字幕列表 影片播放 列印英文字幕 [ ♪ Intro ] Do you want to live a strong, happy life on Mars? Well, drink red wine. At least, that's what a lot of recent headlines will have you believe. Those articles are talking about a study published last week in Frontiers in Physiology, which found that a compound in red wine could help prevent muscle atrophy on the Red Planet. Except, they're also a bit misleading. For one thing, the study didn't actually use wine. It used supplements of a chemical compound called resveratrol, which happens to be in red wine, along with things like blueberries. Also, the scientists didn't test their hypothesis on humans, but on rats. So for now, these results are worth taking with a bit of a grain of salt. But that does not mean they aren't important. When you hear people talk about living on Mars, they often mention challenges like the planet's cold temperatures, or lack of breathable air. But this study was trying to tackle another major obstacle: Mars's gravity. Since it's about sixty percent lower than Earth's, explorers on Mars wouldn't have to exert their bodies as much, so their bone strength and muscle mass would decline. It wouldn't be as extreme as what would happen during their multi-month trip to Mars, where they'd feel completely weightless. But since these people could very well be spending the rest of their lives on that planet, scientists have already started looking for solutions. That is where this pilot study comes in. The work was conducted by scientists at Harvard Medical School, and they performed their tests on twenty-four 14-week-old, male rats. Half of the animals were allowed to roam their cages as normal, and the other half had to move around while being suspended by cute, little, tiny rat harnesses. This mimicked the amount of gravity they'd experience on Mars. Half of each group then got a daily dose of resveratrol dissolved in sugar water, 150 milligrams per kilogram of body weight. Other than that, everybody ate the same diet. Over the course of the two-week experiment, researchers measured the size of the rats' calves, as well as the grip strength of their front and rear paws. Then, after the two weeks had passed, the rats were euthanized so their tricep muscles could be studied in greater detail. After all the data was analyzed, scientists found that the resveratrol didn't completely protect the rats in harnesses from muscle atrophy, but it did appear to prevent some of it. The rats in this group even had a grip strength comparable to the animals in the control condition: those who didn't live in a harness or get any resveratrol. The supplement also appeared to help the harnessed rats maintain the same muscle composition. Previous studies like this have demonstrated that micro-gravity actually causes some muscles fibers to switch from slow-twitch to fast-twitch. In other words, they switch from a type that provides endurance to a type that's good for quick bursts of effort. A change like this would make a Martian colonist tire out way more quickly, which isn't something you'd want for such a harsh lifestyle. So it's promising that resveratrol could maybe help prevent that. As for why resveratrol might be having this positive effect, it may have something to do with the fact that the compound has been shown to increase the body's sensitivity to insulin. Insulin signals your muscle cells to take in glucose, which they need to work and stay healthy. So increased insulin sensitivity could make this process extra effective. Alternatively, resveratrol could have an anti-inflammatory effect that helps conserve muscle and bone cells. It's still too early to reach any conclusions. Because, again, this was a proof-of-concept study. The authors even acknowledged that it has a lot of limitations, like how all the rats were male, and how they only tested one specific dose of resveratrol. So this phenomenon hasn't even been fully investigated in rodents, let alone attempted in humans. And if you look in the literature, well, many results found in mice or rats don't translate to us, especially in nutrition studies. This means we're nowhere near, like, prescribing red wine to astronauts. But it does show that scientists are hard at work trying to figure these problems out. Meanwhile, other researchers are trying to address those more planet-wide challenges: things like how Mars's average temperature is -63 degrees Celsius, and how its air pressure is too low to support liquid water on the surface. All kinds of solutions have been proposed to fix these problems, including an especially extreme terraforming. This would be where we somehow transform Mars into, like, Earth 2.0. Unfortunately, with our current technology and Mars's resources, terraforming the whole planet doesn't seem possible. But new research does suggest that we could potentially terraform a small part of it. In a paper published last week in Nature Astronomy, scientists suggested we could do this by building a dome out of one of the weirdest materials humans have created: aerogels. Aerogels are sometimes referred to as “frozen smoke,” and they're a class of really cool-looking compounds that can be as much as 99% air. They are gels, but the liquid part has been removed, leaving a solid, dry framework with a bunch of air-filled pockets. These compounds can be used for all sorts of things, including as fillers in cosmetics. But this paper suggested that they'd be especially useful for terraforming a part of Mars. For this kind of project, you'd need to build a dome out of something that traps heat, lets light in for photosynthesis, and blocks ultraviolet radiation that could damage DNA. And according to this paper, a thin shield of aerogel would do the job. In this research, the team focused on translucent silica aerogels, which have actually been used on Mars rovers for insulation. The team experimented with both bead-like aerogel particles as well as large tiles, shining light on them that mimicked what hits the Martian surface. And they found that tiles 2 to 3 centimeters thick created a greenhouse effect that raised surface temperatures beneath them by more than 50 degrees Celsius. At mid-latitudes on Mars, that's about what you need to reach the melting point of water. The tiles were likely so effective because air is an awesomely good insulator. But that isn't the only thing this study found. The silica aerogel also reduced the intensity of long-wavelength ultraviolet rays and blocked nearly all of the more dangerous short-wave ones. So, aerogels could potentially make for a great habitat. And as a bonus, they're also incredibly light because of all the air they contain. So taking a bunch to Mars wouldn't cost nearly as much as sending something like concrete or steel. But then again, we're still a long way from building terraforming domes. And even this design isn't perfect: It wouldn't help us make Mars's atmosphere breathable, and there's always the chance it could get covered in dust and block out sunlight. But studies like this one and the one about resveratrol are still significant, because they're setting the stage for future research. So when the day does come that we're thinking of sending people to live on Mars, we'll be prepared. Thanks for watching this episode of SciShow Space News! If you enjoy learning about things like this and want to show off your love for the universe, we have a thing! Every month to celebrate a different space mission in our history we are going to be doing a limited edition pin. The first one is of the Apollo 11 command and service module and it comes in two colors, one of which is glow in the dark. They're both the same price, why wouldn't you get the glow in the dark one? It's available now and only until the end of July, so if you want it, now is your time! In August, we'll be releasing a new space-themed pin. I'm excited about that one too because I know what it is already, even though you don't. You can them at dftba.com, or on our brand new merch shelf right below this video. Isn't that neat? [ ♪ Outro ]
B1 中級 火星上生活的祕密。葡萄酒和氣凝膠?| 科學秀新聞 (The Secrets to Living on Mars: Wine and Aerogel? | SciShow News) 11 0 林宜悉 發佈於 2021 年 01 月 14 日 更多分享 分享 收藏 回報 影片單字