Life in the Universe | Hacker News Reader

Life in the Universe

hawking.org.uk

148 pointskamaal75 comments

Hawking mentions values of physical constants that support life as being often given as an evidence that the Universe was designed. I was wondering once if the values of constants are not enforced by the structure of the Universe, and are not magic numbers that could theoretically be changed. Maybe we don't really understand the underlying mechanism that gives a physical constant a given value, and if we did, it could turn out, that the constant can not possibly have any other value.

Take PI as an example. People very well understand what a PI is and how it can be delivered. Because of this, we do not argue what would happen if PI had a value of 3.15... not 3.14... In a Universe with different PI circles wouldn't be circles, atoms or planets would maybe collapse, but such deliberations do not make any sense because what PI represents enforces the only value that it can have. Maybe the same is true for the electric charge and other constants Hawking mentions?

Math and Physics are two very different realms. There's no a apriori reason for anything in the real world to obey a law or regularity. The fact that it does is amazing. The fact that we are able to think it's amazing is mind blowing. :)

But maybe as we acquire knowledge we will be able to explain why constant have given values. For example: the distance from Earth to the Sun during a given day of a year could in the past be considered a magic number. But today, thanks to Kepler, we understand why this distance has a given value and we know that it could not be different without changing the mass or velocities of bodies.

We use mathematical language to explain things around us. Many of the mathematical 'truths' are based around this. If we saw different things mathematical truths would be totally different.

You can assume anything to be true in Math and build a universe from that truth.

A good book to read around this subject is Godel, Escher, Bach by Douglas Hofstadter

PI has this particular value only in a particular geometry.

http://www.learner.org/courses/mathilluminated/units/8/textb...

This is not just academic, the geometry of the space we are living into is not flat, and thus the PI we measure is not the one you'd expect.

The effect of this space time distortion is what keeps you from floating around, and keeps the air you breath stick to the sphere you call home, which btw has that shape for the same reason.

So, even though the PI value discrepancy caused by earth gravitational field is very small, it shapes our lives and our origins in a dramatic way.

Well, you are measuring two different things. Pi is not changing at all.

exactly, same thing for α: if it were different (numerically) that would mean that we are talking about a different universe, i.e. we would measuring a different fine structure constant. People in that universe would still call it "α", because we define "α" to be the fine structure constant. That wouldn't change the (numerical) value of α in this universe.

In the same way, we define PI to be "the ratio of a circle's circumference to its diameter", and that depends on the kind of geometry where you lay that circle on.

PI is not something that can be delivered? If you're trying to understand why constants have the value they do then you'd need to know more about physics and not mix up math and physics. Math is used to help understand the physical world, but math transcends physics. The universe need not even exist for math to still be whole and complete. Admittedly we probably wouldn't be in much of a position to appreciate it without a universe around to show how clever it all is. What you're alluding to is the anthropic principal.

You misunderstood me a bit. I gave PI as an example of constant that _can be_ delivered and it is well-understood why it has a certain value. I agree this wasn't a good example, PI is indeed mathematical constant, although it appears in physical equations.

Pi is not a physical constant but a mathematical one; I.e. it can be derived a priori, without a physical universe. A physical constant would be Planck's, or the gravitational constant, or c. Those may well be "arbitrary" for all I know.

c, G, and h need predefined measures of meter, second, and kg to be defined, whether or not they're "arbitrary". There true measure is 1, 1, and 1.

Depends. You can choose your measuring system to make some physical constants 1, but not all. And the choice is not obvious for all constants.

Well, some multiverse hypotheses say that there are, in fact, other universes beyond our own that have different values, and that these values are random. Some of these may implode on themselves or expand too quickly for life, but we exist because the numbers for this universe were appropriate for creating life.

In case you missed it, this was written in 1996. A very interesting read indeed. Yet it is somehow disappointing to see that 16 years later, there are yet not a lot of examples of what he calls the "self-designing" of the human race. Quite contrarily there's still a strong opposition (both amongst the legislators and the general public) against stem cell research and human cloning in many countries.

Resistance is an important factor in guarding against runaway phenomena in dynamic systems. History has many examples of severely disappointed humans caused by too little resistance.

Dynamic systems tend to runaway by themselves, whether there is resistance or not. At the very least they tend to become unrecognizable from the original system within a short time whether there was resistance or not (which is chaos theory in a nutshell).

Hawking's point, though, was that it only takes one renegade to start on the track of deliberate genetic improvement, then they'll outcompete and displace the unimproved humans. That may well happen, especially among countries with looser ethical standards than most of Western civilization.

There nothing disappointing about strictly controlling that type of research and the experiments they're allowed to do. If superhuman's were to be developed it could spark off the same type of arms race that defined the cold war. Every country would want to have better humans ot risk being left behind

There is very little risk of this. We don't have the capacity to rival the raw computational power of millions of years of evolutionary trial and error. In the short term, any change to the human genome would lead to a net-negative. You'd have an army of inferior humans, not superior ones.

The goals of evolution are not the same as those of some country's army.

Fun trivia: EVE Online's lore is moving in this direction. And by "moving", I mean "going all in".

Loyal EVE vision believer here; what do you mean? Can you back this up with links and examples?

I would suggest you read cell biology papers from 1996 and from the same authors and institutions today, nearly 20 years later. There has been a pretty staggering amount of insight gained into how cells "work" and by work I mean where folks can predict changes that would occur by making changes in the structure of a cell.

As others have observed it is now possible to 'print' a virus using a DNA printer. Further there is growing evidence that viruses are a change agent for evolution as they physically re-write the genetics of a cell to propagate, and even after the virus is conquered sometimes their structure lives on.

When you combine those, you can see that we're approaching a point where a non-nation state actor (basically a smart biologist in reasonably well funded lab) will be able to code a genetic change, print up a retrovirus to make that change, and then instantiate that change in a test subject (or themselves).

Evidence suggests the first 'customers' for that technology will be athletes who are looking for an 'edge' but when it happens, it will appear to have happened 'over night' where something fundamental about a person can be proactively changed. Whether its baldness, red blood cell production, or the color of your eyes, the changes will be profound and for many quite upsetting.

The key is that people will be able to get changed without the regulating agencies being able to intervene and that will change things quite dramatically.

> Further there is growing evidence that viruses are a change agent for evolution as they physically re-write the genetics of a cell to propagate, and even after the virus is conquered sometimes their structure lives on.

Retro-viri do this. (Not all viri are retro-viri.)

It really is surprising that life could be so rare. But then you realize that the chance of us detecting life from a distant star comes in only very fine bands: in other words our post-SETI civilization needs to be within the light-distance of the star at or after they first produce radio communications but before they start using something far more advanced for communication that we don't yet know how to detect. Plus they need to not destroy themselves. And we need to actually look right at their signal, and notice it!

Basically what this means is: SETI is looking for stars that have developed intelligent life and radio roughly exactly as many years ago as they are light-years away from us. This minimizes the ease of finding significantly.

We could assume civilizations always use advanced forms of radio after they develop it but then why haven't we found life? We assume there must be a limit to the usefulness of radio in that sense. After all, we're moving to fiber etc.

Also, this alien civilization needs to be broadcasting a signal we have a likely chance of detecting, something we're apparently not doing:

http://www.seti.org/faq

Are we also sending any signals?

We conduct a passive experiment, designed only to look for signals, not to send them. However, humankind has been unintentionally transmitting signals into space – primarily high-frequency radio, television, and radar – for more than fifty years. Our earliest TV broadcasts have reached about one thousand nearby stars, although any alien viewers would have to build a very large antenna to detect them.

SETI researchers have not been very interested in broadcasting because of the long time one has to wait for a reply. If the nearest civilization is 100 light-years away, we would have to sit around for 200 years for a reply to a deliberate broadcast.

...

If an extraterrestrial civilization has a SETI project similar to Project Phoenix, could they hear Earth?

In general, no. Most earthly transmitters are too weak to be detectable by Phoenix-type equipment at the distance of even the nearest star. The exceptions are some high-powered radars and the Arecibo broadcast of 1974 (which lasted for only three minutes). To detect "leakage" radiation similar to our own will require instruments that are many times more sensitive than what we now have.

I never thought of the SETI guys as being particularly crackpot, but these answers make little sense to me. They're admitting that even if there's another roughly equivalent SETI project on an Earth-like planet 25 ly away, neither of us will hear each other because we're too impatient (!!) to continuously send a transmission and wait for a response?

I know very little about the propagation of microwaves, but my guess is that SETI doesn't want to admit that real interstellar communication would require vastly more signal power or vastly better detection capabilities than our civilization is capable of mustering.

An assumption of SETI is that we're listening for slightly older civilizations which would use much more energy (many orders of magnitude more). And it's a quite reasonable assumption.

Responding would be possible, if we knew the direction - a focused beam in direction of a specific star can be a billion times stronger than our "leakage", but we can't transmit to all stars, or 1% of all stars, or 0.01% of all stars - there are just too many of them.

I've always wondered what the minimum unit for mechanical life would be. I.e., what's analogious to a biological cell?

It seems to me to have an automated spaceship that can land on planets and produce more automated spaceships, it would require most of the tools available on earth in one way or another; vehicles, mining equipment, refineries, factories, and more. And for each piece say vehicles you need all of the infrastructure to create those.

The simplest possible "mechanical cell" would be a self-contained machine that can reproduce itself given only raw materials and energy. This could theoretically take place on the molecular scale; see http://en.wikipedia.org/wiki/Grey_goo.

It's a different design paradigm than mass manufacturing. Huge refineries and assembly lines are setup because they build large quantities cheaply. Not because this large apparatus is inherently necessary for construction.

Think about it a different way. Imagine you had a robot arm with attachments for every type of tool. Grippers, welders, drills, nut drivers, hammers, etc... Couldn't this single arm build anything given the proper schematic and enough time? To further reduce complexity, you could add design constraints to your 'replicating spaceship' so that only a subset of tools would be required. Finally consider what tools could build the other tools. At some point you approach a minimum amount of gear needed.

Consider that the minimum amount of gear needed could potentially be under 200lbs in weight and under two meters in height.

Hawking is a great writer, I first encountered his writing with his "A brief history of time" book - which was easy to read for someone without much physics knowledge. http://en.wikipedia.org/wiki/A_Brief_History_of_Time

My favorite quote from the article "By contrast, there are about 50,000 new books published in the English language each year, containing of the order of a hundred billion bits of information. Of course, the great majority of this information is garbage, and no use to any form of life"

Never was there a more perfect candidate for the text-to-speech function in Safari.

Evernote is building one in Clearly. I've seen a demo last week and it's working well.

I really hope this was meant to be a joke. If so, it seems to be lost of the guy who mentioned Evernote. Regardless, I thought it was hilarious.

"But Freeman Dyson has shown that, despite this, life could adapt to the ever-decreasing supply of ordered energy, and therefore could, in principle, continue forever".

Does anyone knows what he's talking about ? Dyson's sphere ? Surely there's some energy loss involved in the process ? But if it's true I'm happy to learn that an intelligent lifeform can theoretically live forever.

I think this may be referring to the insight that there won't be a heath death of the universe, due to gravity. Best I could find is here (a book review written by Dyson):

http://www.nybooks.com/articles/archives/2011/mar/10/how-we-...

"Gravitation reverses the usual relation between energy and temperature. In the domain of astronomy, when heat flows from hotter to cooler objects, the hot objects get hotter and the cool objects get cooler. As a result, temperature differences in the astronomical universe tend to increase rather than decrease as time goes on. There is no final state of uniform temperature, and there is no heat death. Gravitation gives us a universe hospitable to life. Information and order can continue to grow for billions of years in the future, as they have evidently grown in the past."

So no heat death, but every computation implies an energy loss, right ? Even with the help of gravity, how do you prevent energy from escaping in EM form ? Even a black hole evaporate if I recall correctly. So I can imagine we could live a loooong time, but indefinitely ? That sounds too good to be true to me, but I don't know much about the physic involved.

>>So no heat death

Unfortunately even if that is true, there is something called as entropy at play here.

Also I would advice you to read Isaac Asimov's "The last question" once. One thing discussed in that book is how quickly human kind or an intelligent being can grow in population and energy consumption.

So even before we reach the point of heat death, if we survive and move out to do the heavens. Then over time, we are likely to run out of resources and space eventually- may be even long before the heat death of the universe itself.

He's talking about the ideas from Dyson's "Time Without End" lectures: http://www.aleph.se/Trans/Global/Omega/dyson.txt

Thank you, looks interesting, I'll have a look, I hope it's not too complicated for a layman like me.

For curiosity and entertainments sake, I would recommend anybody to read Isaac Asimov's "The Last Question". It can be read under 15 minutes and it a entertaining read on this subject and entropy in general.

However for serious arguments sake, the whole problem in this question is "definition of life" itself. However even if we consider that heat death is inevitable and that we are assuming human beings to be around then. Then there are way bigger threats to our future than the heat death of the universe.

This is Dyson's "eternal intelligence" scenario. A summary can be found at [1], but the details are in "Time without end: Physics and biology in an open universe" [2]. wcoenen very helpfully linked to a text version of this paper [3].

[1] http://en.wikipedia.org/wiki/Dyson%27s_eternal_intelligence

[2] "Time without end: Physics and biology in an open universe", Reviews of Modern Physics, Vol. 51, Issue 3 (July 1979), pp. 447-460

[3] https://news.ycombinator.com/item?id=4777857

So, Achilles never caught up with that tortoise, after all.

I believe there is a fourth explanation on why no intelligent life forms have presented themselves to us, and Hawking states the rationale in his article. The fourth explanation is that we have been visited by intelligent aliens, but they have hidden themselves, like the Star Trek "prime directive", so that we don't end up like native Americans to the intelligent aliens' Colombus.

I'm surprised at how little new information I found in this talk. Which is not to suggest I'm very knowledgeable, only that a few of my favorite wikipedia articles must do a damn good job of summarizing these topics, particularly http://en.wikipedia.org/wiki/Fermi_paradox

Note that this talk is way older than Wikipedia though.

About classifying computer viruses as a form of life:

"Maybe it says something about human nature, that the only form of life we have created so far is purely destructive."

Other (constructive) computer programs could just as well be seen as a form of life. The difference would simply be that one spreads without our immediate consent and the other needs to convince us that it is useful to us before being allowed to spread (kind of like pilot fish). Both use a combination of pre-existing infrastructure/ecosystem to procreate - our brains, computers, language and other methods of communication.

They are all the form of life called memes or temes by Susan Blackmore (http://www.ted.com/talks/susan_blackmore_on_memes_and_temes....). (Also Dawkins et al)

Great reading!

I would like to add that the development of a brain is another huge milestone. Somehow Hawking forgets to mention that.

And the development of the computer and Internet is a big milestone in the external transmission period in my opinion.

If you like this kind of reading, I recommend the book: http://www.amazon.com/Short-History-Nearly-Everything/dp/076...

> because there's no way one can show a period of ten thousand years, on the same scale as billions of years

Isn't that what log scales are for?

This was an amazing read. It elegantly covers Life from the inception of the universe to what might occur next.

What I liked the most was when he talked about "externally transmitted information". I never thought of books and written knowledge as being part of human evolution as much as DNA, though it definitely fits the description.

It's easy to regard ideas themselves as having evolution. Only those ideas that resonate with humans are preserved and passed on. The rest die.

Given he so eloquently puts the arguments, it baffles me to think that we might just be an extremely lucky and rare occurrence in the universe. To me, it is more terrifying to think we are the only ones, than to think there are aliens. The vastness of spaces suddenly seems so claustrophobic.

I don't see what difference does it make if we're 7blns on this planet and alone in the Universe, or if there are other planets populated with bacteria or intelligent life.

Actually, I think, it makes no difference. Look at Star Trek, a large series of civilizations which are pretty much variations on the same human theme.

Claustrophobia starts when acknowledging that there's nothing else but the Universe. And nothing beyond our limited life. That's the scary thought.

I like his ideas about biological life not being suited to spread throughout the galaxy, that it's going to be mechanical or at least completely engineered.

If that's the case, why would engineered life ever want to land on a planet? It seems easier to take everything from asteroids and stay near shining stars and away from other gravity wells. Visiting/colonizing planet Earth doesn't make much sense, other than the challenge.

> Actually, I think, it makes no difference. Look at Star Trek, a large series of civilizations which are pretty much variations on the same human theme.

Honestly, without an actual alien sapience to compare ourselves to, we haven't a clue what similarities or differences there can be. Fiction written by human beings is limited to the imagination of human beings and the interest of human beings.

I have never found the authorial claims of how different species or races in science-fiction or fantasy or horror are to be particularly convincing. They're just humans proxying questions of racial stereotypes.

Is there an available Hawking text-to-speech converter? Or perhaps a recording of this by him?

In OS X, you can do this:

1. Copy the text of the talk and save it to a file, say "life.txt"

2. Use the "say" command to read it:

    $ say < life.txt

To change the voice, go to System Preferences > Dictation & Speech and pick the one closest to Hawking's. (On my system, "Fred" comes pretty close.)

I strongly recommend reading the Carl Sagan book in a similar vein called "Shadows of Forgotten Ancestors" for folks interested in a pop-intro to genetics and the history of life.

So many of the points made by Hawking could be used to justify Creationism, and yet it's waved off as 'impossible'. That is bad science.

It's not waved off as impossible, it's waved off as unprovable. For something to be scientific, it has to be possible to be disproven.

A genuine question based on the requirement you gave for something to be scientific: how is Darwinian natural selection and the theory of macro (inter-species) evolution disprovable?

If we were to observe that it does not happen in cases where we see it now?

Students can (and do) perform experiments on evolution+natural selection on bacteria in a lab in reasonable timeframes - put in bacteria, add feed, maybe add extra mutagens or radiation, and then observe the changes in bacteria when a stressor or a particular "poison" is added - the bacteria strain changes, evolving resistance. If one would see simply the strain suffering&not changing, then it would disprove Darwinian selection.

Inter-species evolution for larger organisms is more time-consuming to study (since many generations are needed), but the existing "ring-species" such as some bird groups are a good example - if inter-species evolution would be false, then we'd expect to see distinct species that can successfully interbreed within a species, but not between species; instead, we observe a "ring" where everyone is "the same" as their neighbour, but the opposite sides of the ring are "different species".

If that's the case, then why all the science surrounding String Theory? It's been declared 'unprovable'.

<<This lecture is the intellectual property of Professor S.W.Hawking. You may not reproduce, edit, translate, distribute, publish or host this document in any way with out the permission of Professor Hawking.>> How to write for the net, 1980's style. It feels like a provocation to do so.

One of the greatest minds alive giving a talk about a really interesting thought-provoking topic, and all you can comment on is the top line stating the authors wishes about how his work is used.

If I recall correctly he is in academia dealing with some massive questions, I don't think he has put a lot of emphasis on how his website is constructed or maintained, as long as its readable to the public.

Hmm, I think some people on Hacker News are in too much of a bubble giving no thought to the priorities of others. Not everyone builds web apps. Sorry dude just seems like such a silly thing to comment on. I'll get off my pedestal now. :)

Its his choice how he wants his works to be distributed. You can still link to it. And if you want to translate it just ask him.

you can link to it as long as the court in question agrees that linking is not publishing or distributing. this is (unfortunately) not the case.

I agree with you. Copyright is already automatically applicable. It's not like this further protects anything, it just browbeats the reader. A statement like this at the beginning of an article/talk is a big turnoff for me. Most researchers are excited to share their thoughts and ideas, not interested in jealously guarding them. (Especially when, as here, all the ideas are already known.)

For those saying that Stephen Hawking deserves a free pass, if we apply different standards to different people then that's not morality, it's just convenience. And anyway I doubt it was his idea to post that notice, more likely a misguided publisher.

I haven't read the article yet, but I find the intro

"This lecture is the intellectual property of Professor S.W.Hawking. You may not reproduce, edit, translate, distribute, publish or host this document in any way with out the permission of Professor Hawking."

bad taste for a person carrying a degree granted by the public.

Besides, is my squid proxy already in violation of this?

EDIT: Seriously, why the downvotes?

Hawking received his phd in 1966. Are you seriously saying that he can't can't claim ownership of the products of his intelect, 46 years later?

Maybe I wasn't clear, but I was referring to "reproduce, edit, translate, distribute, publish or host this document" (cf. my remark on the squid proxy). IMHO, prohibiting "distributing" or "hosting" this document is just ridiculous in a world where there is an internet and has nothing to do with "ownership of the products of his intellect".

Further, the "products of his intellect" are themselves a partially reproduced, edited, or translated versions of documents his has read previously, in all likelihoods. I thought, every scientist (in particular, Mr. Hawking) is aware of this and thus claiming "ownership" of this "product" seems unfair. Hence, I find it bad taste.

Of course, we can now start to argue what does "edit", "reproduce" or "document" mean.

I'm confused. Are you implying that studying at and receiving a qualification from a partially or wholly state-funded academic institution necessitates that you forgo any claim to private ownership of your written works and become a sort of intellectual serf to the greater public?

No, of course not. I said "bad taste", not "immoral" or "illegal".

I'd expect more humbleness from people of an academic institution, for the reasons state previously. Slamming the copyright notice into my face before I've even started to read the article, although technically and legally correct, does not qualify in my opinion.

Um. This is like... Copyright 101.

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