We need to find/harness cheap, plentiful, reliable and (hopefully) environmentally friendly fuel. Then we could afford to take vacations in space.Of course that still seems pretty far off considering that we just had rolling blackouts here in California.
Solar is the obvious answer! Space-based solar power systems are potentially (1) plentiful - the sun puts out about a billion times more power than Earth ever sees, (2) reliable - sun's always shining out there, (3) environmentally friendly - if we can manufacture the power systems off-planet (eg. on the moon or asteroids) then the only thing Earth ever needs is the power receiving and distribution stations - absolutely minimal environmental cost.
The only problem is the "cheaply" issue - various estimates range from $7 billion to $100 billion to get a lunar solar cell production system and energy distribution system started. But once active production is functional, the allocated and marginal cost per kWh of received power could be much lower than it is anywhere on earth today.
The real problem is not energy, but politics - and the very ambgiuous rights situation on the moon and elsewhere - various U.N. treaties seem to preclude commercial exploitation, and the big companies that could make a lot of money from this aren't willing to risk anything under the current regime.
Something like this looks ideal for minitiaturization - thousands of copies of a single controllable element - who knows what you could make? You'd probably want to replace the batteries with a power storage system more easily controllable (and refillable) from outside; and all those control cables need to be somehow embedded into the interconnections between modules, rather than strung individually back to the controller. Hmm. An IP network architecture might make a lot of sense for control. Wired or wireless could work with something like this... Still, the concept of embedding everything you need in a single modular element is a great one - no need to sort parts!
The range of responses on here is indicative of why Clinton's statement is important:
(1) A lot of people point out Clinton has presided (with a Republican congress most of the way) over huge cuts to NASA the last 8 years. Clinton also presided over an overhaul of the welfare system, but he's not saying welfare needs more money now. Obviously something in the situation with regard to space has changed significantly, recently. The space station may be part of this - the Mars plans are probably another. For whatever reason we now have realistic, inexpensive approaches to permanent space colonization over the next couple of decades, and NASA seems logical to be at least part of this. But it'll take more money than it's getting now.
(2) A lot of other people claim NASA has failed us, citing ridiculous numbers for how much money it has wasted. As has been pointed out by others here, NASA doesn't get a very large slice of the budget any more. But NASA does have real problems, particular with the "failure is not an option" rigidity that is caused by just such criticism. Look at what the Russians can do with a tenth of the money, and a "fix as we go" approach! At least the "faster, cheaper, better" mantra has made clear that, if you want to do things cost effectively, sometimes you will fail. But you can do much more then, as opposed to when failure is not an option.
(3) And of course a few people continue to say we should spend our money on more important and urgent matters - saving the poor, or tax relief for the rest of us... But if the guy who won on "it's the economy, stupid" thinks NASA needs more money, what could that mean? As countless analyses have shown (check out John Lewis' recent "Mining the Sky" for some big numbers) taking advantage of space gives us far more resources than we have here on earth; the economic payback will be enormous, once we get over that initial hurdle to permanent space industry. And the size of that initial hurdle, estimated various ways, is surely no more than $100 billion - perfectly doable with only a moderate boost in the NASA budget.
But private industry has to be a strong partner, much more so than in the standard military aerospace system we have now. There are a lot of smaller companies coming up with some great ideas for launch systems and other space components - even modest NASA funding for those could make a huge difference. Just compare the numbers for capitalizations of SpaceHab ($100 million revenue, $30 million capitalization) or SpaceDev ($40 million cap) with your typical internet company and you can get the picture...
Wireless and wearable and responsive to natural motions of each finger - that looks to me like the only thing sufficiently better than QWERTY keyboards to actually get people to switch. So has anybody tried putting this together with Bluetooth (or is there another wireless protocol that would work)?
The FOX reporting here looks garbled - they say something about comparing it to the large Sudbury impact, and that Sudbury was formed by a high-velocity comet while the Chicxulub (sp?) crater was formed by an asteroid - however doesn't Sudbury have a huge quantity of asteroidal metals (it provides most of the world's nickel supply, for example)? I didn't think that's what comets were supposed to be made of... So did they just get these switched and it was actually a comet that killed the dinosaurs? Does anybody have any more links/references on this finding?
We have a Ralley (sp? light, made in Sweden) self-sharpening reel mower we've used the last 5 years on our 1/4 acre lot: works wonderfully, and gives us a good work-out while we're at it. And the neighbor kids love to come over and try their hand - it takes a certain level of strength to actually get it to cut, so it's a bit of a test for them. And it seems to compare favorably to their dad's riding mower that he is usually cursing at because it got stuck in the mud on his front slope, or something of the sort. Everybody should own one of these things!
It really sickens me that the only standard by which the internet is measured these days is by how much cash it can generate.
Agreed - for us we expect moving our (publishing) operations onto the web to make everything run smoother, faster, better, but it's not going to produce money out of thin air - quite the contrary as we're still trying to figure out how we're going to end up maintaining the business in the long run!
An article by L. Davidson and K. Douglas in the December 1998 issue of
the Journal of Electronic Publishing raised in a different sense many
of the issues I recently expressed some concern on with the DOI, as
well as other issues I haven't seen discussed here at all. Was there
ever a discussion here of the points in the Davidson and Douglas paper?
The authors indicate a feeling of encouragement that these problems
will be resolved, but has much changed in the six months
since their paper appeared? I'm enclosing their "summary of selected
concerns" below. Point 2 was the one that I particularly was concerned
with in the most recent exchange.
Arthur Smith (apsmith@aps.org)
----------------------------
Summary of Selected Concerns
The importance of the work being done on the design of the DOI
System, and its consequences with respect to digital identifiers in
general, would be difficult to overrate. Solving the problems of
identifying specific objects on the Internet is extremely important,
and the work being done on the DOI System will help with that
solution. Still, there are a number of current issues concerning this
system that have no easy solutions and particularly concern us:
1.At present, only established commercial and society
publishers are purchasing publisher prefixes and so are
allowed to issue DOIs. This means that most individual or
non-traditional publishers are not participating directly in
the DOI System, but are merely acting as end users. Since
the biggest problems with URL stability and the lack of
persistence of Internet objects lies outside the products
provided through large publishers, it is unclear how the DOI
System is going have any generally beneficial effect on the
solution of the Internet's problems.
2.Those who participate in the DOI System will need to
include in their operating costs the overhead of detailed
housekeeping of the DOIs and each item's associated
metadata, upon which many of the DOI's more advanced
functions will depend. In addition, there are the fees that the
Foundation will need to levy to support the maintenance of
the resolver-databases server for the continued tracking of
traded, retired, erased, or simply forgotten and abandoned
identifiers. Even with computerized aids, the cost to
publishers of maintaining the robust and persistent matrix of
numbers and descriptive text that a handle-based system
requires will be considerable. Under the current model, the
annual fees exacted by the Foundation from its participating
publishers must cover operating expenses. Since no one yet
knows how high these fees might be, we are concerned that
costs for smaller publishers and not-for-profit participants
might be so prohibitive that they will be largely excluded.
3.At up to 128 characters, DOIs are simply too long to be
practical outside of the digital universe. The Publisher Item
Identifier (PII), for example, at seventeen characters, is a
much more reasonable length and probably is still long
enough to identify every item we will ever need to identify.
Indeed, Norman Paskin estimates that only 10^11 digital
objects will ever require identification.[33] Since it is
unlikely that we will never need to copy DOIs manually
from print into electronic format, and since both their length
and limited affordance (mnemonic content) will make it
difficult to transfer them accurately by any manual means,
this could turn out to be a nuisance factor that will hinder
their widespread acceptance. Long identifiers are also
harder to code into watermarks, especially in text objects
that lack background noise in which to hide such data.
4.DOIs will probably not lead to more open access to online
materials, at least to those commercially published. In fact,
most DOI queries from most users, except for those that can
demonstrate access rights, will probably lead to invoice
forms of one sort or another rather than directly to the
primarily requested object. This aspect of the DOI System
could make the Internet even more frustrating for the
majority of the users than it is now.
Date: Mon, 24 May 1999 13:21:35 -0400 (EDT)
From: "Arthur P. Smith"
To: discuss-doi@doi.org
Subject: Re: [Discuss-DOI] DOI: Current Status and Outlook
On Sun, 23 May 1999, Larry Lannom wrote:
> [...] I agree with
> Stu's comments on policy development being key. In talks about the
> handle system I usually describe DOI and other handle uses as policy
> laid on top of infrastructure.
I found myself agreeing with Stu's comments on this too. But policies
and practices won't be adopted unless they are either evolutionary,
based on existing well-tested standards, or truly revolutionary,
allowing some wonderful new thing to be accomplished that can't
be done any other way. As I was trying to convey earlier, we have a lot of
choices for both the technology and the content of unique identifiers,
including long-lived ones, and it doesn't look like DOI's or even handles
meet the revolutionary criteria. There are also more application-specific
alternatives to the DOI (such as SICI) that I didn't include earlier, many
of which have also not received much use despite their ease of creation.
If we're talking about identification for the purposes of intellectual
property, shouldn't the Copyright Clearance Center and the other
Reproduction Rights Organizations be at the center of
determining such standards? Don't they already have unique identifiers
that they use (there is some CCC number at the foot of every page
we publish now)?
> [...] there
> are hard technical issues around ease of use, both from an end user as
> well as an administrative point of view. Especially from an
> administrative side, there is a 'good intentions' factor that I believe
> has been here since we all starting talking about this stuff almost ten
> years ago now. The net makes it easy to distribute information in an ad
> hoc fashion. It also makes it easy to lose things.
Things get "lost" either through neglect, deliberate removal, or
relocation (though I would call that "misplaced" rather than "lost").
DOI is unlikely to help either of the first two situations.
If there is no economic incentive for anybody to
support the preservation of some piece of digital information, there
will certainly be no incentive to keep the DOI pointer up to date
for it. And if the owner of a piece of information wants to remove
it, how could a DOI stop them?
Where the DOI would help is if a piece of information is relocated -
but so would any other unique identifier coupled with a location
system (PURL in general, and S-Link-S, Urania, PubMed, etc. specifically
for scholarly articles already exist - A&I services are also doing a lot
in this area). The more such systems pop up
and gain "market share" in different applications, the stronger the
incentive for the publisher never to change the location of anything
ever again because of the work required to keep them all up to date.
Administrative ease is basically a factor of how much work is required
to register each new published item, plus how much work is required
to change all the location information when things are relocated.
One can even write an equation for this:
Burden/year = B * New items/year + R * (total items) * relocations/year
where B is the "burden" associated with inserting a new item,
and R is the "burden" associated with updating an existing item.
Even if much of this is handled with automated systems that make
the initial per-item burdens tiny, there is still a need for quality
control, ensurance of the interoperability of systems (for example,
what is the standard for representation of author names containing
special characters? mathematics in titles? etc) and programming
work whose complexity is at least proportional to the per-item
information and translations required. DOI without metadata
had the advantage that the per-item information required
was minimal. With metadata it's not clear which would have
lowest burdens, though the unfamiliarity and lack of applications
for the handle system could be a disadvantage to DOI here (increasing
the required programming effort).
Except that this formula does not apply to S-Link-S, and in
some cases PURLs. S-Link-S uses rules to locate ALL the articles
for a particular scholarly journal, not on an article by article basis.
PURLs can handle relocation of a large number of URL's with a single
change - but the "suffix" URL's must be unchanged for this to work,
which is not true of many publisher relocations. In those cases
where it is true, and especially for S-Link-S, the burden becomes:
Rule-based Burden/year = B' * New journals/year +
R' * (total journals) * relocations/year
where B' and R' are probably larger than B and R, but comparable
at least for smaller publishers that don't have enough items
to justify a lot of programming work. Once a journal has 10 or so
items to publish, rule-based locating is the easiest approach, and
for larger publishers the zero per-item burden would always be
an advantage.
Now rule-based locating systems are not global unique digital identifiers -
but they keep the administrative burden very low, and so are by
far the most likely candidates to solve the "lost" information problem
as far as it can be solved.
> [...]
> Re. Arthur Smith's wondering about handle system scalability and the
> number of current servers: the global system currently consists of four
> servers - two on each of the US coasts. The primary use of the global
> service currently is to point to other services, e.g., the DOI service,
> for clients who don't know where to start. Most handle clients, e.g.,
> the http proxy, do know where to start most of the time since they cache
> this information, so in fact the global service is not much stressed and
> four servers are plenty at the moment.
Thanks for the clarification - however if we're proposing to put direct
HDL or DOI clients in every web browser, that burden is going to
go way up, unless we get cracking on installing local handle
resolvers in the same way we have local DNS resolvers all
over the place. And then who's going to administer them and ensure
that every client is configured to point to the local servers rather
than the global ones? We at least have an established system for DNS,
that when new machines are configured with an IP address they are
also assigned a local DNS resolver, with several backups. Are we
proposing to add another "local HDL resolver" to the setup
procedure of every machine on the net?
The http proxy of course is even less scalable, since it's a single
machine somewhere (admittedly http servers can be scaled pretty
large, but this really doesn't solve the problem).
And as far as I could tell, the handle system doesn't seem to have
the same redundancy built in that DNS has. Perhaps I misunderstood,
but the four global handle servers seem not to contain duplicate
information - rather they each are responsible for a different group
of handles based on the MD5 hash. The redundancy is really just
a single secondary server, which also as far as I could tell right
now resides on the same physical machine (at least the same IP
address) for all four existing global servers.
And remember the DOI/HDL system needs to be able to handle
hundreds of millions or billions of digital objects - that is
one or two orders of magnitude beyond what DNS has to deal with now.
> [...]
> The four million handles per server is a specific implementation
> limit that will go away later this year, to be replaced by some
> extremely large number that escapes me at the moment.
Well that's good. I'm guessing a 2GB or 4GB file size limit was
the problem? The DOI has several hundred thousand items with
handles - how many do the global handle servers contain right now
for DOI and other uses?
Since I've been involved in this discussion for some time I thought I'd recycle some of my old comments:-)
Date: Thu, 20 May 1999 16:46:26 -0400 (EDT)
From: "Arthur P. Smith"
To: discuss-doi@doi.org
Subject: Re: [Discuss-DOI] DOI: Current Status and Outlook
On Wed, 19 May 1999, Norman Paskin wrote:
> A paper which provides a summary of the current thinking on DOI has
> just been published in D- Lib magazine at
> http://www.dlib.org/dlib/may99/05paskin.html
This does answer a lot of questions we had, mostly in what seems
to be the right direction. The relationship with INDECS on metadata
issues looks like a particularly good resolution ("functional granularity"
is essentially what I was looking for in one of my earlier
questions). It looks like a specific metadata "Genre" needs to be
worked out in detail for journal articles (re reference linking) - and
it's not clear who has responsibility for this (the IDF or someone else?)
but at least at the level specified in this article it looks workable.
But to some extent the paper shows the DOI is a solution in search
of a "killer application" (mentioned several times in the article).
There's a chicken-and-egg problem here: the potential applications seem
to require widespread adoption before they become useful.
As one of the final bullets says: "Internet solutions are unlikely to
succeed unless they are globally applicable and show convincing power
over alternatives" - does the DOI as described show convincing power
over the alternatives?
It's sometimes hard to know what counts as an alternative, but the
following systems (some listed in the article) could be
alternatives for at least some of the things the DOI does:
1. the handle system itself
2. uniform resource names
3. IETF's DNS-based Naming Authority Pointer
4. Persistent URL's (PURL's)
5. rule-based reference linking (link managers, Urania, S-Link-S)
6. a global LDAP/directory service
Alternatives 1-4 provide a variety of routes for creating a unique
digital identifier for something - we really don't NEED the DOI just
to have digital identifiers, though DOI does provide a handy rallying
point for those of us providing intellectual property in digital form.
Alternative 2 is the highest level of digital identifier, but perhaps
that is all we really need? There is room for many "naming authorities" -
perhaps even each publisher could be their own naming authority. That
would depend on widespread adoption of (3) which may or may not happen,
and resolution of general registration processes too.
As the article mentions, general implementation of URN's is quite
limited even after almost a decade of work. Is there a reason why
nobody has found it particularly useful yet?
Alternative 1 is, to some extent, a non-issue (a DOI is, after all,
just a handle) and is also, to some extent, the same issue. Any
publisher could, with or without DOI, register as a handle naming
authority and create handles for its digital objects. Is some of
the DOI work duplicating what has already been done (or should have
been done) for the handle system itself? As the handle system web
pages mention (http://www.handle.net/) it is at least receiving some
use as a digital identifier of intellectual property by NCSTRL,
the Library of Congress, DTIC, NLM, etc. Does the DOI provide
convincing power over using the handle system directly?
Alternative 4 (PURL's) is critiqued at length in the article,
particularly on the issue of resolution (section 3). Perhaps I
don't understand properly, but I don't quite agree with some of
the arguments against PURLs. Any digital identifier can be used to
offer great flexibility in resolution - a local proxy can redirect to a local
cache or resource, for example, for ANY of the unique identifiers
under question. Once resolved, the "document" resolved to can
itself contain multiple alternative resolutions. And a handle is only
going to have multiple resolutions if the publisher puts it there
(who else has the authority to insert the data?). So I think the
single vs. multiple redirection issue is a red herring. I do agree it's
nice to have a more direct protocol (though from looking at the details
of the way handles are supposed to resolve there is a lot of
back-and-forth there too). As far as being a URN or not, there's
no reason why PURLs couldn't be treated as legitimate digital identifiers,
even if they are simply URL's at the moment. On "scalability" - the
current handle implementation doesn't seem particularly scalable
either. Only 4 million handles per server? Only 4 global servers
(with 4 backups that seem to point to the very same machines on
different ports)? And those servers seem to all be in the D.C. area...
Not that I think PURLs are wonderful, but does the DOI provide
convincing power over using PURLs, as far as identification and
resolution goes?
Which is presumably why we've been told DOI's have to do
more than just identification and resolution. Hence metadata, to
provide standard information to allow "look-up", multiple-resolution,
and digital commerce applications. This actually makes a lot of
sense. And the other id/resolution alternatives do not
seem to meet the INDECS criteria as well as the DOI can.
But what does this have to do with reference linking, the
first "killer application" mentioned? The look-ups required there
are almost certainly going to be more easily performed with
specialized databases (A&I services) or direct rule-based
linking (alternative 5) and in fact this is already
being done, generally without the use of DOI's. The DOI does not seem to
make the linking process easier, so there's no "convincing power"
here it would seem.
I added alternative 6 (global directory service) as a wild-card -
this seems to be a major focus of "network operating system" vendors -
Novell's NDS, Oracle's OID, Microsoft's Active Directory - these seem
to be systems intended to hold information on hundreds of
millions of "objects" available on a network - an example being the
personal information of a subscriber to an internet service provider.
But another potential application of these is to identify and provide
data on objects available on the net - intellectual property or other
things available for commerce. Is this something the DOI could
fit into, or is it something that could sweep URN's, handles, DOI and
all the rest away? I really don't know, but it seems like
something to watch closely over the next year or so.
What would happen in a state where both candidates got exactly the same number of votes? Statiscally speaking, at least right now, that's what's happened in Florida. Instead of winner-takes-all, shouldn't both be declared winners and the electoral college vote for that state split? Of course that means Gore wins...
Since the site is/.'ed (and google's cache isn't helpful with no pictures) I don't know what this looks like - but what I've been wanting is something small enough to walk around with and to use easily on wireless devices. We've got to be headed in that direction - conventional keyboards are just way to big for the next generation of computer interfaces - maybe a chorded keyboard of some sort coupled with a mouse pointing device all bundled into one small package makes most sense?
One reply mentioned the SANS GIAC - we haven't actually used it, though it looks like they do have good advice. But I'm not sure they actually do what you suggest, which I think could help a lot. As soon as we installed our firewall a few years back we noticed apparently coordinated scanning attempts from a wide variety of hosts - contacting any of them (even including copies of log info) gave us either no response or a "you must be mistaken, we've checked and we've never been compromised" responses. We basically quit there not knowing who else to report the problems too - at least with the firewall we could monitor things and feel smugly that we were much better off than we had been before it went in...
But a centralized reporting service like the Spam Realtime BlackHole list etc could make a big difference...
Within 10-20 years all our communications are likely to be digital, compressed, encrypted, and spread spectrum - totally different from the trivially modulated analog stream we sent out for about 100 years. From the outside it will probably end up looking like just a few minor bumps in Earth's thermal radiation profile, certainly nothing that can be decyphered by even the most persistant extraterrestrials.
So except for that 100-year gap, communication between alien civilizations will likely only happen when each side deliberately puts in the effort. Luckily the discovery of planets around other stars is starting to give us at least some ideas of where to point our antennas. But my guess is we're more likely to find out about aliens through some physical artifact (possibly detected at great distance, though I wouldn't be surprised if first contact was rather close) than through radio or other electromagnetic means.
The Drake equation already has a term referring to the average length of time a civilization is in existence. For SETI purposes, other than the deliberate communications side of it, that number probably shouldn't be counted as much over 100 years now, based on our experience.
Stirling's on an environmental anti-CO2 kick (I signed up for his "Viridian" newsletters) and in becoming a fanatic in that regard he feels it necessary to disparage any concept that diminishes the import of global warming etc - humanity's possible expansion beyond this planet he sees as a threat to his pet concern, not as the wonderful opportunity it is.
I've actually had a couple of exchanges with him by email on the subject - he didn't respond to my last note though, unless this "eulogy" is a response. Pretty insulting stuff, even if you don't read it carefully.
I'll be the first to say some space efforts have been overhyped. Satellites are unlikely to be a long-run solution for terrestrial communications, when ground-based systems can be built and installed so much more cheaply with such enormously higher bandwidths (4 terabits/sec on a single fiber now!)
But that shouldn't distract from the enormous potentialities of space exploitation, and mass expansion of humanity beyond this planet. Don't forget that 1000 years ago the first Europeans came to America, but apparently technological and economic improvements were needed to make it more directly feasible; even after Columbus arrived it took another 120 or so years before U.S. history really began. Now some people cross that once fearsome ocean on a daily basis.
There are a huge number of proposals out there for more efficient ways of getting into space, for living off the "land" there, etc. Currently the Mars projects are the most enthusiastically supported, and are now actually practical. New types of rockets with new materials and designs, non-rocket designs (electromagnetic launching) and even the skyhook/space elevator approaches are making a mass exodus into space look more and more feasible. 500 years from now Stirling's goal could be more than achieved, as Earth can become a galactic park, free of its human burden. But Stirling isn't interested in that solution to his problem.
I'm heading up a technical group evaluating proposals for a new, hopefully complete, set of scientific/mathematical fonts that we plan to make freely available - obviously Knuth's well-reasoned opinions are highly relevant. What he suggests, that somebody should be out there sponsoring font designers, is exactly what we're trying to do! But it sometimes seems hard to persuade publishers to part with their money for something they won't fully control. Even those who make tens of millions in profits seem reluctant to spend more than a few tens of thousands on something that will be freely distributed - despite the fact that it will likely save a lot in licensing and other proprietary-based costs. Is this a strange psychological problem here?
Anyway, we're trying to work with both the Microsoft side of things and the Mozilla/MathML people, plus support TeX of course. As an advertising plug - if you would like to contribute your thoughts or experience (or cash) towards the effort, send me a note at apsmith@aps.org.
And many thanks to/. for highlighting this wonderful interview with Knuth.
The code is already there. Some on-line science publisher could easily set this up. Question is, would the science community really like being "moderated" in this way, even if it is by their own selves?
I work for the Physical Review journals of the American Physical Society - we've been strong supporters of some of these new ideas, including creating a new mirror of the Los Alamos XXX/arXiv site. Since it's part of my job to bring up new ideas, I've been thinking of setting up a/. site for physics here - having the latest slashdot code available would probably help us get going...
I think scientists really would support something that worked as well as/. seems to. The critical thing is getting enough comments and contributors - if you only get 1 comment or rating for every 100 featured articles (as some trial comment systems out there seem to), you just won't have a statistically valid sampling, no matter how unbiased your pool of moderators attempts to be. Part of the difficulty of doing this (and why Lederman's probably wrong that this will make anybody a pot of money) is that most scientific articles are pretty boring, and you have to motivate reviewers with some sense of duty or something to get even one or two of them to read an article with any degree of care. But it's definitely worth experimenting with - something along these lines has GOT to be the way to go in the long run, we just haven't quite figured out the systemic structures needed yet...
Wonderful ideas in his writing
on
Childhood's End
·
· Score: 2
All three favorites of mine too. I got my start in SF on Arthur Clarke books (it didn't hurt he had the same first name as me - I was only about 8 or 10 when I started reading them!) and he's still my favorite author. A lot of people know him through 2001 - I didn't see or read that until much, much later. I think The City and the Stars is still my favorite of his; both it and Childhood's End were the kind of book that afterwards I put down and just sat, thinking, for quite some time. Profound.
People criticize Clarke's characters - but I think like a lot of good SF, the plot ideas take the place of the human characters in carrying the story forward, and I really don't have a problem with that. The later Rama books were pretty horrible though...
While this sounds pretty neat (rhombic dodecahedral "bricks" that roll across one another to self-assemble) it seems like the ultimate building brick has been around for decades: Legos! At least the things you can do with lego bricks give some perspective on what it takes to make larger structures out of smaller standard units. All that's needed is to give each lego brick some kind of mobility and control mechanisms and you'll be way beyond what these rhombic dodecahedra can do.
Or more efficient perhaps would be to have several types - assembler bricks that are motile and controllable, and which can pick up and move around other bricks, and building bricks which just sit there as structural supports. I.e. kind of like Mindstorms, but with some individual bricks that are themselves miniature, remotely controllable robots.
Some questions arise for any such scheme: (1) Power source - do you dump a battery in each of the motile units? Or can they get energy "out of the air" somehow? (2) Control - what degree of autonomy would each mini-bot have? I think they would still need to receive at least general instructions from "above" once in a while. (3) Communications - the mini-bots would also probably have to communicate back at times: "Reporting for duty!", "Got a 2x6 yellow brick, where does it go?", "Bot is stuck: send assistance" Wireless ethernet? (4) Addressability - each bot with an IP address? No wonder we needed IP v6 !
Sounds like a bunch of electronics for a mini lego-assembler, but hey, it could probably all go on a single chip and be made for under a dollar en masse. Does anything like this already exist?
The others have at least partly rocky surfaces though, don't they? I thought Europa was the only one that had the smooth (except where cracked) ice cover.
The picture at CNN looked like it had black vertical bars between the colors - probably just a lighting artifact, but it looked kind of cool like that. The background to the picture was the usual black space background, and it occurred to me it might be even better to have, instead of black bars, transparent bars separating the colors. That would make it uniquely different from any Earth flag, don't you think?
By the way - how long has this slashdot science section been up? A good idea, though not many people seem to frequent it...
Yes, a tube-shaped ship would go well with that sort of radiation protection scheme. If the magnetic field was just a dipole though (like Earth's field) the particles would come in equal numbers via the north and south poles - it wouldn't be any good for actual propulsion, unless you used RF fields of some sort in the central cavity. Maybe that could work like the ion-drive propulsion as used by the Deep Space 1 probe? It seems to me though you'll have to have some regular propulsion system and not rely on solar wind/cosmic ray particles; putting the propulsion system in a central cylinder with an outer cylinder for radiation-sensitive stuff (people and electronics) and this kind of magnetic field shielding might work well...
Well, it's pretty much impossible to talk about the exact moment of infinite energy density, so you have to look at the states of the universe shortly before the final crunch, and the corresponding states just after the original bang. Hawking's argument is that in some way (perhaps the smoothness of the energy distribution?) the states shortly after the big bang were very orderly and structured and therefore of low entropy, whereas the corresponding states just before the final crunch would be highly disordered and of high entropy. At least that's how I remember it. I'm not sure this argument entirely makes sense - entropy by definition is either a property of ensembles - many copies of the same system, or else is a measure of the observer's lack of knowledge about a particular system, the two definitions being interrelated - I don't see how either definition strictly applies to our unique universe unless we have a particular observer in mind, and then isn't it a subjective argument?
In fact there was a recent physics paper (check out http://focus.aps.org/ for a link to it) that suggested our universe could have two opposite arrows of entropic time in different regions of space. So I don't think this is exactly a settled issue.
Sounds like you need to read Stephen Hawking's "Brief History of Time"...
Basically his argument was that the beginning and the end of the universe are quite different - specifically that the initial entropy was very small, and the final entropy will not be.
Of course the latest observations indicate the universe will not collapse but go on expanding forever anyway.
I've wondered about this (your last question) and done a few calculations - it seems a not unreasonably-sized ring or cylinder of superconductor might be able to produce a magnetic field sufficient to turn away particles with energies up to 100 MeV or so - maybe higher. Actually it wouldn't turn them away so much as make them loop around the field lines and drop in through the poles - but that leaves a much smaller area to protect, I think. Do you know if any research has been done on this kind of approach to radiation shielding?
Slashdot Mirror
Solar is the obvious answer! Space-based solar power systems are potentially (1) plentiful - the sun puts out about a billion times more power than Earth ever sees, (2) reliable - sun's always shining out there, (3) environmentally friendly - if we can manufacture the power systems off-planet (eg. on the moon or asteroids) then the only thing Earth ever needs is the power receiving and distribution stations - absolutely minimal environmental cost.
The only problem is the "cheaply" issue - various estimates range from $7 billion to $100 billion to get a lunar solar cell production system and energy distribution system started. But once active production is functional, the allocated and marginal cost per kWh of received power could be much lower than it is anywhere on earth today.
The real problem is not energy, but politics - and the very ambgiuous rights situation on the moon and elsewhere - various U.N. treaties seem to preclude commercial exploitation, and the big companies that could make a lot of money from this aren't willing to risk anything under the current regime.
Something like this looks ideal for minitiaturization - thousands of copies of a single controllable element - who knows what you could make? You'd probably want to replace the batteries with a power storage system more easily controllable (and refillable) from outside; and all those control cables need to be somehow embedded into the interconnections between modules, rather than strung individually back to the controller. Hmm. An IP network architecture might make a lot of sense for control. Wired or wireless could work with something like this... Still, the concept of embedding everything you need in a single modular element is a great one - no need to sort parts!
The range of responses on here is indicative of why Clinton's statement is important:
(1) A lot of people point out Clinton has presided (with a Republican congress most of the way) over huge cuts to NASA the last 8 years. Clinton also presided over an overhaul of the welfare system, but he's not saying welfare needs more money now. Obviously something in the situation with regard to space has changed significantly, recently. The space station may be part of this - the Mars plans are probably another. For whatever reason we now have realistic, inexpensive approaches to permanent space colonization over the next couple of decades, and NASA seems logical to be at least part of this. But it'll take more money than it's getting now.
(2) A lot of other people claim NASA has failed us, citing ridiculous numbers for how much money it has wasted. As has been pointed out by others here, NASA doesn't get a very large slice of the budget any more. But NASA does have real problems, particular with the "failure is not an option" rigidity that is caused by just such criticism. Look at what the Russians can do with a tenth of the money, and a "fix as we go" approach! At least the "faster, cheaper, better" mantra has made clear that, if you want to do things cost effectively, sometimes you will fail. But you can do much more then, as opposed to when failure is not an option.
(3) And of course a few people continue to say we should spend our money on more important and urgent matters - saving the poor, or tax relief for the rest of us... But if the guy who won on "it's the economy, stupid" thinks NASA needs more money, what could that mean? As countless analyses have shown (check out John Lewis' recent "Mining the Sky" for some big numbers) taking advantage of space gives us far more resources than we have here on earth; the economic payback will be enormous, once we get over that initial hurdle to permanent space industry. And the size of that initial hurdle, estimated various ways, is surely no more than $100 billion - perfectly doable with only a moderate boost in the NASA budget.
But private industry has to be a strong partner, much more so than in the standard military aerospace system we have now. There are a lot of smaller companies coming up with some great ideas for launch systems and other space components - even modest NASA funding for those could make a huge difference. Just compare the numbers for capitalizations of SpaceHab ($100 million revenue, $30 million capitalization) or SpaceDev ($40 million cap) with your typical internet company and you can get the picture...
Wireless and wearable and responsive to natural motions of each finger - that looks to me like the only thing sufficiently better than QWERTY keyboards to actually get people to switch. So has anybody tried putting this together with Bluetooth (or is there another wireless protocol that would work)?
The FOX reporting here looks garbled - they say something about comparing it to the large Sudbury impact, and that Sudbury was formed by a high-velocity comet while the Chicxulub (sp?) crater was formed by an asteroid - however doesn't Sudbury have a huge quantity of asteroidal metals (it provides most of the world's nickel supply, for example)? I didn't think that's what comets were supposed to be made of... So did they just get these switched and it was actually a comet that killed the dinosaurs? Does anybody have any more links/references on this finding?
We have a Ralley (sp? light, made in Sweden) self-sharpening reel mower we've used the last 5 years on our 1/4 acre lot: works wonderfully, and gives us a good work-out while we're at it. And the neighbor kids love to come over and try their hand - it takes a certain level of strength to actually get it to cut, so it's a bit of a test for them. And it seems to compare favorably to their dad's riding mower that he is usually cursing at because it got stuck in the mud on his front slope, or something of the sort. Everybody should own one of these things!
It really sickens me that the only standard by which the internet is measured these days is by how much cash it can generate.
Agreed - for us we expect moving our (publishing) operations onto the web to make everything run smoother, faster, better, but it's not going to produce money out of thin air - quite the contrary as we're still trying to figure out how we're going to end up maintaining the business in the long run!
And another old reference on this:
l
Date: Tue, 1 Jun 1999 14:02:29 -0400 (EDT)
From: "Arthur P. Smith"
To: discuss-doi@doi.org
Subject: December '98 JEP article?
See: http://www.press.umich.edu/jep/04-02/davidson.htm
An article by L. Davidson and K. Douglas in the December 1998 issue of
the Journal of Electronic Publishing raised in a different sense many
of the issues I recently expressed some concern on with the DOI, as
well as other issues I haven't seen discussed here at all. Was there
ever a discussion here of the points in the Davidson and Douglas paper?
The authors indicate a feeling of encouragement that these problems
will be resolved, but has much changed in the six months
since their paper appeared? I'm enclosing their "summary of selected
concerns" below. Point 2 was the one that I particularly was concerned
with in the most recent exchange.
Arthur Smith (apsmith@aps.org)
----------------------------
Summary of Selected Concerns
The importance of the work being done on the design of the DOI
System, and its consequences with respect to digital identifiers in
general, would be difficult to overrate. Solving the problems of
identifying specific objects on the Internet is extremely important,
and the work being done on the DOI System will help with that
solution. Still, there are a number of current issues concerning this
system that have no easy solutions and particularly concern us:
1.At present, only established commercial and society
publishers are purchasing publisher prefixes and so are
allowed to issue DOIs. This means that most individual or
non-traditional publishers are not participating directly in
the DOI System, but are merely acting as end users. Since
the biggest problems with URL stability and the lack of
persistence of Internet objects lies outside the products
provided through large publishers, it is unclear how the DOI
System is going have any generally beneficial effect on the
solution of the Internet's problems.
2.Those who participate in the DOI System will need to
include in their operating costs the overhead of detailed
housekeeping of the DOIs and each item's associated
metadata, upon which many of the DOI's more advanced
functions will depend. In addition, there are the fees that the
Foundation will need to levy to support the maintenance of
the resolver-databases server for the continued tracking of
traded, retired, erased, or simply forgotten and abandoned
identifiers. Even with computerized aids, the cost to
publishers of maintaining the robust and persistent matrix of
numbers and descriptive text that a handle-based system
requires will be considerable. Under the current model, the
annual fees exacted by the Foundation from its participating
publishers must cover operating expenses. Since no one yet
knows how high these fees might be, we are concerned that
costs for smaller publishers and not-for-profit participants
might be so prohibitive that they will be largely excluded.
3.At up to 128 characters, DOIs are simply too long to be
practical outside of the digital universe. The Publisher Item
Identifier (PII), for example, at seventeen characters, is a
much more reasonable length and probably is still long
enough to identify every item we will ever need to identify.
Indeed, Norman Paskin estimates that only 10^11 digital
objects will ever require identification.[33] Since it is
unlikely that we will never need to copy DOIs manually
from print into electronic format, and since both their length
and limited affordance (mnemonic content) will make it
difficult to transfer them accurately by any manual means,
this could turn out to be a nuisance factor that will hinder
their widespread acceptance. Long identifiers are also
harder to code into watermarks, especially in text objects
that lack background noise in which to hide such data.
4.DOIs will probably not lead to more open access to online
materials, at least to those commercially published. In fact,
most DOI queries from most users, except for those that can
demonstrate access rights, will probably lead to invoice
forms of one sort or another rather than directly to the
primarily requested object. This aspect of the DOI System
could make the Internet even more frustrating for the
majority of the users than it is now.
Another old comment here:
...] I agree with
Date: Mon, 24 May 1999 13:21:35 -0400 (EDT)
From: "Arthur P. Smith"
To: discuss-doi@doi.org
Subject: Re: [Discuss-DOI] DOI: Current Status and Outlook
On Sun, 23 May 1999, Larry Lannom wrote:
> [
> Stu's comments on policy development being key. In talks about the
> handle system I usually describe DOI and other handle uses as policy
> laid on top of infrastructure.
I found myself agreeing with Stu's comments on this too. But policies
and practices won't be adopted unless they are either evolutionary,
based on existing well-tested standards, or truly revolutionary,
allowing some wonderful new thing to be accomplished that can't
be done any other way. As I was trying to convey earlier, we have a lot of
choices for both the technology and the content of unique identifiers,
including long-lived ones, and it doesn't look like DOI's or even handles
meet the revolutionary criteria. There are also more application-specific
alternatives to the DOI (such as SICI) that I didn't include earlier, many
of which have also not received much use despite their ease of creation.
If we're talking about identification for the purposes of intellectual
property, shouldn't the Copyright Clearance Center and the other
Reproduction Rights Organizations be at the center of
determining such standards? Don't they already have unique identifiers
that they use (there is some CCC number at the foot of every page
we publish now)?
> [...] there
> are hard technical issues around ease of use, both from an end user as
> well as an administrative point of view. Especially from an
> administrative side, there is a 'good intentions' factor that I believe
> has been here since we all starting talking about this stuff almost ten
> years ago now. The net makes it easy to distribute information in an ad
> hoc fashion. It also makes it easy to lose things.
Things get "lost" either through neglect, deliberate removal, or
relocation (though I would call that "misplaced" rather than "lost").
DOI is unlikely to help either of the first two situations.
If there is no economic incentive for anybody to
support the preservation of some piece of digital information, there
will certainly be no incentive to keep the DOI pointer up to date
for it. And if the owner of a piece of information wants to remove
it, how could a DOI stop them?
Where the DOI would help is if a piece of information is relocated -
but so would any other unique identifier coupled with a location
system (PURL in general, and S-Link-S, Urania, PubMed, etc. specifically
for scholarly articles already exist - A&I services are also doing a lot
in this area). The more such systems pop up
and gain "market share" in different applications, the stronger the
incentive for the publisher never to change the location of anything
ever again because of the work required to keep them all up to date.
Administrative ease is basically a factor of how much work is required
to register each new published item, plus how much work is required
to change all the location information when things are relocated.
One can even write an equation for this:
Burden/year = B * New items/year + R * (total items) * relocations/year
where B is the "burden" associated with inserting a new item,
and R is the "burden" associated with updating an existing item.
Even if much of this is handled with automated systems that make
the initial per-item burdens tiny, there is still a need for quality
control, ensurance of the interoperability of systems (for example,
what is the standard for representation of author names containing
special characters? mathematics in titles? etc) and programming
work whose complexity is at least proportional to the per-item
information and translations required. DOI without metadata
had the advantage that the per-item information required
was minimal. With metadata it's not clear which would have
lowest burdens, though the unfamiliarity and lack of applications
for the handle system could be a disadvantage to DOI here (increasing
the required programming effort).
Except that this formula does not apply to S-Link-S, and in
some cases PURLs. S-Link-S uses rules to locate ALL the articles
for a particular scholarly journal, not on an article by article basis.
PURLs can handle relocation of a large number of URL's with a single
change - but the "suffix" URL's must be unchanged for this to work,
which is not true of many publisher relocations. In those cases
where it is true, and especially for S-Link-S, the burden becomes:
Rule-based Burden/year = B' * New journals/year +
R' * (total journals) * relocations/year
where B' and R' are probably larger than B and R, but comparable
at least for smaller publishers that don't have enough items
to justify a lot of programming work. Once a journal has 10 or so
items to publish, rule-based locating is the easiest approach, and
for larger publishers the zero per-item burden would always be
an advantage.
Now rule-based locating systems are not global unique digital identifiers -
but they keep the administrative burden very low, and so are by
far the most likely candidates to solve the "lost" information problem
as far as it can be solved.
> [...]
> Re. Arthur Smith's wondering about handle system scalability and the
> number of current servers: the global system currently consists of four
> servers - two on each of the US coasts. The primary use of the global
> service currently is to point to other services, e.g., the DOI service,
> for clients who don't know where to start. Most handle clients, e.g.,
> the http proxy, do know where to start most of the time since they cache
> this information, so in fact the global service is not much stressed and
> four servers are plenty at the moment.
Thanks for the clarification - however if we're proposing to put direct
HDL or DOI clients in every web browser, that burden is going to
go way up, unless we get cracking on installing local handle
resolvers in the same way we have local DNS resolvers all
over the place. And then who's going to administer them and ensure
that every client is configured to point to the local servers rather
than the global ones? We at least have an established system for DNS,
that when new machines are configured with an IP address they are
also assigned a local DNS resolver, with several backups. Are we
proposing to add another "local HDL resolver" to the setup
procedure of every machine on the net?
The http proxy of course is even less scalable, since it's a single
machine somewhere (admittedly http servers can be scaled pretty
large, but this really doesn't solve the problem).
And as far as I could tell, the handle system doesn't seem to have
the same redundancy built in that DNS has. Perhaps I misunderstood,
but the four global handle servers seem not to contain duplicate
information - rather they each are responsible for a different group
of handles based on the MD5 hash. The redundancy is really just
a single secondary server, which also as far as I could tell right
now resides on the same physical machine (at least the same IP
address) for all four existing global servers.
And remember the DOI/HDL system needs to be able to handle
hundreds of millions or billions of digital objects - that is
one or two orders of magnitude beyond what DNS has to deal with now.
> [...]
> The four million handles per server is a specific implementation
> limit that will go away later this year, to be replaced by some
> extremely large number that escapes me at the moment.
Well that's good. I'm guessing a 2GB or 4GB file size limit was
the problem? The DOI has several hundred thousand items with
handles - how many do the global handle servers contain right now
for DOI and other uses?
Arthur (apsmith@aps.org)
Since I've been involved in this discussion for some time I thought I'd recycle some of my old comments :-)
Date: Thu, 20 May 1999 16:46:26 -0400 (EDT)
From: "Arthur P. Smith"
To: discuss-doi@doi.org
Subject: Re: [Discuss-DOI] DOI: Current Status and Outlook
On Wed, 19 May 1999, Norman Paskin wrote:
> A paper which provides a summary of the current thinking on DOI has
> just been published in D- Lib magazine at
> http://www.dlib.org/dlib/may99/05paskin.html
This does answer a lot of questions we had, mostly in what seems
to be the right direction. The relationship with INDECS on metadata
issues looks like a particularly good resolution ("functional granularity"
is essentially what I was looking for in one of my earlier
questions). It looks like a specific metadata "Genre" needs to be
worked out in detail for journal articles (re reference linking) - and
it's not clear who has responsibility for this (the IDF or someone else?)
but at least at the level specified in this article it looks workable.
But to some extent the paper shows the DOI is a solution in search
of a "killer application" (mentioned several times in the article).
There's a chicken-and-egg problem here: the potential applications seem
to require widespread adoption before they become useful.
As one of the final bullets says: "Internet solutions are unlikely to
succeed unless they are globally applicable and show convincing power
over alternatives" - does the DOI as described show convincing power
over the alternatives?
It's sometimes hard to know what counts as an alternative, but the
following systems (some listed in the article) could be
alternatives for at least some of the things the DOI does:
1. the handle system itself
2. uniform resource names
3. IETF's DNS-based Naming Authority Pointer
4. Persistent URL's (PURL's)
5. rule-based reference linking (link managers, Urania, S-Link-S)
6. a global LDAP/directory service
Alternatives 1-4 provide a variety of routes for creating a unique
digital identifier for something - we really don't NEED the DOI just
to have digital identifiers, though DOI does provide a handy rallying
point for those of us providing intellectual property in digital form.
Alternative 2 is the highest level of digital identifier, but perhaps
that is all we really need? There is room for many "naming authorities" -
perhaps even each publisher could be their own naming authority. That
would depend on widespread adoption of (3) which may or may not happen,
and resolution of general registration processes too.
As the article mentions, general implementation of URN's is quite
limited even after almost a decade of work. Is there a reason why
nobody has found it particularly useful yet?
Alternative 1 is, to some extent, a non-issue (a DOI is, after all,
just a handle) and is also, to some extent, the same issue. Any
publisher could, with or without DOI, register as a handle naming
authority and create handles for its digital objects. Is some of
the DOI work duplicating what has already been done (or should have
been done) for the handle system itself? As the handle system web
pages mention (http://www.handle.net/) it is at least receiving some
use as a digital identifier of intellectual property by NCSTRL,
the Library of Congress, DTIC, NLM, etc. Does the DOI provide
convincing power over using the handle system directly?
Alternative 4 (PURL's) is critiqued at length in the article,
particularly on the issue of resolution (section 3). Perhaps I
don't understand properly, but I don't quite agree with some of
the arguments against PURLs. Any digital identifier can be used to
offer great flexibility in resolution - a local proxy can redirect to a local
cache or resource, for example, for ANY of the unique identifiers
under question. Once resolved, the "document" resolved to can
itself contain multiple alternative resolutions. And a handle is only
going to have multiple resolutions if the publisher puts it there
(who else has the authority to insert the data?). So I think the
single vs. multiple redirection issue is a red herring. I do agree it's
nice to have a more direct protocol (though from looking at the details
of the way handles are supposed to resolve there is a lot of
back-and-forth there too). As far as being a URN or not, there's
no reason why PURLs couldn't be treated as legitimate digital identifiers,
even if they are simply URL's at the moment. On "scalability" - the
current handle implementation doesn't seem particularly scalable
either. Only 4 million handles per server? Only 4 global servers
(with 4 backups that seem to point to the very same machines on
different ports)? And those servers seem to all be in the D.C. area...
Not that I think PURLs are wonderful, but does the DOI provide
convincing power over using PURLs, as far as identification and
resolution goes?
Which is presumably why we've been told DOI's have to do
more than just identification and resolution. Hence metadata, to
provide standard information to allow "look-up", multiple-resolution,
and digital commerce applications. This actually makes a lot of
sense. And the other id/resolution alternatives do not
seem to meet the INDECS criteria as well as the DOI can.
But what does this have to do with reference linking, the
first "killer application" mentioned? The look-ups required there
are almost certainly going to be more easily performed with
specialized databases (A&I services) or direct rule-based
linking (alternative 5) and in fact this is already
being done, generally without the use of DOI's. The DOI does not seem to
make the linking process easier, so there's no "convincing power"
here it would seem.
I added alternative 6 (global directory service) as a wild-card -
this seems to be a major focus of "network operating system" vendors -
Novell's NDS, Oracle's OID, Microsoft's Active Directory - these seem
to be systems intended to hold information on hundreds of
millions of "objects" available on a network - an example being the
personal information of a subscriber to an internet service provider.
But another potential application of these is to identify and provide
data on objects available on the net - intellectual property or other
things available for commerce. Is this something the DOI could
fit into, or is it something that could sweep URN's, handles, DOI and
all the rest away? I really don't know, but it seems like
something to watch closely over the next year or so.
What would happen in a state where both candidates got exactly the same number of votes? Statiscally speaking, at least right now, that's what's happened in Florida. Instead of winner-takes-all, shouldn't both be declared winners and the electoral college vote for that state split? Of course that means Gore wins...
Since the site is /.'ed (and google's cache isn't helpful with no pictures) I don't know what this looks like - but what I've been wanting is something small enough to walk around with and to use easily on wireless devices. We've got to be headed in that direction - conventional keyboards are just way to big for the next generation of computer interfaces - maybe a chorded keyboard of some sort coupled with a mouse pointing device all bundled into one small package makes most sense?
One reply mentioned the SANS GIAC - we haven't actually used it, though it looks like they do have good advice. But I'm not sure they actually do what you suggest, which I think could help a lot. As soon as we installed our firewall a few years back we noticed apparently coordinated scanning attempts from a wide variety of hosts - contacting any of them (even including copies of log info) gave us either no response or a "you must be mistaken, we've checked and we've never been compromised" responses. We basically quit there not knowing who else to report the problems too - at least with the firewall we could monitor things and feel smugly that we were much better off than we had been before it went in...
But a centralized reporting service like the Spam Realtime BlackHole list etc could make a big difference...
Within 10-20 years all our communications are likely to be digital, compressed, encrypted, and spread spectrum - totally different from the trivially modulated analog stream we sent out for about 100 years. From the outside it will probably end up looking like just a few minor bumps in Earth's thermal radiation profile, certainly nothing that can be decyphered by even the most persistant extraterrestrials.
So except for that 100-year gap, communication between alien civilizations will likely only happen when each side deliberately puts in the effort. Luckily the discovery of planets around other stars is starting to give us at least some ideas of where to point our antennas. But my guess is we're more likely to find out about aliens through some physical artifact (possibly detected at great distance, though I wouldn't be surprised if first contact was rather close) than through radio or other electromagnetic means.
The Drake equation already has a term referring to the average length of time a civilization is in existence. For SETI purposes, other than the deliberate communications side of it, that number probably shouldn't be counted as much over 100 years now, based on our experience.
Stirling's on an environmental anti-CO2 kick (I signed up for his "Viridian" newsletters) and in becoming a fanatic in that regard he feels it necessary to disparage any concept that diminishes the import of global warming etc - humanity's possible expansion beyond this planet he sees as a threat to his pet concern, not as the wonderful opportunity it is.
I've actually had a couple of exchanges with him by email on the subject - he didn't respond to my last note though, unless this "eulogy" is a response. Pretty insulting stuff, even if you don't read it carefully.
I'll be the first to say some space efforts have been overhyped. Satellites are unlikely to be a long-run solution for terrestrial communications, when ground-based systems can be built and installed so much more cheaply with such enormously higher bandwidths (4 terabits/sec on a single fiber now!)
But that shouldn't distract from the enormous potentialities of space exploitation, and mass expansion of humanity beyond this planet. Don't forget that 1000 years ago the first Europeans came to America, but apparently technological and economic improvements were needed to make it more directly feasible; even after Columbus arrived it took another 120 or so years before U.S. history really began. Now some people cross that once fearsome ocean on a daily basis.
There are a huge number of proposals out there for more efficient ways of getting into space, for living off the "land" there, etc. Currently the Mars projects are the most enthusiastically supported, and are now actually practical. New types of rockets with new materials and designs, non-rocket designs (electromagnetic launching) and even the skyhook/space elevator approaches are making a mass exodus into space look more and more feasible. 500 years from now Stirling's goal could be more than achieved, as Earth can become a galactic park, free of its human burden. But Stirling isn't interested in that solution to his problem.
I'm heading up a technical group evaluating proposals for a new, hopefully complete, set of scientific/mathematical fonts that we plan to make freely available - obviously Knuth's well-reasoned opinions are highly relevant. What he suggests, that somebody should be out there sponsoring font designers, is exactly what we're trying to do! But it sometimes seems hard to persuade publishers to part with their money for something they won't fully control. Even those who make tens of millions in profits seem reluctant to spend more than a few tens of thousands on something that will be freely distributed - despite the fact that it will likely save a lot in licensing and other proprietary-based costs. Is this a strange psychological problem here?
/. for highlighting this wonderful interview with Knuth.
Anyway, we're trying to work with both the Microsoft side of things and the Mozilla/MathML people, plus support TeX of course. As an advertising plug - if you would like to contribute your thoughts or experience (or cash) towards the effort, send me a note at apsmith@aps.org.
And many thanks to
The code is already there. Some on-line science publisher could easily set this up. Question is, would the science community really like being "moderated" in this way, even if it is by their own selves?
/. site for physics here - having the latest slashdot code available would probably help us get going...
/. seems to. The critical thing is getting enough comments and contributors - if you only get 1 comment or rating for every 100 featured articles (as some trial comment systems out there seem to), you just won't have a statistically valid sampling, no matter how unbiased your pool of moderators attempts to be. Part of the difficulty of doing this (and why Lederman's probably wrong that this will make anybody a pot of money) is that most scientific articles are pretty boring, and you have to motivate reviewers with some sense of duty or something to get even one or two of them to read an article with any degree of care. But it's definitely worth experimenting with - something along these lines has GOT to be the way to go in the long run, we just haven't quite figured out the systemic structures needed yet...
I work for the Physical Review journals of the American Physical Society - we've been strong supporters of some of these new ideas, including creating a new mirror of the Los Alamos XXX/arXiv site. Since it's part of my job to bring up new ideas, I've been thinking of setting up a
I think scientists really would support something that worked as well as
All three favorites of mine too. I got my start in SF on Arthur Clarke books (it didn't hurt he had the same first name as me - I was only about 8 or 10 when I started reading them!) and he's still my favorite author. A lot of people know him through 2001 - I didn't see or read that until much, much later. I think The City and the Stars is still my favorite of his; both it and Childhood's End were the kind of book that afterwards I put down and just sat, thinking, for quite some time. Profound.
People criticize Clarke's characters - but I think like a lot of good SF, the plot ideas take the place of the human characters in carrying the story forward, and I really don't have a problem with that. The later Rama books were pretty horrible though...
While this sounds pretty neat (rhombic dodecahedral "bricks" that roll across one another to self-assemble) it seems like the ultimate building brick has been around for decades: Legos! At least the things you can do with lego bricks give some perspective on what it takes to make larger structures out of smaller standard units. All that's needed is to give each lego brick some kind of mobility and control mechanisms and you'll be way beyond what these rhombic dodecahedra can do.
Or more efficient perhaps would be to have several types - assembler bricks that are motile and controllable, and which can pick up and move around other bricks, and building bricks which just sit there as structural supports. I.e. kind of like Mindstorms, but with some individual bricks that are themselves miniature, remotely controllable robots.
Some questions arise for any such scheme:
(1) Power source - do you dump a battery in each of the motile units? Or can they get energy "out of the air" somehow?
(2) Control - what degree of autonomy would each mini-bot have? I think they would still need to receive at least general instructions from "above" once in a while.
(3) Communications - the mini-bots would also probably have to communicate back at times: "Reporting for duty!", "Got a 2x6 yellow brick, where does it go?", "Bot is stuck: send assistance" Wireless ethernet?
(4) Addressability - each bot with an IP address? No wonder we needed IP v6 !
Sounds like a bunch of electronics for a mini lego-assembler, but hey, it could probably all go on a single chip and be made for under a dollar en masse. Does anything like this already exist?
The others have at least partly rocky surfaces though, don't they? I thought Europa was the only one that had the smooth (except where cracked) ice cover.
The picture at CNN looked like it had black vertical bars between the colors - probably just a lighting artifact, but it looked kind of cool like that. The background to the picture was the usual black space background, and it occurred to me it might be even better to have, instead of black bars, transparent bars separating the colors. That would make it uniquely different from any Earth flag, don't you think?
By the way - how long has this slashdot science section been up? A good idea, though not many people seem to frequent it...
Yes, a tube-shaped ship would go well with that sort of radiation protection scheme. If the magnetic field was just a dipole though (like Earth's field) the particles would come in equal numbers via the north and south poles - it wouldn't be any good for actual propulsion, unless you used RF fields of some sort in the central cavity. Maybe that could work like the ion-drive propulsion as used by the Deep Space 1 probe? It seems to me though you'll have to have some regular propulsion system and not rely on solar wind/cosmic ray particles; putting the propulsion system in a central cylinder with an outer cylinder for radiation-sensitive stuff (people and electronics) and this kind of magnetic field shielding might work well...
Well, it's pretty much impossible to talk about the exact moment of infinite energy density, so you have to look at the states of the universe shortly before the final crunch, and the corresponding states just after the original bang. Hawking's argument is that in some way (perhaps the smoothness of the energy distribution?) the states shortly after the big bang were very orderly and structured and therefore of low entropy, whereas the corresponding states just before the final crunch would be highly disordered and of high entropy. At least that's how I remember it. I'm not sure this argument entirely makes sense - entropy by definition is either a property of ensembles - many copies of the same system, or else is a measure of the observer's lack of knowledge about a particular system, the two definitions being interrelated - I don't see how either definition strictly applies to our unique universe unless we have a particular observer in mind, and then isn't it a subjective argument?
In fact there was a recent physics paper (check out http://focus.aps.org/ for a link to it) that suggested our universe could have two opposite arrows of entropic time in different regions of space. So I don't think this is exactly a settled issue.
Sounds like you need to read Stephen Hawking's "Brief History of Time"...
Basically his argument was that the beginning and the end of the universe are quite different - specifically that the initial entropy was very small, and the final entropy will not be.
Of course the latest observations indicate the universe will not collapse but go on expanding forever anyway.
I've wondered about this (your last question) and done a few calculations - it seems a not unreasonably-sized ring or cylinder of superconductor might be able to produce a magnetic field sufficient to turn away particles with energies up to 100 MeV or so - maybe higher. Actually it wouldn't turn them away so much as make them loop around the field lines and drop in through the poles - but that leaves a much smaller area to protect, I think. Do you know if any research has been done on this kind of approach to radiation shielding?