Visitors from throughout Southern California often park their beach chairs and fishing gear on the narrow stretch of rocky sand that surrounds the Big Bear Solar Observatory, as it juts into Big Bear Lake from the north shore.
Few realize that the mysterious, white-domed facility behind them is home to one of the highest resolution solar telescopes in the world, or that a team of 14 experts keeps that telescope trained on the sun whenever it’s shining. And few know that the images and data captured by the observatory over the past half century have helped scientists unlock numerous mysteries about the star that powers our solar system, giving us a better understanding of the sun’s oscillations and magnetic fields, and other solar phenomena with fun names like flux ropes and sausage waves.
It’s not easy to translate much of that research into terms the general public can appreciate. That’s likely why, though more than 200 articles citing data from the Big Bear observatory have been published in scientific journals just in the past two years, even many locals don’t know much about what goes on inside the observatory.
But Wenda Cao, a physics professor and director of the Big Bear Solar Observatory, hopes a current project — which will expand the site’s purpose from one centered on discovery to one that includes practical applications — might change that.
After some recent upgrades, the observatory’s main telescope is offering a continuous feed of high-resolution images of electromagnetic storms taking place on the sun — and what that ball of glowing gas 93 million miles away looks like just before those storms get started. Another, recently-installed telescope will soon help collect long-term measurements of solar magnetic fields. And yet another is one of six in the world that helps to capture images of the sun 24 hours a day.
When this data is considered together, Cao and his team hope to identify patterns that could lead to an early warning system for solar storms.
Such a system could help travelers better plan to see the Northern Lights, which are triggered by solar storms. But it would also function much like systems that now warn us about coming tornadoes or hurricanes, offering a heads up to help minimize damage caused by solar flares and mass solar ejections. Such events can take out electrical grids, disrupt satellites and radios, put astronauts at risk and deliver an elevated dose of radiation to people on commercial flights in the North and South poles.
“That will be the holy grail of space weather predictions,” said Antti Pulkkinen, director of the Heliophysics Science Division at NASA’s Goddard Space Flight Center in Maryland.
Keeping an eye on solar storms
Space weather events become more common and intense each time the sun nears the peak of its 11-year cycle, during which its magnetic field completely flips. With the current cycle expected to peak by 2025, massive sunspots are now forming. Such spots often are precursors to solar storms, which Pulkkinen noted will be particularly worrisome as NASA gets ready to send astronauts back to the moon on its Artemis mission.
Researchers know sunspot formations greatly increase the odds for large solar storms. And Bill Murtagh, program coordinator for the National Oceanic and Atmospheric Administration’s Space Weather Prediction Center, said that if he gets images from the Big Bear Solar Observatory that show such clusters, he can issue a space weather forecast that might predict a 70% chance of a major solar flare in the next 24 hours.
But Murtagh said there are still gaps in our understanding that prevent him from being able to get on what he terms the “bat phone” to warn electrical grid operators or airlines of the day a solar storm is expected to hit Earth or how intense it might be.
First, he said, we can’t yet predict when and where sunspots will develop. We also don’t know how they’re going to evolve; some grow from nothing to 10 times the size of Earth in 48 hours, but never trigger storms. And for those that do, Murtagh said, they currently can’t tell if a flare is coming even five minutes before it happens. Eight minutes later, that flash of radiation can reach Earth. Most solar flare radiation bounces off our atmosphere, though it can throw off GPS systems and reach passengers in jets near the poles, where the Earth’s magnetic field is weakest.
The sun also throws out highly magnetized plasma, known as coronal mass ejections. Those take 24 hours to reach us. But, for now, we can’t predict mass ejections in advance any better than we can predict solar flares. And until these ejections pass spacecraft deployed by NASA or the National Oceanic Atmospheric Administration (NOAA), Murtagh said, we don’t know their heat or density or, critically, how their magnetized material is oriented.
This last point matters because a mass ejection acts like a magnet. If the ejection happens to be polarized in a way that is repelled by the Earth’s own magnetism, Murtagh said the threat is low. But if it’s polarized in a way that makes it attracted to Earth, the result can be intense — and potentially catastrophic — geomagnetic storms.
Currently, we can make the polarization call only about 20 minutes before a mass ejection would hit Earth.
An extreme geomagnetic storm has hit the Earth only once in recorded history. In 1859, in what’s known as the Carrington Event, a solar flare lit up the night sky so brightly that people got up for work, thinking the sun had risen. Northern Lights were visible in places like Cuba. And the electronic devices of the day — telegraph machines — failed and sparked and shocked their operators.
In 1989, a smaller solar storm took out the power grid in Quebec for nine hours, though its effects were felt as far south as California. Murtagh said we were lucky the grid didn’t fail here.
We all got even luckier 10 years ago.
The last time the sun’s cycle neared its peak, in 2012, the biggest solar storm in more than 150 years narrowly missed our planet. Had we taken a direct hit, scientists say it could have triggered widespread blackouts and damaged electrical systems. Repairs could have taken years and cost trillions of dollars.
A better advanced warning system could stave off a lot of damage in the event the next storm doesn’t miss us. Murtagh said grid operators could protect their systems from the coming surge of energy, airlines could delay or reroute flights and NASA could adjust missions. And the public could take steps to prepare, such as storing water, charging devices and filling gas tanks.
That might all sound pretty apocalyptic. But if you’re an astronomer at one of the world’s top solar observatories — with access to tools that didn’t exist the last time solar storms peaked and a list of mysteries you still hope to unravel — it also means things are about to get very interesting.
Winning location
The Big Bear Solar Observatory has been instrumental in helping to map the anatomy and behavior of the sun since its inception in 1969, said Kenneth Libbrecht, who did research at the site in his early years as a physics professor at Caltech in Pasadena.
Under late solar astronomer Harold Zirin, Caltech decided, during the thick of the space race in the 1960s, to build a solar observatory within driving distance of its Pasadena campus. There was a site already nearby, at Mount Wilson. But Libbrecht said air bouncing off the mountain there means that site isn’t known for great “seeing” — an astronomy term for how clear celestial images appear based on how much turbulence is in the atmosphere. (To understand the effect, look up at the stars and watch them appear to twinkle. Neat if you want inspiration for a lullaby, not so neat if you want a clear view of objects millions of miles away.)
On the hunt for an ideal spot in sunny Southern California for a new solar observatory, Zirin’s team selected a few dozen potential sites and spent several years gathering data. Lake Elsinore actually scored the best for seeing, Libbrecht said. Since water absorbs heat, they discovered there’s less turbulence when observatories overlook lakes.
It makes sense, then, that Big Bear came in No. 2 for seeing. But it had the added advantages of being at high altitude, where the atmosphere is thinner, and along a lake with a dam. That meant they wouldn’t have to worry about flooding, such as the one that hit Lake Elsinore in 1980.
Big Bear is now facing the opposite problem. When the lake is full, water surrounds the observatory site minus a narrow causeway that connects it to land. But the West’s climate change-fueled megadrought has dropped lake levels nearly 17 feet, creating a strip of beach around the observatory and along the causeway.
Cao said they haven’t yet noticed an increase in turbulence due to the lake drop. But he said it has posed security problems, since the public could walk right up to the facility’s door. So they recently installed chain link fence along the causeway.
Before the pandemic, the observatory was open for public tours as often as twice a month. Cao said they hope to resume those tours soon. But for now, other than occasional tours for curious reporters, the site is only open to the scientists and engineers who keep it running.
Life at the observatory
Down the causeway from the observatory, just across a forest road, a cluster of matching buildings might look like another small mountain resort.
But one building houses the newly installed SOLIS telescope, which Pulkkinen of NASA said will be critical in the quest to improve space weather predictions. Another building has offices and labs and a machine shop, where mechanical engineer Jeff Nenow crafts parts to repair equipment or to facilitate whatever latest project researchers have dreamed up. And another building is Cao’s home for the half the year he doesn’t spend teaching at the New Jersey Institute of Technology.
Since 1997, Caltech has leased the observatory to NJIT, which operates the site in conjunction with its Center for Solar-Terrestrial Research. The site gets grant funding from, among others, the National Science Foundation, NASA, the U.S. Air Force and the Korean National Science Foundation.
Researchers come from as far as South Korea to live and work for weeks at a time in the observatory complex. Top scientists can then debate their latest findings over coffee in the communal kitchen or jump on zoom chats with NASA in the conference room before their five-minute walk out to the observatory itself.
Research institutions apply to come and to share the site’s data. Right now, Cao said 42 institutions from 15 countries are on that list, with strong global collaboration around missions such as predicting space weather events.
Several employees spend their days inside the observatory dome, opening and closing it as needed, keeping the main telescope pointed in the right direction and running related instruments. While some systems can be operated remotely, Cao said, “Because this one is so very complicated, you don’t want to take the risk.”
As evidence of what can go wrong without careful monitoring, telescope operator Alex Bogdanovich pointed at burn marks in a steel plate that happened within seconds of the sun bouncing off the telescope’s mirror system on a cloudy day.
Safe to say this team never stops thinking about the power of the sun — both to sustain life and to potentially disrupt life as we now know it.
Planning ahead
We may not have a Doppler-style advance warning system for solar storms yet. But Murtagh, Pulkkinen and Cao all said they’re optimistic we can get there within the next 10 years.
On a monitor in his office, Cao played a timelapse video, made from images captured by Big Bear’s main telescope, that showed the sun before a recent storm. If his team can keep capturing such images and use them to discover patterns, he hopes they’ll soon be able to tell when solar storms are coming and how intense they might be.
That belief soon might be tested. The heliophysics team at NASA submitted proposals this week for its priorities over the coming decade. Pulkkinen said he’s confident that resources to develop solar weather prediction system will make the cut.
Given the dangers of an extreme space weather event, Murtagh said such a system is considered a matter of national security.
Along with offering advance warning, his agency wants to also give grid operators hard numbers for the voltage surge expected from a Carrington-level event. Regulators could then potentially require operators to build systems to withstand such an event, the way engineers have to build bridges in California to survive earthquakes of a certain size.
If facilities like the Big Bear Solar Observatory get the funding they need to continue their work, and so long as private companies do their part to prepare, Murtagh said he’s confident that risks from an extreme solar storm will drop before we hit the next peak of solar activity.
“That’s the hope,” Cao said.
Source: Orange County Register
Be First to Comment