November 13, 2025
People across the United States weren’t the only ones treated to a spectacular celestial show. This week’s intense geomagnetic storm illuminated the night sky around the world. Check out some of the most stunning displays from Europe to Mongolia to Australia.
(July 19, 2024)
The current solar cycle, named Cycle 25 because it is the 25th since 1755 when extensive recording of solar sunspot activity began, started in 2019.
It is not expected to end for another six years but the first signs that the next solar cycle is beginning have been spotted by researchers from the University of Birmingham and presented at the Royal Astronomical Society‘s National Astronomy Meeting in Hull.
(July 23, 2024)
Solar max affects activity on the sun’s surface. Sunspots, flares and coronal mass ejections are all more rampant at solar maximum. This leads to a surge in electromagnetic energy hurtling toward Earth, making auroras visible more often and at lower altitudes.
The current solar cycle – Cycle 25 – started in 2019. It has the name Cycle 25 because it’s the 25th since 1755, when extensive recording of solar sunspot activity began.
It is not expected to end for another six years, but researchers have spotted the first signs that the next solar cycle is beginning. Researchers from the University of Birmingham presented their findings at the Royal Astronomical Society’s National Astronomy Meeting in Hull on July 18, 2024.
(June 10, 2024)
Evidence of a long-ago collision involving the Earth was there in the form of specific radioactive isotopes deposited across the Earth and Moon. There were, however, skeptics.
But now researchers have tracked the sun’s path through the Milky Way back to a crash 2 to 3 million years ago with a dense interstellar cloud. The event was so violent it appears to have collapsed the sun’s protective bubble around the solar system and possibly even affected life on Earth.
(…)
“We don’t often discuss the impact of astrophysics on Earth because the astronomical timescales are very long, and the human species emerged on Earth just a few million years ago,” Loeb said. “But a few million years ago there was the potential for us to be passing through a very dense cloud. We didn’t work out the biological implications, but it’s clear that if you shrink the heliosphere to within the orbit of the Earth around the sun, we are not protected anymore. It could have significant implications for life on Earth.”
(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.
(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.
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.
(November 6, 2025)
According to NASA, Voyager 1 has now encountered what researchers describe as a “wall of fire,” a zone where temperatures reach between 30,000 and 50,000 kelvin — roughly 30,000 degrees Celsius. The finding was made as part of ongoing efforts to understand the boundary separating our Solar System from interstellar space.
(…)
“An observation made by Voyager 2 confirms a surprising result from Voyager 1: the magnetic field in the region just beyond the heliopause is parallel to the magnetic field inside the heliosphere,” NASA noted. With data from both spacecraft, scientists can now confirm that this alignment is not a coincidence but a defining characteristic of the boundary region.
628,218 views Aug 31, 2017
This visualization tracks the trajectory of the Voyager 1 spacecraft through the solar system. Launched on September 5, 1977, it was one of two spacecraft sent to visit the giant planets of the outer solar system. Voyager 1 flew by Jupiter and Saturn before being directed out of the solar system.
To fit the 40 year history of the mission into a short visualization, the pacing of time accelerates through most of the movie, starting at about 5 days per second at the beginning and speeding up to about 11 months per second after the planet flybys are past.
The termination shock and heliopause are the ‚boundaries‘ created when the plasma between the stars interacts with the plasma flowing outward from the Sun.
Launched in 1977, Voyager 1 has been cruising through space for nearly 47 years, traveling a mind-boggling distance of almost 16 billion miles from Earth. This journey has already broken records—it was the first spacecraft to cross the heliopause, the boundary where the Sun’s solar wind yields to interstellar space. Now, it is on course to reach a distance known as a light-day, meaning the distance that light travels in 24 hours.
Traveling at about 38,000 miles per hour, Voyager 1’s progress may seem slow compared to light speed, but it reveals the vast scales of cosmic distance. Radio signals sent from the spacecraft take nearly 23 hours to reach Earth, which offers a glimpse into the immense challenges of communicating across these astronomical expanses.
The northern lights lit up the night sky across America on Tuesday, dazzling stargazers from New Hampshire to the heartland with eerie green and orange streaks of cosmic fire.
The Aurora Borealis was spotted in a large swath of states, including Idaho, Iowa, Missouri, New Mexico, New York, Oklahoma, South Dakota, Tennessee, Texas and Washington state. Northern lights were visible as far south as parts of Florida and Alabama, a relatively rare occurrence that highlights the severity of this week‘s storms.
A surge in solar activity fueled the vibrant display as the sun reached the peak of its 11-year solar cycle, a period marked by a sharp increase in sunspots and geomagnetic storms.
Around 2019–2020, the sun was at its quietest point; however, with more frequent bursts of solar wind erupting from those sunspots, Earth is now experiencing more substantial and more frequent auroral events.
Etwas Besonderes sind die Polarlichter in Süddeutschland auch, weil sie kein häufiges Phänomen sind. Skandinavien ist für die Sonnenstürme bekannt. „Tatsächlich ist Polarlicht in Süddeutschland schon sehr, sehr selten“, sagt Liefke.
(Oct. 12, 2024)
From their unique vantage points – Voyager 1 in the northern hemisphere and Voyager 2 in the southern hemisphere – the spacecraft have already detected differences and asymmetries in the solar wind termination shock, where the wind abruptly slows as it approaches the heliopause. For example, Voyager 2 crossed the termination shock at a distance of about 83.7 AU in the southern hemisphere. (One AU, or astronomical unit, is equal to 150 (million) kilometers (93 million miles), the distance between Earth and the Sun.) That’s about 10 AU closer to the Sun than where Voyager 1 crossed the shock in the north. As shown in this diagram, Voyager 1 traveled through the compressed “nose” of the termination shock and Voyager 2 is expected to travel through the flank of the termination shock.
628,218 views Aug 31, 2017
This visualization tracks the trajectory of the Voyager 1 spacecraft through the solar system. Launched on September 5, 1977, it was one of two spacecraft sent to visit the giant planets of the outer solar system. Voyager 1 flew by Jupiter and Saturn before being directed out of the solar system.
To fit the 40 year history of the mission into a short visualization, the pacing of time accelerates through most of the movie, starting at about 5 days per second at the beginning and speeding up to about 11 months per second after the planet flybys are past.
The termination shock and heliopause are the ‚boundaries‘ created when the plasma between the stars interacts with the plasma flowing outward from the Sun.
(June 16, 2024)
But only two human-made objects have crossed the boundary of the solar system and entered interstellar space.
In 1977, NASA launched Voyager 1 and Voyager 2, equipped with tools to measure the magnetic fields and the particles it is directly passing through. After traveling for over three decades in space, they finally exited the outer layer of the heliosphere—heliopause in 2012 and 2018 respectively. They discovered that cosmic rays are about three times more intense outside the heliopause than deep inside the heliosphere.
Key Questions
The PUNCH mission will use four suitcase-sized satellites to observe the Sun and its environment. Working together, the four PUNCH satellites will create a combined field of view and map the region where the Sun’s corona (or outer atmosphere) transitions to the solar wind (the constant outflow of material from the Sun).
The PUNCH mission will answer questions about:
How the Sun’s atmosphere transitions to the solar wind.
How structures in the solar wind are created.
How these processes affect the solar system.
On March 2, a SpaceX Falcon 9 rocket is scheduled to launch the Polarimeter to Unify the Corona and Heliosphere (PUNCH) mission into low Earth orbit. From this location, its four satellites will have nearly constant views of the Sun to help researchers answer questions about how activity near our star propagates through the inner solar system, influencing the space weather we experience here on Earth.
(April 19, 2021)
The researchers examined the rings of the tree to look for changes in the amount of carbon-14 over a period of years, Gramling explains. Carbon-14 is useful not only for dating things, but because the interaction of cosmic rays with molecules in the atmosphere produces a lot of it. And when the Earth has a weakened magnetic field, more cosmic rays hit the planet.
The scientists indeed found a large spike in carbon-14 in the tree, which they could then compare with the rock record that indicated a magnetic reversal. (…)
In addition, there is the documented rise in cave art right about 41,000-42,000 years ago, Gramling points out.
(24 April 2024)
The preservation of a temperate climate and liquid water on early Earth depends critically upon the strength of the magnetosphere (Sterenborg et al., 2011; Tarduno et al., 2014). Recent atmospheric escape models have suggested that both weak (<10 μT) and strong (>1 mT) magnetic fields could substantially enhance atmospheric escape under present-day solar wind conditions via the polar wind or cusp escape, respectively (Gronoff et al., 2020; Gunell et al., 2018; Lundin et al., 2007). During the Archean, the Sun was rotating faster, generating a stronger stellar dynamo and therefore the solar wind was more intense than today (Vidotto, 2021). An increased solar wind strength causes greater interaction with the upper atmosphere and greater escape of ions assuming a constant level of protection from Earth‘s magnetosphere. Previous magnetohydrodynamic simulations have suggested that if Earth‘s magnetic field was half its present day strength 3.5 Ga ago, the area of the polar cap (the area containing open dipolar magnetic field lines, allowing atmospheric escape via the polar wind) could increase by up to 50% (Sterenborg et al., 2011).
The age of the Earth’s magnetic field remains under question in part because we don’t fully understand what causes it today. We know it is a product of movements in the molten outer core, whose high iron content turns convection currents into a dynamo, and these currents in turn are produced by the solidification of the inner core.
(24 April 2024)
Today, the magnetic field is driven by the churning of the liquid part of the core and the transfer of heat from the solid inner core to the convective outer core as the former cools. But researchers think the core didn‘t solidify until about a billion years ago.
Pioneer 10: Pioneer 10 was launched in 1972 to explore the planets of the solar system. It achieved the first flyby of Mars, the first trip through the asteroid belt, and Jupiter‘s first flyby. It was the first time NASA had used nuclear energy to power its spacecraft. So, after Pioneer 10 passed Jupiter in 1973, it still had ample energy to keep going. Initially planned for 21 months, it continued to communicate with Earth for a total of 30 years.
(January 30, 2019)
This milestone — reaching interstellar space — can be considered leaving the solar system by a certain definition. Let‘s be clear about what that entails. In 1990, the New York Times reported that Pioneer was reported to leave the solar system when it flew past Neptune‘s orbit. That‘s not what Voyager 2‘s scientists used to make their determination, however. Instead, the more recent measurements consider the crossing of the sun‘s heliopause, the theoretical boundary to its heliosphere, to be the determining factor for entering interstellar space. The heliosphere is a bubble of charged particles created by and flowing past the sun. Scientists use it to mark where interstellar space begins.
Am 13. Juni 1983 durchflog „Pioneer 10“ die Umlaufbahn des Neptun und wurde so laut NASA zum ersten menschengemachten Raumschiff, das am weitestentfernten bekannten Planeten unseres Sonnensystems vorbeiflog. Neptun ist im Mittel etwa 4,5 Milliarden Kilometer von der Sonne entfernt.
Mit „Pioneer 11“ und den beiden „Voyager“-Sonden folgten später ähnliche Missionen. „Voyager 1“ überholte „Pioneer 10“ schließlich als am weitesten von der Erde entferntes menschengemachtes Objekt. Zum bisher letzten Mal schickte „Pioneer 10“ im Jänner 2003 Daten, ein Kontaktversuch im März 2006 scheiterte.
(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.
(2010)
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 Introduction
The heliosphere is the cavity curved by the solar wind into the interstellar medium. Its extension is determined by the equality of the solar wind pressure and the stellar wind pressure. For this reason, we will first study past, present and future status of solar activity and then we will reflect this study into the heliosphere.
(18.10.2008)
New data has revealed that the heliosphere, the protective shield of energy that surrounds our solar system, has weakened by 25 per cent over the past decade and is now at it lowest level since the space race began 50 years ago. (…)
„Around 90 per cent of the galactic cosmic radiation is deflected by our heliosphere, so the boundary protects us from this harsh galactic environment.“
The heliosphere is created by the solar wind, a combination of electrically charged particles and magnetic fields that emanate a more than a million miles an hour from the sun, meet the intergalactic gas that fills the gaps in space between solar systems.
(December 21, 2022)
As hinted at above, Mauna Loa began erupting on Nov 27 and stopped on Dec 13.
It was the first time it has actively erupted since 1984 (solar minimum of cycle 20) — and is a sign of the times…
Volcanic eruptions are one of the key climatic forcings driving Earth into its next bout of global cooling. They have been shown to increase in both number and explosivity during times of prolonged solar decline, which is thought to be due to an influx of cosmic rays (CRs) penetrating/exciting silica-rich magma. During solar mins the Sun’s magnetic field weakens and the outward pressure of the solar wind decreases, which allows more CRs to enter the inner solar system, including our planet’s atmosphere.
(Published: 13 September 2021)
Here, we show that a high-resolution calculation succeeds in reproducing the solar-like differential rotation. Our calculations indicate that the strong magnetic field generated by a small-scale dynamo has a significant impact on thermal convection. The successful reproduction of the differential rotation, convection and magnetic field achieved in our calculation is an essential step to understanding the cause of the most basic nature of solar activity, specifically, the 11 yr cycle of sunspot activity.
(08.11.2021)
Japanese scientists said they have created the first accurate computer simulation of how the Sun rotates, reproducing a phenomenon in which its equatorial area spins faster than its polar regions. The insight could help explain the whys and hows of the solar cycle, one of the biggest mysteries of our star.