Over the 25 years I’ve written this column, I’ve often marveled at the mind-boggling distances to many celestial objects. Astronomers don’t often use miles to express stellar and galactic distances because the numbers would quickly become unwieldy. Instead, light-years are used because the numbers are more manageable, and they’re also a testament to the unfathomable scale of the universe. All light travels at the speed of 186,300 miles a second in the vacuum of space. A light-year is defined as the distance that light travels at that speed in one year.

Given that there are about 31.5 million seconds in a year, you can calculate that a single light-year equals around 5.8 trillion miles. So, saying a star is 70 light-years away, which is pretty typical for stars we see with the naked eye, means that the star is about 406 trillion miles away. That’s 406, followed by 15 zeros! Also, by definition, the light we see from that star tonight left that star 70 years ago. We actually see the star the way it looked in 1954. If we see a star tonight that’s 3,000 light-years away, we see it as it was in 976 B.C.! Whenever you look at the stars, you’re looking back into the past, sometimes the very distant past!

So how do astronomers know how far away these stars are? Unfortunately, it’s not a short and easy answer. You use the stellar parallax method to determine the distance for stars less than 2,000 to 3,000 light-years away. This method is like measuring the distance to an object by looking at it with one eye, then shutting that eye and looking at it with the other eye and noticing how its position seems to shift. You take a picture of a star when the Earth is on one side of the sun in its orbit, and then you take another picture six months later when the Earth is on the other side of the sun. If the star is not too distant, you’ll see it shift slightly against the background stars. This process comes down to simple high school trigonometry. The shifting of the star against the background stars creates a parallax angle. You can draw a triangle between the Earth, the sun, and the star using basic geometry rules that say opposite angles are equal. You take the parallax angle and cut it in half. Since you know what that angle is and the length of one side of the triangle (the distance between the Earth and the sun), the distance x (to the star) = 93,000,000 miles divided by the tangent of the parallax angle.

As simple as the math is, measuring that parallax angle is challenging because it’s such a tiny angle. You must also assume that the background stars you’re using to measure the stellar parallax angle are stationary. In reality, they’re shifting as well!

Measuring the distance to stars using stellar parallax is also extremely difficult from the Earth’s surface because you have to endure the blurring effects of our atmosphere. That’s why satellites have been launched into orbit to measure the stellar parallax more precisely and calculate distances to thousands of stars.

Stars farther than 3,000 light-years away require other methods to determine stellar distance. One method is the famous Hertzsprung-Russel diagram, developed in the early 1900s by Ejnar Hertzsprung of Holland and Henry Norris Russel from the United States. They studied the spectrums of thousands of stars, which are like fingerprints. If you take starlight and send it through a spectrograph, you can spread out the various wavelengths that make up that light and learn much about a star. These rainbow-like displays show signatures of different chemical elements, temperature, and more. Hertzsprung and Russel found a definite relationship between the spectral type of a star and its luminosity, which is the amount of light a star produces. They discovered a distinct pattern when plotting a spectral type vs. luminosity graph. Most stars fit right along a nice curve. The beauty of this is that by just getting the spectrum of a star, you can determine its luminosity. Once you know the luminosity, figuring out the distance is an easy math equation using the straightforward inverse-square law of light.

For really distant stars, Cepheid variable stars are used. This was a huge discovery made by Henrietta Leavitt early in the last century at Harvard University. She studied thousands of variable stars that varied regularly in brightness over several hours to hundreds of days. In her observations, she discovered that the variable stars called Cepheids were extraordinarily regular and extremely bright, shining 500 to 10,000 times the sun’s luminosity.  They varied in brightness because of cycle changes within the star. Leavitt found a near-perfect relationship between a star’s period of variation and its average luminosity, or light output. Cepheid variables could then be used as mile markers in deep space because of their brightness. If you spot a Cepheid variable, you can determine how far away it is just by observing its period. Once you have the period, you can get its luminosity, and from there, relatively simple math can be used to determine the distance of extremely far away places!

The famous astronomer Edwin Hubble used observations of Cepheid variable stars in what was then known as the Andromeda Nebulae to determine that Andromeda was a whole other galaxy, over 2 million light-years away. Until then, our Milky Way was thought to be the only galaxy in the universe.  This is Hubble’s discovery, but he could not have done it without Henrietta Leavitt and her Cepheid variables. What a tremendous celestial yardstick!

Mike Lynch is an amateur astronomer and retired broadcast meteorologist for WCCO Radio in Minneapolis/St. Paul. He is the author of “Stars: a Month by Month Tour of the Constellations,” published by Adventure Publications and available at bookstores and adventurepublications.net. Mike is available for private star parties. You can contact him at mikewlynch@comcast.net.

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DULUTH — The number of male ruffed grouse heard drumming in April and May as part of their spring mating ritual was up again this year in the Northland, signaling a continued higher population, but a soggy June may have reduced this year’s crop of young grouse on the landscape.

A male ruffed grouse “drums” or beats its wings on its chest to attract a mate in spring. The 2024 drumming count across the ruffed grouse range in Minnesota was the highest since 1972, but a wet June may have reduced the number of newly hatched chicks, which will impact the overall population. (Courtesy of the North Dakota Game and Fish Department)

That’s the word from the Minnesota and Wisconsin departments of natural resources, along with other biologists and grouse enthusiasts who have spent time in the woods this spring and early summer.

The spring drumming counts, conducted before the rains came hard, showed that a good portion of last year’s thriving population of grouse managed to survive over a winter with little or no snow.

That lack of snow could have been a disaster because grouse usually burrow in deep snow at night to escape cold temperatures and predators in winter. Instead, grouse had to nest in trees, but were not subject to much extreme cold and apparently survived just fine

In Minnesota, the drumming survey — where biologists stop at predetermined locations across the grouse range to listen for male grouse beating their wings — hit 2.3 drumming birds per stop across their entire range, up from 2.1 last year and way up from 1.3 in 2021, now believed to be the low year of the bird’s mysterious 10-year cycle in Minnesota.

This year saw the highest drumming count in Minnesota since 1972.

Northeastern Minnesota saw 2.7 drums per stop, compared to 1.6 in the central region. But northwestern Minnesota has been seeing fewer ruffed grouse of late, with just 0.66 drums per stop this year, down from 1.5 in 2023 and 2.9 in 2022. Charlotte Roy, Minnesota DNR grouse research biologist, said it’s unclear why the northwestern grouse population is declining while it is increasing elsewhere in the state.

In Wisconsin, the 2024 drumming survey was up a startling 60% in the north from 2023 and up 41% in the central regions but down 56% in the southwest where declining habitat has been a problem for decades.

In the north, the 2.32 drums per stop heard this year was up from 1.45 drums per stop in 2023, the highest since 2011. In northern counties, 34 routes saw increases in drumming, eight saw declines and 10 were unchanged from 2023.

Last year, biologists and hunters in both states agreed that grouse had perfect nesting conditions with a warm and dry spring that spurred high survival of young grouse. That’s especially important for hunters because surveys show nearly two-thirds of all grouse that hunters shoot each season were hatched that same year.

“The late spring and summer of 2023 were abnormally dry, which resulted in prime nesting and brooding conditions for ruffed grouse,” said Alaina Roth, Wisconsin DNR ruffed grouse specialist. “This is likely the most influential factor explaining the increase in the number of drumming grouse this year. We are also likely entering the ‘up’ phase of our 10-year population cycle, which may be an influencing factor, too.”

Ruffed grouse, for reasons still not fully understood, typically follow a 10-year population cycle.

Wisconsin biologists believe their cycle peaked earlier, dropped and is now on the rise again, set to peak by about 2029. Minnesota drumming counts show a continued rise in drumming for several years, with no recent drop yet.

For more information regarding grouse hunting or managing habitat for ruffed grouse in Wisconsin, visit dnr.wisconsin.gov/topic/hunt/ruffedgrouse.

Heavy rain tough on chicks, but some have survived

Many ruffed grouse enthusiasts were concerned in June when multiple heavy rains hit much of the region, more than 3 inches in many areas and up to 9 inches in one downpour across parts of Minnesota’s Arrowhead.

A wet June, when grouse hatch and fledge, sometimes means that grouse chicks perish from exposure, drowning or other complications. Biologists say some of that probably did occur, but maybe not as bad as expected. Many people in the woods say they are seeing at least some grouse chicks that persevered.

Roy said she had been concerned that the rains were too much for small grouse but that she has been hearing “decent brood reports, too, so hoping that continues.”

“While ruffed grouse drumming counts are high in the core of ruffed grouse range, indicating a strong breeding population this spring, drumming counts are not an accurate way to predict the birds that will be present during the fall hunting season,” Roy said. “Nesting success and chick survival during the spring and summer are among the factors that influence the number of birds present in the fall. These factors can be reduced by heavy rain during June when nests are hatching and chicks are young.”

Bailey Peterson, a grouse hunting enthusiast and Minnesota DNR wildlife manager, said she didn’t see as many young grouse early in the summer as expected considering the non-winter and early spring.

“But I did see a brood of teenagers two days after the 7.5 inches of rain fell here, on a road that was closed for a washout, so I take that as a decent sign of hope,” she said. “A few co-workers have seen broods of short fliers in the last week. It’s not going to be outstanding but it’s not a total failure of a brood year either at this point.”

Mike Amman, a forester for Ashland County and a grouse hunting enthusiast, said the spring and early summer have been incredibly wet. But he said the high drumming counts showed there were plenty of birds to start the year.

“I am assuming we lost a decent number of chicks to the wet weather, but having said that, I am still seeing broods of grouse. Most are one-third-to-half grown already,” Amman said. “I haven’t seen a ton of broods but … when I have been out, I have seen some … averaging about one to two broods a day in decent cover.”

Greg Kessler, Wisconsin DNR wildlife manager in Douglas County, said several upland bird species may see fewer chicks survive the heavy rains, including grouse, turkey and woodcock, which may stall or even reverse what had been a few years of population increases.

Debbie Petersen, grouse and woodcock expert who has spent a lot of time in the woods this spring and early summer conducting breeding bird surveys, said she has seen some decent-sized broods, although that was before the most recent round of heavy rain.

“I saw the most broods up by Wirt (in Itasca County). I had one half-mile stretch of trail there where I encountered three separate very young broods. Each had six to 10 chicks,” Petersen noted.

Minnesota sharptails up in northwest, east-central regions

Minnesota’s northwest sharp-tailed grouse population is higher this year than last year and the highest it’s been since 2009, according to spring population counts conducted by the Minnesota DNR and cooperating organizations.

A male sharp-tailed grouse dances in the spring of 2019 on his mating territory, called a lek. The number of sharptails seen at leks was up in 2024 in Minnesota. (Steve Kuchera / Forum News Service)

The number of grouse seen per lek, or dancing area, hit 15.9 birds this year in the northwest, up from 12.4 last year.

The population level remains low in east-central Minnesota, including Pine, Carlton, Aitkin and St. Louis counties, but is up from crippling-low numbers a few years ago. This year, 11.8 grouse were counted per lek, up from 8.0 in 2023 and considerably higher than the lowest-ever count of 4.8 in 2012. Sharptails were counted at 25 areas in the east-central region, down from more than 80 areas in the 1980s and hundreds in the mid-1900s.

The Minnesota DNR closed the sharptail hunting season in the east-central zone in 2021 due to chronically low numbers compared to a half-century ago. The season will be closed again this year.

Lower population levels in this area in recent decades are thought to be driven largely by changing habitat conditions. The birds require vast areas of 1-3 square miles of open grassland and brushland, without crops or trees, so managing their habitats often requires cooperation between multiple landowners.

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It’s time for the little ones to slow down after the recent long holiday weekend with picture books that are fun and teach a few lessons, although the smalls won’t realize they are learning.

(Courtesy of HarperCollins Publishers)

“A Family Tree”: by Staci Lola Drouillard, illustrated by Kate Gardiner (Clarion Books, $19.99 on book jacket; $15.99 on publisher’s website)

What a beautiful and important book for children of all ethnicities. Drouillard, a descendant of the Grand Portage Band of Ojibwe, tells a tender story about a little girl who is the same age as a spruce tree sapling on her grandparents’ land:

“The tree, like Francis, grew slowly. While Francis learned to walk on two little feet, the spruce tree walked in her own way — stretching her roots out into the ground, where they talked to the roots of the other trees in the garden.”

Eventually Grandma and Grandpa grow too old to keep up their property and have to move. Francis worries that the new owners might not understand that trees talk to each other underground, or that mother trees help keep their little ones strong by feeding the saplings with their own roots. And so the family decides to take the young spruce with them to plant at Auntie’s home where the grandparents will live. Grandpa plants it facing North, its former home, and soon the little tree is taller than Francis. She decorates her friend with bright lights in winter, celebrating the family’s connection to the trees, rocks and water of far northern Minnesota.

In an author’s note Drouillard, who lives in Grand Marais, writes that the book is based on the true story of a tiny white spruce that once lived in Grand Portage and now puts out new buds every spring from the safety of her yard. She gives a brief summary of the history of the Ojibwe people and their connection to the land from which they were removed.

“For Ojibwe people, losing access to our traditional homelands is like losing one’s place in the cyclical world of natural things,” she writes. “But, like the little spruce tree, we continue to adapt and change while retaining the wisdom and knowledge of the forest, which was taught to us by our elders, who learned from those who came before them.”

Drouillard, who won a Minnesota Book Award for “Seven Aunts,” sprinkles words from the Ojibwemowin language in the story, with a glossary at the end. This is also a physically beautiful book, with Kate Gardiner’s clean-lined, contemporary artwork in subdued colors of nature that sometimes wrap around the text or complement one line on a page. Gardiner is a New England-based illustrator with Native roots.

(Courtesy of Nancy Paulsen Books)

“Loaf the Cat Goes to the Powwow”: by Nicholas DeShaw, illustrated by Tara Audibert (Nancy Paulson Books, $18.99)

Loaf, the cat, loves living with “his boy.”  One day, there was lots of ribbon around for him to pounce on: ” ‘This is my regalia, Loaf. I’m going to be a grass dancer at the powwow,’ my boy told me. He began to jump and spin around.”

Loaf senses there is something big going on in his boy’s life, and when the family leaves he jumps out a window and follows them to the powwow grounds. He watches the Grand Entry, hears the honor song for veterans accompanied by the host drum, and is proud when his boy is welcomed as the newest grass dancer: “The ribbons that I like moved with him so fast!/It was so good! I loved to see him!”

In the end, the boy and the purring cat snuggle down and take a nap.

This is the debut picture book from DeShaw, who lives in St. Paul. An Anishinaabe, he is a father, educator and traditional lacrosse coach. Illustrator Audibert, of Native and French lineage, enhances the light-hearted text with endearing characters with huge eyes and mouths. And Loaf does look exactly look like a loaf of brown bread.

(Courtesy of Free Spirit Publishing)

“Quiet Violet Finds Her Voice”: by Gabrielle Nidus, illustrated by Stephanie Dehennin (Free Spirit Publishing, $18.99)

Violet likes to blend in so nobody at school notices her. But she’s confident in the kitchen, which is lucky because when a hands-on lesson about measurement goes haywire, Violet is the only one who can save a celebrated chef from an awful encounter with a very salty cookie. The author lives in Houston, and the illustrator in the Flemish countryside. Their book is part of Minneapolis-based Free Spirit Publishing’s 19 mental health kindergarten, first/second-grade series by different authors.

“Birth of the Bicycle: A Bumpy History of the Bicycle in America 1819-1900”: by Sarah Nelson, illustrated by Iacopo Bruno (Candlewick Press, $18.99)

(Courtesy of Candlewick Press)

This lively book begins with wooden velocipedes of the 1800s and concludes with the sleek machines that today have their own dedicated lanes in some cities, including St. Paul and Minneapolis. The author traces the bike’s journey from a luxury for the wealthy to a necessity for the working class. Illustrations are wonderful, from the top-hatted gentlemen riding bikes with big front wheels in 1819 to the 1868 carnival act with men balancing bikes on the high wire and the first fashionable garments for bicycle-riding women.

Sarah Nelson writes children’s books in prose and poetry, including “Frogness” and “A Park Connects Us,” inspired by St. Paul’s Lake Como. Bruno is an Italian graphic designer whose illustrations for “Birth of the Bicycle” capture the past.

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