Banner image: A filament of ultra-hot, ionized gas, or "plasma," leaps off the surface of the sun in 2012. (Credit: NASA Goddard Space Flight Center)
Meet the fans of big data who are helping to shape the scientific consensus on climate change鈥攁nd revealing new information about the workings of Earth鈥檚 favorite star.听
For more than four decades, generations of scientists, both in Colorado and beyond, have kept a close eye on the sun. They use a range of tools, from ancient maps to satellites in space, to track the sun鈥檚 energy output as it cycles between moods鈥攂lazing bright, then dimming back down again over years and decades.
These researchers, and their datasets, may not often make the headlines, said Odele Coddington, a research associate at the (LASP) at 麻豆免费版下载Boulder. But in a , Coddington and her colleagues have expanded scientists鈥� understanding of how the brightness of this star听shifts over time. In doing so, they鈥檝e helped to show how humans, not the sun, are changing the planet鈥檚 climate at a dangerous pace.
鈥淒ata stewardship isn鈥檛 always glamorous,鈥� Coddington said. 鈥淏ut these data are really important for teasing out how the sun鈥檚 brightness changes, now and in the past.鈥�
She would know. For more than 10 years, Coddington has helped to make precise space-based measurements of the sun鈥檚 energy output and convert them into data that climate scientists around the world can use. She and her colleagues are also trying to jump further back in time, drawing on historical records to estimate the sun鈥檚 activity during the time of Galileo Galilei and even earlier.听
It鈥檚 a pursuit that leaves little room for error, said Judith Lean, who retired in 2019 as a solar scientist at the U.S. Naval Research Laboratory. 听
鈥淭he sun鈥檚 energy is so strong, there鈥檚 so much energy, you really need to get your numbers right,鈥� she said.
A fickle star
Odele Coddington
Lean, who now collaborates with Coddington as a part-time research associate at LASP, has investigated the sun鈥檚 variability and its influence on Earth for more than 30 years. And, she noted, scientists have learned a lot about the orb during her career.
Star-gazers, of course, have 鈥攔eally, really hot. More than 1 million Earths could fit inside the sun. Its core reaches temperatures of millions of degrees, toasty enough for hydrogen atoms to meld together into helium atoms through nuclear fusion.听
Then the space era arrived.
In 1978, NASA launched a satellite called to measure the magnitude of the sun鈥檚 total brightness at Earth, which scientists call 鈥渟olar irradiance.鈥� It was followed by a series of spacecraft carrying increasingly advanced instruments, including the (SORCE). This intrepid vehicle launched in 2003 and remained in operation until 2020. It also carried four instruments designed and built by teams at LASP.听
From these orbiting sentinels, scientists realized the sun鈥檚 energy isn鈥檛 constant at all but goes through regular cycles lasting about 11 years. Between relatively quiet periods, the sun鈥檚 energy output increases until it reaches a 鈥渟olar maximum.鈥� At that stage, dark regions called sunspots crawl more often over the solar surface. Flares and events called coronal mass ejections burst frequently from the sun鈥檚 atmosphere.
Lean noted that these cycles matter. If you want to understand how humans are changing the Earth鈥檚 environment, including its climate and atmosphere, you first need to grasp how the sun influences the planet through natural processes.听
鈥淚f we didn't have the sun, we wouldn't have a greenhouse effect,鈥� Lean said. 鈥淚t鈥檚 the balance between incoming energy from the sun and the outgoing energy radiating from Earth to space that establishes temperatures on the planet. We now know that this incoming solar energy changes with time.鈥�
Historic records
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The SORCE spacecraft in a cleanroom before its launch. (Credit: NASA)
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Drawing of a sunspot made by the English monk John of Worcester in 1128 A.D. (Credit: image via )
Which is where Coddington comes in.听
She and her colleagues, including Lean, have built some of the most detailed records of ups and downs in the sun鈥檚 brightness over the last 20 years using data from space instruments. They include sensors aboard SORCE and, more recently, a new LASP instrument that sits on the International Space Station called the (TSIS-1). Coddington and her team at LASP provide quarterly updates of their solar irradiance records to the National Oceanic and Atmospheric Administration (NOAA). Scientists can then plug these numbers into global climate models鈥攈uge computer simulations that recreate the many factors that shape Earth鈥檚 climate and soaring temperatures over time.听
Earlier this year, Codding and her colleagues received major recognitions from an international body called the Committee on Earth Observation Satellites. The committee named one of the team鈥檚 records of the sun鈥檚 irradiance during a week in December 2019 as the 鈥�.鈥� In other words, international scientists consider these solar data to be the most accurate determination of the sun鈥檚 irradiance during a solar minimum.
Coddington also isn鈥檛 content to remain in the modern era. She explained that, for centuries, scientists from Chinese astronomers in the courts of Song dynasty emperors to Galileo himself have kept track of sunspots鈥攖hose shadowy features that dot the sun鈥檚 surface. These early researchers even drew maps of their observations, which are coming in handy today. In a counterintuitive twist, when you see more of these dark blotches on the sun, the star tends to grow brighter overall. 听
Coddington, Lean and their colleagues have drawn on those same maps to try to estimate just how much the sun鈥檚 variations in energy influenced Earth before the space era. Their most recent findings
鈥淧eople are uncovering sunspot records from even further back in the past,鈥� Coddington said. 鈥淔rom Chinese artifacts or tucked away in some file cabinet somewhere, there鈥檚 historical data recovery still being done today."听
For the scientist, the findings show just how many researchers have come together over the years to establish the scientific consensus on climate change鈥攆rom solar scientists and geologists to biologists, mathematicians, historians and many others.听
It鈥檚 a community Coddington is proud to be a part of.
鈥淚 wouldn鈥檛 even know how to begin to list out all of the names,鈥� she said, 鈥渢he whole family tree of scientists around the world who have had their fingers in shaping everything from the theory of how the sun behaves to observing its activity at the surface.鈥�
As a global leader in climate, environmental and energy research, the 麻豆免费版下载 is partnering with United Nations Human Rights to co-host the Right Here, Right Now Global Climate Summit in fall 2022.听
