Once a week.
Subscribe to our weekly newsletter.
Was ‘Oumuamua a rock or an alien scout? Harvard astronomer talks controversial hypothesis in new book
Ari Loeb, who suggested in 2018 that the mysterious object was an alien craft, is back to discuss the evidence.
If we became especially interested in another solar system and wanted to send an exploratory craft, how would we do it? Even the nearest solar system—Proxima Centauri is its sun—is about 40,208,000,000,000 kilometers from here, so there's no way our scout could carry enough fuel to get there. Might we could use something like a light, or solar, sail? Light-sail craft already exist, and they do work.
Harvard University astronomer Avi Loeb made headlines in 2018 when he suggested that the extra-solar object 'Oumuamua—which, after all, does mean "scout" in Hawaiian—was just such a craft sent to have a look at our solar system. Since then, if anything he's become even more convinced, and Loeb has just published his reasoning and other thoughts in a new book, "Extraterrestrial: The First Sign of Intelligent Life beyond Earth."
But it's a rock
Credit: M. Kornmesser, European Southern Observatory (top)/ K. Meech et al., NASA (bottom)
The visual image that comes to mind in thinking about 'Oumuamua is the artist's rendition (above top) that was released by the European Southern Observatory when the object was discovered on its way out of our solar system in 2017. Listening to Loeb's claims, one may think, "What light sail? It's a rock."
However, it's all too easy to forget that this ubiquitous image is just an artists' rendition after all, based on the assumption that our visitor was a rock. It need not have looked like this at all. We have no idea what 'Oumuamua really looked like, since the image at the bottom shows the best look at the object we really got.
What is a light sail?
The camera on Planetary Society's Light Sail 2 capture an image of northern Brazil
Credit: Planetary Society
A light sail is a spacecraft constructed from panels of a lightweight, reflective material such as Mylar or polyimide treated with a metallic reflective coating. When photons from a star, such as our Sun, hit the sail, they give it a small push. When the photons bounce back off of the sail, they give it another one. It doesn't take much of a shove to move a light sail through a vacuum of space, and it's believed light sails can pick up quite a lot of speed as they go. Loeb himself is involved in the Breakthrough Starshot project that envisions light-sail craft shooting through space at 100 million miles an hour.
The first functioning light sail, LightSail Sail 2 was sent aloft by the Planetary Society in June 2019, and is currently orbiting the Earth. This year, NASA plans to deploy the NEA Scout mission that will send an 86-square-meter light sail off from Moon orbit to explore the near-Earth asteroid Itokawa.
To Loeb, the object's apparent appearance and behavior doesn't suggest a rock.
First off, what appears to be 'Oumuamua's shape—described as being about 100 meters long and resembling either a cigar or pancake—doesn't describe previously seen comets or asteroids. Second, 'Oumuamua was also exceptionally bright, 10 times moreso than space rocks typically seen whizzing around our solar system. This high level of reflectivity would consistent with a shiny, metallic surface.
Finally, 'Oumuamua accelerated as it whipped around the sun as if it was picking up energy from the star. While such behavior is common when comets speed up, pushed forward by evaporating gasses from the sun's warm, no such gases were observed with 'Oumuamua.
With all this in mind, Loeb, along with co-author Shmuel Bialy, published a controversial paper in Fall of 2018 in the Astrophysical Journal Letters hypothesizing the object might be an extraterrestrial craft. The paper suggested that maybe "'Oumuamua is a lightsail, floating in interstellar space," perhaps "debris from advanced technological equipment." It also posited an admittedly more "exotic" possibility, "that 'Oumuamua may be a fully operational probe sent intentionally to Earth vicinity by an alien civilization."
Needless to say, the paper was met with a great deal of excitement. Did 'Oumuamua signify the presence of intelligent life beyond our solar system, or—as many scientists felt—was such conjecture unworthy of serious consideration?
Welcome to 2021
As the title of his new book implies, Loeb continues to assert the validity of his earlier analysis, demanding that the scientific community at least consider the possibility that 'Oumuamua was an exploratory craft.
One of the underlying themes of the book is Loeb's concern about the "health" of a scientific community that can't even entertain a hypothesis such as his and Bialy's. (This month, Scientific American published an extended and thought-provoking interview with Loeb.) In the book and interview, Loeb attributes his notoriety to an overreaction by the scientific community to his 2018 paper. While much of the book is autobiographical, Loeb claims he isn't interested in his own fame, and he recently stepped down from Harvard's Astronomy department.
"My message is that something is wrong with the scientific community today in terms of its health," Loeb told Scientific American, adding that too many in the science community are motivated by ego and self-image, when science should be about taking risks and trying to understand the world.
"People ask why I get this media attention. The only reason is because my colleagues are not using common sense," Loeb said. "Contrast string theory and multiverses with what I and many others say, which is that based on the data from NASA's Kepler mission, roughly half of the galaxy's sunlike stars have a planet about the size of the Earth, at about the same distance of the Earth from the sun, so that you can have liquid water on the surface and the chemistry of life as we know it. So if you roll the dice on life billions of times in the Milky Way, what is the chance that we are alone?"
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.