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NASA's Perseverance rover lands on Mars in 18 days
The space agency describes the process of landing rovers on Mars as "seven minutes of terror."
- NASA's Perseverance is the largest and most technologically advanced rover ever launched into space.
- On February 18, Perseverance is set to land on the Martian surface. NASA plans to livestream the event.
- The rover will spend about two years on Mars, where its chief mission is to search for signs of ancient life.
NASA's Perseverance is 18 days from landing on Mars and starting its mission of searching for ancient alien life in the planet's Jezero Crater.
But first Perseverance has to stick the landing. The spacecraft carrying the rover will be flying roughly 3.5 miles per second when it's approaching the thin Martian atmosphere. To slow the descent, the spacecraft will deploy a parachute and activate thrusters, while a shield will protect it from heat caused by friction. After separating from a protective capsule, a "skycrane" vehicle will lower the rover to the ground.
Perseverance will perform its EDL (entry, descent and landing) autonomously, the first spacecraft to ever do so. To save mission time and land safely, the rover will use Terrain-Relative Navigation technology to quickly identify and move to an optimal landing site within Jezero Crater.
But while Perseverance is the most technologically advanced rover ever launched into space, there's no guarantee it'll land safely on the Red Planet. After all, only 40 percent of missions sent to Mars have succeeded. What's more: NASA won't instantly know whether the landing succeeded because of the radio communication delay between Earth and Mars.
It's maybe no wonder NASA often describes Mars landings as "seven minutes of terror."
"Don't let anybody tell you different – landing on Mars is hard to do," John McNamee, project manager for the Mars 2020 Perseverance rover mission, said in a NASA blog post. "But the women and men on this team are the best in the world at what they do. When our spacecraft hits the top of the Mars atmosphere at about three-and-a-half miles per second, we'll be ready."
NASA plans to livestream the landing, starting at 2:15 p.m. EST on February 18.
"If all goes well, the public will be able to experience in high-definition what it's like to land on Mars – and hear the sounds of landing for the first time with an off-the-shelf microphone," NASA wrote.
Illustration of NASA's "skycrane" lowering Perseverance onto the Martian surface.
Within days of landing, Perseverance is set to transmit high-resolution images of the Martian surface back to Earth. The rover is equipped with 19 specialized cameras, more than any mission before it.
"Mastcam-Z's cameras can zoom in on rock textures from as far away as a soccer field, while SuperCam will use a laser to zap rock and regolith (broken rock and dust) to study their composition in the resulting vapor," NASA wrote. "RIMFAX (short for Radar Imager for Mars' Subsurface Experiment) will use radar waves to probe geological features underground."
Perseverance, accompanied by a drone helicopter named Ingenuity, has four main scientific objectives:
- Looking for habitability: identify past environments capable of supporting microbial life.
- Seeking biosignatures: seek signs of possible past microbial life in those habitable environments, particularly in special rocks known to preserve signs over time.
- Caching samples: collect core rock and "soil" samples and store them on the Martian surface.
- Preparing for humans: test oxygen production from the Martian atmosphere, and test the viability of five spacesuit materials.
But the key focus is to determine whether life ever existed on Mars. That's why NASA plans to land the rover in Jezero Crater, which 3.5 billion years ago contained a body of water roughly the size of Lake Tahoe. NASA scientists think sediments in the crater may contain traces of organic molecules and, potentially, ancient microbial life.
There's good reason to think Mars may have once harbored life. Although the Red Planet is cold and barren today, it once had an atmosphere that was likely substantial enough to support a greenhouse effect and liquid water. But that was billions of years ago, so it's hard to nail down the specifics, especially without soil and rock samples.
"We know Mars had more atmosphere," Timothy Livengood of the University of Maryland, College Park and NASA's Goddard Space Flight Center, told NASA. "We know it had flowing water. We do not have a good estimate for the conditions apart from that — how Earthlike was the Mars environment? For how long?"
Perseverance could help clear up some of these mysteries about the Red Planet, the biggest of which is whether life exists outside of Earth. And if the rover finds no signs of ancient life? As microbiologist Andrew Steele told the Smithsonian Magazine:
"If you find a habitable environment and don't find it inhabited, then that tells you something," he said. "If there is no life, then why is there no life? The answer leads to more questions."
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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.