chill!

The solar minimum: A reasonable explanation based on scientific evidence (not hysteria)

The Sun is a busy star. This fiery ball of hot gas goes through periods of violent eruptions and magnetic explosions that send flashes of radiation into space. But every now and then, even the Sun needs to chill.

Our host star is currently in its downtime mode, a period known as solar minimum.

However, this current lack of activity from the Sun has some worried that it will lead to a dark, cold summer with possible famine, war — and even volcanoes. So, what exactly is a solar minimum? And is the Sun experiencing an unusually inactive cycle?

Inverse breaks down the science behind this phase of the solar cycle, and why we should all do like the Sun and chill.

What is a solar minimum?

A solar minimum is when fewer sunspots appear on the Sun, marking the end of a solar cycle.

Every 11 years, the Sun embarks on a new solar cycle which scientists believe is controlled by the Sun's magnetic field. We are currently on solar cycle 25.

An illustration of the Sun that shows the star throughout one solar cycle.

Solar activity largely depends on the Sun's magnetic field. The Sun’s magnetic field goes through a periodic cycle in which the south and north poles essentially switch spots, and it takes another 11 years or so for them to switch back.

The midpoint of the solar cycle is when things really pick up, with the Sun's activity increasing and that means more solar flareups and outflow of radiation from our host star. However, as this solar cycle winds down, the Sun becomes less active.

And the Sun's activity is measured by its sunspots.

What are sunspots?

Sunspots are dark spots that mark the Sun's surface. They are caused by the magnetic field inhibiting the transfer of energy on the surface of the Sun through the process of convection, where hot fluid rises and cooler fluid sinks.

Therefore, sunspots are an indication of solar activity. As the solar cycle reaches its halfway point, the Sun reaches its 'solar maximum' where the most amount of sunspots can be seen across its surface. The last solar cycle, cycle 24, reached its solar maximum in April, 2014 with a peak average of 82 sunspots.

As the solar cycle comes to an end, there are less and less sunspots, a period known as solar minimum.

"Even with the solar minimum, the magnetic field of the Sun is not actually zero, it just changes configuration," Alexander Shapiro, a scientist at the Max Planck Institute for Solar System Research in Germany, tells Inverse.

Are we experiencing an unusual solar minimum?

There have been reports claiming that this solar cycle's minimum is unusually low, with over 100 days already in the year 2020 where the Sun has had no sunspots at all, according to spaceweather.com.

The year 2019 saw another unusually low number of sunspots, with a total of 281 days where there were no sunspots on the Sun. "Two consecutive years of record-setting spotlessness adds up to a very deep solar minimum,” spaceweather.com reads.

However, Shapiro explains that the Sun is not experiencing an unusually low period of activity. Instead, it is resuming its regular activity.

For the past 50 years, around four solar cycles or so, the Sun has been unusually active, according to Shapiro.

A powerful eruption from the surface of the Sun captured in the year 2013.NASA

"Some people are speculating that the behavior of the solar cycle is extremely weak," he says. "But it’s not extremely weak, it’s probably just the weakest one in the past four solar cycles."

Therefore, if we were to put the current solar cycle in perspective of the last 1,000 years of the Sun's history, then there would be no indication that it is unusual.

And the current solar cycle is only just beginning. Although it may have a bit of a slow start, experts are predicting that the solar cycle will reach its maximum by the year 2023 to 2026, according to the National Oceanic and Atmospheric Administration.

Is this another Dalton Minimum?

The Dalton Minimum was a period of time between around 1790 to 1830 with an extremely low count of sunspots. The Dalton Minimum era also experienced a global drop in temperatures, which may have been due to a spike in volcanic activity with the 1815 volcanic eruption in Indonesia.

However, some blame the drop in temperatures on the solar minimum, and the volcano too.

With reports of a supposedly unusual solar minimum, some have claimed that we're entering into a second Dalton Minimum.

"In my personal opinion, that is total rubbish," Shapiro says. "The Sun is still more active than during Dalton Minimum, significantly more active."

According to Shapiro, the difference between a solar maximum and minimum is not significant enough to have an impact on Earth. Instead, the Sun's effect on Earth is based on its ultraviolet radiation, rather than its total amount of energy or activity.

He describes it as a 'top-down' mechanism, whereby the Sun's radiation has a slight effect on Earth's atmosphere, which would, in turn, change the amount of UV radiation in some sense, but the difference during the solar minimum is not that huge.

Can we forecast solar weather?

As reassuring as that sounds, Shapiro does admit that the Sun's activity is rather hard to predict.

Although the Sun shines down on us day in and day out, there's still a lot that we don't know about our host star.

The Sun has been difficult to observe since most spacecraft aren't built to get close enough and survive the heat of the star. However, that may soon change with the launch of Solar Orbiter earlier this year, which joins NASA's Solar Parker Probe in exploring the elusive star.

And yet as scientists try to understand the Sun better, they also admit that there is some randomness involved in its activity.

"The solar cycle itself, it’s to some extent very random," Shapiro says. "It’s a highly nonlinear system, the process of interaction between magnetic field and charged particles."

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