话题讨论:深空有外星人吗?网友:不要自恋,在大约2万年的时间里,我们人类文明的巅峰是罗马和中国。我们只是在过去300年里成为了“先进”文明。
2021-05-16 熊猫永不为奴 14149
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schwit1 writes:
Are there aliens out there? Breakthrough Listen, a privately-funded project searching for evidence of alien life, has released the first results from its survey of 60 million stars in an area looking towards the galactic center, noting that it found no evidence of any technological transmissions signaling an alien civilization from any of those stars. The kind of signals they were looking for were not beacons sent out intentionally by alien civilizations, such as television or radio broadcasts, but unintentional transmissions, such as radar transmissions meant for other purposes but still beamed into space. They found none. The paper can be downloaded here (PDF).

schwit1报道:
外面有外星人吗?“聆听突破”是一个私人资助的寻找外星生命证据的项目,该项目对银河系中心区域的6000万颗星球进行了调查,发布了他们的第一个研究结果,表示没有发现任何证据表明存在外星文明,这些星球中没有任何一个出现技术传输信号。
他们寻找的信号并不是外星文明故意发出的信标,比如电视或无线电广播,而是无意的传输,比如用于其他目的,无意中发送到太空的雷达传输。但他们什么也没找到。

That's basically zero. (Score:3, Informative)
by Agent Fletcher ( 624427 ) on Friday May 07, 2021 @03:16AM (#61357640)
SearchIng 60,000,000 stars with an estimated 1,000,000,000,000,000,000,000 stars in space that we know of means we searched about 0.00000000000006% of known stars for life. Yeah basically zero.

在银河系搜索60000000颗行星,但整个银河系大概有1000000000000000000000颗行星,我们由此知道,我们只搜查了大约0.00000000000006%的已知的恒星的生命,所以这种搜索基本上是零。
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Re:
We're more certain of the impossibility of winning the Powerball jackpot than we are of intelligent life in the galaxy.

我觉的彩票中头奖的可能性,都比我们在星系中发现智慧生命的可能性更高。
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Re: That's basically zero.
Somebody is going to win. It just wont be you.

有人总会成功的,但反正不可能是你。

Re: That's basically zero. (Score:5, Informative)
by jcochran ( 309950 ) on Friday May 07, 2021 @03:54AM (#61357714)
Quite a few zeros you've placed there for no reason. The researchers aimed their search at our galactic center. The Milky Way has somewhere between 100 to 400 billion stars. The reason they aimed at the GC was because there is the highest density of stars to observe.
"The evolutionary program of organic life doesn't iterate effectively when the sky mashes the reset button every five to ten thousand years."
The authors do take into consideration some of the issues with instability near the GC, but there's quite a bit of handwaving involved.

你对银河系行星数量的说法少了很多0。
研究人员把他们的搜索目标放在银河系中心,整个银河系有1000亿到4000亿颗恒星。他们之所以选择那里,是因为那里有最高密度的恒星可供观测。
“当星空每五到一万年按一次重置键时,生命的进化并不会真的重复。”
作者确实考虑了附近的一些不稳定的问题,只不过其中涉及到相当多的问题。

Re: That's basically zero. (Score:5, Funny)
by DamnOregonian ( 963763 ) on Friday May 07, 2021 @05:23AM (#61357870)
"The evolutionary program of organic life doesn't iterate effectively when the sky mashes the reset button every five to ten thousand years."
They just need to invent a god that made their planet in 4000 years. problem solved.

楼上。
他们只需要创造出一个能在四千年内创造他们星球的神,问题解决了。

Re:That's basically zero. (Score:5, Interesting)
by MightyMartian ( 840721 ) on Friday May 07, 2021 @09:18AM (#61358370) Journal
It's worse than that. Considering that any signal of normal power would lose coherency over a few dozen to maybe a few hundred light years, unless an alien civilization is pointing a highly directional and very powerful signal right at us, we're not likely to ever see it. As a technique for catching bits of some nearby civilization's version of "I Love Lucy", these projects are an utter waste of time, since such signals will be of relatively low power, will dissipate over any significant distance, if not outright swamped by other sources of radiation.

考虑到任何正常功率的信号,都会在几十光年到几百光年之间消失,所以除非有外星文明在用高强度信号定向地向我们发出信号,我们不太可能看到它。
作为一种捕捉附近文明版本的“我爱露西”项目,这个项目完全是在浪费时间,因为这些信号的功率相对较低,哪怕没有完全被其他辐射源淹没,也会在一定的传播距离内消散。

I suspect when we seriously starting looking for life (intelligent or otherwise) in other stellar systems, it will be through future generations of telescopes which will be able to image alien worlds sufficiently to detect continents, oceans, and makeup of atmospheres. Looking for radio signals is a fool's errand.

我怀疑,当我们真正能成功的在其他恒星系统中寻找生命(智能的或非智能的)时,将会是通过未来的望远镜来拍摄外星世界的图像,足以探测到大陆、海洋和大气的构成的超时代望远镜。
寻找无线电信号是件徒劳的事。

Re:That's basically zero. (Score:5, Insightful)
by cusco ( 717999 ) on Friday May 07, 2021 @09:40AM (#61358440)
They're not looking for 'I Love Lucy', they're looking for the DEW Line. The much-lamented Arecibo telescope dish would have been able to detect its twin sending from the Andromeda Galaxy. That they haven't found it yet is not surprising, if other technological civilizations follow our trajectory (a dubious assumption, but we only have a sample size of one). A hundred and fifty years ago we would have been undetectable by radio signals. As we move away from powerful broadcasts to weak directed signals it looks like in another fifty years we will probably again be undetectable. That's less than two percent of the length of our civilization so far, and we barely have space flight.

他们要找的不是“我爱露西”,他们要找的是DEW。
Arecibo望远镜本来可以探测到来自仙女座星系的孪生星系。
如果其他科技文明的发展轨迹和我们类似(这是一个可能的假设,但我们在宇宙文明中毕竟只有自己一个样本),所以他们还没有发现新的文明并不奇怪。
150年前,我们也是无法被无线电信号探测到的文明。现在随着我们正从强大的广播转向微弱的定向信号,似乎再过50年,我们可能又将无法被探测到。现代文明的时间,还不到我们文明的2%,而且我们几乎无法进行太空飞行。
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Re:
They did not search for life.
They searched for transmissions.Even if all those stars (erm a planet around those stars) would send out transmission:
* how likely is it that one can be detected from our position?
* how old would be the transmission?
* how can you even be sure it is from that star/plant which was a few thousand years ago at a different position?
* why would they - and how would they - aim a transmission at us, as we also were a few thousand years ago at an totally d

他们不是寻找生命。
他们只是在寻找传输信号。即使所有这些恒星(恒星周围的行星)都会发出信号:
从我们的位置被探测到的可能性有多大?
传播多久了?
你怎么能确定它来自几千年前位于不同位置的那颗恒星/植物?
他们为什么——以及他们是如何——把传播的目标对准我们的?

Re:
Well, not so "totally different position in the galaxy" as all that. We've moved maybe 25 light years in the last 30000 years. Of course, we haven't been capable of doing anything detectable for much longer than a century, so it'll be 60K years (39K years before they detect us, another 30K years before they can signal get a signal back to us) before someone down near the core of the Milky Way could possibly respond to us.

好吧,并不是“完全不同的星系位置”。在过去的3万年间,我们已经移动了25光年的距离。
当然,在一个多世纪以来,我们都无法探测到任何东西,所以在银河系核心附近的某个文明对我们做出反应之前,我们将需要6万年(在他们发现我们之前需要3万年,在他们能够发出信号返回我们之前还需要3万年)。

Re:That's basically zero
Assuming that there are at least 10^20 stars, that means we look at 1 in 10^12 stars. That is like looking at a 10 centimeter square piece of the earth and saying there is no life. As always, a random positive result would have been interesting, but a negative results shows nothing.

假设至少有10的20次方颗恒星,这意味着我们看到的是10的12次方颗恒星。这就像看着一片10平方厘米的地球,说整个地球上没有生命一样。一个随机的积极结果会很有趣,但一个消极的结果什么也不能证明。

Re:That's basically zero (Score:4, Informative)
by EnigmaticSource ( 649695 ) on Friday May 07, 2021 @11:56AM (#61359022)
If you can't find life in any random 10cm^3 bit of the surface of the earth, you really aren't looking that hard. Life is stupidly pervasive on earth, and if you're looking at unicellular things and spores you'd probably have a hard time finding a cubic decemeter of air devoid of life.
However, you're completely right about the absence of evidence is not evidence of absence... Your metaphors could use a bit of work though ;)

如果你无法在地球表面任意10cm^3的地方找到生命,那你就真的无法找到了。因为生命在地球上无处不在,如果你观察单细胞生物和孢子,你可能很难找到一立方厘米没有生命的空气。
然而,你说的其实也完全正确,没有确定证据并不意味着没有文明……不过,你的比喻可能需要改变一下。
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Re:
I invite you to go look for life in a ten cubic centimeter patch of hot magma. Go on, you could make the breakthrough of the year xD
It would be very exciting to find microbial life on Mars, for instance, but somehow I doubt it'd return our calls if we tried sending radio broadcasts at it.

我邀请你去10立方厘米的炽热岩浆中寻找生命。加油,你肯定可以在xD年取得突破
比如在火星上发现微生物是一件非常令人兴奋的事情,但我怀疑,如果我们试图向火星上的微生物发送无线电广播,它们恐怕不会回复我们。

Re:
To make the analogy work, we are looking for intelligent life, radio signals, not just bacteria. I think there is a much greater than 50% chance there is no sign of intelligent life on a random 10 cm square of earth.

我们正在寻找智慧生命,寻找无线电信号,而不仅仅只是微生物。我认为在方圆10厘米的地球上,没有生命迹象的可能性远远超过50%。

What are the chances? (Score:5, Insightful)
by Maelwryth ( 982896 ) on Friday May 07, 2021 @03:28AM (#61357666) Homepage Journal
In the last two hundred years we have gone from radio to the Internet. In another two hundred who knows what we will be using. Sure, we have to look. You don't generally get to find things if you don't but it's a little hopeful to imagine that not only is there intelligent life but that it is at the same level as us.
I imagine that when we do find evidence of another civilization they will be either way ahead of us or way behind. Probably the former. And we will say, "Of course, how could we have missed it!"

在过去的两百年里,我们已经从无线电到互联网。再过200年谁知道我们会用什么。当然,我们得拭目以待。
通常情况下,如果你不去找,就永远也找不到。但想象一下不仅有智慧的生命存在,而且他们还与我们处在同一水平上的可能。
不过我想,当我们找到另一种文明存在的证据时,他们要么远远领先我们,要么远远落后我们。
也许到时候,我们会说:
“当然,我们不能错过!”

Re:What are the chances? (Score:5, Insightful)
by DamnOregonian ( 963763 ) on Friday May 07, 2021 @03:51AM (#61357708)
They don't even need to be way ahead for us to miss them.
Further more, there's no saying "way ahead" is actually any harder to see than we are now.
The truth of the matter is that our ability to observe such signals is very, very poor.

他们甚至不需要遥遥领先我们,我们就会错过他们。
此外,没有人说他们“遥遥领先”会让我们更难寻找到他们。
事实的真相是,我们观察这些信号的能力非常非常差。

This study was looking for signals with a minimum EIRP of 10^14W/Hz.
This means they're looking for things stronger than Arecibo blasting its radar full power. Directly at us.
Since we ourselves weren't even ever sweeping the skies with Arecibo firing at full blast, it seems bizarre to be surprised by aliens not also doing that.

本研究寻找到的最小为10^14W/Hz的信号。
这意味着他们需要比Arecibo更强的设备,成功的关键在我们。
最后,我们自己都没有用Arecibo对深空肆无忌惮的发射信号,所以外星人没有这么做,似乎也并不奇怪。
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Re:
And even if we were doing so, an alien civilisation looking for us located further than 120 ly away wouldn't detect us either.

楼上,即使我们这样做了,一个在120光年之外寻找我们的外星文明,也不可能发现我们。

Re:
And if their version of Arecibo was pointed in a different direction at the time we were monitoring their system we would still have missed it.

如果他们 Arecibo在我们观察深空的时候指向不同的方向,我们仍然会错过它发射的信号。

Re:
Precisely.
And if they've got a spherical reflector visible from orbit pointed directly at us, transmitting with enough power for us to catch it with ours, for long enough for us to tell what's coming out of it, I'm really not sure if I feel good about that.

不错。
如果他们有一个球形反射器从轨道上直接对着我们,发射的能量足够让我们用我们的能量去捕捉它,有足够长的时间让我们判断出它是什么意思,不过我真的不确定我说的是否会发生。

Re:
Well, since they would have had to send that signal two and a half million years ago I wouldn't worry overly. We had barely come down out of the trees by that time.

很好,我不会太担心,因为他们要在250万年前发送这个信号,而250万年前我们刚从树上下来。

Re:
Well, I was thinking a bit closer than Andromeda... We were looking core-ward after all ;)

好吧,我想的是比仙女座更近的地方……我们需要向正中心的区域看

Re: What are the chances?
Wish I had mod points. The broadcast power question is what I was wondering about as well. There are lots of questionable pieces to this, including only looking at the galactic center, how much radio power can they really see, and how small of a fraction of the sky/stars this really was.OTOH, this seems like a swing-for-the-stands approach. If they HAD found something, they could have said "even in an inhospitable environment, only a small fraction of stars is teeming with civilizations that are absolutely

信号传输能力的问题也是我想了解的问题。这其中有很多值得怀疑的地方,包括只看银河中心区域,他们能看到多少无线电能量?这片区域的星球只是银河系的一小部分。
而且,这个项目似乎是为了迎合现状,就算他们真的发现了什么,他们也会说:“即使在一个不适宜居住的环境中,也只有一小部分星球上充满了绝对适宜居住的文明…… ”

Re:
Broadcast power is one thing, but consider that the rest of the universe doesn't have to follow our evolution, and the signals we use today. It's almost narcissistic to believe that others would follow the same path we have, and therefore, we listen to signals from ourselves, rather than a broader context-- if within the constraints of physics.We flatter ourselves that we might see modulations and signal propagation behaviors of Faraday, Maxwell, etc. These are not the only ones, just the ones of inventors

信号传输能力是一回事,但考虑到宇宙的其他文明不一定会和我们走一样的发展,相信别人会和我们走同样的路几乎可以说是一种自恋。
因此,如果在物理学的限制下,我们倾听我们自己的信号,而不是更广泛的深空背景,我认为我们可能会看到法拉第、麦克斯韦等的调制和信号传播行为。科学的可能性是无限的……

Re:
While I certainly understand the point you're trying to make, I think you're invested too much in the idea of "the possibilities of science are limitless"
How many entirely separated human civilizations developed bows, clubs, and swords?
Sure, they're all human, you may say. But those things weren't built into our DNA.
It's also quite possible (and I'd argue likely) that science evolves, in general, along the progressive path we have taken, more or less.This is a great example.

我能理解你的观点,但我认为你对“科学的可能性是无限的”这一观点投入太多了。
有多少完全独立的人类文明发明了弓、棍棒和剑?
当然,你可能会说,他们都是人。但我们的DNA里其实并没有这些发明。
也很有可能(我认为很有可能),总的来说,科学或多或少是沿着我们所走过的道路逐渐发展的。

Re:
I certainly don't believe aliens can defy physics, although humans do on a daily, even hourly basis, demonstrated by the morning traffic reports on the radio.Transmitters in the 1920s used hundreds of thousands of watts because little was known of the layers of the ionosphere, the effects of sunspots on radio propagation, and we need only look at how WiFi evolved from data rates of a signal flagger to something that we call gigabits/sec.As discoveries march on, we learn more and more. I maintain that it's h

我不相信外星人可以违背物理定律,因为人类每天,甚至每小时都在物理定律之中,从每天早晨的交通广播就可以看出来。
而20世纪20年代的发射机使用了数十万瓦特的功率,因为当时人们对电离层的层次、太阳黑子对无线电传播的影响知之甚少,我们只需要看看WiFi是如何从一个信号标记的数据速率演变成我们所说的千兆/秒。随着科学发现的不断深入,我们学到的东西也越来越多。

Re:
I'm not insulting the intelligence of every human alive, rather, just because we're at the top of one food chain doesn't mean we're either overly-intelligent, or at the top of far more sophisticated food chains that we could not have imagined.I cite the near-megawatt transmitter of yore because we can do the same thing with a microwatt today. The data density/sec of WiFi fifteen years ago was laughable by today's standards, and we've not pushed the boundaries of physics.These are examples, but also examples

我不是在侮辱每一个活着的人类的智力,而是,仅仅因为我们在一条食物链的顶端,并不意味着我们就一定很聪明,或在我们也站在我们无法想象的更复杂的食物链的顶端。
我引用以前的近兆瓦发射机对比,因为我们今天可以用一微瓦做同样的事情。以今天的标准来看,15年前WiFi每秒的数据密度是无比可笑的,而且我们还没有突破物理学的极限。这些是例子,但也只是例子
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Re:
Let's look at modulation, phase delay, timing/periodicity, isochronicity, duration, and more. Zero of these were understood in 1895. Our understanding of physics has changed breathtakingly, too.Someone else in the universe will come to understand these in *their* order, and more.Here on Earth: We listen for a little while and go, "nothing there, let's move on" and I giggle.

让我们看看电子调制、相位延迟、定时/周期性、等时性、持续时间等等。这些在1895年都没有被发现,这些年来我们对物理学的理解也发生了惊人的变化。宇宙中的其他人将会按照他们的顺序理解这些,甚至更多。在地球上:我们听了一会儿宇宙,然后说:“那里没有东西,我们继续下一个吧”,我狂笑。

Re:
I take your point, but I think other posters' points are that we can only observe with the technology we have and are aware of.Let's say the aliens are chitchatting via controlled neutrino oscillation (totally making that up). We don't have a way to easily detect that, so we can't search for E.T. that way. So we miss them. But if an alien civilization is using it for communication there's a good bet they're doing it because they already have used "old-fashioned" radio waves, and neutrino oscillations are

我接受你的观点,但我认为其他帖子的观点不行,我们只能用我们拥有和知道的技术来观察。让我们假设外星人通过受控中微子振荡聊天(完全是瞎编的)。我们没有办法轻易地探测到它,所以我们不能用这种方法寻找外星人。所以我们错过了他们。
但如果有外星文明正在用它进行交流,很有可能他们已经正在这么做,因为他们已经不再使用“老式”无线电波,而是中微子振动。

Re: What are the chances? (Score:4)
by jwhyche ( 6192 ) on Friday May 07, 2021 @11:17AM (#61358850) Homepage
We can actually take this one step farther. There is no reason that a civilization needs to develop in to a technological advanced civilization. For around 20K years the height of our civilization was Rome, and China. We have only been a "advanced" civilization for the past 300 years. Even today there are still societies living in jungles and on islands with nothing but stone age tools all fat and happy.

我们可以更进一步,没有任何原因,因为一个文明需要发展成为一个技术先进的文明。在大约2万年的时间里,我们文明的巅峰是罗马和中国。我们只是在过去300年里成为了“先进”文明。即使在今天,仍有一些社会生活在丛林和岛屿上,除了石器时代的工具一无所有,却又肥胖又快乐。

Re:
Very insightful.

很有见地。

Re:
Perhaps you imagine aliens with big steam punk victorian power supplies driving crude lasers on space ships with spikes on them or something?
You forgot that those ships are crewed by vampires and weres!

也许你会想象,拥有维多利亚时代蒸汽朋克式大电源的外星人在带有尖刺的宇宙飞船上驱动简陋的激光?
你忘了那些船的船员都是吸血鬼!

Re:
. It's almost narcissistic to believe that others would follow the same path we have, and therefore, we listen to signals from ourselves, rather than a broader context-- if within the constraints of physics. I think the logic is more "We know XYZ is a practical thing that an advanced civilization might do, because we did it, therefore it's worth looking for", not "The only way an advanced civilization would ever do is stuff we do." Plus we know how to look for stuff we've done.

“相信别人会和我们走同样的路几乎是一种自恋,因此,如果在物理学的限制下……”
我认为你的逻辑应该是“我们知道XYZ是一个先进文明可能会做的实际事情,因为我们已经做了,所以值得去寻找”,而不是“一个先进文明唯一会做的事就是做我们做过的事”。而且我们知道怎么寻找我们做过的东西。
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Re:
True. And with the times involved they could be on our metaphorical doorstep by the time we spotted anything weird. Its 27,000 or so light years to the galactic core...

真实。随着时间的推移,等我们发现一些奇怪的事情时,他们可能已经出现在我们的家门口了,毕竟我们距离银河系中心只有大约27000光年……
原创翻译:龙腾网 http://www.ltaaa.cn 转载请注明出处


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The problem is that we really don't know what the chances are. Maybe in few hundred years we figure out that the great filter for all the ones to come after is the first civilization to get up and running and we are it. I mean chimps will never get to build their own civilization unless its in a zoo managed by us and Neanderthals sure aren't around to ask "Where are the others?". Why would you think this must be all that different on cosmic scale?

问题是我们真的不知道机会有多大。也许在几百年后,我们会发现,所有未来文明的伟大过去都是建立在第一个出现并延续的文明之上,而我们就是第一个文明。
我的意思是,黑猩猩永远不会建立自己的文明,除非是在由我们管理的动物园里,而尼安德特人肯定不会问“其他人在哪里?”为什么你会认为在宇宙范围内会有那么大的不同呢?

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Also people often forget a very important thing, time scales. It took all of human history up to this point for us to develop enough technologies and knowledge to be able to "listen" in on the universe. These 200 thousand years, or even millions, are still a mere fraction of the universe's time lapse.
There could have been millions of space-faring civilizations before, and there will maybe be millions more after that, but all of them would come and go at different times and just miss each other by mere secon

人们还经常忘记一件非常重要的事情,时间尺度。到目前为止,人类发展出了足够的技术和知识来“聆听”宇宙。这20万年,甚至数百万年,仍然只是宇宙整体时间流逝的一小部分。
以前可能有数百万个太空文明,以后可能还会有数百万个,但它们都在不同的时间来来去去,只差几秒就错过了对方

Re:
The filter does not even need to press the reset. It might be that interstellar travel is more or less simply beyond our reach.As it stands today physics says chemical energy just won't take us many of the places we want to go. Atomic energy might but only if we are willing to go slow. The energy required to go anyway fast in terms of human life times juxtaposed against stellar distances rapidly moves beyond anything we have the ability to generate or manage if we could

过去甚至不能重复。也许星际旅行或多或少超出了我们的能力范围,而且就目前的情况来看,物理学认为化学不能带我们去很多我们想去的地方。但原子能或许可以。
只有在我们愿意放慢脚步的情况下,以人类生命的时间和恒星的距离来衡量,无论如何快速移动所需要的能量,都超出了我们能够产生或掌控的能力范围。

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Most Apes are in the stone age. If mankind would disappear one or more of them would likely evolve and take our place. There is no scientific reason why they would not.

大多数猿类生活在石器时代。如果人类消失了,它们中的一个或多个可能会进化并取代我们。没有任何科学能证明他们不可以。

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No scientific reason other than the fact that intelligent life has only arisen once in 4 billion years on earth. I mean, dinosaurs might evolve again too, but I wouldn't bet on it.

除了地球上40亿年才出现一次智能生命这一事实外,没有其他科学原因。我的意思是,恐龙也可能再次进化,但我不敢打赌。

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Today, we still speak in terms of light years when it comes to searching for other life forms. And yet, we still don't hold technology that comes anywhere close to getting us anywhere near that.To put that into perspective, it takes us humans months to travel less than three light minutes between here and Mars.) It's taken half a human lifetime for Voyager 1 to travel a whopping twenty one light hours. THAT is how far we humans have sent anything from this planet.

今天,我们在寻找其他生命形式时,仍然用光年来衡量。然而,我们仍然没有任何技术能让我们接近光年这个目标。从这个角度来看,我们人类从地球到火星需要几个月的时间,行程不到3光分钟。
“旅行者1号”用了一个人的半个生命时间才旅行了21光小时。这就是我们人类,将任何东西从这个星球送出的‘残酷’距离。

原创翻译:龙腾网 http://www.ltaaa.cn 转载请注明出处


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