Since December 2019, the sun has been moving into a busier part of its cycle in which increasingly intense pulses of energy can shoot in all directions. Some of these large bursts of charged particles are heading straight for Earth. Without a good way to anticipate these solar storms, we are vulnerable. A big one could turn off some of our communications systems and power grids before we even knew what was happening to us.
A recent near miss occurred in the summer of 2012. A huge solar storm hurled a high-radiation lump at more than 9 million kilometers per hour in the direction of the earth. The potentially debilitating eruption quickly traversed nearly 150 million kilometers towards our planet and would have hit Earth if it had come just a week earlier. Scientists found out about it afterwards just because it hit a NASA satellite that was designed for this type of space weather.
This 2012 storm was the most intense that researchers have measured since 1859. When a strong storm hit the northern hemisphere in September of this year, people weren’t so lucky. Many telegraph systems across Europe and North America failed, and the electrified lines shocked some telegraph operators. It came to be known as the Carrington Event, named after British astronomer Richard Carrington, who experienced intensely bright spots of light in the sky and recorded what he saw.
The world has gone far beyond telegraph systems. A Carrington level impact today would turn off satellites and disrupt GPS, cellular networks and internet connections. Banking systems, aviation, trains and traffic signals would also be affected. Repairing damaged power grids would take months or more.
Right now, during a pandemic where many of us rely on Zoom and other video communication programs to work and go to school, it is hard to imagine the sweeping upheaval such an event would create. In a pre-pandemic worst-case scenario, researchers estimated that the U.S. economic toll could reach trillions of dollars, according to a 2017 review Risk analysis.
To avoid such destruction, then-President Donald Trump signed a bill in October to aid research into making better space weather forecasts and assessing possible impacts, and allowing better coordination between agencies such as NASA and the National Oceanic and Atmospheric Administration.
“We understand a little bit about how these solar storms form, but we can’t predict it [them] good, ”says atmosphere and space scientist Aaron Ridley of the University of Michigan at Ann Arbor. Just as scientists know how to map the likely path of tornadoes and hurricanes, Ridley hopes to see the same possibilities for predicting space weather.
The ideal scenario is to receive alerts before a storm deactivates satellites or lands, and possibly even before the sun sends charged particles in our direction. With advance warning, utilities and governments could turn off networks and move satellites out of the way.
Ridley is part of a U.S. collaboration that is creating simulations of solar storms to help scientists quickly and accurately predict where the storms will go, how intense they will be, and when they could affect major satellites and power grids on Earth. Given the chaos that an extreme solar storm could cause, many scientists and governments want to get better predictions as soon as possible.
ebb and flow
When scientists talk about space weather, they usually refer to two things: the solar wind, a constant stream of charged particles flowing away from the sun, and coronal mass ejections, huge bursts of charged particles or plasma blown out of the outer layers of the sun (SN Online: 07.03.19). Some other phenomena, such as high-energy particles known as cosmic rays, are also considered space weather, but they do not cause much concern.
Mass coronal ejections, or CMEs, the most threatening type of solar storms, aren’t always harmful – they eventually create iridescent aurors near the poles. Given the risks of a storm shutting down critical military and commercial satellites or affecting the health of orbiting astronauts, it is understandable that scientists and governments are concerned.
Astronomers have looked at our sun companion for centuries. In the 17th century, Galileo was one of the first to spy on sunspots, slightly cooler areas on the solar surface with strong magnetic fields, which are often the precursors of more intense solar activity. His successors later noticed that sunspots often produce bursts of radiation known as solar flares. The sun’s complex, shifting magnetic field sometimes also causes filaments or plasma loops thousands of kilometers in diameter to break out of the sun’s outer layers. These types of solar flares can create CMEs.
“The sun’s magnetic field lines can become complicated and twisted in certain regions,” says Mary Hudson, a physicist at Dartmouth College. These lines can break like a rubber band and carry a large piece of corona into interplanetary space.
It was the 19th century German astronomer Samuel Heinrich Schwabe who recognized that this solar activity drained and drained during 11-year cycles. This happens because the sun’s magnetic field is completely reversed every 11 years. The last solar cycle ended in December 2019 and we are leaving the bottom of solar activity as we approach the maximum of cycle 25 (astronomers started numbering solar cycles in the 19th century). Solar storms, especially the dangerous CMEs, are becoming more frequent and intense and should peak between 2024 and 2026.
Solar storms arise from the complex magnetic field of the sun. The sun rotates faster at its equator than at its poles. Since it is not a solid ball, its magnetic field constantly twirls and twirls around. At the same time, the heat from inside the sun rises to the surface, with charged particles bringing new magnetic fields with them. The most intense CMEs usually come from the strongest phase in a particularly active solar cycle, but there are many variations. The 1859 CME came from a modest solar cycle, says Hudson.
A CME consists of several components. If the CME is on a trajectory towards Earth, the first thing – just eight minutes after leaving the sun – is the electromagnetic radiation, which moves at the speed of light. CMEs often create a shock wave that accelerates electrons to extremely fast speeds, and these arrive within 20 minutes of the light. Such energetic particles can damage the electronics or solar cells of satellites in high orbits. These particles could also harm astronauts outside of Earth’s protective magnetic field, including those on the moon. However, a crew on board the International Space Station in the Earth’s magnetic field would most likely be safe.
The greatest threat to a CME – its giant plasma cloud, which can be millions of kilometers wide – usually takes between one and three days to reach our planet, depending on how fast the sun has driven the flood of particles from the shotgun towards us. The Earth’s magnetic field, our first defense against space weather and space radiation, can only protect us from so much. Satellites and ground-based observations have shown that the charged particles of a CME interact with and distort the magnetic field. These interactions can have two major implications: creating more intense electrical currents in the upper atmosphere and moving those stronger currents away from the poles to places with more people and more infrastructure, says Ridley. In an extremely strong storm, it is these potentially massive currents that endanger satellites and power grids.
Anyone who depends on long distance signals or telecommunications may have to forego them until the storm is over and damaged satellites are repaired or replaced. A strong storm can also disrupt aircraft in flight, as pilots lose contact with air traffic controllers. While the effects are temporary, usually lasting up to a day, the effects on the power grids can be worse.
A massive CME could suddenly and unexpectedly drive currents of kilo-amps instead of the usual amps through power cords on Earth, overwhelming transformers and causing them to melt or explode. Thanks to such a CME, the entire province of Quebec, with a population of almost 7 million, suffered a power outage during a particularly active solar cycle that lasted more than nine hours on March 13, 1989. The CME also covered New England and New York. If the power grid operators had known what was coming, they could have reduced the flow of electricity to lines and connections in the power grid and set up emergency power generators if necessary.
But planners need more heads-up than they do today. Perhaps within the next decade, thanks to improved computer modeling and new space weather monitoring capabilities, scientists will be able to predict solar storms and their likely effects more accurately and earlier, says physicist Thomas Berger, director of the Center for Space Weather Technology, Research and Education at the University of Colorado Boulder.
Space meteorologists classify solar storms on a five-point scale like hurricanes based on disturbances in the earth’s magnetic field. In contrast to these tropical storms, the likely arrival of a solar storm is not precisely known using available satellites. The National Weather Service has access to constantly updated data for storms on earth. However, space weather data is too sparse to be very useful and there are few storms to monitor and provide data to.
Two US satellites monitoring space weather are NASA’s ACE spacecraft from the 1990s, which is scheduled to collect data for a few more years, and NOAA’s DSCOVR, which was developed at a similar point in time but was not launched until 2015. Both orbit about 1.5 million kilometers above the earth – which seems far, but is hardly in front of our planet from the point of view of a solar storm. The two satellites can only detect and measure a solar storm if its impact is imminent: 15 to 45 minutes away. This is more like “nowcasting” than forecasting, and offers little more than a warning to prepare for impact.
“That’s one of the big challenges of space weather: predicting the magnetic field of a CME long before it comes [here] so that you can prepare for the incoming storm, ”says Berger. However, aging satellites such as SOHO, a satellite launched in 1995 by NASA and the European Space Agency, as well as ACE and DSCOVR, only monitor a limited range of directions that do not include the sun’s poles, leaving a large void in those Observations.
Ideally, scientists want to be able to predict a solar storm before it is blown into space. This would give network operators more than a day’s lead time to protect transformers from voltage spikes, and satellites and astronauts could get out of the way if possible.
This requires collecting more data, especially from the sun’s outer layers, as well as better estimating when a CME will break out and whether it can be expected to arrive with a bang or a whimper. To aid this research, NOAA scientists will equip their next space weather satellite, due to launch in early 2025, with a coronagraph, an instrument to study the outermost part of the sun’s atmosphere, the corona, while blocking most of the sunlight. otherwise it would blind his vision.
A second major improvement could come just two years later, in 2027, with the launch of ESA’s Lagrange mission. It will be the first space weather mission that one of their spaceships will launch in a unique location: 60 degrees behind the earth in their orbit around the sun. Once in position, the spaceship will be able to see the sun’s surface from the side before the sun’s face has turned and turned towards the earth, says Juha-Pekka Luntama, head of ESA’s space weather office.
This allows Lagrange to monitor an active, flaring area of the sunny days earlier than other spaceships, determining the speed and direction of a new solar storm more quickly so scientists can make a more accurate prediction. With these new satellites, there will be more spaceships watching for incoming space weather from different locations, giving scientists more data for forecasting.
In the meantime, Berger, Ridley, and colleagues are focused on developing better computer simulations and models of the behavior of the solar corona and the effects of CMEs on Earth. Ridley and his team are developing a new software platform that will allow researchers anywhere to quickly update models of the upper atmosphere affected by space weather. Ridley’s group also models how a CME shakes our planet’s magnetic field, releasing charged particles towards the land below.
Berger is also working with other researchers to model and simulate the Earth’s upper atmosphere to better predict how solar storms will affect their density. When a storm hits, it compresses the magnetic field, which can alter the density of the outer layers of the Earth’s atmosphere and affect how much resistance satellites have to fight to stay in orbit.
There have been a few cases of satellites damaged by solar storms. The Japanese ADEOS-II satellite stopped working in 2003 after a period of intense solar eruptions. And the Solar Maximum Mission satellite appeared to have been dragged into lower orbit – and eventually burned up in the atmosphere, after the same 1989 solar storm that left Quebec in the dark.
Satellites affected by solar storms can collide with each other or space debris. With mega constellations of satellites like SpaceX launched by the hundreds (SN: 28.03.20, p. 24) and with tens of thousands of satellites and debris already in crowded orbits, there is a risk that something will drift in the path of something else. Every space crash will surely also generate more space debris and throw away debris that also endangers the spaceship.
These are all powerful motivators for Ridley, Berger, and colleagues to investigate how storm-powered pulling works. The U.S. military tracks satellites and debris and predicts where they’re likely to be in the future, but all of those calculations are worthless without knowing the effects of solar storms, says Boris Kramer, an aerospace engineer at the University of California in San Diego working with Ridley. “In order to place satellites on trajectories to avoid collisions, you have to know the space weather,” says Krämer.
It takes time to create simulations that estimate the drag of a single satellite. Current models run on powerful supercomputers. However, if a satellite has to use its on-board computer to perform these calculations on the fly, researchers need to develop sufficiently accurate models that run much faster and with less power.
New data and new models are unlikely to be online in time for the upcoming solar storm season, but should be available for solar cycle 26 in the 2030s. Perhaps by then, scientists can give earlier red warnings to warn of an incoming storm and have more time to move satellites, prop up transformers, and fend off the worst.
The goal of improving space weather forecasts has attracted widespread support and interest from the federal government, including Lockheed Martin, because of the threat to key satellites, including the 31 that make up the U.S. GPS network.
Growing interest in space weather led to the 2020 Act known as Promoting Space Weather Research and Monitoring to Improve Tomorrow’s Forecast (PROSWIFT). And the National Science Foundation and NASA have provided support for space weather research programs like Berger and Ridley. For example, Ridley, Krämer and their employees recently received NSF grants of US $ 3.1 million to develop new space weather computer simulations and software, among other things.
Our dependence on technology in space is fraught with increasing vulnerabilities. Some space scientists speculate that we did not find any extraterrestrial civilizations because some of those civilizations have been wiped out by the very active stars that orbit them. This could destroy the atmosphere of a once habitable world and expose life on the surface to harmful stellar radiation and outer space weather. Our sun is not as dangerous as many other stars that are magnetically active more frequently and intensely, but it can endanger the way we live.
“Worldwide we have to take space weather seriously and prepare. We don’t want to wake up one day and our entire infrastructure has failed, ”says Luntama from ESA. With critical satellites and power grids suddenly destroyed, we can’t even call for help with our phones.