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One billion galaxies: Astronomers unveil largest sky map ever made
Scientists with the the Dark Energy Spectroscopic Instrument (DESI) Legacy Imaging Surveys spent six years creating a detailed map of more than 1 billion galaxies.
- An international team of scientists created the world's largest astronomical map in an effort to better understand dark energy.
- Dark energy is the force that's thought to be driving the expansion of the universe.
- The ultimate goal of the team is to develop a three-dimensional map of the universe, which could help scientists unravel the mysteries of dark energy.
The universe is constantly expanding: Galaxies are hurtling away from each other—and from our own—at ever-increasing speeds. But why? In 1998, scientists theorized that a repulsive force called dark energy is causing the universe to expand, though much remains unknown about this mysterious, invisible energy, which makes up 70 percent of our universe.
To better understand dark energy, an international team of scientists has spent years creating the largest map ever of the sky. The scale of the map is enormous, covering half of the visible sky and comprising more than 1 billion galaxies, depicted through some 10 trillion pixels. That's equivalent to 833,000 high-resolution smartphone photos.
It's the product of the Dark Energy Spectroscopic Instrument (DESI) Legacy Imaging Surveys, a collaborative effort involving the Kitt Peak National Observatory and Cerro Tololo Inter-American Observatory (CTIO), and images from NASA's Wide-field Infrared Survey Explorer (WISE) mission. You can view the two-dimensional interactive map on the Legacy Survey Sky Viewer website.
CosmoView Episode 18: Giant Map of the Sky Sets Stage for Ambitious DESI Survey
"For millennia humans have used maps to understand and navigate our world and put ourselves in context: we rely on maps to show us where we are, where we came from, and where we're going. Astronomical maps continue this tradition on a vast scale," the National Science Foundation's NOIRLab, which is involved in the project, wrote in a blog post.
"They locate us within the cosmos and tell the story of the history and fate of the Universe: it will expand forever, the expansion currently accelerating because of an unknown quantity called dark energy. Astronomical maps may help explain what this dark energy is and why it exists. Capitalizing on that possibility requires an unprecedented map — one that charts faint galaxies more uniformly and over a larger area of sky than ever before."
Credit: NASA/STSci/Ann Feild
The vast amounts of data collected by the DESI Legacy Imaging Surveys has already led to significant scientific discoveries, including some of the coolest brown dwarfs ever discovered, active black holes in galaxies, and light-bending gravitational lenses, discovered through machine-learning algorithms.
But the new map is only the first stage in DESI's main goal: Creating a three-dimensional map of the universe. Over the next five years, scientists with DESI will use the data to measure the spectra of 35 million galaxies and 2.4 million quasars in the map. (Spectra is the intensity of light emitted over a range of energies.)
DESI/Legacy Survey Sky Viewer
By determining these galaxies' positions and distance from Earth, the team will be able to plot them in three dimensions, and potentially help scientists learn more about arguably the biggest puzzle in cosmology.
"Capturing the spectra of so many galaxies so quickly requires a high degree of automation," wrote NOIRLab. "DESI — equipped with an array of 5000 swiveling, automated robots, each toting a thin fiber-optic cable that can point at individual galaxies — is designed to measure the spectra of 5000 galaxies at a time. The results will ultimately provide new insights into the mysterious dark energy that is driving the Universe's accelerating expansion."
- Mystery effect speeds up the Universe – not dark energy, says study ... ›
- Dark matter theory: Information has mass, says physicist - Big Think ›
- Dark Energy: The Energy of Nothing - Big Think ›
A new study finds that dogs fed fresh human-grade food don't need to eat—or do their business—as much.
- Most dogs eat a diet that's primarily kibble.
- When fed a fresh-food diet, however, they don't need to consume as much.
- Dogs on fresh-food diets have healthier gut biomes.
Four diets were tested<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yNTU5ODI1MS9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTY1NjY0NjIxMn0._w0k-qFOC86AqmtPHJBK_i-9F5oVyVYsYtUrdvfUxWQ/img.jpg?width=980" id="1b1e4" class="rm-shortcode" data-rm-shortcode-id="87937436a81c700a8ab3b1d763354843" data-rm-shortcode-name="rebelmouse-image" data-width="1440" data-height="960" />
Credit: AntonioDiaz/Adobe Stock<p>The researchers tested refrigerated and fresh human-grade foods against kibble, the food most dogs live on. The <a href="https://frontierpets.com.au/blogs/news/how-kibble-or-dry-dog-food-is-made" target="_blank">ingredients</a> of kibble are mashed into a dough and then extruded, forced through a die of some kind into the desired shape — think a <a href="https://en.wikipedia.org/wiki/Food_extrusion" target="_blank">pasta maker</a>. The resulting pellets are sprayed with additional flavor and color.</p><p>For four weeks, researchers fed 12 beagles one of four diets:</p><ol><li>a extruded diet — Blue Buffalo Chicken and Brown Rice Recipe</li><li>a fresh refrigerated diet — Freshpet Roasted Meals Tender Chicken Recipe</li><li>a fresh diet — JustFoodforDogs Beef & Russet Potato Recipe</li><li>another fresh diet — JustFoodforDogs Chicken & White Rice Recipe.</li></ol><p>The two fresh diets contained minimally processed beef, chicken, broccoli, rice, carrots, and various food chunks in a canine casserole of sorts. </p><p>(One can't help but think how hard it would be to get finicky cats to test new diets. As if.)</p><p>Senior author <a href="https://ansc.illinois.edu/directory/ksswanso" target="_blank" rel="noopener noreferrer">Kelly S. Swanson</a> of U of I's Department of Animal Sciences and the Division of Nutritional Sciences, was a bit surprised at how much better dogs did on people food than even refrigerated dog chow. "Based on past research we've conducted I'm not surprised with the results when feeding human-grade compared to an extruded dry diet," he <a href="https://aces.illinois.edu/news/feed-fido-fresh-human-grade-dog-food-scoop-less-poop" target="_blank">says</a>, adding, "However, I did not expect to see how well the human-grade fresh food performed, even compared to a fresh commercial processed brand."</p>
Tracking the effect of each diet<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yNTU5ODI1OC9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTY3NjY1NTgyOX0.AdyMb8OEcjCD6iWYnXjToDmcnjfTSn-0-dfG96SIpUA/img.jpg?width=980" id="da892" class="rm-shortcode" data-rm-shortcode-id="880d952420679aeccd1eaf32b5339810" data-rm-shortcode-name="rebelmouse-image" data-width="1440" data-height="960" />
Credit: Patryk Kosmider/Adobe Stock<p>The researchers tracked the dogs' weights and analyzed the microbiota in their fecal matter.</p><p>It turned out that the dogs on kibble had to eat more to maintain their body weight. This resulted in their producing 1.5 to 2.9 times the amount of poop produced by dogs on the fresh diets.</p><p>Says Swanson, "This is consistent with a 2019 National Institute of Health study in humans that found people eating a fresh whole food diet consumed on average 500 less calories per day, and reported being more satisfied, than people eating a more processed diet."</p><p>Maybe even more interesting was the effect of fresh food on the gut biome. Though there remains much we don't yet know about microbiota, it was nonetheless the case that the microbial communities found in fresh-food poo was different.</p><p>"Because a healthy gut means a healthy mutt," says Swanson, "fecal microbial and metabolite profiles are important readouts of diet assessment. As we have shown in <a href="https://academic.oup.com/jas/article/92/9/3781/4702209#110855647" target="_blank">previous studies</a>, the fecal microbial communities of healthy dogs fed fresh diets were different than those fed kibble. These unique microbial profiles were likely due to differences in diet processing, ingredient source, and the concentration and type of dietary fibers, proteins, and fats that are known to influence what is digested by the dog and what reaches the colon for fermentation."</p>
How did kibble take over canine diets?<p>Historically, dogs ate scraps left over by humans. It has only been <a href="https://www.thefarmersdog.com/digest/the-history-of-commercial-pet-food-a-great-american-marketing-story/" target="_blank">since 1870</a>, with the arrival of the luxe Spratt's Meat Fibrine Dog Cakes—made from "the dried unsalted gelatinous parts of Prairie Beef", mmm—that commercial dog food began to take hold. Dog bone-shaped biscuits first appeared in 1907. Ken-L Ration dates from 1922. Kibble was first extruded in 1956. Pet food had become a great way to turn <a href="https://www.dogfoodadvisor.com/choosing-dog-food/animal-by-products/" target="_blank">human-food waste</a> into profit.</p><p>Commercial dog food became the norm for most household canines only after a massive marketing campaign led by a group of dog-food industry lobbyists called the Pet Food Institute in 1964. Over time, for most households, dog food was what dogs ate — what else? Human food? These days more than half of U.S. dogs are <a href="https://www.nytimes.com/2014/08/03/magazine/who-made-that-dog-biscuit.html" target="_blank">overweight or obese</a>, and certainly their diet is a factor.<span></span></p><p>We're not so special among animals after all. If something's healthy for us to eat—we're <em>not</em> looking at you, chocolate—maybe we should remember to share with our canine compatriots. Not from the table, though.</p>
What makes some people more likely to shiver than others?
Some people just aren't bothered by the cold, no matter how low the temperature dips. And the reason for this may be in a person's genes.
Eating veggies is good for you. Now we can stop debating how much we should eat.
- A massive new study confirms that five servings of fruit and veggies a day can lower the risk of death.
- The maximum benefit is found at two servings of fruit and three of veggies—anything more offers no extra benefit according to the researchers.
- Not all fruits and veggies are equal. Leafy greens are better for you than starchy corn and potatoes.