TED演讲宇宙中最诡异的恒星的多音字
演说者：Tabetha Boyajian
蒸凤爪演说题目：宇宙中最诡异的恒星！
一个巨大、地球1000倍大小的物体遮蔽了遥远的一颗名为KIC 8462852的星星，但没人可以确知那是什么样的物体。在天文学家塔贝莎．菠耶金调查这颗巨大、奇特的物体可能是什么的时候，她的一位同事有个奇特的猜想：会不会是外星文明盖的巨型建筑结构呢？这样超凡的想法，需要超凡的证据。这场演讲，菠耶金将带我们一起来看看面对未知事物时，科学家如何研究和验证假说。
宇宙中最诡异的恒星 来自学英语练口语 00:00 14:09 00:12
Extraordinary claims require extraordinary evidence, and it is my job, my responsibility, as an astronomer to remind people that alien hypothes should always be a last resort.
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保险客服
Now, I want to tell you a story about that. It involves data from a NASA mission, ordinary people and one of the most extraordinary stars in our galaxy.
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It began in 2009 with the launch of NASA's Kepler mission. Kepler's main scientific objective was to find planets outside of our solar system. It did this by staring at a single field in the sky, this one, with all the tiny boxes. And in this one field, it monitored the brightness of over 150,000 stars continuously for four years, taking a data point every 30 minutes. It was looking for what astronomers call a transit. This is when the planet's orbit is aligned in our line of sight, just so that the planet cross in front of a star. And when this happens, it blocks out a tiny bit of starlight, which you can e as a dip in this curve.
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And so the team at NASA had developed very sophisticated computers to arch for transits in all the Kepler data.
女人心态阳光的句子01:39
At the same time of the first data relea, astronomers at Yale were wondering an interesting thing: What if computers misd something?
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And so we launched the citizen science project called Planet Hunters to have people look at the same data. The human brain has an amazing ability for pattern recognition, sometimes even better than a computer. However, there was a lot of skepticism around this. My colleague, Debra Fischer, founder of the Planet Hunters project, said that people at the time were saying, 'You're crazy. There's no way that a computer will miss a signal.' And so it was on, the classic human versus machine gamble. And if we found one planet, we would be thrilled. When I joined the team four years ago, we had already found a couple. And today, with the help of over 300,000 science enthusiasts, we have found dozens, and we've also found one of the most mysterious stars in our galaxy.
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你还在等吗So to understand this, let me show you what a normal transit in Kepler data looks like. On this graph on the left-hand side you have the amount of light, and on the bottom is time. The white line is light just from the star, what astronomers call a light curve. Now, when a planet transits a star, it blocks out a little bit of this light, and the depth of this transit reflects the size of the object itlf. And so, for example, let's take Jupiter. Planets don't get much bigger than Jupiter. Jupiter will make a one percent drop in a star's brightness. Earth, on the other hand, is 11 times smaller than Jupiter, and the signal is barely visible in the data.
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So back to our mystery. A few years ago, Planet Hunters were sifting through data looking for transits, and they spotted a mysterious signal coming from the star KIC 8462852. The obrvations in May of 2009 were the first they spotted, and they started talking about this in the discussion forums.
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They said and object like Jupiter would make a drop like this in the star's light, but they were also saying it was giant. You e, transits normally only last for a few hours, and this one lasted for almost a week.
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They were also saying that it looks asymmetric, meaning that instead of the clean, U-shaped dip that we saw with Jupiter, it had this strange slope that you can e on the left side. This emed to indicate that whatever was getting in the way and blocking the starlight was not circular like a planet. There are few more dips that happened, but for a couple of years, it was pretty quiet.
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And then in March of 2011, we e this. The star's light drops by a whole 15 percent, and this is huge compared to a planet, which would only make a one percent drop. We described this feature as both smooth and clean. It also is asymmetric, having a gradual 可爱mm
dimming that lasts almost a week, and then it snaps right back up to normal in just a matter of days.
04:52
家庭会议记录And again, after this, not much happens until February of 2013. Things start to get really crazy. There is a huge complex of dips in the light curve that appear, and they last for like a hundred days, all the way up into the Kepler mission's end. The dips have variable shapes. Some are very sharp, and some are broad, and they also have variable durations. Some last just for a day or two, and some for more than a week. And there's also up and down trends within some of the dips, almost like veral independent events were superimpod on top of each other. And at this time, this star drops in its brightness over 20 percent. This means that whatever is blocking its light has an area of over 1,000 times the area of our planet Earth.
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暑假中
This is truly remarkable. And so the citizen scientists, when they saw this, they notified the science team that they found something weird enough that it might be worth following up. And so when the science team looked at it, we're like, 'Yeah, there's probably just something wrong with the data.' But we looked really, really, really hard, and the data were good. And so what was happening had to be astrophysical, meaning that something in space was getting in the way and blocking starlight. And so at this point, we t out to learn everything we could about the star to e if we could find any clues to what was going on. And the citizen scientists who helped us in this discovery, they joined along for the ride watching science in action firsthand.
