its monthly graph showing the long term trends in the Sun’s sunspot activity. As I do every month, I post it below, annotated with additional data to provide some context.

In March the Sun continued its unexpected high activity since the end of the solar minimum in 2020. The number of sunspots once again rose steeply, while also exceeding the predicted count for the month. The actual sunspot count for March was 78.5, not 34.1 as predicted. The last time the count was that high for any month was September 2015, when the Sun was just beginning its ramp down from solar maximum.
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Sunspot update: The Sun rages on

10:54 am

Time for my monthly sunspot cycle update, where I take NOAA’s monthly graph showing the long term trends in the Sun’s sunspot activity, and annotate it with additional data to provide some context.

The trend of sunspot activity exceeding the predictions continued in February. While the increase in activity from January still left it less than the activity in December, the total number of sunspots is still far above the number predicted by NOAA’s panel of solar scientists in 2020, with the rise towards a solar maximum also much steeper and far faster than predicted.
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Sunspot Update: The Sun quiets down, but just a little

11:50 am

With the posting yesterday by NOAA of its monthly update to its graph showing the long term trends in the Sun’s sunspot activity, it is time for me to do my own update, showing this graph below with annotations in order to provide some context.

While sunspot activity dropped slightly in January, the activity still remained well above the prediction made by NOAA’s panel of solar scientists in 2020, with the upward trend towards a solar maximum much steeper than predicted as well.
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Sunspot update: The Sun blasts off!

10:16 am

Over the weekend NOAA posted its monthly update to its graph showing the long term trends in the Sun’s sunspot activity. As I do every month, I have posted that graph below, annotated to show the previous solar cycle predictions and thus provide context.

In December the Sun’s sunspot activity not only continued the pattern of the past two years — whereby sunspot activity has consistently exceeded the prediction of NOAA’s solar scientist panel — the amount of activity shot up like a rocket. December 2021 saw the most sunspots in a single month since September 2015, when the Sun was about a third of the way into its ramp down from the solar maximum in 2014.

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Sunspot update: Sun continues to be more active than predicted

12:45 pm

Time for our monthly sunspot update, using NOAA’s most recent monthly graph of sunspot activity. That graph is below, annotated to show the previous solar cycle predictions and thus provide context. It covers all activity through the month of November.

The pattern for the past two years since the end of the solar minimum continues, with sunspot activity consistently exceeding the prediction of NOAA’s panel of solar scientists, as indicated by the red curve. The activity in November dropped very slightly from October, but remained more active than the prediction.

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Sunspot update: Sun continues its higher than predicted activity

11:57 am

With the beginning of a new month comes my monthly sunspot update, based on NOAA’s most recent monthly graph of sunspot activity. That graph is below, annotated to show the previous solar cycle predictions and thus provide context. It has now been extended from last month to include the Sun’s sunspot activity in October.

Sunspot activity in October continued to be higher than predicted, though the month saw a slight drop from September. Even so, the number of sunspots seen on the Sun’s facing hemisphere in October were the most since August of 2016, when the Sun was ramping down to solar minimum.

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Sunspot update: The boom in sunspots returns!

12:11 pm

It is time for my monthly sunspot update, based on the most recent NOAA monthly graph, showing the changes in the Sun’s sunspot activity during September. That graph is below, annotated to show the previous solar cycle predictions and thus provide context.

In September sunspot activity boomed once again, producing the most sunspots in a month since 2016 and ending the slight drop in activity in August to return to the pattern the Sun has exhibited since the end of solar minimum. Consistently the number of sunspots on the visible hemisphere of the Sun since 2020 has exceeded the April 2020 prediction of the NOAA scientist panel, as indicated by the red curve in the graph.

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Sunspot update: Activity declines in August to just above prediction

12:02 pm

On September 1st NOAA released its update of its monthly sunspot cycle graph, showing the Sun’s sunspot activity for the past month. That graph is below, annotated to show the previous solar cycle predictions and thus provide context.

In August sunspot activity dropped from July so that it was only slightly above the prediction of NOAA’s panel of solar scientists, as indicated by the red curve. The blank streak at the very end of July ended on August 2nd (a streak of seven days and the longest in years), but was followed during the month by an additional five blank days.

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Sunspot update: Another month of greater activity than predicted

10:11 am

NOAA this past weekend released an update of its monthly sunspot cycle graph, showing the Sun’s sunspot activity for the past month. That graph is below, annotated to show the previous solar cycle predictions and thus provide context.

In July the Sun’s hot streak of sunspot activity continued. The number of sunspots on its visible hemisphere continued to exceed the prediction of NOAA’s solar science panel, with the numbers in July easily topping June’s numbers. Only at the very end of July was there a streak of five blank days, the first time the Sun has been blank of sunspots since May 6th, a stretch of activity not seen for years, since the last solar maximum was ramping down to solar minimum in ’16-’17.

The political consequences of this continuing high activity could be quite profound.
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Sunspot update: The hot streak continues

8:01 am

This past weekend NOAA released its monthly update of its graph showing the Sun’s sunspot activity, with the new update covering the period through the end of June 2021. As I have done since I began this website eleven years ago, I post that monthly graph below, annotated to show the previous solar cycle predictions and thus provide context.

In June the hot streak of sunspot activity exceeding the prediction of NOAA’s solar science panel continued, with activity rising again after a tiny dip in May. Except for two months, since 2019 the number of sunspots each month has consistently exceeded the prediction. Furthermore, the ramp up of activity has been faster than expected.
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Sunspot update: Activity in May continued to exceed predictions

11:07 am

Time for our monthly sunspot update. On June 1st NOAA updated its monthly graph showing the Sun’s sunspot activity through the end of May 2021. Below is that updated graph, annotated as always to show the previous solar cycle predictions.

As has happened now for almost every month since the Sun’s sunspot cycle began to increase following the long and deep minimum in 2019, the activity in June exceeded the numbers predicted by the computer models of NOAA’s panel of solar scientists. While the activity dipped slightly from April, it still was more active than predicted.

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Sunspot update: Sunspot activity continues to exceed predictions

1:29 am

The uncertainty of science: On May 1st NOAA updated its monthly graph to show the Sun’s sunspot activity through the end of April 2021. As I do every month, I have annotated it to show the previous solar cycle predictions and posted it below.

In my sunspot update last month I reviewed in detail the range of predictions by solar scientist for the upcoming solar maximum, noting that based on the higher than expected sunspot activity that has been occurring since the ramp up to solar maximum began in 2020, it appeared that all of their predictions might be wrong. The continuing high activity that occurred in April continued that trend.

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