第3章 埃文斯牧师的宇宙 The Reverend Evans's Universe · 第4讲S4

1. 老师，讲稿里说超新星爆发需要恒星质量是太阳的10到20倍，那像我们太阳这样的小质量恒星，是不是永远不可能变成超新星呀？
2. Betelgeuse（参宿四）虽然离我们要比别的候选恒星近，但讲稿里提到它‘sputterings’（喷发）说明它不稳定，这跟它最终会不会爆炸有啥关系？
3. 1054年的超新星爆发留下了蟹状星云，现代天文学是怎么通过观测这个星云，反过来确认它就是我们史书里记载的那次爆炸的？
4. 既然超新星爆发威力这么大，为什么讲稿最后说‘Without them, we wouldn't be here’（没有它们我们就不存在）？它们对生命到底有什么关键作用？
5. 讲稿里提到最近一次肉眼勉强可见的超新星在大麦哲伦星云，离我们有16.9万光年。如果未来有一颗超新星在10光年外爆发，除了辐射，还会对地球产生哪些具体影响？

1. Since the lecture says a supernova requires a star to be 10 to 20 times as massive as our Sun, does that mean small stars like our Sun will never become supernovae?
2. The lecture mentions that Betelgeuse's 'sputterings' suggest it is unstable; how does this instability relate to its potential to explode as a supernova?
3. How did modern astronomers use observations of the Crab Nebula to confirm that it is indeed the remnant of the supernova recorded in Chinese historical texts in 1054?
4. The lecture ends by saying 'Without them, we wouldn't be here.' What is the crucial role supernovae play in making life on Earth possible?
5. The most recent barely visible supernova was 169,000 light-years away. If a supernova were to explode at a distance of only 10 light-years, what specific effects would it have on Earth beyond just radiation?

1 00:00:06,800 --> 00:00:10,860 The reason we can be reasonably confident that such an 2 00:00:10,860 --> 00:00:13,580 event won't happen in our corner of the galaxy, 3 00:00:14,320 --> 00:00:15,480 Thor Stenson said, 4 00:00:15,680 --> 00:00:18,980 is that it takes a particular kind of star to make a 5 00:00:18,980 --> 00:00:20,860 supernova in the first place. 6 00:00:22,830 --> 00:00:24,410 Thor Stenson 说, 7 00:00:24,630 --> 00:00:29,690 我们之所以可以有理由如此的有信心, 8 00:00:29,810 --> 00:00:33,410 相信在 this corner of the galaxy, 9 00:00:33,590 --> 00:00:35,950 在整个星系的我们的这个角落, 10 00:00:35,950 --> 00:00:40,690 也就是我们地球上不会发生这种事情那是因为呢 It 11 00:00:40,690 --> 00:00:43,790 takes a particular kind of star to make a supernova in 12 00:00:43,790 --> 00:00:48,510 the first place 首先并不是所有的星星都可以成为超 13 00:00:48,510 --> 00:00:54,280 新星必须是 a particular kind 必须是某一种达到某一 14 00:00:54,280 --> 00:00:57,050 个条件的某一种星星 A 15 00:00:57,210 --> 00:01:01,610 candidate star must be 10 to 20 times as massive as our 16 00:01:01,610 --> 00:01:08,080 own suncandidate 做名词的时候是候选人的意思这里 17 00:01:08,080 --> 00:01:13,920 说的候选恒星其实也就是符合条件的行星符合条件的 18 00:01:13,920 --> 00:01:20,720 恒星必须是我们太阳的它的质量必须是达到我们太阳 19 00:01:20,720 --> 00:01:25,800 的 10 到 20 倍像我们的太阳都没有资格成为 supernova 20 00:01:26,500 --> 00:01:30,180 and we don't have anything of the requisite size that's 21 00:01:30,180 --> 00:01:31,000 that close 22 00:01:31,820 --> 00:01:32,960 大家可以看一下 23 00:01:33,520 --> 00:01:39,220 of the requisite size 跟 that's that close 这两个部分 24 00:01:39,220 --> 00:01:43,760 呢其实都在修饰 anything 我们根本就没有这样的东西 25 00:01:43,760 --> 00:01:47,100 没有什么样的东西呢就是 of the requisite 26 00:01:47,100 --> 00:01:52,440 sizerequisite means necessary 就是必须的它必须要 27 00:01:52,440 --> 00:01:57,380 达到这样的质量但是根本就没有哪个东西能达到这样 28 00:01:57,380 --> 00:02:03,020 的质量还有 that's that close 这也是一个定语从句修 29 00:02:03,020 --> 00:02:04,860 饰这个 anything 也 30 00:02:05,620 --> 00:02:10,500 就是这里要满足两个条件一是质量要达到这个 31 00:02:10,500 --> 00:02:11,660 recursive size 32 00:02:12,400 --> 00:02:17,120 还有一个条件就是要够近离我们要够近 that's that 33 00:02:17,120 --> 00:02:21,100 close 前面说了大概要十光年吧同 34 00:02:21,200 --> 00:02:26,080 时满足这两个要求的我们根本就没有 The nearest 35 00:02:26,080 --> 00:02:27,780 likely candidate,he added, 36 00:02:27,960 --> 00:02:29,520 is Betelgeuse Betelgeuse, 37 00:02:29,620 --> 00:02:33,080 whose various sputterings have for years suggested 38 00:02:33,080 --> 00:02:36,580 that something interestingly unstable is going on 39 00:02:36,580 --> 00:02:36,860 there 40 00:02:37,970 --> 00:02:41,930 离我们最近的最有可能发生爆炸的恒星是 41 00:02:41,930 --> 00:02:45,640 Betelgeusewhose various sputterings, 42 00:02:45,660 --> 00:02:50,140 sputterings 指的是喷出来的东西它不时地喷发出一 43 00:02:50,140 --> 00:02:53,500 些东西来,这几年 suggested that, 44 00:02:53,700 --> 00:02:54,600 这表明呢, 45 00:02:54,660 --> 00:03:00,700 这个恒星不是很稳定有一些有趣的不稳定的现象正在 46 00:03:00,700 --> 00:03:03,980 发生 But Betelgeuse is 50, 47 00:03:04,200 --> 00:03:09,460 000 light years away So we are safely distant from it 我 48 00:03:09,460 --> 00:03:11,200 们离它很远很安全 49 00:03:12,920 --> 00:03:16,860 Only half a dozen times in recorded history have 50 00:03:16,860 --> 00:03:20,360 supernovae been close enough to be visible to the naked 51 00:03:20,360 --> 00:03:23,020 eye 在有史以来 52 00:03:23,740 --> 00:03:29,060 我们肉眼可见的距离之内发生的超新星爆炸可能只有 53 00:03:29,060 --> 00:03:34,300 half a dozen times 也就是五六次吧 One was a blast in 54 00:03:34,300 --> 00:03:38,540 1054 that created the Crab Nebula 55 00:03:39,430 --> 00:03:45,770 其中一次就是 1054 年发生的大爆炸那次的大爆炸产生 56 00:03:45,770 --> 00:03:50,150 了蟹状星云也就是这张图这 57 00:03:50,560 --> 00:03:55,540 次的超新星爆炸我们在宋惠耀里边也就是我们中国的 58 00:03:55,540 --> 00:04:01,920 史料里边是有记载的治和元年也就是 1054 年 5 月陈出 59 00:04:01,920 --> 00:04:06,140 东方守天官天官是天官星 60 00:04:06,880 --> 00:04:13,800 骤见如太白白天看过去都很亮就像太白那么亮太白是 61 00:04:13,800 --> 00:04:18,240 哪一颗星呢大家看过西游记一定会记得有一个太白金 62 00:04:18,240 --> 00:04:21,640 星这个太白就是金星芒 63 00:04:21,680 --> 00:04:29,860 角四出光芒四射色赤白凡见二十三日白天都能够看到 64 00:04:29,860 --> 00:04:36,240 它的景象是持续了二十三天但是晚上也能看到它呢这 65 00:04:36,240 --> 00:04:40,730 种状况持续了多久两年以后又有记录 66 00:04:42,250 --> 00:04:49,230 四天剑言自治河元年五月就是从一零五四年开始克星 67 00:04:49,230 --> 00:04:56,890 沉出东方有一颗来做客的星星克星沉出东方守天关至 68 00:04:56,890 --> 00:05:04,190 是末是就表示今天到现在就没有了消失不见了他所说 69 00:05:04,190 --> 00:05:09,270 的克星其实就是超新星啊彗星啊这种 70 00:05:10,040 --> 00:05:14,940 不是在天空中永恒出现的天体八 71 00:05:18,050 --> 00:05:24,070 百多年后有人用望远镜在天关星附近看到了这样的蟹 72 00:05:24,070 --> 00:05:29,190 状星云当然他当时看到的没有这么清晰又过了一百多 73 00:05:29,190 --> 00:05:34,090 年在 1921 年的时候有人发现这个蟹状云在不断的向外 74 00:05:34,090 --> 00:05:40,330 膨胀根据膨胀速度去反推计算出这块星云物质是大概 75 00:05:40,330 --> 00:05:46,250 900 多年前从一个中心飞出来的这个时间与送汇药里 76 00:05:46,250 --> 00:05:51,810 的记载是相符的位置也是一致的所以经过许多天文学 77 00:05:51,810 --> 00:05:57,070 家的研究证明蟹状星云正是我们中国史料上记载的 78 00:05:57,070 --> 00:06:00,350 1054 年的超新星爆炸的遗迹 79 00:06:20,700 --> 00:06:21,200 这是 80 00:06:21,550 --> 00:06:27,530 现代天文学家们看到的最近的一次超新星的爆炸之前 81 00:06:27,530 --> 00:06:30,870 的都是从史书上看到史书上记载的 82 00:06:31,100 --> 00:06:34,660 那这个时候 A supernova flared in the zone of the 83 00:06:34,660 --> 00:06:39,920 cosmosknown as the Large Magellanic Cloud 是在大麦哲 84 00:06:39,920 --> 00:06:45,040 伦星云附近观测到了超行星爆炸 But that was only 85 00:06:45,040 --> 00:06:51,420 barely visible 只是勉强可见 B arely means hardly 几乎 86 00:06:51,420 --> 00:06:55,160 都快看不见了 And only in the southern hemisphere 而且 87 00:06:55,160 --> 00:06:57,540 只在南半球才勉强可见。 88 00:06:57,980 --> 00:07:02,600 And it was a comfortably safe 169, 89 00:07:02,860 --> 00:07:04,060 000 light years away. 90 00:07:04,820 --> 00:07:07,080 还是离我们非常的遥远, 91 00:07:07,120 --> 00:07:08,720 我们完全没必要担心。 92 00:07:11,090 --> 00:07:14,610 Well,this is the end of today's session.A summary. 93 00:07:15,340 --> 00:07:17,640 If a star exploded nearby, 94 00:07:18,200 --> 00:07:22,420 various types of radiation would kill all life on the 95 00:07:22,420 --> 00:07:23,840 Earth.Luckily, 96 00:07:23,880 --> 00:07:27,940 we are at a safe distance from any stars big enough to be 97 00:07:27,940 --> 00:07:2 ……（后略，完整文稿见视频页字幕）