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18-ton section of Chinese rocket crash lands following uncontrolled reentry
If you were awaiting screaming death from the skies, you can relax. For now.
- China's Long March 5 rocket core has landed safely in the Atlantic Ocean following an uncontrolled entry.
- Most of the time, returning hardware that doesn't burn up plunges into the ocean or uninhabited areas.
- There have been two larger returnees in the past, though this one was quite big.
Maybe future generations will look back on these early days of space exploration and chuckle at what we had to suffer through. We live in a time when, every now and then, word goes out that some giant chunk of uncontrolled defunct space junk is about to crash down upon us somewhere, so, um, duck? The hope during such moments is that the deadly debris will land in the ocean that covers most of the Earth's surface or in some unpopulated area, and it usually does. Usually.
Anyhow, if you've been anxiously looking up this week — either at the sky or your ceiling in quarantine — waiting for the core section of China's Long March 5 (CZ-5B) rocket to end you, you can breathe a sigh of relief. It landed safely, for humans anyway, in the ocean off the west coast of Mauritania in northwest Africa on May 11.
Long March into the sea
The CZ-5B-Y1 core stage is in a 155 x 366 km orbit, and is expected to reenter around May 11. At 17.8 tonnes, it is the most massive object to make an uncontrolled reentry since the 39-tonne Salyut-7 in 1991, unless you count OV-102 Columbia in 2003.— Jonathan McDowell (@planet4589) May 7, 2020
Though CZ-5B is one of the largest craft to come down in an uncontrolled reentry, its size is not the only thing that had astronomers like Jonathan McDowell, of the Harvard-Smithsonian Center for Astrophysics, on the edge of their seats. "I've never seen a major reentry pass directly over so many major conurbations!" he tweeted. (A conurbation is an extended urban area.)
While some debris comes down via a controlled landing, that was not the plan for CZ-5B. McDowell tells CNN, "For a large object like this, dense pieces like parts of the rocket engines could survive reentry and crash to Earth." No biggie, he says, since, "Once they reach the lower atmosphere they are traveling relatively slowly, so worst case is they could take out a house."
CZ-5B took off just a week or so ago, on May 5 for just a few days in orbit. Some of its 30-meter-long core stage burned up on reentry, and apparently none of what remained hit anyone, but there are reports of property damage in the Côte d'Ivoire village of N'guinou.
We’ve ducked debris before
A no-doubt radioactive piece of Cosmos 954
Image source: Natural Resources Canada/Wikimedia
At this point, there have been a number of well-publicized spacecraft plummeting down destination-unknown. Probably the scariest was the return of the 4.4-ton Soviet-era spy satellite Cosmos 954. What made its uncontrolled re-entry so frightening is that it was nuclear-powered and threatened to spew radioactive material all over wherever or whomever. The original plan had been to boost it high into a nuclear-safe orbit, but a separation failure doomed the craft to fall back to Earth.
In the end, Cosmos 954 did crash in Northwestern Canada, blowing radioactive debris over a wide area. Canada billed the U.S.S.R $6 million for the cleanup, of which only $3 million was eventually paid.
Probably the first widely publicized uncontrolled return, and one of the two most massive, was of Skylab in 1979. It was another case of a craft coming back earlier than intended, and though NASA couldn't control the 77-ton craft's reentry point, it could control the manner in which it tumbled on down. The nail-biting ended on July 11, 1979, when most of Skylab burned up over the Indian Ocean, though some big pieces survived the descent and landed southeast of Perth, Australia. No one got hurt. The Australian town of Esperance charged NASA $400 for littering. The U.S. also didn't pay up.
Another piece of debris larger than CZ-5B was the Soviet Salyut 7 after nine years in orbit. At the time it came down, it was docked with another spaceship, Cosmos 1686. Salyut 7 weighted in at about 22 tons, as did Cosmos 1686. The connected pair of craft reentered together, burning up and breaking apart over Argentina, with bits raining down on the town of Capitan Bermudez. Amazingly, no one was injured.
One could say we've been pretty lucky so far, though it's hard not to look forward to a time when dying spacecraft can be somehow vaporized out in space where it's safe instead putting those of us down here at absolutely-nothing-you-can-do-about-it risk.
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.