October 1, 2014
Monarch butterflies have the right idea.
Instead of sleeping, shivering, or hiding their way through a snowy winter, monarch butterflies take to the skies every fall for their annual migration to warmer climates.
From as far north as the northeastern United States and Canada, where monarch caterpillars feed on milkweed plants, these insects travel hundreds of miles to mountainous spots in Mexico and southern California where they spend the winter hibernating.
Reports of hibernating butterflies in southern California date back to the 1860s, but scientists believe the butterflies were in the habit of migrating long before humans noticed. Even after we realized monarch butterflies were leaving home come fall, nobody figured out where else they went until 1975, when scientists tracked them down in the mountains of central Mexico.
These butterflies require a very specific winter habitat that only a few areas offer. The Oyamel fir forests take up a very small area of the mountaintops of central Mexico. The roosting sites are about 2 miles above sea level and the fog and clouds that surround them provide essential moisture for the butterflies, who cluster together on protective trees.
How do they know where to go? Nobody knows for sure. Only about every fifth generation makes the migration, so they don’t learn from their parents. Monarch butterflies probably use the sun combined with their own circadian rhythm to establish which direction they need to fly. They might also use an internal magnetic compass. The earth is one giant magnet, and birds and insects can sense the magnetic field and follow it south. Neither of these hypotheses explain how they manage to find the same small area year after year. Scientists are still studying.
As our instruments become more advanced, we’re better able to study migrating butterflies. This fall, satellites over St. Louis, Missouri, captured a picture of a large, butterfly-shaped cloud heading south.
After some confusion, scientists realized they were seeing a swarm of migrating butterflies. This was an especially welcome sight, since butterfly populations have been decreasing in recent years, due to changing weather patterns. The site of thousands of flying butterflies is a hopeful sign!
Thursday, November 6, 2014, 9:00 am
Gaylord Opryland Resort & Convention Center, 2800 Opryland Dr, Nashville, TN 37214, United States
Come visit Nomad Press at the 2014 AMLE annual conference, see why Nomad titles are the perfect resource for the Middle School classroom. Don’t forget to ask about our show specials.
Show runs November 6 -7, 2014.
September 18, 2014
It’s not every person who wakes up one day and says, “I think I’ll spend the next seven years walking!”
But not everyone has the guts and smarts of Paul Salopek.
Why is Paul taking such a long walk? He’s following the track of human migration. He started nearly two years ago in northern Ethiopia, from which our first human cousins began to wander between 50,000 and 70,000 years ago. He’s now walking through the Middle East and will continue into Asia, across into the Americas, to end his journey at the tip of South America, Tierra del Fuego.
His walk is not the same as the walk you might take after dinner. This is not a stroll through your friendly neighborhood. Not only is his walk much longer, it’s also much more dangerous. He’s walking through parts of the world where political tensions run high, and even had to alter his route to avoid particularly steamy hot spots, such as Syria and Iraq. He carries on, though.
His is not a political journey, though human history is shaped by politics. He describes conflict, but more often he describes people and their relationship to place. He talks about families sitting down to meals, he’s sure to mention the hospitality he encounters nearly everywhere, and he is charmed by the beauty he sees in the landscape, in faces, in food, in the layers of history and present. National Geographic, who is sponsoring Paul’s reporting, says on their website, “Moving at the slow beat of his footsteps, Paul is engaging with the major stories of our time—from climate change to technological innovation, from mass migration to cultural survival—by walking alongside the people who inhabit them every day.”
Another fascinating aspect of his journey is the ever-changing stream of people who choose to walk with him. Like Doctor Who, Paul is rarely without a companion. Yuval Ben-Ami, Bassam Almohor, Savvas Sakkadas, and hundreds of others have joined him on his hike, some of them as hired guides but many of them as curious locals who simply want to be a part of something larger than daily life.
Everyone in the world can be part of this something larger. Paul is keeping a journal of his travels online called Out of Eden. Not only can you read about his days as a nomad, you can also see pictures of the places and people he encounters. Also available is an interactive map of Paul’s progression.
He’s a terrific writer and his blog is perfect for middle school and high school classrooms. Ask your students to see the larger picture—Paul is doing a great job of painting it, right now.
August 11, 2014
The nighttime sky is always interesting to look at, but perhaps this week more than usual.
Image by Marco Langbroek
If you happened to watch the moonrise last night, you might have seen a cape flying out behind the giant moon. Well, not really, no cape, but last night’s moon was this year’s supermoon, and it did look bigger than usual–about 8 percent bigger. The above image shows the potential difference in size.
What’s a supermoon? A supermoon, or perigree moon, occurs when a full moon is at its closest point to the earth, or its perigree, in its yearly elliptical orbit. It looks bigger than usual to all of us on earth gazing up because it’s only 221,765 miles (356,896 kilometers) away. So close!
Usually a supermoon happens every 13 months, but this year we are going to be treated to supermoon spectacles three times over the course of three months! A supermoon rose on July 12th and we’ll have a chance to marvel at yet another supermoon on September 9th. The one in August, however, is the closest. Astronomers warn that this trifecta of supermoons won’t happen again until 2034.
If you happen to miss the supermoon, fear not, there is more great stuff happening in the sky this week. The Perseid meteor shower is making its annual visit. Though actually, the Earth and the meteor shower are visiting each other.
Every year around this time in August, Earth crosses the orbital path of Comet Swift-Tuttle and encounters loads of comet debris. The dust and ice particles that make up this debris burn up as they zip through the earth’s atmosphere, letting us catch a glimpse of their paths across the sky. If a meteor is lucky enough to travel all the way to earth, it’s called a meteorite. Before the meteor hits the earth’s atmosphere, when it’s still just a rock minding its own business out in space, it’s called a meteoroid.
The best time for viewing the Perseid meteor shower is usually in the early morning. This year, however, the supermoon might get in the way with all its bright light. You can also spot meteors during early evening.
Choose a spot with little light pollution, such as an empty field or park. A few minutes after turning out all lights, your eyes will be adjusted to the dark and you’ll be able to see plenty of stuff in the sky.
These meteors are called the Perseid meteors because they look like they originate from the same area as the Perseus constellation, which can be found in the northeastern part of the sky, as you can see in the above illustration from NASA. Don’t worry too much about facing the right direction, though. Simply look up and a meteor will catch your eye.
Happy star gazing!