Every 11 years or so, dark blemishes begin to dot the sun’s surface.
These sunspots, composed of intense magnetic fields, indicate areas known to expel bursts of electronically charged energy — so forcefully that they reach the Earth’s atmosphere, causing interferences with human-made technologies like satellites.
This year, the sunspots are returning — this time with greater vigor. According to Jennifer Morcone, spokesperson at NASA’s Marshall Space Flight Center, some scientists have predicted this year’s sunspot activity to be exceedingly strong.
“What makes us pay attention to solar cycles is that we expect to see more solar storms than we’ve seen in the past cycle,” Morcone said.
And what arrives with an increase in storms could affect day-to-day life on Earth.
Seeing spotsChinese civilizations have been documenting sunspots for thousands of years, Robert Egler, assistant head of the physics department, said. Western civilizations began searching the sky for these marks since Galileo was alive in the 1600s.
“You can see sunspots with your unaided eye, if you wish to do that,” Egler said. “But I don’t recommend it.”
It is because of these intensive records that astronomers noticed an unusual absence in the sun’s typically cyclical and predictable pattern in sunspot development.
“For unexplained reasons, there were very, very few sunspots for a long period,” Egler said.
But recent trends have shown that sunspots follow relatively stable cycles, on average leaving a solar minimum — a period during which there are few solar storms — every 11 years.
Once the sun enters solar maximum, the active period of sunspots and coronal mass ejections — which release bursts of electronically charged material — last for about two years.
“The sun’s surface is highly magnetized with positive and negative energy,” Morcone said. “[It] is covered in plasma — which is a collection of energetic particles — and when these magnetic fields clash they can eject all this energy off of the Sun’s surface.”
Solar stormsCoronal mass ejections are composed of charged particles — electrons and protons — which can travel as far as the Earth’s atmosphere and have the potential to interfere with technologies, such as satellites, orbiting the Earth.
“The technology gets overloaded with electricity,” Egler said. “It’s like plugging your 110-volt toaster into a 220-volt outlet.”
Although the last cycle of sunspots did have some impact on technologies in space, Egler said the average person wouldn’t have noticed its effects.
This year, because of society’s increased dependency on technology and electricity, Morcone said sunspots could have a tangible effect on the Earth’s human populations.
“The start matters to us here on Earth because of our increasingly space-based technology society,” Morcone said. “Satellites are not protected by the strength of the atmosphere, so they’re vulnerable to particles. … A solar storm can disable satellites or interrupt satellites that deliver weather forecast or GPS navigation or cell phone reception.”
Although sunspots rarely pose any physical danger to those within the bounds of the Earth’s atmosphere, those working in outer space face increasingly hazardous conditions when sunspots interfere with space weather. Scientists who performed space walks on the Columbus Module Thursday, for instance, faced the wrath of solar flares — with no atmosphere to protect them.
Protecting spacecraftTo guard their sensitive electronic equipment from radiation, aerospace engineers have two options, according to Andre Mazzoleni, associate professor of mechanical and aerospace engineering.
Radiation hardening, a technique with which engineers apply special coatings to electronic equipment, is one such option. The coating shields spacecrafts from radioactivity, protecting it from radiation damage.
For particularly sensitive components, the spacecraft can be rotated so that those components are facing away from the radiation’s source.
“If scientists knew exactly when [the radiation] was coming, they could reorient their spacecraft so, at that time, it is protected,” Mazzoleni said.
But the biggest danger, Mazzoleni said, is from orbiting debris, which can collide into spacecrafts.
“There are literally thousands of pieces of debris up there now — parts from previous space missions that have stopped working and exploded,” Mazzoleni said. “If it’s a big piece you can track it and sometimes maneuver away from it. If it’s a small piece, all you can do is hope for the best.”
Cycle 24Prior to January 4, when satellites detected a sunspot on the sun’s photosphere, the Sun was in a solar minimum.
Each time the sun switches from a period of minimum to maximum sunspots, it changes polarity.
“What signals the start of the next cycle is that change in polarity,” Morcone said. “Once we’re in solar maximum, you expect during that phase that there will be more energy emitted from the sun in terms of flares and sunspots. During a solar minimum, you see less.”
And the sun is not the only body that experiences this magnetic transition.
“Earth’s magnetic field does that as well, about every 10,000 years,” Egler said. “When the Earth’s magnetic field goes away … it’s not protected from cosmic rays.”
