Archiv: solar cycle 24


13.11.2025 - 17:36 [ Harvard University ]

Detailed understanding of reduced geoeffectiveness of solar cycle 24 in association with geomagnetic storms

(May 2025)

Solar Cycle 24, the weakest in over a century, exhibited significant deviations from previous cycles, beginning with a prolonged minimum, weak polar fields, and asynchronous polar field reversal, leading to hemispheric asymmetry. Sunspot activity declined by approximately 30% compared to Cycle 23, while the overall occurrence rate of coronal mass ejections (CMEs) decreased, although some studies suggest that the rate of halo CMEs relative to total CMEs may have remained relatively stable. This study investigates the impact of weaker solar activity on geomagnetic storm dynamics by analyzing CME properties, solar wind conditions, and their influence on magnetospheric energy transfer. Key findings indicate that a lower heliospheric pressure in Cycle 24 caused CMEs to expand more than in Cycle 23, altering energy transfer to Earth‘s magnetosphere.

13.11.2025 - 17:34 [ SkyandTelescope.org ]

The Weakest Solar Cycle in 100 Years

(July 24, 2013)

The Sun is acting weird. It typically puts on a pageant of magnetic activity every 11 years for aurora watchers and sungazers alike, but this time it overslept. When it finally woke up (a year late), it gave the weakest performance in 100 years.

What’s even weirder is that scientists, who aren’t usually shy about tossing hypotheses about, are at a loss for a good explanation.

13.11.2025 - 17:25 [ Cairo University / Researchgate.net ]

The Shrinking of the Heliosphere Due to Reduced Solar Wind

(December 2009)

Abstract. The heliosphere is the space within which the solar wind dominates and the solar interplanetary magnetic field prevails. Its boundary is determined by the balance between stellar and solar winds. Owing to the present reduction in the solar wind pressure, one would expect that the stellar wind would push the heliosphere inward leading to its shrinkage. In this paper we calculate the extent of the heliosphere at different solar wind status. Backward estimation of the extent of the heliosphere since 1890 is done. It is found that the heliosphere oscillated between 75 and 125 AU between 1890 – 2010. Most important is the forecast of the shrinkage and oscillations of the heliosphere and their implications on the earth. The shrinkage of the heliosphere would allow more invasions of cosmic rays to the earth and planets, increased cloud cover and a cooler Earth.

(…)

1.4 Prediction of the State of solar Activity During The Next Few Decades

Weak solar cycles occur at the bottom of Wolf-Gleissberg cycles. They tend to occur in series of 3-4 cycles. A single weak cycle also occurs in between the two maximums of Wolf-Gleissberg cycle. Since the last weak solar cycles occurred around 1900 while the previous ones occurred around 1800 then the newly started cycle 24 should be a weak solar cycle. However, owing to the 200-years de Verie cycle of the sun, it is more likely that the status of the coming solar activity would be something like those weak cycles around 1800 as shown in Fig 1. Svalgaard (2005) also predicted that cycle 24 would be the lowest so far in the past 100 years with the maximum sunspot number around 75.

13.11.2025 - 16:14 [ NASA Goddard / Youtube ]

11 Years Charting Edge of Solar System

Jun 11, 2020
Far, far beyond the orbits of the planets lie the hazy outlines of the magnetic bubble in space that we call home.

This is the heliosphere, the vast bubble that is generated by the Sun’s magnetic field and envelops all the planets. The borders of this cosmic bubble are not fixed. In response to the Sun’s gasps and sighs, they shrink and stretch over the years.

Now, for the first time, scientists have used an entire solar cycle of data from NASA’s IBEX spacecraft to study how the heliosphere changes over time. Solar cycles last roughly 11 years, as the Sun swings from seasons of high to low activity, and back to high again. With IBEX’s long record, scientists were eager to examine how the Sun’s mood swings play out at the edge of the heliosphere. The results show the shifting outer heliosphere in great detail, deftly sketch the heliosphere’s shape — a matter of debate in recent years, and hint at processes behind one of its most puzzling features. These findings, along with a newly fine-tuned data set, are published in The Astrophysical Journal Supplements on June 10, 2020.

24.04.2023 - 11:25 [ Times of India ]

Study: Sun’s magnetic field is weakening

(Oct 7, 2019)

The research, according to the team, will help monitor and evaluate the influence of solar activities and their implications on the Earth’s climate. The astrophysicists’ team included experts from Ahmedabad’s Physical Research Laboratory (PRL), Japan, and China.

14.11.2021 - 11:19 [ National Aeronautics and Space Administration ]

Solar Activity Forecast for the Next Decade

(12.06.2019)

The results show that the next Solar Cycle will start in 2020 and reach a maximum in 2025.Cycle 25 is expected to be even weaker than the current solar cycle.

According to this forecast, upcoming solar activity will be the weakest in the last 200 years.

25.10.2021 - 18:30 [ Electroverse.net ]

Solar Cycle 25 Progressing Similarly to 24, + Fairbanks sees Record-Breaking Snowfall

(October 6, 2021)

The official forecast by the NOAA/NASA Solar Cycle 25 Prediction Panel (made in 2019, and visualized by the red line above) called for a weak cycle 25, peaking in July 2025. And while things are currently tracking slightly ahead of schedule, NOAA don’t believe that the cycle will peak any higher than SC24. Instead, they simply see the peak arriving earlier, in late-2024 (rather than mid-2025). If this plays out it would of course mean an earlier start to Solar Cycle 26, too …

25.10.2021 - 18:04 [ Times of India ]

Study: Sun’s magnetic field is weakening

(Oct 7, 2019)

The research, according to the team, will help monitor and evaluate the influence of solar activities and their implications on the Earth’s climate. The astrophysicists’ team included experts from Ahmedabad’s Physical Research Laboratory (PRL), Japan, and China.

15.07.2021 - 08:10 [ NationalGeographic.com ]

Surprise: Solar System „Force Field“ Shrinks Fast

(October 1, 2010)

It‘s cold, dusty, and bereft of planets, but the outskirts of our solar system are anything but dull, according to increasing evidence from NASA‘s Interstellar Boundary Explorer (IBEX) craft.

As charged particles flow out from the sun, they eventually bump up against interstellar medium—the relatively empty areas between stars. These interactions „inflate“ a protective bubble that shields Earth and the entire solar system from potentially harmful cosmic rays (solar system pictures).

15.09.2020 - 13:26 [ EOS.org ]

The Thermosphere Responds to a Weaker Than Normal Solar Cycle

(05.04.2019)

The cooling near solar minimum is natural and specific to the thermosphere. The cooling thermosphere does not affect the troposphere, the layer of the atmosphere closest to Earth’s surface where people live. The temperatures we experience on the ground do not get colder because of this solar cycle. NASA and other climate researchers continue to see a warming trend in the troposphere. These two effects are ongoing but unrelated.

Nitric oxide and carbon dioxide play important roles in cooling the thermosphere.

14.05.2020 - 20:55 [ Unilad.co.uk ]

The Sun Has Entered ‘Very Deep’ Solar Minimum

(today)

While these things are still ongoing debates, one thing that NASA did find to happen during solar minimum was an increased number of galactic cosmic rays that reach Earth’s upper atmosphere.

Galactic cosmic rays are high energy particles accelerated toward the solar system by distant supernova explosions and other violent events in the galaxy.

02.01.2020 - 16:39 [ HNGN.com ]

Sun’s Magnetic Field To ‚Flip‘ Causing ‚A Ripple Effect‘ Past Pluto (VIDEO)

(06.08.2013)

The polar switch also affects cosmic rays, which can endanger satellites and astronauts. Disturbances in the rays could even affect Earth’s climate.

The sheet acts as a „shield“ against these rays, and a wavy current sheet can be even more effective.

01.11.2019 - 06:33 [ Telegraph.co.uk ]

Sun’s protective ‚bubble‘ is shrinking

(18.10.2008)

The protective bubble around the sun that helps to shield the Earth from harmful interstellar radiation is shrinking and getting weaker, Nasa scientists have warned.

11.08.2019 - 14:14 [ National Aeronautics and Space Administration ]

The Space Station Crosses a Spotless Sun

(15.07.2019)

Transiting the Sun is not very unusual for the ISS, which orbits the Earth about every 90 minutes, but getting one‘s timing and equipment just right for a great image is rare. Strangely, besides that fake spot, in this recent two-image composite, the Sun lacked any real sunspots. The featured picture combines two images — one capturing the space station transiting the Sun — and another taken consecutively capturing details of the Sun‘s surface. Sunspots have been rare on the Sun since the dawn of the current Solar Minimum, a period of low solar activity. For reasons not yet fully understood, the number of sunspots occurring during both the previous and current solar minima have been unusually low.

11.08.2019 - 14:03 [ Global Warming Policy Forum (GWPF) ]

Solar Cycle 25: May Be The Smallest In Over 300 Years

(26.01.2012)

Livingston and Penn provided the first hard estimate of Solar Cycle 25 amplitude based on a physical model. That estimate is 7, which would make it the smallest solar cycle for over 300 years.

This is figure 2 from their paper:

Livingston and Penn have been tracking the decline in sunspot magnetic field, predicting that sunspots will disappear when the umbral magnetic field strength falls below 1,500 gauss, as per this figure from their 2010 paper:

11.08.2019 - 13:58 [ NationalGeographic.com ]

Sun Headed Into Hibernation, Solar Studies Predict: Sunspots may disappear altogether in next cycle.

(14.06.2011)

This time, however, the rush to the poles is more of a crawl, which means we could be headed toward a very weak solar maximum in 2013—and it may delay or even prevent the start of the next solar cycle.

Taken together, the three lines of evidence strongly hint that Solar Cycle 25 may be a bust, the scientists said today during a meeting of the American Astronomical Society in Las Cruces, New Mexico.

11.08.2019 - 13:45 [ National Aeronautics and Space Administration ]

Long Range Solar Forecast: Solar Cycle 25 peaking around 2022 could be one of the weakest in centuries.

(10.05.2006)

How do you observe a belt that plunges 200,000 km below the surface of the sun?

„We do it using sunspots,“ Hathaway explains. Sunspots are magnetic knots that bubble up from the base of the conveyor belt, eventually popping through the surface of the sun. Astronomers have long known that sunspots have a tendency to drift—from mid solar latitudes toward the sun‘s equator. According to current thinking, this drift is caused by the motion of the conveyor belt. „By measuring the drift of sunspot groups,“ says Hathaway, „we indirectly measure the speed of the belt.“

13.07.2019 - 16:40 [ EOS.org ]

The Thermosphere Responds to a Weaker Than Normal Solar Cycle

The cooling near solar minimum is natural and specific to the thermosphere. The cooling thermosphere does not affect the troposphere, the layer of the atmosphere closest to Earth’s surface where people live. The temperatures we experience on the ground do not get colder because of this solar cycle. NASA and other climate researchers continue to see a warming trend in the troposphere. These two effects are ongoing but unrelated.

Nitric oxide and carbon dioxide play important roles in cooling the thermosphere.

05.06.2019 - 19:41 [ Metro.co.uk ]

The sun has ‘reached solar minimum’ and its surface is ominously calm

But Nasa images have revealed that the face of our star is looking ominously calm right now, prompting claims it’s reached a stage of its cycle called the solar minimum.

During the minimum, there are significantly fewer sunspots and its magnetic field weakens, allowing cosmic rays from outside our solar system to rain down on Earth.

25.05.2019 - 15:17 [ Phys.org ]

Scientists predict sun‘s activity will be weak during next solar cycle

(08.04.2019)

„We expect Solar Cycle 25 will be very similar to Cycle 24: another fairly weak cycle, preceded by a long, deep minimum,“ said panel co-chair Lisa Upton, Ph.D., solar physicist with Space Systems Research Corp. „The expectation that Cycle 25 will be comparable in size to Cycle 24 means that the steady decline in solar cycle amplitude, seen from cycles 21-24, has come to an end and that there is no indication that we are currently approaching a Maunder-type minimum in solar activity.“

25.05.2019 - 15:09 [ NationalGeographic.com ]

Surprise: Solar System „Force Field“ Shrinks Fast

(01.10.2010)

„If we’ve learned anything from IBEX so far, it is that the models that we’re using for interaction of the solar wind with the galaxy were just dead wrong,“ David McComas, principal investigator for the IBEX program, said during a NASA press conference Thursday.

For starters, it’s been assumed that the heliosphere’s expansion and contraction follows the sun’s roughly 11-year activity cycle, during which the flow rate of charged particles, or solar wind, fluctuates.

25.05.2019 - 13:27 [ HNGN.com ]

Sun‘s Magnetic Field To ‚Flip‘ Causing ‚A Ripple Effect‘ Past Pluto (VIDEO)

(06.08.2013)

The polar switch also affects cosmic rays, which can endanger satellites and astronauts. Disturbances in the rays could even affect Earth‘s climate.

The sheet acts as a „shield“ against these rays, and a wavy current sheet can be even more effective.

29.04.2019 - 10:51 [ Phys.org ]

Scientists predict sun‘s activity will be weak during next solar cycle

(8. April 2019)

„We expect Solar Cycle 25 will be very similar to Cycle 24: another fairly weak cycle, preceded by a long, deep minimum,“ said panel co-chair Lisa Upton, Ph.D., solar physicist with Space Systems Research Corp. „The expectation that Cycle 25 will be comparable in size to Cycle 24 means that the steady decline in solar cycle amplitude, seen from cycles 21-24, has come to an end and that there is no indication that we are currently approaching a Maunder-type minimum in solar activity.“

14.04.2019 - 19:50 [ Washington Post ]

Scientists predict a new solar cycle is about to begin and that it might be stronger than the last one

(11. April 2019)

The decline in sunspot activity through cycle 24 was worrisome to some space weather scientists in that it suggested a return to a lengthy “solar drought,” reminiscent of the Maunder Minimum period of 1645-1715. Records show the sun was essentially spotless for this lengthy period, coinciding with the “Little Ice Age” in Europe and tickling the interest of scientists to wonder whether there is a cause-and-effect relationship between solar behavior and Earth’s climate.

14.04.2019 - 19:47 [ Phys.org ]

Scientists predict sun‘s activity will be weak during next solar cycle

(8. April 2019)

„We expect Solar Cycle 25 will be very similar to Cycle 24: another fairly weak cycle, preceded by a long, deep minimum,“ said panel co-chair Lisa Upton, Ph.D., solar physicist with Space Systems Research Corp. „The expectation that Cycle 25 will be comparable in size to Cycle 24 means that the steady decline in solar cycle amplitude, seen from cycles 21-24, has come to an end and that there is no indication that we are currently approaching a Maunder-type minimum in solar activity.“

14.04.2019 - 19:46 [ National Aeronautics and Space Administration ]

Solar Wind Loses Power, Hits 50-year Low

(23. September 2008)

In a briefing today at NASA headquarters, solar physicists announced that the solar wind is losing power.

„The average pressure of the solar wind has dropped more than 20% since the mid-1990s,“ says Dave McComas of the Southwest Research Institute in San Antonio, Texas. „This is the weakest it‘s been since we began monitoring solar wind almost 50 years ago.“

14.04.2019 - 18:54 [ Telegraph.co.uk ]

Sun’s protective ‚bubble‘ is shrinking

(18.10.2008)

The protective bubble around the sun that helps to shield the Earth from harmful interstellar radiation is shrinking and getting weaker, Nasa scientists have warned.

29.03.2019 - 10:02 [ Forbes ]

Earth‘s Magnetic North Pole Has Officially Moved

Earth‘s magnetic North Pole has drifted so fast that authorities have had to officially redefine the location of the magnetic North Pole. The extreme wandering of the North Pole caused increasing concerns over navigation, especially in high latitudes.

29.03.2019 - 09:05 [ CBC.ca ]

The sun is quieter than normal, but don‘t panic

(11.3.2019)

Over the past three decades, the sun has been consistently dropping in activity. Maximum has been quieter than is typical; minimum has been particularly quiet. And this has caused some to make the false assumption that, as a result, Earth is going to cool.

29.03.2019 - 08:41 [ Nature.com ]

Earth’s magnetic field is acting up and geologists don’t know why

(9.1.2019)

Something strange is going on at the top of the world. Earth’s north magnetic pole has been skittering away from Canada and towards Siberia, driven by liquid iron sloshing within the planet’s core. The magnetic pole is moving so quickly that it has forced the world’s geomagnetism experts into a rare move.

29.03.2019 - 08:25 [ NationalGeographic.com ]

Sun Is Moving Slower Than Thought

(12.5.2012)

„Having learned for nearly three decades about it, I was literally shocked when we found it was missing.“

(…)

Still, considering the rays‘ expected effects, Redfield said, „it seems obvious to me that there will be scenarios or times when the cosmic-ray flux on a planet is important and [is] having a major influence on the evolution of the planetary atmosphere or even on biological processes on its surface.“

29.03.2019 - 08:23 [ NationalGeographic.com ]

Surprise: Solar System „Force Field“ Shrinks Fast

(1.10.2010)

„If we‘ve learned anything from IBEX so far, it is that the models that we‘re using for interaction of the solar wind with the galaxy were just dead wrong,“ David McComas, principal investigator for the IBEX program, said during a NASA press conference Thursday.

For starters, it‘s been assumed that the heliosphere‘s expansion and contraction follows the sun‘s roughly 11-year activity cycle, during which the flow rate of charged particles, or solar wind, fluctuates.

08.12.2018 - 15:25 [ Resonance.is ]

Is our solar system heating up?

With the decrease of solar activity, the magnetic field of oursun is losing power too. This heliosphere shields us forming a gigantic bubble which surrounds and protects our solar system from harmful galactic cosmic rays, these high-energy particles that zip through the universe. Thanks to Voyagers 1 leaving the Solar system, we now have a good vision of it and of its shielding effect. It appears to be an indispensable protection for our fast moving throughout the Universe. But, with a weaker heliosphere Earth will begin to endure more and more the cosmic rays.