
Life in the Universe - kamaal
http://www.hawking.org.uk/life-in-the-universe.html
======
mixedbit
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?

~~~
cristianpascu
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. :)

~~~
mixedbit
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.

------
jcfrei
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.

~~~
ChuckMcM
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.

~~~
eru
> 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.)

------
redwood
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.

~~~
twoodfin
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.

~~~
PeterisP
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.

------
tocomment
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.

~~~
johngalt
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.

------
damian2000
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>

------
xntrk
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"

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

~~~
jh3
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.

------
pingou
"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.

~~~
andyjohnson0
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>

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

------
joshuaheard
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.

------
jere
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>

~~~
kleiba
Note that this talk is way older than Wikipedia though.

------
worldsayshi
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....](http://www.ted.com/talks/susan_blackmore_on_memes_and_temes.html)).
(Also Dawkins et al)

------
JimWestergren
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...](http://www.amazon.com/Short-History-Nearly-
Everything/dp/076790818X)

------
confluence
> _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?

------
pioul
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.

~~~
ISL
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.

------
simondlr
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.

~~~
cristianpascu
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.

~~~
axusgrad
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.

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

~~~
mhartl
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.)

------
redwood
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.

------
ygmelnikova
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.

~~~
mratzloff
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.

~~~
calebmpeterson
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?

~~~
PeterisP
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".

------
onze
<<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.

~~~
johannh
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.

~~~
polymatter
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.

------
lysium
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?

~~~
andyjohnson0
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?

~~~
lysium
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.

