LAKEPORT, Calif. – The Lake County Library’s Summer Reading Program is in full swing.
Librarian Christopher Veach announced that so far 634 people have signed up. That’s 40 teens, 449 kids and 145 adults who have accrued a combined total rapidly approaching 311,000 points. Each page read counts as a point.
The Summer Reading Program has a few more weeks to go so there is still time to join the fun. You can sign up at any Lake County Library branch.
The last day to return books for credit is July 28. Prizes will be awarded in August.
Awards parties for kids will be held at all four branch libraries. Lakeport Library will have its party on August 4 at 10 a.m. Redbud Library will hold its party on Aug. 4 at 10 a.m. Middletown Library’s party will be Aug. 7 at 11:30 a.m. Upper Lake Library will celebrate on August 2 at 2 p.m.
The teen Summer Reading Program party will be Aug. 1 at 4 p.m. at Lakeport Library.
For adult participants, the prizes will be announced on Aug. 4. Winners will be notified that they can pick up their prizes.
Your prize will be available to pick up at the same library where you signed up even after the Summer Reading Program party. Prizes will be held until Sept. 1.
Jan Cook is a technician with the Lake County Library.
NORTHERN CALIFORNIA – The region’s largest wildland fire was fully contained on Saturday, while officials confirmed that a Cal Fire equipment operator was killed on the Ferguson fire on Saturday morning.
The County fire’s vast area – it has burned 90,288 acres since June 30 – was fully contained as of Saturday night, when Cal Fire issued its final report on the incident.
The fire, which began in Guinda in Yolo County before burning into Napa County, destroyed 20 structures and damaged three others.
Cal Fire said fire suppression repair teams continue working around the fire perimeter and affected areas.
In Butte County, the Stoney fire in Chico’s Bidwell Park continued to burn on Saturday.
The fire, which began on Thursday night, has so far burned 956 acres and was 65-percent contained as of Saturday night, Cal Fire said.
To the south, tragedy struck on Saturday on the lines of the Ferguson fire on the Sierra National Forest.
Officials confirmed on Saturday that Cal Fire Heavy Fire Equipment Operator Braden Varney, 36, from the agency’s Madera-Mariposa-Merced Unit, was killed.
Varney, a second generation Cal Fire employee who had worked with the agency for 10 years, is survived by his wife, Jessica, 5-year-old daughter Malhea and 3-year-old son Nolan.
Cal Fire said the Ferguson fire started Friday at 10:35 p.m. near El Portal in Mariposa County. The fire was under Unified Command with Cal Fire Madera-Mariposa-Merced Unit and the US Forest Service-Sierra National Forest but was turned over to the Forest Service on Saturday.
The Ferguson fire on Saturday night was 1,000 acres and 5 percent contained.
On Saturday Gov. Jerry Brown honored Varney.
“Anne and I were deeply saddened to learn of the death of Heavy Equipment Operator Braden Varney, a man who dedicated his life to protecting his fellow Californians. We extend our deepest sympathies to his family, friends and many colleagues who are mourning this sudden and tragic loss,” Gov. Brown said.
In honor of Varney, Capitol flags will be flown at half-staff, the Governor’s Office reported.
Email Elizabeth Larson at This email address is being protected from spambots. You need JavaScript enabled to view it.. Follow her on Twitter, @ERLarson, or Lake County News, @LakeCoNews.
LAKE COUNTY, Calif. – With temperatures expected to climb early next week, the National Weather Service issued a heat advisory for Lake County and other portions of Northern California.
The National Weather Service said the advisory will be in effect from noon to Sunday to 8 p.m. Monday.
A heat advisory means that a prolonged period of hot temperatures is expected and will create a situation in which heat illnesses are possible.
Forecasters said building high pressure will bring hot temperatures over the weekend with daytime highs from 10 to as much as 15 degrees above normal.
The specific Lake County forecast calls for temperatures topping the century mark on Monday, and remaining in the high 90s throughout much of the week.
The National Weather Service said thunderstorms are possible in the mountains at that time.
Close to next weekend, temperatures will drop as cloudy conditions arrive, according to the forecast.
Email Elizabeth Larson at This email address is being protected from spambots. You need JavaScript enabled to view it.. Follow her on Twitter, @ERLarson, or Lake County News, @LakeCoNews.
LAKEPORT, Calif. – Staff of the California Regional Water Quality Control Board, Central Valley Region, will hold a board workshop on Wednesday, July 18, to discuss the status and the board’s potential next steps associated with the Clear Lake Nutrient Total Maximum Daily Load Control Program.
The Central Valley Water Board workshop will take place in two sessions: an on-site discussion from 11 a.m. to noon at Library Park with a meeting to take place from 2:30 to 5:30 p.m. at Lakeport City Hall, 225 Park St., across the street from the park.
In August 2017, Central Valley Water Board staff conducted a public meeting in Lake County regarding the status of the Clear Lake Nutrient TMDL Control Program. The upcoming board workshop is a response to the concerns heard during that meeting.
Stakeholders expressed concerns regarding a proposed extension of the June 2017 TMDL compliance date.
In response to the stakeholder concerns associated with an extension to the TMDL, board staff is recommending revising the next steps for the TMDL.
Though an extension of the compliance date continues to be a potential option, staff is prioritizing assessment of attainment of the waste load allocations by further gathering and evaluating water quality data and information from the responsible parties identified in the TMDL.
Once the board makes additional determinations regarding attainment of allocations, appropriate next steps will be identified.
At the August 2017 workshop, stakeholders also expressed a desire to speak directly to the board decision makers.
To address this request, and to provide an update to stakeholders on the status of TMDL implementation activities, the Central Valley Water Board will be hosting a workshop in Lakeport.
Board members and management will attend and be available to hear input directly from stakeholders on the TMDL, priorities the board should focus on within the Clear Lake watershed, and recommended next steps.
Stakeholders will also hear updates on various water quality efforts currently taking place within the watershed by other organizations.
At the afternoon meeting, board staff will present their current assessment of each responsible party’s load allocation progress, next steps in this process, and other board activities taking place related to the Clear Lake Nutrient TMDL Control Program.
In addition, other organizations will give presentations on their current efforts within the watershed. This will allow board members and the public an opportunity to learn about current water quality initiatives in the Clear Lake watershed.
A technical memorandum for the meeting can be found here.
LAKE COUNTY, Calif. – Lake County Animal Care and Control has several big dogs waiting for homes at its shelter this week.
Dogs available for adoption this week include mixes of border collie, German Shepherd, Labrador Retriever, mastiff, pit bull and and spaniel.
Dogs that are adopted from Lake County Animal Care and Control are either neutered or spayed, microchipped and, if old enough, given a rabies shot and county license before being released to their new owner. License fees do not apply to residents of the cities of Lakeport or Clearlake.
If you're looking for a new companion, visit the shelter. There are many great pets hoping you'll choose them.
The following dogs at the Lake County Animal Care and Control shelter have been cleared for adoption (additional dogs on the animal control Web site not listed are still “on hold”).
Male border collie
This young male border collie has a short black and white coat.
He’s in kennel No. 11, ID No. 10334.
‘Wrynn’
“Wrynn” is a female German Shepherd with a medium-length black and brown coat.
She’s in kennel No. 17, ID No. 10433.
Spaniel-border collie
This male spaniel-border collie mix has a black and white coat.
He’s in kennel No. 19, ID No. 10380.
Male mastiff mix
This male mastiff mix has a short tan and white coat.
He’s in kennel No. 26, ID No. 10191.
Male mastiff mix
This male mastiff mix has a short tan and white coat.
He’s in kennel No. 27, ID No. 10192.
‘Yogi’
“Yogi” is a male Labrador Retriever-pit bull mix with a medium-length brown and black coat.
He already has been neutered.
He’s in kennel No. 31, ID No. 10082.
‘Lala’
“Lala” is a female German Shepherd with a brown and black coat.
She’s in kennel No. 32, ID No. 10420.
‘Kumo’
“Kumo” is a male pit bull terrier with a short blue and white coat.
He’s in kennel No. 34, ID No. 10424.
Lake County Animal Care and Control is located at 4949 Helbush in Lakeport, next to the Hill Road Correctional Facility.
Office hours are Monday through Friday, 11 a.m. to 5 p.m., and 11 a.m. to 3 p.m., Saturday. The shelter is open from 11 a.m. to 4 p.m. Monday through Friday and on Saturday from 11 a.m. to 3 p.m.
For more information call Lake County Animal Care and Control at 707-263-0278.
Email Elizabeth Larson at This email address is being protected from spambots. You need JavaScript enabled to view it.. Follow her on Twitter, @ERLarson, or Lake County News, @LakeCoNews.
NORTHERN CALIFORNIA – As major wildland fires around Northern California neared full containment on Friday, a new incident erupted in Chico, threatening dozens of homes.
The County fire in Napa and Yolo counties is expected to be fully contained on Sunday and the Klamathon fire in Siskiyou County also rose in containment, while the Stoney fire in Chico began Thursday night.
Cal Fire said the County fire, remaining at 90,288 acres, reached 97 percent containment on Friday night.
The fire began on June 30 near Guinda. Cal Fire investigators said it began as a result of an improperly installed electric fencing unit.
The Klamathon fire grew to 37,900 acres on Friday, with containment up to 85 percent, Cal Fire said.
The fire began July 5, and has killed one civilian, injured three firefighters and destroyed 82 structures, according to Cal Fire.
In Chico, the Stoney fire near Bidwell Park began late Thursday night, burning more than 600 acres overnight and causing the evacuation of about 50 homes, according to Cal Fire.
By Friday night, Cal Fire said the Stoney fire was up to 700 acres, with containment at 40 acres.
The Stoney fire evacuations were lifted on Friday, officials said.
Email Elizabeth Larson at This email address is being protected from spambots. You need JavaScript enabled to view it.. Follow her on Twitter, @ERLarson, or Lake County News, @LakeCoNews.
LAKEPORT, Calif. – A decade ago, a project of the Lake County Arts Council, the Soper Reese Theatre, reopened as the only dedicated performing arts center in Lake County.
The facility provides the community with a stage and venue for live music and dancing, theater productions, movie screenings, a space to rent for conferences and meetings, and is home to the Lake County Symphony – but fundraising is still under way.
Committed to providing a venue for a variety of performing arts, Soper Reese Executive Director Michael Adams – one of the many volunteers pitching in to make this center a success – said recently that, to date, they have raised more than $1.7 million.
However, the next phase – refurbishing the restrooms and constructing ADA-compatible access to the theatre – is still not quite funded.
The fundraising goal for the first phase of renovation, the “Restroom Re-Do,” is $350,000, Adams said.
“When we reach $300,000, we will break ground,” Adams said, noting that they have raised over half of that goal to date.
Being fiscally responsible for the funds raised, Adams explained that it made no financial sense to repaint the outside of the building, when it will have stucco applied for waterproofing and painted in the future.
“I don’t want to spend money doing the same thing twice,” Adams said.
Early on after reopening the theatre, a major donor chose another community project in Ukiah to give their $1 million donation to because, at that point, the Soper Reese did not have a financial reserve, nor had they raised all of the funds to complete projects once they were under way.
“We learned a valuable lesson from losing that major donation,” Adams explained, and they now have a policy that requires them to maintain a financial reserve, and added that they have no debt.
After Phase I, the Restroom Re-Do, Phase II will expand the lobby facade and the stage at an estimated cost of $250,000, Adams said.
He said Phase III will create a multipurpose room that can be used for conference breakout rooms on the Martin Street side and add another marquee for $200,000, for a total of $800,000 that will need to be raised to complete all major renovations.
Depending on the type of event, seating capacity at the Soper Reese ranges from 271 to 300 guests, making it an ideal venue to rent for large meetings and trainings, as well as musical and theatrical productions, movie screenings and more.
Regularly scheduled events at the theatre include two movie series – Classic Cinema and Gen X Cinema – which can be sponsored by an individual or business, the Lake County Symphony, Chamber Music series and Third Friday Live, along with other recurring events like Bastille Day Fete, Harmonica Slapdown, comedy shows, fundraisers with live music and more to come, including a jazz music series.
Beginning in October, another way to help the theatre – and have a good time – will be to sponsor a movie that you would like to see again on a big screen in a theatre.
“For $150, any member of the public will be able to sponsor a movie, as long as we can get the licensing and we’ll show it,” Adams said, and the sponsor will get to take the copy of the movie home.
For more information on events, to donate, or to volunteer with the Soper Reese theatre, visit www.soperreesetheatre.com or call 707-263-0577.
Terre Logsdon is a freelance correspondent for Lake County News.
BERKELEY, Calif. – Human activity is causing the planet’s mammals to flee daylight for the protection of night, according to a new study from UC Berkeley.
The study, published in the journal Science, and supported in part by the National Science Foundation, represents the first effort to quantify the global effects of human activity on the daily activity patterns of wildlife.
Its results highlight the powerful and widespread process by which animals alter their behavior alongside people: human disturbance is creating a more nocturnal natural world.
“Catastrophic losses in wildlife populations and habitats as a result of human activity are well documented, but the subtler ways in which we affect animal behavior are more difficult to detect and quantify,” said Berkeley PhD candidate and study lead author Kaitlyn Gaynor.
Gaynor, along with co-authors Justin Brashares and Cheryl Hojnowski of UC Berkeley, and Neil Carter of Boise State University, applied a meta-analysis approach, using data for 62 species across six continents to look for global shifts in the timing of daily activity of mammals in response to humans.
These data were collected by various approaches, including remotely triggered cameras, GPS and radio collars, and direct observation. For each species in each study site, the authors quantified the difference in animal nocturnality under low and high human disturbance.
On average, mammals were 1.36 times more nocturnal in response to human disturbance. This means that an animal that naturally split its activity evenly between the day and night increased its nighttime activity to 68 percent around people.
This finding was consistent across carnivore and herbivore species of all body sizes greater than 1 kg (small mammals were not included in the study).
The pattern also held across different types of human disturbance, including activities such as hunting, hiking, mountain biking, and infrastructure such as roads, residential settlement, and agriculture.
“While we expected to find a trend towards increased wildlife nocturnality around people, we were surprised by the consistency of the results around the world,” said Gaynor. “Animals responded strongly to all types of human disturbance, regardless of whether people actually posed a direct threat, suggesting that our presence alone is enough to disrupt their natural patterns of behavior.”
According to Brashares, a professor in the Department of Environmental Science, Policy, and Management and the study’s senior author, the consequences of the behavioral shift in wildlife can be seen through contrasting lenses.
“On the positive side, the fact that wildlife is adapting to avoid humans temporally could be viewed as a path for coexistence of humans and wild animals on an increasingly crowded planet,” said Brashares. “However, animal activity patterns reflect millions of years of adaptation – it’s hard to believe we can simply squeeze nature into the dark half of each day and expect it to function and thrive.”
The authors describe a range of potential negative consequences of the shifts they report in wildlife, including mismatches between the environment and an animal’s traits, disruption of normal foraging behavior, increased vulnerability to non-human predators, and heightened competition.
They point out, however, that while many of the studies included in their analysis documented a clear increase in nocturnal activity, few examined the consequences for individual animals, populations, or ecosystems.
“We hope our findings will open up new avenues for wildlife research in human-dominated landscapes. We still have a lot to learn about the implications of altered activity patterns for the management of wildlife populations, interactions between species, and even human-induced evolution,” said Gaynor.
Mackenzie Smith writes for the UC Berkeley News Center.
NORTH COAST, Calif. – A paraglider escaped injury after authorities say he crashed at Del Rio Woods Beach east of Healdsburg Friday.
At approximately 9:20 a.m. Friday, Misti Harris of the Sonoma County Sheriff’s Office said the agency received a call of a paraglider crash at Del Rio Woods Beach, just off of South Fitch Mountain Road.
A Geyserville man was paragliding south from Geyserville. He clipped some power lines near Del Rio Woods Beach and crash landed on the beach, Harris said.
Harris said power was shut off in the area due to the damaged power lines.
The man was not hurt. He removed the parachute from the trees and walked away, according to Harris
Local fire and medical crews responded, including Healdsburg Fire Department. Harris said the man was medically evaluated and released at the scene.
PG&E crews responded and repaired the lines, Harris said.
Each decade, the Census calculates the mean center of population – the place where an imaginary map of the U.S. would balance perfectly if every American weighed the same.
In other words, it’s the middle point of where all Americans live.
The first census of 1790 located this center of population 23 miles east of Baltimore, Maryland.
By the next decade, the point had moved to 18 miles west of Baltimore and by 1820, the migration of Americans had tipped the center even further westward to a point 16 miles east of Moorfield, West Virginia.
The history of the United States is a story of movement – of restless men and women spreading out across the continent, over mountains and across prairies like the spores of a great fungus cast to the wind.
And like a fungus, wherever these wayward people landed, they propagated and expanded, consuming the nutrients of the land and driving out all native life before sending forth their own spores to race ever westward.
That’s one analogy for our nation’s westward migration. Another, far rosier, version positions the migrant at the center of some divine prerogative. In this schema, the western land and its people were put on this earth to test the mettle of the young nation, to harden and temper the raw material so that it could go on to do greater things still.
Horace Greeley, famous American journalist and then vice president during the mid-19th century, canonized this vision of the west when he exhorted his readers to, “Go west, young man, and grow up with the country!” We’re told that he wrote those famous words on July 15, 1865, as the editor of the New York Tribune.
But, like so much of the golden west itself, this now famous slogan is just a mirage – its pomp and esteem billow away to nothing upon closer inspection. If you were to search out a copy of the July 15, 1865, Tribune, you would be rightly frustrated in not finding this phrasing anywhere. If you happen to look at other issues of the paper during that week, or month, or year, you still wouldn’t find it. In fact, here is no evidence whatsoever that Horace Greeley ever wrote those words.
Sure, he said things similar to that slogan, like the following:
“We earnestly urge upon all such [returning Civil War veterans] to turn their faces Westward and colonize the public lands.”
“O, deceive not yourselves thus, young men! To the rightly constituted Man, there always is, there always must be, opportunity.”
“Fly, scatter through the country – go to the Great West.”
“I hold that tens of thousands, who are now barely holding on at the East, might thus place themselves on the high road to competence and ultimate independence at the West.”
All in their own right decent sentences, but none quite as punchy as “Go West, young man, and grow up with the country!” So who has the honor of bringing forth the motto of westward migration?
No one, actually. The earliest written occurrence of that exact phrasing appears the August 20, 1870 issue of the magazine Punchinello, in a piece titled “The Mystery of Mr. E. Drood: An Adaptation,” by Orpheus C. Kerr (the pseudonym of Robert Henry Newell:
“As for you, an American boy, why don’t you go to h-I mean to the West. Go West, young man! Buy a good, stout farming outfit, two or three serviceable horses, or mules, a portable house made in sections, a few cattle, a case of fever medicine and then go out to the far West upon Government-land. You’d better go to one of the hotels for to-night, and then purchase Mr. GREELEY’s What I Know About Farming, and start as soon as the snow permits in the morning.”
Wouldn’t it be grand if this were the actual origin of that phrase? Rather than coming from the most eloquent writer of his generation, the now-famous slogan was actually written by a famous humorist for a satirical magazine, which went out of business after only nine months of operation (seriously, Punchinello was inspired by the British satirical magazine Punch, and it only lasted from April to December of 1870).
Alas, we don’t know if that is true or not. But even if the exact phrasing can’t be attributed to him, it is true to say that Greeley was the loudest proponent of westward migration at the time.
Although he himself never went farther west than Colorado, he some form or another, he urged his nation to cast its spores to the westward-blowing wind. By the time of this admonition to “Go West,” the center point of the United States’ population had already crossed the Appalachians and settled in the fertile valleys of Ohio.
After more than a century of inching westward, the mean center entered the state of Missouri, where it has remained since 1980.
Antone Pierucci is curator of history at the Riverside County Park and Open Space District and a freelance writer whose work has been featured in such magazines as Archaeology and Wild West as well as regional California newspapers.
NORTHERN CALIFORNIA – You’ve probably seen them leafing out and blossoming all over the region, their newly formed leaves a bright chartreuse that will eventually turn darker green and take on a kind of fuzzy matt finish.
They’re trees that ignore the pre-set seasons so strictly adhered to by other trees: they wake up in the winter and settle down to sleep in the late summer.
They’re California Buckeyes (Aesculus californica), a species endemic to California – meaning that they grow here and nowhere else on earth.
The buckeye tree can grow up to 20 feet tall and have a branch-span of about 30 feet. When planted from seed it can sprout up 10 inches each year, and has the capacity to live for over 250 years. And it’s this tree’s seeds that are so spectacular.
Getting as a large as a fist, the dark chestnuts look like polished mahogany when they’re released from their leathery husks. The chestnuts drop to the ground in the wettest part of winter.
Each one sends out a long pinkish taproot that bores into the earth, and also releases a finely leafed sprout that forms above ground on a rose-colored stem. If it survives, this sprout will become the new tree.
Although they’re beautiful and fascinating, these are not the kind of chestnuts you can eat.
Sweet chestnuts are actually an entirely different species: Castanea sativa.
California Buckeye chestnuts contain a neurotoxic glucoside called “aesculin,” among other compounds, that can cause severe stomach pains, disorientation, muscle weakness and death in mammals, including humans.
Ingestion of the sprouts, leaves and seeds is also known to be linked to the spontaneous abortion of calves in grazing cattle.
Adult California ground squirrels, however, have a natural immunity to the toxins – just as they have a natural immunity to rattlesnake venom.
In the winter, you’ll often see the forest floor and areas around the squirrels’ burrows littered with chewed up, half-eaten Buckeye chestnuts.
Mule deer and Steller’s Jays have also been known to eat the leaves and chestnuts, but only in very small quantities.
Although not good as shade trees because they lose their leaves in the summer, California Buckeyes are great at binding the soil with their roots and are often used for erosion control. They can also thrive in drought stricken areas and in nutrient-poor soils where other trees fail.
In the spring, they display long 4- to 8-inch panicles of small, sweet-scented flowers (white or pink) which attract a wide variety of pollinators.
The blossoms are a favorite of the tiger swallowtail butterflies, and the trees are also the hosts to the caterpillars of the echo blue butterfly (Celastrina argiolus).
Care has to be taken not to plant the trees near apiaries, however, because the blossoms’ inviting nectar and pollen are poisonous to European honeybees.
Additionally, according to the USDA, “Human beings have been poisoned by eating honey made from California Buckeye.”
Of all of the flowers displayed on its panicles, only one will survive to actually develop into a chestnut. In the later summer months, you can see single chestnuts dangling here and there from branches of the trees like leathery bobs on pendulum strings.
As we mentioned before, the California Buckeye is one of the few trees in our state that “estivates” in summer.
All of its leaves shrivel and turn golden brown, and most fall off as the tree goes dormant. It’s this summer leaf-drop that can add fuel for wildfires in some of the trees’ natural range.
The chestnuts ripen in the fall, and then fall to the ground in the winter, starting the cycle from tree, to flower, to seed all over again.
Mary K. Hanson is a Certified California Naturalist, author, nature photographer and blogger (https://chubbywomanwalkabout.com/). She also teaches naturalist classes through Tuleyome, a501(c)(3) nonprofit conservation organization based in Woodland, Calif. For more information, visit www.tuleyome.org.
Doug Cowen, Pennsylvania State University; Azadeh Keivani, Columbia University, and Derek Fox, Pennsylvania State University
About four billion years ago, when the planet Earth was still in its infancy, the axis of a black hole about one billion times more massive than the sun happened to be pointing right to where our planet was going to be on September 22, 2017.
Along the axis, a high-energy jet of particles sent photons and neutrinos racing in our direction at or near the speed of light. The IceCube Neutrino Observatory at the South Pole detected one of these subatomic particles – the IceCube-170922A neutrino – and traced it back to a small patch of sky in the constellation Orion and pinpointed the cosmic source: a flaring black hole the size of a billion suns, 3.7 billion light years from Earth, known as blazar TXS 0506+056. Blazars have been known about for some time. What wasn’t clear was that they could produce high-energy neutrinos. Even more exciting was such neutrinos had never before been traced to its source.
Finding the cosmic source of high-energy neutrinos for the first time, announced on July 12, 2018 by the National Science Foundation, marks the dawn of a new era of neutrino astronomy. Pursued in fits and starts since 1976, when pioneering physicists first tried to build a large-scale high-energy neutrino detector off the Hawaiian coast, IceCube’s discovery marks the triumphant conclusion of a long and difficult campaign by many hundreds of scientists and engineers – and simultaneously the birth of a completely new branch of astronomy.
The detection of two distinct astronomical messengers -– neutrinos and light –- is a powerful demonstration of how so-called multimessenger astronomy can provide the leverage we need to identify and understand some of the most energetic phenomena in the universe. Since its discovery as a neutrino source less than a year ago, blazar TXS 0506+056 has been the subject of intensive scrutiny. Its associated stream of neutrinos continues to provide deep insights into the physical processes at work near the black hole and its powerful jet of particles and radiation, beamed almost directly toward Earth from its location just off the shoulder of Orion.
As three scientists in a global team of physicists and astronomers involved in this remarkable discovery, we were drawn to participate in this experiment for its sheer audacity, for the physical and emotional challenge of working long shifts at in a brutally cold location while inserting expensive, sensitive equipment into holes drilled 1.5 miles deep in the ice and making it all work. And, of course, for the thrilling opportunity to be the first people to peer into a brand new kind of telescope and see what it reveals about the heavens.
A remote, frigid neutrino detector
At an altitude exceeding 9,000 feet and with average summertime temperatures rarely breaking a frigid -30 Celsius, the South Pole may not strike you as the ideal place to do anything, aside from bragging about visiting a place that is so sunny and bright you need sunscreen for your nostrils. On the other hand, once you realize that the altitude is due to a thick coat of ultrapure ice made from several hundred thousand years of pristine snowfall and that the low temperatures have kept it all nicely frozen, then it might not surprise you that for neutrino telescope builders, the scientific advantages outweigh the forbidding environment. The South Pole is now the home of the world’s largest neutrino detector, IceCube.
It may seem odd that we need such an elaborate detector given that about 100 billion of these fundamental particles sashay right through your thumbnail each second and glide effortlessly through the entire Earth without interacting with a single earthly atom.
In fact, neutrinos are the second most ubiquitous particles, second only to the cosmic microwave background photons left over from the Big Bang. They comprise one-quarter of known fundamental particles. Yet, because they barely interact with other matter, they are arguably the least well understood.
To catch a handful of these elusive particles, and to discover their sources, physicists need big – kilometer-wide – detectors made of an optically clear material – like ice. Fortunately Mother Nature provided this pristine slab of clear ice where we could build our detector.
At the South Pole several hundred scientists and engineers have constructed and deployed over 5,000 individual photosensors in 86 separate 1.5-mile-deep holes melted in the polar ice cap with a custom-designed hot-water drill. Over the course of seven austral summer seasons we installed all the sensors. The IceCube array was fully installed in early 2011 and has been taking data continuously since.
This array of ice-bound detectors can sense with great precision when a neutrino flies through and interacts with a few Earthly particles that generate dim patterns of bluish Cherenkov light, given off when charged particles move through a medium like ice at close to light speed.
Neutrinos from the cosmos
The Achilles’ heel of neutrino detectors is that other particles, originating in the nearby atmosphere, can also trigger these patterns of bluish Cherenkov light. To eliminate these false signals, the detectors are buried deep in the ice to filter out interference before it can reach the sensitive detector. But in spite of being under nearly a mile of solid ice, IceCube still faces an onslaught of about 2,500 such particles every second, each of which could plausibly have been due to a neutrino.
With the expected rate of interesting, real astrophysical neutrino interactions (like incoming neutrinos from a black hole) hovering at about one per month, we were faced with a daunting needle-in-a-haystack problem.
The IceCube strategy is to look only at events with such high energy that they are exceedingly unlikely to be atmospheric in origin. With these selection criteria and several years of data, IceCube discovered the astrophysical neutrinos it had long been seeking, but it could not identify any individual sources – such as active galactic nuclei or gamma-ray bursts – among the several dozen high-energy neutrinos it had captured.
To tease out actual sources, IceCube began distributing neutrino arrival alerts in April 2016 with help from the Astrophysical Multimessenger Observatory Network at Penn State. Over the course of the next 16 months, 11 IceCube-AMON neutrino alerts were distributed via AMON and the Gamma-ray Coordinates Network, just minutes or seconds after being detected at the South Pole.
Swift was the first facility to identify the flaring blazar TXS 0506+056 as a possible source of the neutrino event. The Fermi Large Area Telescope then reported that the blazar was in a flaring state, emitting many more gamma-rays than it had in the past. As the news spread, other observatories enthusiastically jumped on the bandwagon and a broad range of observations ensued. The MAGIC ground-based telescope noted our neutrino came from a region producing very high-energy gamma-rays (each about ten million times more energetic than an X-ray), the first time such a coincidence has ever been observed. Other optical observations completed the puzzle by measuring the distance to blazar TXS 0506+056: about four billion light years from Earth.
With the first-ever identification of a cosmic source of high-energy neutrinos, a new branch on the astronomy tree has sprouted. As high-energy neutrino astronomy grows with more data, improved inter-observatory coordination, and more sensitive detectors, we will be able to map the neutrino sky with better and better precision.
And we expect exciting new breakthroughs in our understanding of the universe to follow suit, such as: solving the century-old mystery of the origin of astoundingly energetic cosmic rays; testing if spacetime itself is foamy, with quantum fluctuations at very small distance scales, as predicted by certain theories of quantum gravity; and figuring out exactly how cosmic accelerators, like those around the TXS 0506+056 black hole, manage to accelerate particles to such breathtakingly high energies.
For 20 years, the IceCube Collaboration had a dream to identify the sources of high-energy cosmic neutrinos – and this dream is now a reality.