Canada Science and Technology Museum
3 things you should know about the untapped potential of millet, the permanence of tattoos, and asteroid airbursts
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Feb 17, 2023
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Canada Agriculture and Food Museum
Canada Aviation and Space Museum
Meet Cassandra Marion, Renée-Claude Goulet, and Michelle Campbell Mekarski.
They are Ingenium’s science advisors, providing expert scientific advice on key subjects relating to the Canada Aviation and Space Museum, the Canada Agriculture and Food Museum, and the Canada Science and Technology Museum.
In this colourful monthly blog series, Ingenium’s science advisors offer up quirky nuggets related to their areas of expertise. For the February edition, they explain why millet might be a super crop in the future, why tattoos are permanent, and what happens when an asteroid explodes before impact.
Photo Credit
Hulled millet is a nutritious cereal that can be cooked and prepared like rice and quinoa.
Celebrating the unsung hero of the cereals: millets
Millet, what many of us know as the tiny round seeds in birdseed mix, was declared star of the cereal world for 2023! The United Nations’ International Year of Millets aims to bring attention to the untapped potential of this ancient crop for food security and farm sustainability. So what makes millet so great? Though it represents a minor crop in Canada, it has been a staple food in many parts of the world for millennia. In fact, it may be one of the first crops to be domesticated by humans!
Millets are cereals, just like rice and wheat, but contain more protein, fibre, iron, and calcium than other staple grains. It is an important part of many peoples' diets in sub-Saharan Africa and Asia, and both the seeds and plant feed livestock around the world. In North America, we often find it as a substitute to ingredients that are common allergens like wheat flour and sesame seeds.
Millet isn't a very popular crop in Canada, and the kind we do grow - proso millet - is mainly for birdfeed or used to make ethanol, a biofuel. Millets like hot, dry climates, so they can grow with less water than other cereal crops, and they can withstand extreme heat. They can grow in unproductive lands, which aren't well-suited for high-need crops. With these traits, millets make a great candidate to help us adapt our farming systems to the impacts of climate change, such as drier, hotter summers. Incorporating them more widely in our cropping systems could help us save on inputs and grow food in places that would require too many resources to support other crops.
Currently, farmers in Canada use millet as a cover crop, which is planted with the main crop or right after its harvest. The cover crop's purpose is to keep the soil covered, which prevents erosion and provides shelter and food for living things. Later, once it has died back after winter, it serves as fertilizer for the field. Another trending benefit being studied is the ability of cover crops to store carbon in the soil.
With the extra attention millets are getting this year, some are wondering if they could follow in the footsteps of quinoa, which started as a relatively unknown grain here in Canada to become a common ingredient found in kitchens across the country. So whether it’s new to you or an old pantry staple, go ahead and enjoy a helping of millet to celebrate this crop’s bright future!
By Renée-Claude Goulet
Photo Credit
Tattoo artists create designs using several techniques, including hand-tapping and modern tattoo machines.
What makes tattoos permanent?
Tattoos are an important part of many cultures worldwide and have been around since the dawn of civilization. Tattoos can represent rites of passage, marks of status, celebrations of accomplishment, memories, symbols of devotion, personal identifiers, or decorations. Part of their symbolic power comes from the fact that they are permanent. But why do they last do long?
Tattoos are a skin modification made by inserting a foreign substance, typically tattoo ink, dyes, or pigments, into the second layer of skin (the dermis). This is the living layer of cells that contains nerves, blood vessels, sweat glands, and hair follicles. The dermis sits below the outermost layer of skin (the epidermis) which is primarily made of dead cells that are continuously shed from the body.
Inserting a foreign substance into the dermis activates your body’s immune system. One of the cells involved in this response are macrophages. Macrophages are a type of large white blood cell whose job it is to detect and engulf foreign substances (kind of like mini vacuum cleaners). The macrophages “vacuum up” the ink particles in an attempt to clean up the mess, but they cannot break down the particles. Most of these macrophages remain stuck in the dermis holding on to the ink particles that they cannot get rid of. So, the dyes remain visible through the skin where the ink was placed.
When the macrophages eventually die, they get vacuumed up – ink and all – by other macrophages in the area. This endless cycle is what keeps the tattoo permanently in place. Over time, tattoos do fade as the body is able to remove a small amount of the ink particles. However, since the cells of your dermis are relatively stable, most of the ink will remain embedded in the skin for your entire life.
So how do you get rid of a tattoo? To do this, you must interrupt the macrophages’ continuous cycle. The most common way to do this is with laser treatment. Lasers break the ink particles into small enough pieces that your immune system is able to remove them. However, this usually requires multiple treatments, and some tattoos can never be fully removed since cells are continuously picking up and holding on to the small pieces of ink.
By Michelle Campbell Mekarski
Photo Credit
Cassandra Marion
View of Meteor Crater, a 1.2 km wide meteorite impact crater in Arizona.
Airbursts: meteoroid explosions in the sky
A decade ago, on February 15, 2013, an asteroid approximately 18 m in diameter entered the Earth’s atmosphere without warning, caused a bright fireball to streak across the sky at a speed of 30 km/s, and exploded about 25 km above the ground near the city of Chelyabinsk, Russia. The explosion, a sonic boom, released the energy equivalent of some 470 kilotons of TNT. The shockwave from the explosion reached the city of Chelyabinsk 1 minute 24 seconds after the fireball was observed. More than 1,500 injuries were reported and damage to buildings was documented up to 100 km away, consisting of shattered windows and collapsed infrastructure. Car alarms were triggered throughout the city. This type of event, classified as an airburst, is when a meteoroid (space rock) explodes, or catastrophically fragments in the air before impacting the ground. Dozens of small stony meteorites were recovered from the area after the event, but no crater was formed.
Everyday the Earth is impacted by rocky and/or icy material from space but our atmosphere acts as a screen to reduce the chance of an impact. The result depends on the size, speed, and composition of the projectile. Smaller meteoroids, known as meteors or shooting starts, tend to burn up in the atmosphere. Larger objects burn brighter and are termed a fireball or a bolide. Less dense stony meteorites tend to break up more easily than iron meteorites, particularly if they enter the atmosphere at a shallow angle.
The Chelyabinsk meteoroid approached the Earth from the direction of the Sun. Under these conditions, prediction is nearly impossible as it’s extremely difficult to observe an object that faint and small, hidden by both its own shadow and the blinding light of the sun. Recorded telescope images were examined after the event, and in no images could the asteroid be seen, and, therefore, foreseen. Not to worry, though; much larger, more hazardous objects are easier to identify in advance.
The most of powerful airburst on record was the Tunguska event in 1908 which occurred in a remote region of central Siberia. Working from eyewitness accounts, scientists estimate a 5 to 20 megatons explosion at an altitude of 5 to 15 km. More than 2,000 square kilometers of forest were devastated in a butterfly shape of torched and/or flattened trees.
The 1.2 km wide bowl-shaped Meteor Crater in Arizona (shown above) is a prime example of what happens when a large hypervelocity (going more than 11 km/s) meteoroid, estimated to be 30 to 50 m in diameter, hits the surface. The shock wave generated in an impact event moves through the ground, effectively fracturing, fragmenting, and melting rock, and setting the material in motion to excavate a large hole. Meteorites – fragments of the impactor – recovered from Meteor crater identify the impact as an iron meteorite and are famously known as the Canyon Diablo meteorites.
Go Further
NASA’s Near Earth Asteroid Fireball and Bolide data
Citizen scientists watch for fireballs in the sky
By Cassandra Marion
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Michelle Campbell Mekarski, PhD
As the Science Advisor at the Canada Science and Technology Museum, Michelle’s goal is to bridge the gap between the scientific community and the public — specializing in making science and technology engaging, accessible, and fun. Michelle earned a PhD in evolutionary biology and paleontology and has many years of experience developing and delivering science outreach activities. When away from her job at the museum, she can be found teaching at the University of Ottawa or Carleton University, digging for fossils, or relaxing by the water.
Renée-Claude Goulet
Renée-Claude Goulet is the Science Advisor at the Canada Agriculture and Food Museum, with over 15 years of experience in science communication. At the Museum, she develops exhibitions, educational programs, and resources that explore the science and innovation behind agriculture and food production. An Ontario Certified Teacher with a BSc in Biology and a BEd in Sciences, Renée-Claude is passionate about making complex topics accessible and engaging for all audiences.
Cassandra Marion, PhD
Cassandra is the Science Advisor for the Canada Aviation and Space Museum. She has a PhD in geology and planetary science and exploration. Her research is focused on meteorite impact craters in the Canadian Arctic. She has more than a decade of experience in education and public outreach, developing and delivering science programming. She is dedicated to sharing her passion for Earth and planetary sciences with communities near and far, and improving science literacy in Canada.
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