Hacker News new | past | comments | ask | show | jobs | submit login
Arecibo message (wikipedia.org)
73 points by Hooke on May 9, 2018 | hide | past | favorite | 46 comments

I created an animation of the Arecibo message in less than 1kb of Javascript: https://js1k.com/2017-magic/demo/2843

Here's a video of the animation playing: https://www.youtube.com/watch?v=zMzwmdaloXc

It was a lot of fun to put together, and I know where was a lot of human thought put into the message, but after working with the data of this message for dozens (hundreds?) of hours finessing it and making it as small as possible, the longer I looked at it the less I believe any alien receiving it would be able to decode the meaning we communicated in it. I imagine it's evidence of terrestrial intelligence for aliens who might wonder if they're alone, but I'm not sure how well the intended meaning of the message itself will come through to a non-human being if it's not even obvious to a human being that already knows what it is.

It's a big problem not knowing the audience.

[1] 47:00 https://youtu.be/_ZG8HBuDjgc?t=47m10s

The message looks a lot like Native American Wampum belts: https://en.wikipedia.org/wiki/Wampum

I can wonder how many of those Wampum belts which remain are still well understood?

(Given the use of Wampum to store and transfer knowledge, the reason Native Americans were so eager to trade beaver pelts and such for small colorful beads from Europe was essentially equivalent to people today being willing to trade used empty Starbucks coffee cups for new Flash IC storage chips...)

I can’t be the only person who thinks that broadcasting with the intent of advertising our presence is at best, pointless, and at worse dangerous, right? Passive SETI is great, if unlikely to succeed, but this just seems like a bad idea.

I see you're also a proponent of the "Dark Forest theory".


It doesn’t really matter who’s a proponent of what - if life is not singular then you have to assume it’s relatively common, and then you have to assume that messages like this will reach aliens on a wide spectrum of hostility and advancement.

Unless some unknown physics makes space-opera style fast travel possible, what would be the meaning of hostility? Based on what motive? Expressed how? Space isn't tribes of chimps in adjacent trees.

If we find aliens it will be more like "Don't let the Great Filter get you and maybe we'll have a really slow conversation."

Relativity muddles things a bit. If any civilization lives on a ship that can get near the speed of light, coming to destroy us would take only a few hours or days in their time, even if it took hundreds of years in hours.

But why bother using all that energy? And It will be a huge amount to get light years down to hours.

What threat would we be to them?

We're always a threat. All we need today is a closet Hitler type rising to power in any of the nuclear countries - and that's just today. No idea what socio political landscape will be when the world is hot, water and food scarce, and we know there are aliens out there.

I suppose there will be more people thinking about it now, after Cixin Liu published his book about it.

For sure. It was the first time I saw it articulated so well.

It was articulated so well in the dark forest that I have trouble seeing it any other way now.

There could be many explanations for us not hearing from extraterrestrials. I think you are falling in a cognitive bias trap of having learned too much about one of the reasons and thus assigning it higher probability. Memory is associative, so the more you know about something, more likely you are to use that concept when trying to solve problems or explain mysteries.

To ameliorate that I would suggest reading up on other theories. For example great filter or simulation argument.

Those theories are also too exciting (and hence likely to be overbelieved).

A more mundane reason might be that interstellar travel and communication turns out to be impossible (or near enough).

This is actually Central Park theory from The Killing Star.

Also described in xkcd:


SMBC has covered Fermi’s paradox a few times. I prefer this answer: http://smbc-comics.com/comic/monkey .

I don't think it's dangerous. Light is too slow and space too vast

At human timescales, yes. Think of it from the other side - the immediate reaction to humans finding the existence of extraterrestrial life will be the start of an interstellar weapons program in every country. Now ask yourself what happens if an advanced civilisation reads the message, assumes correctly that these humans ought to have working weapons by now. They’re just going to dispatch a fire and forget drone and set a watchpoint to make sure we’re taken out cleanly.

Right back atcha.

On interstellar timescales, any civilization that fears we will develop interstellar offensive capabilities would need to also seriously consider the possibility that we would survive their first strike.

Some relativistically distant foe tries to wipe us out from some time in the past (light speed, so many many years ago). We recover from this event fully and locate the source.

Why attempt to retaliate? This would be like waging war on Italy for atrocities committed in roman times wouldn't it? Even if you could guarantee success, you have no information about the moral culpability of the target, and would have to assume they have lifespans many multiples of humans to assume any such quality, wouldn't you?

It's not about (justified) revenge, it's about security. 1500's Spain was as dangerous to the natives of the Americas as the Romans were to the Carthaginians 2000 years earlier. If some society didn't have qualms with attempting planetary scale biocide, who's to say their genetically practically identical successors won't do the same?

> Why attempt to retaliate?

Because retaliation shifts our foe's "risk of destruction if drone sent" vs "risk of destruction if drone not sent" tradeoff toward "don't attack".

Sure, but shouldnt really matter. It's very unlikely that any civilization launches anything from the homeworld, more likely they have the space equivalent roving nuclear submarines. Even if we survive the first hit, it's unlikely we can figure catch the launcher submarine or work out its homeworld.

The return-on-investment, time horizon, and C&C complexities are bad enough for one-off missions, they would be worse for an actively maintained fleet, and they would be abysmal for a minefield. How do you do IFF when latency is years / decades / centuries / millenia? If human history is any indication, you don't, and suffer the consequences. A planet-buster minefield is much more of a threat to you great-grandchildren than the new-kid-on-the-block aliens ever will be.

I don't find this scenario remotely convincing. A good premise for a scifi novel though.

Return on investment depends on both the return and investment. Once a civ hits Type 1 or Type 2, what they would consider an "expensive" investment is very different from what we would today. To a sufficiently advanced civ, destroying planets would be no more expensive than setting a sentry turret or an automated Predator drone.

Say you're in Alaska in 1800's. Don't know how many others are out there, what condition they are and what intentions they have. It makes sense in a way: maybe they solve all your problems, but maybe you have have something they really want /need. Take your chances?

But then humanity is such, exploring, connecting...and fighting :)

I guess we're broadcasting it inadvertently anyway, with all the radio noise we create.

Most broadcasts quickly attenuate into noise.

That's the trick, right? In the year I was born, the signals that my mobile phone creates and decodes were impossible to separate from noise.

It's very hard to say how sensitive listeners might become given enough time for technological development.

A lot of that is fancy algorithms and not much distance compared to telling an encoded, attenuated interstellar broadcast apart from the background radiation.

This is actually a really big debate within the scientific community.

There is also WETI, which might be the better approach: http://weti-institute.org

Yep, it's game theory at it's best and the equilibrium is indeed destroying each other or at least destroy your neighbour

No kidding, and now the aliens can say we cooperated in being found, which will lead to some pretty boring dialogue.

> The number 1,679 was chosen because it is a semiprime (the product of two prime numbers), to be arranged rectangularly as 73 rows by 23 columns.

Why not pick the square of a prime number, so that it can't be arranged to wrong way?

Perhaps the clear difference in entropy between 23x73 and 73x23 renderings actually stresses the fact that the data conveys a thoughtfully arranged message of some sort.

IMO the choice of a nondiscrete semiprime data length is a pretty good indicator that it isn't random either…

Is the first column of 111000111 "111" or "101"?

Does it matter? Why should we assume that whoever receives our message prefers reading it from left-to-right rather than top-to-bottom?

Something that always bothered me about this transmission is the fact that the numbers at the top are said to represent 1-10 in binary format. However, when I look at this, when you get to the 8th digit, it shoves the next block out to the side, representing an overflow so that additional numbers can be represented. Is this not representative of the very definition of how to express numbers in a different base? This isn't binary, it's octal. When you rollover after the 7th digit, you have a new set of 8 characters that can represent a discreet unit. I sort of understand how they are passing this off as binary, but without reading an explanation of what this represents, my first instinct is to consider it octal.

Don't get too hung up on notation of numbers. It is just notation after all. If you group binary digits into fours is it octal? When we group decimal digits into threes are we really using base 1000?

yeah it's weird, first they encode numbers one to ten, then the information is in binary, then is pictographic, there's no key to split the sections by encoding, and the key at the beginning is not used.

> This isn't binary, it's octal

Potato, potahto.

Not if you own a Heathkit H-8, it isn't.

(Possibly the only computer made ...note that qualifier, please ... that required most users to learn a number base in order to operate it.)

Guidelines | FAQ | Lists | API | Security | Legal | Apply to YC | Contact