January
Meteors
I had heard of the Perseid Meteor shower (it always happens around my dad’s birthday) but have to admit I was not aware that each year roughly a dozen major meteor showers occur that are fairly easy to observe. We’ve missed the first one of the year (Quadrantid, which peaked on January 3rd, 2018) but I’m gearing up for the next one, Lyrids, which is active from April 16th – 25th, 2018. While major, minor, and variable meteor showers span many days of the calendar, meteorites – the pieces of space rock that survive the fiery journey through the atmosphere to land on Earth’s surface – are quite rare. To learn more about meteors and meteorites I turned to the best geologic knowledge source in town: the UW Geology Museum. Here’s what Assistant Director & Outreach Program Specialist, Brooke Norsted, has to say about meteorites and the significant collection housed at the Museum:
More meteorites have been recovered from Antarctica than any other continent, with roughly 21,000 found there to date. Finding meteorites on the ice sheets of Antarctica is easier than in places with dirt and trees, where they are camouflaged. In Wisconsin, fourteen confirmed meteorites have been found so far. Five of these were seen falling from the sky – one in particular, the Kilbourn meteorite, smashed through the roof of a barn near Wisconsin Dells in 1911. Another specimen was used as an anvil for many years before it was recognized as being a meteorite. In the UW Geology Museum you can see six of the fourteen Wisconsin meteorites on display.
Although meteors are sometimes called “shooting stars” they are not really stars, but rather pieces of space rock that have entered the Earth’s atmosphere. These objects can travel at speeds of 6 to 45 miles per second. As they zip through the atmosphere, meteors become very hot and most burn up before reaching the surface of the Earth, producing bright streaks in the sky. Should a meteor survive this fiery plunge and hit the ground, it then is called a meteorite.
Some meteors, as they come through the atmosphere, break into many pieces before hitting the ground. Large ones, however, can strike the Earth, leaving scars that last millennia. There is evidence of a large impact crater across a 4-mile area called Rock Elm about 70 miles east of Minneapolis. The culprit was a meteorite 550 feet across that crashed into the earth ~450 million years ago. Over time, the crater has been partially filled with sediment making the impact site virtually indistinguishable from the surrounding land. Worldwide, there are only about 200 such impact craters, and only a couple dozen in the United States.
Meteorites can be traced back to one of three original “homes” in our Solar System. The majority hail from the asteroid belt which is debris left over from the formation of our Solar System that now is between Mars and Jupiter. These broken up chunks of proto-planets occasionally bump into each other, knocking some in toward the Sun. These then, may crash into Earth as they hurtle through space. Secondly, we have meteorites on Earth that are from the Moon. These are pieces of Moon rock that have been broken off after an asteroid knocks into the Moon. Similarly, the third place we know meteorites come from is Mars. The only place you can see a piece of Mars on display in Wisconsin is at the UW Geology Museum – this particular meteorite landed in Morocco in 2011.
As Brooke mentions, each meteor comes from a “home” in the Solar System. Turns out, each regularly occurring meteor shower is created by debris from a “parent object.” I learned the upcoming Lyrid meteor shower, for example, is caused by the comet C/1861 G1 – also known as the Thatcher comet – which has a 415.5 year orbit around the sun. It last reached perihelion (the point nearest to the sun) in 1861 but the debris left in its wake is what causes the Lyrid meteor shower. Find out more, including how this comet got its strange name, from NASA. You can also find the dates of upcoming major meteor showers (and their parent objects) from the American Meteor Society.
PS: Remember that huge meteor that streaked through the sky over Russia a few years ago? Scientists are still trying to figure out its parent material. The superbolide (so named because of its extreme brightness (an apparent magnitude of -17 (the sun, by comparison, is -27)) released 500 kilotons of energy, causing a shock wave across six Russian cities. A 1,400 pound piece of the Chelyabinsk meteorite was recovered from Lake Chebarkul and its trajectory was tracked but scientists still aren’t sure of its origin. Find out more from Space.com or EarthSky.org.
Did you know…
According to NASA, a meteor is the flash of light that we see in the night sky when a small chunk of interplanetary debris burns up as it passes through the atmosphere. “Meteor” refers to the flash of light caused by the debris, not the debris itself.
The debris is called a meteoroid. A meteoroid is a piece of interplanetary matter that is smaller than a kilometer and frequently only millimeters in size. Most meteoroids that enter the Earth’s atmosphere are so small that they vaporize completely and never reach the planet’s surface.
If any part of a meteoroid survives the fall through the atmosphere and lands on Earth, it is called a meteorite.
To Do This Month:
Check out this beautiful collection of time-lapse shots from 7 years of meteor showers. The footage was shot during the Perseid, Geminid and Leonid Meteor showers.
Bring your kiddos down to learn about history at the UW Geology Museum Storytime on January 18th @ 10:30am! This event is free and happens twice a month. Every event features a new book, a specimen, and a craft to take home!
WAEE Winter Workshop January 19th-21st in Tomahawk. This year’s theme is EnCOMPASSing: Progress, Perspectives, and Possibilities in Environmental Education.
Join naturalist Eric Volden for an entertaining morning of bird watching and bird lore at Bethel Horizons’ bird feeding station on January 20th from 9-11am. A hearty breakfast will be served with each session as Eric identifies birds coming to the feeders and relates bird feeding information, stories, and recent sightings. Bring binoculars if you have them, and bird stories to share.
Interested in learning about ice fishing? Come join the MacKenzie Center Educators on January 21st from 12-5pm for an Ice Fishing Clinic. This event is free (no fishing license required on winter Free Fishing Weekend) and open to all ages. All equipment will be provided, but feel free to bring any materials you may have. Please register at (608) 635-8105.
Come learn about animals that stay in Wisconsin through the winter and how they survive the cold at the UW Arboretum. Naturalist-led walk January 28th, 1:30–2:30pm, indoor activities, 2:30–3:30 p.m. Free, no registration required. Meet at the Visitor Center.
UW Geology Museum
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For Educators:
Meteor Minded
One of the go-to sources for anything space related is the National Aeronautics and Space Administration (NASA) website. And of course they offer an overview of meteors and meteorites, including a photo gallery, FAQs, news updates, and fun facts like these:
- Many meteor showers are associated with comets. The Leonids are associated with comet Tempel-Tuttle; Aquarids and Orionids with comet Halley, and the Taurids with comet Encke
- Meteoroids, meteors, and meteorites cannot support life. However, they may have provided the Earth with a source of amino acids: the building blocks of life.
Additionally – and of interest to educators – they offer a lesson plan and board game for teaching grades 4-6 about meteors. The “Space Rocks!” game has “children assume the roles of meteorites…to learn about meteors, meteoroids, and meteorites. They compete to get to Antarctica, where they have the chance to be found and studied by scientists!” The lesson is tied to National Science Education Standards (Earth & Space Science and Science as Inquiry) and provides enrichment links to other NASA resources, including NASA Space Place, a kid-friendly website for exploring Earth and space.
If you’re looking for local resources and ideas for your Earth and space learning, the UW Geology Museum offers custom tailored guided tours of the Museum’s collections and the UW Space Place offers topical programs for grades K through 8. [Side note: my daughter had her 7th birthday party at UW Space Place – here’s her friend, Ruby, circa 2009 with a homemade comet.]
For Families:
Meteor Shower Photography
I’ve always marveled at photos – like those featured in the video above – that capture the streak of stars and “shooting stars” across the night sky. I wondered how easy it would be to take photos like that myself and if it might be something I could tackle with my kids. It’s my own dad, after all, who sparked my interest in photography and prolonged shutter speeds when I was in middle school. Here’s what I found out:
Photo by Mike Hankey – Perseid Meteor
Some special equipment is needed. A tripod is a must and really, a DSLR camera is too. I looked into what it takes to capture the night sky with a smart phone and based on resulting photos, it doesn’t seem worth it. A wide angle lens is also suggested, as is a wired cable release.
Getting out of areas with light pollution will also help – find out more about dark skies from Nature Net’s January 2017 post – and being prepared with extra batteries or an external power supply wont hurt either.
Once the gear is assembled, use the following camera settings:
- Focus = infinity
- Aperture = as wide the lens will allow
- ISO = highest you are comfortable with (some recommend 400-800, others suggest 1600)
- Exposure = set to manual and test times around 10-30 seconds based on location, light, and phase of the moon.
I like this final tip from the pros. “Composition — after all the techy stuff, you still want to make a compelling image. Choose a foreground element, such as as stand of trees, a rock formation, or mountains. Something to anchor the photo and give it a great look rather than just a shot of the stars and meteors alone in sky.”
Some photographers set up their cameras to take photos on a regular, timed basis through out the night. This takes a bit more gear and patience but if you’re interested, there’s a detailed article featured on the American Meteor Society website. You can also find some great tips on PetaPixel, photography blog, or Sky & Telescope.
Betsy Parker is an environmental educator who supports all children, families, and classrooms getting their recommended daily allowance of #VitaminN.