About every 11 years, the sun goes through what’s known as ‘solar maximum’, when many bizarre dark spots appear on its surface.
These ‘sunspots’ – which can cluster together and form what looks like an archipelago – are caused by massive changes in our star’s magnetic field.
They also shoot out violent explosions of energy towards Earth, causing ‘solar storms’ that can potentially damage satellites and disrupt the internet.
Unfortunately, a new study reveals that this solar maximum is coming sooner than expected – most likely in early 2024.
Researchers have discovered a new relationship between the Sun’s magnetic field and its sunspot cycle, that can help predict when the peak in solar activity will occur. This image from the Solar Dynamics Observatory shows the sun with multiple sunspots, which appear dark compared with their surroundings.
The new study was led by Dr Dibyendu Nandi, a physicist from the IISER Kolkata Center of Excellence in Space Sciences in India.
He said it is ‘not possible to predict the intensity and consequences’ of solar storms this early, but we should learn more as the new year approaches.
‘The most intense storms can sometimes result in catastrophic orbital decay of low Earth orbiting satellites and disrupt satellite based services such as communications and navigational networks,’ he told MailOnline.
‘They can also induce strong disturbances in the geomagnetic field tripping electric power grids located in high latitude regions.
‘Of course, they also create beautiful auroras so we can expect 2024 to be a good year for aurora hunters.’
Dr Nandi and his colleagues have managed to come up with a new way to detect the solar maximum, but understanding it requires some basic knowledge about our solar system’s life-giving star.
The sun is a huge ball of electrically-charged hot gas that moves, generating a powerful magnetic field, officially known as the dipole field.
This dipole field – which stretches from one pole of the sun to the other much like Earth’s – goes through a cycle, called the solar cycle.
Roughly every 11 years or so, the sun’s magnetic field completely flips, meaning the north and south poles switch places.
Every 11 years, the sun’s magnetic dipole field (which stretches from one pole of the sun to the other much like Earth’s) completely flips, meaning the sun’s north and south poles switch places
This solar cycle affects activity on the surface of the sun, including the dark sunspots which are caused by the sun’s magnetic fields.
One way scientists can track the solar cycle is by counting the number of sunspots and when exactly they appear, mostly using satellites.
The beginning of an 11-year solar cycle, when the sun has the fewest sunspots, is known as the solar minimum – but over time the number of sunspots increases.
The middle of the solar cycle is the solar maximum, when the sun has the most sunspots.
It’s during this solar maximum when the most violent space weather is expected.
The researchers say predicting exactly when this peak is going to occur – and therefore when the most violent space weather hits Earth – has been challenging.
We know that solar cycles last roughly every 11 years – but this is only an average, as Dr Nandi explains.
‘Eleven years is a mean periodicity, implying this is determined by averaging the individual periods of all observed solar cycles in the modern era,’ he told MailOnline.
‘Individual cycles can vary in length from nine to 14 years.’
The scientists demonstrate how observations of the rate of decrease of the Sun’s dipole magnetic field can be usefully combined with sunspot observations to predict when the ongoing cycle would peak. Their analysis suggests that the maximum of solar cycle 25 is most likely to occur in early 2024
Scientists already rely on clues gathered by Swiss astronomer Max Waldmeier nearly 100 years ago, to make the best estimates of when the solar maximum will arrive.
It was back in 1935 that Waldmeier found the faster the rise of a sunspot cycle, the stronger its strength.
Pictured, Swiss astronomer Max Waldmeier, responsible for the Waldmeier effect
Therefore, as Waldmeier explained, stronger cycles – i.e. ones with more sunspots – take less time to rise to their peak intensity.
This relationship – known as the ‘Waldmeier effect’ – has often been used to forecast the strength of a sunspot cycle based on observations of its early rising phase.
What the Indian researchers have done is find a new relationship, using decades-old data archives from multiple ground-based solar observatories around the world.
Namely, the rate of decrease in the sun’s dipole magnetic field is also correlated with the rate of rise of the ongoing sunspot cycle.
‘The sun’s dipole field waxes and wanes roughly in antiphase with the sunspot cycle,’ Dr Nandi told MailOnline.
‘During solar cycle minimum, when almost no sunspots are observed on the sun, the dipole field strength is maximum.
‘When the sunspot cycle starts rising, the large-scale solar dipole field starts weakening and assumes more complex configuration.
This 24-hour movie from NASA’s Solar Dynamics Observatory shows sunspots on November 18
‘The dipole field vanishes during sunspot cycle peak and following this, it flips its direction and starts growing slowly again.’
Scientists used their new knowledge to predict exactly when the solar maximum of the current cycle would peak – early 2024.
‘Predicting the time of maximum amplitude of sunspot cycle is important for gauging when the most adverse space environmental conditions (space weather) are expected,’ they say in their paper.
The new research appears in Monthly Notices of the Royal Astronomical Society.