The sun had more sunspots in June than it had in any other month in more than 20 years, according to scientists.
The National Oceanic and Atmospheric Administration (NOAA) said it recorded 163 sunspots last month, about twice as many as had been anticipated for the period.
The last time there were this many sunspots on the sun’s surface was in September 2002, per NOAA.
Scientists are paying close attention to this number because it can help predict if powerful solar flares may cause problems for Earth.
The more sunspots scientists see on the sun, the more likely the sun is to release powerful space weather, such as solar flares that could trigger radio blackouts, ground flights, and cause power grid disruptions. Solar flares can also produce stunning auroras.
Why sunspots are being tracked so closely
Sunspots are cooler than other parts of the sun’s surface because they form in areas where our star’s magnetic fields are strong.
The more sunspots are on the surface, the more scientists know that the magnetic activity is disrupted at the surface of the sun.
NASA says that the more magnetic fields disrupted are, the greater the likelihood of a solar flaring, a powerful explosion.
Because we’re seeing more sunspots than expected, we’re likely to see a much stronger solar maximum than had been anticipated.
A solar maximum is on its way
The sun follows a solar cycle, whereby its activity grows and wanes approximately every 11 years. Currently, our star’s activity is increasing towards the solar maximum.
Scientists keep a close eye on our star because as it gets more active, it’s more likely to send charged particles to Earth that can mess with our infrastructure.
Our Earth’s magnetic shield protects us against most space weather. However, charged particles that break through this barrier can cause minor disturbances such as radio blackouts.
These mostly go unnoticed, but can temporarily ground flights as the Federal Aviation Administration won’t allow planes to fly without both radio and satellite communications.
Experts are most concerned that this peak of activity could bring a solar storm so powerful it could knock our crucial infrastructure like power grids.
This solar cycle has already provided some spectacular space weather. This year, a powerful solar flare caused widespread radio blackouts in North America, Central America, and South America, and an unexpected solar storm caused auroras so bright they were spotted as far south as Arizona.
A false sense of security
Experts had forecast that this solar maximum would be fairly mild, peaking at 115 sunspots per month.
Solar physicist Keith Strong shared on Twitter a forecast from the Royal Observatory of Belgium suggesting the sun could peak at just under 200 monthly sunspots. That would be higher than the last solar maximum, which peaked at 146 monthly sunspots in 2014.
Experts previously told Insider this could be an issue. With each decade, we become more dependent on electrical infrastructure, according to Mathew Owens, a professor of space physics and the University of Reading.
The latest solar cycle was particularly quiet and may have lulled us into a false sense of security, he added.
“It was the smallest we’d had for about a hundred years,” Owens said, adding, “The danger of going from a small cycle to a slightly bigger one is that you then realize where all the vulnerabilities are.”
Still, if the sun peaks at 200 sunspots, it will be far from the biggest solar maximum on record. Solar cycle 19 peaked at 359 sunspots in October 1957, per NOAA.