> Well, the BB story has gone along for so much time... some new data whacks it, ok... small nudge and it's consistent.
Can you give an example?
*laugh* I'll bite:) Here are a few:
* The "flat universe" case gives a Hubble constant of 65 km/s/Mpc (megaparsec). This amounts to an age of the universe of ~10 billion years. This is one of the "age paradoxes" that have led to some of the more interesting revisions and proposed revisions.
* The temperature of the cosmic background radiation was a retrodiction, not a prediction. Alpher and Herman got the closest, with a prediction of 5 Kelvins, but what you don't often hear is that the prediction was later adjusted to 28 Kelvins.
* Inflation theory was introduced by Linde in the mid 80's to help solve the "bubble" problem by having a massive FTL expansion in space for 10^-30 s, and co-opted to help squeeze in some extra universe age. The theory, as it got refined, placed more constraints on the universe (e.g. it has to be flat, not open or closed, for inflation theory to work), and gives us our "refined" universe age of 13.7 billion years
* The age problem, in light of recent Hubble observations, has caused a few new proposals to sprout. The "cosmological constant" as a repulsive force has sprouted up on a few a occasions. It has been proposed in the past year that the universe may
have decelerated in the past and is now accelerating.
There's a lot more, and I can get you sources:)
The Big Bang model makes no predictions whatsoever about the existence of any hypothetical particles, let alone a "nasty slew."
I think what he's referring to is the tack a number of scientists have gone off on in the search for enough dark energy to make the universe "flat" or "closed", and they have invoked a nasty number of theoretical particles. He might also be referring to the slew of theoretical particles some scientists are hypothesizing to explain how galaxies managed to form so soon after the big bang (with quotes like "The majority, perhaps a sea of "non-baryonic," exotic particles, is likely to have played the key role in assembling the first galaxy-sized masses." from NASA's Origins page).
I love quantum physics, myself. It makes some pretty interesting (and good!) predictions, but (as you say), the Big Bang Theory doesn't 'predict' them per se.
Personally, I find it strange that the particles from quantum physics and its forces have been been apportioned a timeline in Big Bang Theory for times of creation and symmetry-breaking. I've seen some folks imply that the two line up well, and by implication that the successes of quantum physics should prop up the Big Bang Theory as well. However, Big Bang Theory just apportions particles a time closer to t=0, the more MeV they require to manufacture in a cyclotron, so it's a lot more 'arbitrary' than would be implied. What it means for me is that quantum physics cannot 'falsify' BBT, by definition.
H, He, and Li concentrations
These are also numbers that have "floated" with time, and the baryonic numbers have been kept consistent with observations. Observed deuterium levels are ten times below BBT predictions, and distant young stars have proved out to have much too much boron and beryllium (which are not in BBT nucleosynthesis as a general rule) in them.
Hubble expansion
Most cosmologists selectively quote Hubble from around 1929. If you read some of his later work, you'll find more of an emphasis on the "apparent velocities" from the redshift not being actual velocities. He had a graph from one of his presentations in the early 1940s showing how luminosities would have to decl
Well, at 11.9 light-years away, it's the closest unary G-class star, so it has made its appearance in a number of science fiction novels (Transition, The Sails of Tau Ceti, Arthur C. Clarke's The Fountains of Paradise, C. Cherryh's Cyteen, etc. etc. etc.) and video games (System Shock, Marathon).>/p>
It's not always the focus, but is even more often simply referred to as a colony. I guess too close = not exotic enough for some folks:)
P.S. Whatever you do, for goodness sake's, don't flash 132 in binary at anyone:)
The book Pushing Gravity: New Perspectives on Le Sage's Theory of Gravitation consists of a number of speculative papers on the underlying cause of gravity, but in a "pushing" mode that lends itself to theorizing gravity particles (gravitons, although in a more 'concrete' sense than many theorists espouse). The papers are pretty fascinating, all arriving at near-Newtonian/Einsteinian equations, but predicting certain testable aberrations (e.g. changes with distance that might suit the rotation rates of galaxies without having to postulate large amounts of dark matter in the arms).
The proposed mechanisms by the various authors vary, but a couple of general points of agreement emerge:
gravitons push
gravitons must be absorbed to do work*
One topic that gets discussed is that there may come a density and thickness of matter which absorbs practically all incoming gravitons.
This may put a limit on how dense a star can get, as regardless of how much matter is in the star, there will come a point where the innards get more and more shielded from graviton interaction.
Wouldn't be exactly like the gravastar, but one could imagine that the densest part of such a star wouldn't be in the center; it would be between a high-pressure, graviton-shielded inside, and a high-density, graviton-compacted outside.
It's an interesting possibility, anyhow:)
(*They do get into interesting questions like "where does the energy from the gravitons go?", and a couple tackle the question, "How do gravitons get regenerated?" - with the presumption that gravity isn't "running down" in the universe)
I've read their book, and it's a pretty good, biting, albeit repetitive tome. We've been interested in XP practices a little, but try as we might, we haven't been able to find much common ground between what we're doing (which consists of a lot of foundational programming, because it is actually a framework).
Clearwater consulting came up with an attempt to bridge foundational programming (which Kent Beck said "might not be appropriate for XP" in one of his books, but didn't state why) - but it was also a relatively poor fit. Essentially, what seems to be the case is that you keep all the quality-oriented XP practices, and toss all the rest.
The major points that come out of the Extreme Programming Refactored book, for me, seemed to be:
The "customer" role is stressful (which is why XP modified it to be a 'team') - making all the decisions on the project, controlling the schedule and (?!) writing acceptance tests
It's very high-discipline, which in a negative sense means that someone has to keep pushing employees to do it
XP in theory is very little like XP in practice, especially when it comes to keeping up code quality
Folks might not agree with them, but it is definitely worth a read, even if just to make sure that if you're doing an XP project, that you don't fall into the real-world pitfalls that happen when you let up your guard for a second.
Altho' I suppose it would be possible for a culture to exist where all mass communication was one-way (i.e. broadcasting) but what're the chances of such a culture becoming technologically sophisticated?
*laugh* You raise a good point. Such a culture would have to be mired in a "couch potato" phase, and be happy about it, for... how long? What sort of cultural circumstances would ever let that happen?
Perhaps Max Headroom's version of the future came to pass somewhere out there:)
One thing that's already been happening as technologies mature is that many 'obvious signals' are one-by-one being either silenced (e.g. the push to end broadcast TV) or, more commonly, compressed.
Compare the sounds of a 300 baud modem to the sounds of a modern-day modem - the former is incredibly artificial; the latter, if it weren't for the training signals in it, you'd hardly be able to tell it from static.
There are a considerable number of clear signals yet (though how many have the strength to be easily detectable at any distance outside of the solar system?), but this move to compression, and current/future moves to security, will in all likelihood make the future Earth show up even less on the interstellar scale of things.
The other thing to note is how precious little of the communication is intended for interpretation by extraterrestrials. If we were going to be "nice", even with television signals, we might strengthen and slow them down (maybe to 1-4 fps, about the rate that Half-Life 2 will display on a two-year-old box:)
If there are intelligent aliens already out there, they've doubtless gone through this narrow 50-150 year "clear transmission" window. The chances of us managing to "catch" it would be infinitesimal.
Back to SETI@Home for a second - it's not geared to be able to pick up interstellar TV signals - they're too weak and we don't have the computing power to sort any such thing out from the general noise (on all frequencies to boot); they're geared for what we can conceivably calculate - an unambiguous "YO!" signal directed more or less in our direction.
Who's to say that we aren't awash in interstellar communication as we sit here? My Linux box churns through several SETI@Home work units per day (I also run Folding@Home to keep the other foot in more 'practical' pursuits:), and every now and again, you'll look and see a nifty collection of spikes around a triplet it's discovered. Who's to say that's not "hello"? It's a narrow window, they can only process so much on their algorithms (if the 3 points aren't evenly spaced, nothing is detected), and it takes a long while before Arecibo makes a reobservation of any point in the sky.
For the record, I conjecture that life per se is common, but that intelligent life could be unique to us in the entire galaxy, or even local group. It took a long time (billions of years) for even multicellular life to evolve on Earth, and that's under some pretty ideal conditions, as the cosmos goes.
Actually, it's not so much "more telomerase" as "any telomerase". There are precious few cells in the body that naturally produce telomerase. Crypt cells in the stomach are one, but the other, more disturbing possibility, is germ-line cells. Women don't have much to worry about in this regard, as eggs undergo meiosis early and lie dormant until needed, but sperm production is an ongoing process, and sperm has long telomeres.
In Michael West's book, The Immortal Cell (a very good read, BTW), they detail the search for what kept cancer cells alive, and found that (p.103) 90 of their 101 tumor samples were telomerase positive, and none of the 50 somatic (normal body) cell samples were.
Blocking telomerase on its own is also thought to be a possibility for fighting cancer, because cancer cells typically express telomerase only in enough quantities to extend the telomere slightly. Normal cells don't express it at all and would be unaffected. Testis cells wouldn't be harmed as badly, as their telomeres are long, but I can imagine (if telomere shortening is a major contributor to aging) that if you had a child during treatment, you'd be knocking the number of years of treatment off the life of your child.
The cancer cells would run out their fuse and senesce (like moles). They could still pose a health hazard because there's still some growth potential up until the point where the fuse runs out, but it beats months of unchecked growth.
As a personal note, I still think it's "freakishly cool" to see how far we've come in our understanding of life, aging, cancer, genetics and evolution in the past two decades:)
P.S. You're all invited to my 200th birthday party:)
I would highly, highly recommend a read of Michael West's The Immortal Cell, especially if you're curious as to where some of the research in therapeutic cloning is going.
Replacement of the egg nucleus with an adult nucleus and spurring on the growth with hormones (to replace the signals the sperm would give) has the potential to give us grown tissue that wouldn't be rejected by the body. What they're finding is that it's tough to coax this zygote to multiply, but findings are that, unlike Dolly's mature cells, the cellular "fuse" (telomeres) are re-extended.
It's a fascinating read.
P.S. If you want to be grossed out by some mutant things the human body does when it decides to re-specialize a bunch of cells in one area, take a Google search for teratomas:)
If we limit the age of the universe to 13.7 billion years, that puts some fairly tight constraints on the evolution of life, especially advanced civilizations, in the universe.
If the universe is older by a older by a small amount or perhaps a few billion years, or even greater (which an eventual solution to the age paradox might bring us to), the possibilities for extra-terrestrial life become more and more possible.
Given enough time, even "kooky" theories like the panspermia hypothesis become more and more likely, since distance, lack of speed, and survivability drastically cut the probabilities of anything resembling viable life making it across the vast tracts of space, but time increases it.
(Not to say that it happened, of course - run-of-the-mill abiogenesis could easily have happened instead... or as well.)
Panspermia is a bit worrisome a possibility, in some ways. It would mean that some/many/all alien civilizations might share anything from RNA to DNA to histones to mitochondria. Depending on how advanced the 'seeded' lifeform was (could be anything from a fragment of proto-RNA to a whole eukaryote), we might have to worry about not only bacteria on our future journeys to the stars, but viruses as well. On the plus side, chirality may be conserved, so we don't end up starving to death eating left-handed sugar (L-sucrose) and starch on alien worlds when some layabout gardener on staff mixes salt and Roundup in the fertilizer in the Earth terrarium.
There, that's my fun little bit of tinfoil hat speculation:)
But look at what has happened here on earth as we moved toward digital communications. The more we compress the data, the more random it seems at first glance.
It certainly does seem more random. I dealt a lot with modems in the early stages of my computing adventures. I could practically whistle along to 110 bps, could convince 300 bps that I was there, certainly could tell when things were going on in 1200 and 2400 bps... by 14,400, it just sounded like emanations from the Dogbert Static Network (TM) apart from the 'training' signals at the start.
Compression is likely to be de facto in the universe when distance and transmission speed are limiting factors. They'd have to be sending something really unambiguous, which would be hard for advanced civilizations to "think down to". It might be like sending radio waves to lost tribes who communicate with drums, never mind trying to speak English with them.
I just sincerely hope that the aliens have some sort of anti-spam laws in place by now. Heaven help us when the alien pornography e-mails start coming in.
C++Builder X, hosted in a Java-based IDE (so that it can run on a number of back-ends) is set up to integrate with a goodly native back-end compilers and debuggers. The demonstration they had debugging ARM code running on an actual mobile device over Bluetooth was fairly impressive.
C++Builder X can target gcc on Linux, which addresses the needs (from what I could tell) of a lot of Borland's complainants. There's a modicum of an IDE for designing things for wxWindows as well, which can target the multiple platforms quite well, including mobile.
Borland is really working their buns off trying to get Delphi 8 for.NET ready and working. It will be using the new Galileo interface (the same one C#Builder uses), and includes a number of language additions (including attributes, like [Serialize] and [WebMethod], operator overloading, value types), a purportedly much smoother means of porting VCL apps, and compiles straight into IL as well.
Rumor has it that a Win32 version might be in the works to come out 6 months - 1 year afterwards, including the majority of the language improvements (anything that doesn't require a garbage collector).
They would need to finish that Win32 stage before even thinking about another Kylix.
There's also the possibility that someone will make a.NET host properly on the Linux platform, with proper hooks into the visual systems as well. That would likely be a more tempting target for a next-gen Kylix (if ever) than trying to tie directly to Qt again.
Kylix was too soon; its best target market would be enterprise desktop computing, and Linux isn't there in force yet. I aired my prediction at the conference that SCO's blundering and the resultant backlash from abroad and from a much more organized and militant group of Linuxites will see an invasion of Desktop Linux over the next couple of years, but nobody seemed to believe me:) Time will tell.
From the sounds of it, Kylix wasn't a "waste" in terms of experience - Borland now knows how to do a port better; the.NET one likely would have gone awry without Linux as a testbed.
For my own purposes, Kylix was invaluable for preparing my code for portability. I'll be targetting Win32,.NET and Linux from a single codebase (most of my code is classes, not RAD, so CLX troubles don't affect me much).
Be interesting to see how Lazarus shapes up, too. Getting a new machine at work - it's a Windows shop, but here's a chance for a Linux install at last:)
There are a few science show gems out there - what would a decent lineup look like?
Some of the shows I've enjoyed watching:
Beakman's World (for the kiddles and young-at-heart:)
Bill Nye the Science Guy
Connections (James Burke)
Cosmos (Carl Sagan)
Nova
Wild Kingdom (watched an episode a couple of years back - was surprised at how informative and unpatronizing it was)
A few sundry IMAX shows, perhaps Donald Duck in Mathmagic Land on Sunday...
...and late-night, whatever that show was way back when on Access channel here with the bearded geologist guy explaining rocks and volcanoes. (Anyone remember him?)
Much as I love the Discovery Channel (and I do), the Space Channel actually has much more interestingly-presented news bytes. A new channel would do well to follow a similar format.
I don't think engineering can be lumped in with science and math when it comes to jobs.
Engineering as "applied science" has a lot of direct, commercial use. There are often co-op programs and, around these parts, the two years of EIT (Engineer-in-Training) under a professional engineer before you earn your professional title.
You certainly go through the mill in most educational institutions for engineering degrees. Entire classes with marks around 12% on final exams seems not uncommon. The attrition rate for those unable to give a lot of time (or, in some cases, collude on assignments:) is very high - that cuts down the attendance from most cultures; I imagine Hong Kong may slowly "calm down" in the future, evening out the ratios slightly, but that's a hard culture to shake:)
You don't start at the top, but under the engineering professional societies, you have a semi-"unionized" group that tries to ensure that their members stay up to date, and get fairly compensated.
Many companies can use their services directly, especially here in oil-rich Alberta. By contrast, the number of companies (as opposed to universities) that need the services of scientists and mathematicians is comparatively sparse.
Gandering through a number of the classifieds, in New Scientist, on government job postings, etc., it seems that scientists (haven't encountered mathematician job postings yet) get paid a pittance by comparison - even the senior jobs. Especially badly too, it would seem, in the UK. Academic institutions look positively generous by comparison.
It seems the globe goes through doldrums where the focus is all on the bottom line, on what you can squeeze out in the next two weeks. The situation probably reflects that we're in such 'doldrums'. Not sure what's going to spur on the next set of interest in research (although some branches of biology are still "hot"... or at least "warmer" at the moment) - it might, sadly, end up being something political again (I'm sure the moon landing was just scientifically motivated:)
If you say that this experiment "confirms" GR, then it also "confirms" many theories that otherwise wildly disagree with GR.
I would concur.
The assumption is often that, since a particular mechanism was proposed along with a particular equation, that if the equation is right, the mechanism has to be.
That simply doesn't have to be the case, any more than deriving an equation describing the falling activity of Slashdot threads would lend 100% credence to my hypothesis that the light from the Slashdot home page casts light evenly on the topics, and thus causes activity, until they pass beyond the Oldnewsii Shell at some distance and get progressively more shielded from the light by other articles.:)
There are plenty of means to get to the same sorts of relationships as GR presents in terms of light bending. Etheric, tired light, and other particle, flux, or field-based theories can arrive at the same observations.
Sometimes it's a primacy (who got there first) or popularity contest. That's perhaps sad in a way, but the devil is really in the anomalies - sometimes brushed away as 'error', other times requiring some other body acting on it (that can lead to discovering Pluto, or a need for dark matter). The anomalies are where alternate explanations might really prove their mettle.
Here's an example:
There are anomalies in the in-track acceleration of the LAGEOS satellites.
I guess it's easier to say "X confirms GR" than "X confirms list of equations here", but it does imply that much more in physics has been 'set in stone' than actually has been.
Deepness in the Sky was a pretty good novel as well.
Joan D. Vinge, his ex-wife, wrote the Catspaw series, as well as the Snow Queen series. She brushes on fantasy a little in style, but with science fiction underpinnings, and they deal nicely with topics such as racism, questioning the status quo, rising above your station, and the limits on freedom when you're at the very top.
...of course, during the time it took me to write this, Stephen King came out with another book... doh!:)
I've read a few accounts of how the shortening of the telomeres causes troubles. A lot of them seem to have to do with "unravelling" as though the ends were aglets (plastic bits on the end of a shoelace). I believe it was Ben Bova's Immortality (a decent read, although Ben Bova isn't necessarily the be-all end-all of references) talking about how when the telomere is down to its last few hundred base pairs, it attracts a protein that stops cell death transcription in much the same manner as "too much mutation" does, shutting the cell down.
There's likely an electrical explanation to it somehow as well - strings of G-C have a unique electrical signature. It's posited that pairs and triplets of G-C attract the electron holes that result from chemical/thermal attacks on DNA. Artifical DNA created solely from G-C can actually wind the other way - a form called z-DNA (from a textbook a fair while back). Since the telomere is a repeated TTAGGG,
it's possible that it's not just recognized as a starting point for DNA replication, but may act as a 'sacrificial anode' as well.
New Scientist has an issue this past while with a good series of articles on electrical activity in DNA.
...
So what are we going to do if they succeed? Francis Fukuyama's Our Post-Human Future has some interesting if not terribly "far out" views on the political and human landscape in a life-extended world.
Personally, I'd be quite happy to celebrate my 200th birthday party, by hook or by crook! You're all invited... if I can afford it by then;)
I sure hope antiagathics arrive soon... and get cheap in a hurry:)
I prefer Ada's treatment of generics for the way it makes the use of the generic explicit. To make an integer-based stack, you'd declare a new type based on the Stack generic with an Integer as a type.
I remember when C++ got its templates (IIRC, that was in the 2.0 specification); it took compiler developers a long time to integrate the features. Before that, we'd put together token-pasting (##) macros.
Trying to track down troubles in a C++ template used to be utterly atrocious; define-at-first-use (e.g. first time the compiler encounters Stack<int> per target file) combined with the way the compile/link actually generated the templates behind the scenes made for... to put it mildly... a cryptic experience in a very long error log, usually at link-time. *laugh* Based on some more recent MSVC error listings I've seen, I don't think it's gotten much better;)
(P.S. Does anyone know whether IBM has removed all the unnecessary #pragmas from their 'STL' implementation?:)
I'm personally interested in generics in any given language for a few reasons:
Less typing
Less typecasting
Changes to the algorithm occur in one spot
Type-safety at compile-time
None of those reasons make or break using a language. I've survived with and without generics for years on end.
Java should do quite well by generics. They will be useful. C++ got along famously without them, but did better with them. Indeed, lack of them in a language is no indication that the language wouldn't be useful with them.
Delphi has no official generics, either, but just like C++'s old token-pasting, there are ways to do generics in Delphi, too.
Re:Lorentzian Relativity
on
Blind Lake
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· Score: 1
One of the alternate theories to General Relativity is Lorentzian Relativity. It doesn't require (or indeed, perhaps, allow) time to run backwards, or time to stop, which also doesn't leave us in the lurch the same way trying to imagine what a 0 or -n result from General Relativity means.
Tom Van Flandern uses it to postulate FTL behavior of gravity and electromagnetic effects. Electromagnetic effects include the deflection of particles based on the other particle's "actual location" (as would be based on a much faster than light propagation) as opposed to their "apparent location" (which would be based on a propagation of the field at the speed of light). He proposes something similar for gravity.
Far-flung, perhaps, but objecting to it solely on the grounds that GR is "right" would fly in the face of the whole research process.
The attenuation of gravity, according to one of the papers I ran across is about a kiloparsec, or about 3,300 light years from each single source.
It can help get around the apparent contradiction that intact spiral galaxies present.
Regardless, the attenuation is one of the predictions of one of the theories, and can be used to prove or disprove it. Currently, very little resources are being expended on such observations. Even Majorana's careful gravity shielding experiments have not yet been redone.
Other LeSagian-type theories make no such assertion at a distance, but still modify the Newtonian equation for the insides of bodies. They establish upper and lower bounds on the strength of gravity with a 'weak' solution (negligible graviton absorption) to a 'strong' solution (complete graviton absorption).
Gravity at long distances is still open to interpretation. You have some of the more recent cosmological theories posit cosmos-wide antigravity to 'speed up the expansion of the universe', and other more mundane Big Bang interpretations assuming that the universe is flying apart, there's the "Great Attractor" purportedly pulling us towards it, but is still red-shifted.
As to the anomalous acceleration of the Pioneer probes, there's another potential explanation with some good links to various other explanations.
We're unfortunately a bit hamstrung in that we can rarely ever see phenomena happen, so a lot of interpretation of what we see - and those are what frequently get overturned.
On a more personal note, I'm just a little shocked at how much the 'party line' is expected to be followed in most fields of physics. In biology, there's not nearly the same embarrassment about being wrong, and it's a vibrant field. In physics, most work outside of quantum physics and computing seems (on a relative scale) practically dead.
Black holes rely on an assumption that gravity has no limits on its strength, and to some extent on it following a strict Newtonian curve.
Thinking of "curves" in space-time is an interesting analogy for gravity, but still doesn't address the mechanism - sure, the planet may be on a "45 degree" incline in spacetime, but what forces it down... and not up? You would nearly have to posit the existence of some constant stream of gravitons coming at 'right angles' to three-dimensional space in order to actually push things 'down the well'.
There are alternate corpuscular (i.e. caused by particles; "quantum") models of the mechanism of gravity. There's the LeSagian model, with modern reworks that range from the bizarre-yet-possible theories of Tom Van Flandern, to the more "moderate" theories of Paul Stowe explaining how the "drag" factor that detractors expect doesn't show up, in exactly the sort of way that Feynman expressed it for electromagnetism.
The LeSage-type theories are, in general, "push" theories, which operate in a medium filled with gravitons (just as space is filled with photons) that are deflected/absorbed near bodies and cast 'shadows' that create a low "pressure" area close to surfaces and, to a lesser extent, between bodies.
The formulae calculate out approximately to Newton's/GR's gravity equation, but with some interesting exceptions:
There is a stronger fall-off at greater distances, which limits the effective range of gravity (surprisingly, this reduces the need for 'dark matter' to keep galaxies in the shape they're in)
Inside denser and denser bodies, graviton absorption reaches a point where matter on the inside hardly contributes at all (a complete gravity "shadow")
This upper limit on the strength of gravity may prevent the ultimate collapse that black hole theory requires.
Black holes are still a theoretical construct. Even the jets, now often taken as a 'sign' of a black hole, are still a largely unexplained phenomenon, one that is also associated with accretion disks for newly-forming stars.
So if something's singing in that cloud, it may not be as dense as it's accused of being.
I apologize for all the jargon. I shall go read another thread on SCO as just punishment:)
One thing unit testing is often spectacularly good at is pointing out where assumptions have been made and not spelled out. This often takes the form of "negative testing". (What happens if you add a NULL to that list? What happens if you try to access the -1th element in an array? What happens if you neglect to set an IP address?)
What you'll likely find is that, in a number of spots, the refusal or assertion is not spelled out. Occasionally, it can take some mulling to figure out how to deal with those edge cases (could NULL be valid in some circumstances? Should we make a different derivative or member variable to determine that behavior?)
There's much positive testing to do, too.
Don't bother with testing the extremely simple stuff. If it's to the point where you might as well be questioning whether the compiler can do its job, you won't gain value from it, and it will bore you to tears. (Mind you, if you have one of "those" compilers whose very foundations you question...:)
If you have classes that produce output lists/objects, one nice technique to use is, instead of checking the output manually, is to create an equals/== method for your output, then create the expected output in your test and compare it (via your equals) with the output from the class.
Some other miscellaneous observations I've made:
Unit testing gets a lot more interesting and a lot easier the first time it flags something real. Fortunately, it often happens just as unit testing was becoming boring again.
Always throw in a negative check (something designed to produce the wrong output) - it's easy to produce checks that always return true even if the output is wrong (e.g. I had a list comparison function to determine equality which would kick out if one of the lists was shorter, but the elements were equal up to that point - doh!)
Isolate the class as much as you possibly can. There's a whole technique to creating "mock objects" to help. For example, instead of using a real database object, make a fake one that returns specific rows, or instead of creating something that listens for a hardware signal, create one that waits for a command from the test.
If you think of some condition your class might violate, avoid the temptation to go off and fix the class first. (At the very least for motivation's sake so you can see a failed test - seriously!) This is also a good thing to do if you're having a debugging session and one of those so-called "impossible!" conditions is happening (this could never be negative! there should always be something on the command line!).
If there's an illegal condition you want to test for, add an assertion/exception into your class instead of merely checking the result. This helps 'fail' other tests and code that aren't setting up objects properly but report that they 'pass'.
One of the hardest things about writing unit tests is trying to interface to the outside world. Whenever you can, avoid it. You can fake things to a point (using 127.0.0.1 as an IP address in some tests, for example), but you'll have to fall back on functional testing at some point. That's another good reason for keeping as much logic out of the view as you can.
One note of hope: the most difficult part of unit testing is getting started. Honestly. Once you "get it", you will always "get it", so hang in there:)
Slashdot Mirror
> Well, the BB story has gone along for so much time... some new data whacks it, ok... small nudge and it's consistent.
Can you give an example?
*laugh* I'll bite :) Here are a few:
* The "flat universe" case gives a Hubble constant of 65 km/s/Mpc (megaparsec). This amounts to an age of the universe of ~10 billion years. This is one of the "age paradoxes" that have led to some of the more interesting revisions and proposed revisions.
* The temperature of the cosmic background radiation was a retrodiction, not a prediction. Alpher and Herman got the closest, with a prediction of 5 Kelvins, but what you don't often hear is that the prediction was later adjusted to 28 Kelvins.
* Inflation theory was introduced by Linde in the mid 80's to help solve the "bubble" problem by having a massive FTL expansion in space for 10^-30 s, and co-opted to help squeeze in some extra universe age. The theory, as it got refined, placed more constraints on the universe (e.g. it has to be flat, not open or closed, for inflation theory to work), and gives us our "refined" universe age of 13.7 billion years
* The age problem, in light of recent Hubble observations, has caused a few new proposals to sprout. The "cosmological constant" as a repulsive force has sprouted up on a few a occasions. It has been proposed in the past year that the universe may have decelerated in the past and is now accelerating.
There's a lot more, and I can get you sources :)
The Big Bang model makes no predictions whatsoever about the existence of any hypothetical particles, let alone a "nasty slew."
I think what he's referring to is the tack a number of scientists have gone off on in the search for enough dark energy to make the universe "flat" or "closed", and they have invoked a nasty number of theoretical particles. He might also be referring to the slew of theoretical particles some scientists are hypothesizing to explain how galaxies managed to form so soon after the big bang (with quotes like "The majority, perhaps a sea of "non-baryonic," exotic particles, is likely to have played the key role in assembling the first galaxy-sized masses." from NASA's Origins page).
I love quantum physics, myself. It makes some pretty interesting (and good!) predictions, but (as you say), the Big Bang Theory doesn't 'predict' them per se.
Personally, I find it strange that the particles from quantum physics and its forces have been been apportioned a timeline in Big Bang Theory for times of creation and symmetry-breaking. I've seen some folks imply that the two line up well, and by implication that the successes of quantum physics should prop up the Big Bang Theory as well. However, Big Bang Theory just apportions particles a time closer to t=0, the more MeV they require to manufacture in a cyclotron, so it's a lot more 'arbitrary' than would be implied. What it means for me is that quantum physics cannot 'falsify' BBT, by definition.
H, He, and Li concentrations
These are also numbers that have "floated" with time, and the baryonic numbers have been kept consistent with observations. Observed deuterium levels are ten times below BBT predictions, and distant young stars have proved out to have much too much boron and beryllium (which are not in BBT nucleosynthesis as a general rule) in them.
Hubble expansion
Most cosmologists selectively quote Hubble from around 1929. If you read some of his later work, you'll find more of an emphasis on the "apparent velocities" from the redshift not being actual velocities. He had a graph from one of his presentations in the early 1940s showing how luminosities would have to decl
Well, at 11.9 light-years away, it's the closest unary G-class star, so it has made its appearance in a number of science fiction novels (Transition, The Sails of Tau Ceti, Arthur C. Clarke's The Fountains of Paradise, C. Cherryh's Cyteen, etc. etc. etc.) and video games (System Shock, Marathon).>/p>
It's not always the focus, but is even more often simply referred to as a colony. I guess too close = not exotic enough for some folks :)
P.S. Whatever you do, for goodness sake's, don't flash 132 in binary at anyone :)
I like David Nash's list of 50 nearby sunlike stars within 50 light years.
18 Scorpii is on there, as is the infamous Tau Ceti. 18 Scorpii was one of the four closest matches.
The book Pushing Gravity: New Perspectives on Le Sage's Theory of Gravitation consists of a number of speculative papers on the underlying cause of gravity, but in a "pushing" mode that lends itself to theorizing gravity particles (gravitons, although in a more 'concrete' sense than many theorists espouse). The papers are pretty fascinating, all arriving at near-Newtonian/Einsteinian equations, but predicting certain testable aberrations (e.g. changes with distance that might suit the rotation rates of galaxies without having to postulate large amounts of dark matter in the arms).
The proposed mechanisms by the various authors vary, but a couple of general points of agreement emerge:
One topic that gets discussed is that there may come a density and thickness of matter which absorbs practically all incoming gravitons.
This may put a limit on how dense a star can get, as regardless of how much matter is in the star, there will come a point where the innards get more and more shielded from graviton interaction.
Wouldn't be exactly like the gravastar, but one could imagine that the densest part of such a star wouldn't be in the center; it would be between a high-pressure, graviton-shielded inside, and a high-density, graviton-compacted outside.
It's an interesting possibility, anyhow :)
(*They do get into interesting questions like "where does the energy from the gravitons go?", and a couple tackle the question, "How do gravitons get regenerated?" - with the presumption that gravity isn't "running down" in the universe)
I've read their book, and it's a pretty good, biting, albeit repetitive tome. We've been interested in XP practices a little, but try as we might, we haven't been able to find much common ground between what we're doing (which consists of a lot of foundational programming, because it is actually a framework).
Clearwater consulting came up with an attempt to bridge foundational programming (which Kent Beck said "might not be appropriate for XP" in one of his books, but didn't state why) - but it was also a relatively poor fit. Essentially, what seems to be the case is that you keep all the quality-oriented XP practices, and toss all the rest.
The major points that come out of the Extreme Programming Refactored book, for me, seemed to be:
Folks might not agree with them, but it is definitely worth a read, even if just to make sure that if you're doing an XP project, that you don't fall into the real-world pitfalls that happen when you let up your guard for a second.
Altho' I suppose it would be possible for a culture to exist where all mass communication was one-way (i.e. broadcasting) but what're the chances of such a culture becoming technologically sophisticated?
*laugh* You raise a good point. Such a culture would have to be mired in a "couch potato" phase, and be happy about it, for... how long? What sort of cultural circumstances would ever let that happen?
Perhaps Max Headroom's version of the future came to pass somewhere out there :)
One thing that's already been happening as technologies mature is that many 'obvious signals' are one-by-one being either silenced (e.g. the push to end broadcast TV) or, more commonly, compressed.
Compare the sounds of a 300 baud modem to the sounds of a modern-day modem - the former is incredibly artificial; the latter, if it weren't for the training signals in it, you'd hardly be able to tell it from static.
There are a considerable number of clear signals yet (though how many have the strength to be easily detectable at any distance outside of the solar system?), but this move to compression, and current/future moves to security, will in all likelihood make the future Earth show up even less on the interstellar scale of things.
The other thing to note is how precious little of the communication is intended for interpretation by extraterrestrials. If we were going to be "nice", even with television signals, we might strengthen and slow them down (maybe to 1-4 fps, about the rate that Half-Life 2 will display on a two-year-old box :)
If there are intelligent aliens already out there, they've doubtless gone through this narrow 50-150 year "clear transmission" window. The chances of us managing to "catch" it would be infinitesimal.
Back to SETI@Home for a second - it's not geared to be able to pick up interstellar TV signals - they're too weak and we don't have the computing power to sort any such thing out from the general noise (on all frequencies to boot); they're geared for what we can conceivably calculate - an unambiguous "YO!" signal directed more or less in our direction.
Who's to say that we aren't awash in interstellar communication as we sit here? My Linux box churns through several SETI@Home work units per day (I also run Folding@Home to keep the other foot in more 'practical' pursuits :), and every now and again, you'll look and see a nifty collection of spikes around a triplet it's discovered. Who's to say that's not "hello"? It's a narrow window, they can only process so much on their algorithms (if the 3 points aren't evenly spaced, nothing is detected), and it takes a long while before Arecibo makes a reobservation of any point in the sky.
For the record, I conjecture that life per se is common, but that intelligent life could be unique to us in the entire galaxy, or even local group. It took a long time (billions of years) for even multicellular life to evolve on Earth, and that's under some pretty ideal conditions, as the cosmos goes.
The problem with that is that bit 10 (if we're going zero-based here) is a sticky bit. :)
Actually, it's not so much "more telomerase" as "any telomerase". There are precious few cells in the body that naturally produce telomerase. Crypt cells in the stomach are one, but the other, more disturbing possibility, is germ-line cells. Women don't have much to worry about in this regard, as eggs undergo meiosis early and lie dormant until needed, but sperm production is an ongoing process, and sperm has long telomeres.
In Michael West's book, The Immortal Cell (a very good read, BTW), they detail the search for what kept cancer cells alive, and found that (p.103) 90 of their 101 tumor samples were telomerase positive, and none of the 50 somatic (normal body) cell samples were.
Blocking telomerase on its own is also thought to be a possibility for fighting cancer, because cancer cells typically express telomerase only in enough quantities to extend the telomere slightly. Normal cells don't express it at all and would be unaffected. Testis cells wouldn't be harmed as badly, as their telomeres are long, but I can imagine (if telomere shortening is a major contributor to aging) that if you had a child during treatment, you'd be knocking the number of years of treatment off the life of your child.
The cancer cells would run out their fuse and senesce (like moles). They could still pose a health hazard because there's still some growth potential up until the point where the fuse runs out, but it beats months of unchecked growth.
As a personal note, I still think it's "freakishly cool" to see how far we've come in our understanding of life, aging, cancer, genetics and evolution in the past two decades :)
P.S. You're all invited to my 200th birthday party :)
I would highly, highly recommend a read of Michael West's The Immortal Cell , especially if you're curious as to where some of the research in therapeutic cloning is going.
Replacement of the egg nucleus with an adult nucleus and spurring on the growth with hormones (to replace the signals the sperm would give) has the potential to give us grown tissue that wouldn't be rejected by the body. What they're finding is that it's tough to coax this zygote to multiply, but findings are that, unlike Dolly's mature cells, the cellular "fuse" (telomeres) are re-extended.
It's a fascinating read.
P.S. If you want to be grossed out by some mutant things the human body does when it decides to re-specialize a bunch of cells in one area, take a Google search for teratomas :)
If we limit the age of the universe to 13.7 billion years, that puts some fairly tight constraints on the evolution of life, especially advanced civilizations, in the universe.
If the universe is older by a older by a small amount or perhaps a few billion years, or even greater (which an eventual solution to the age paradox might bring us to), the possibilities for extra-terrestrial life become more and more possible.
Given enough time, even "kooky" theories like the panspermia hypothesis become more and more likely, since distance, lack of speed, and survivability drastically cut the probabilities of anything resembling viable life making it across the vast tracts of space, but time increases it.
(Not to say that it happened, of course - run-of-the-mill abiogenesis could easily have happened instead... or as well.)
Panspermia is a bit worrisome a possibility, in some ways. It would mean that some/many/all alien civilizations might share anything from RNA to DNA to histones to mitochondria. Depending on how advanced the 'seeded' lifeform was (could be anything from a fragment of proto-RNA to a whole eukaryote), we might have to worry about not only bacteria on our future journeys to the stars, but viruses as well. On the plus side, chirality may be conserved, so we don't end up starving to death eating left-handed sugar (L-sucrose) and starch on alien worlds when some layabout gardener on staff mixes salt and Roundup in the fertilizer in the Earth terrarium.
There, that's my fun little bit of tinfoil hat speculation :)
Klaatu berrada nicto...
Er, I mean, back to your irregular program...
But look at what has happened here on earth as we moved toward digital communications. The more we compress the data, the more random it seems at first glance.
It certainly does seem more random. I dealt a lot with modems in the early stages of my computing adventures. I could practically whistle along to 110 bps, could convince 300 bps that I was there, certainly could tell when things were going on in 1200 and 2400 bps... by 14,400, it just sounded like emanations from the Dogbert Static Network (TM) apart from the 'training' signals at the start.
Compression is likely to be de facto in the universe when distance and transmission speed are limiting factors. They'd have to be sending something really unambiguous, which would be hard for advanced civilizations to "think down to". It might be like sending radio waves to lost tribes who communicate with drums, never mind trying to speak English with them.
I just sincerely hope that the aliens have some sort of anti-spam laws in place by now. Heaven help us when the alien pornography e-mails start coming in.
Just got back from BorCon, myself...
Odds of Kylix being resurrected are quite small.
C++Builder X, hosted in a Java-based IDE (so that it can run on a number of back-ends) is set up to integrate with a goodly native back-end compilers and debuggers. The demonstration they had debugging ARM code running on an actual mobile device over Bluetooth was fairly impressive.
C++Builder X can target gcc on Linux, which addresses the needs (from what I could tell) of a lot of Borland's complainants. There's a modicum of an IDE for designing things for wxWindows as well, which can target the multiple platforms quite well, including mobile.
Borland is really working their buns off trying to get Delphi 8 for .NET ready and working. It will be using the new Galileo interface (the same one C#Builder uses), and includes a number of language additions (including attributes, like [Serialize] and [WebMethod], operator overloading, value types), a purportedly much smoother means of porting VCL apps, and compiles straight into IL as well.
Rumor has it that a Win32 version might be in the works to come out 6 months - 1 year afterwards, including the majority of the language improvements (anything that doesn't require a garbage collector).
They would need to finish that Win32 stage before even thinking about another Kylix.
There's also the possibility that someone will make a .NET host properly on the Linux platform, with proper hooks into the visual systems as well. That would likely be a more tempting target for a next-gen Kylix (if ever) than trying to tie directly to Qt again.
Kylix was too soon; its best target market would be enterprise desktop computing, and Linux isn't there in force yet. I aired my prediction at the conference that SCO's blundering and the resultant backlash from abroad and from a much more organized and militant group of Linuxites will see an invasion of Desktop Linux over the next couple of years, but nobody seemed to believe me :) Time will tell.
From the sounds of it, Kylix wasn't a "waste" in terms of experience - Borland now knows how to do a port better; the .NET one likely would have gone awry without Linux as a testbed.
For my own purposes, Kylix was invaluable for preparing my code for portability. I'll be targetting Win32, .NET and Linux from a single codebase (most of my code is classes, not RAD, so CLX troubles don't affect me much).
Be interesting to see how Lazarus shapes up, too. Getting a new machine at work - it's a Windows shop, but here's a chance for a Linux install at last :)
There are a few science show gems out there - what would a decent lineup look like?
Some of the shows I've enjoyed watching:
A few sundry IMAX shows, perhaps Donald Duck in Mathmagic Land on Sunday...
...and late-night, whatever that show was way back when on Access channel here with the bearded geologist guy explaining rocks and volcanoes. (Anyone remember him?)
Much as I love the Discovery Channel (and I do), the Space Channel actually has much more interestingly-presented news bytes. A new channel would do well to follow a similar format.
I don't think engineering can be lumped in with science and math when it comes to jobs.
Engineering as "applied science" has a lot of direct, commercial use. There are often co-op programs and, around these parts, the two years of EIT (Engineer-in-Training) under a professional engineer before you earn your professional title.
You certainly go through the mill in most educational institutions for engineering degrees. Entire classes with marks around 12% on final exams seems not uncommon. The attrition rate for those unable to give a lot of time (or, in some cases, collude on assignments :) is very high - that cuts down the attendance from most cultures; I imagine Hong Kong may slowly "calm down" in the future, evening out the ratios slightly, but that's a hard culture to shake :)
You don't start at the top, but under the engineering professional societies, you have a semi-"unionized" group that tries to ensure that their members stay up to date, and get fairly compensated.
Many companies can use their services directly, especially here in oil-rich Alberta. By contrast, the number of companies (as opposed to universities) that need the services of scientists and mathematicians is comparatively sparse.
Gandering through a number of the classifieds, in New Scientist, on government job postings, etc., it seems that scientists (haven't encountered mathematician job postings yet) get paid a pittance by comparison - even the senior jobs. Especially badly too, it would seem, in the UK. Academic institutions look positively generous by comparison.
It seems the globe goes through doldrums where the focus is all on the bottom line, on what you can squeeze out in the next two weeks. The situation probably reflects that we're in such 'doldrums'. Not sure what's going to spur on the next set of interest in research (although some branches of biology are still "hot"... or at least "warmer" at the moment) - it might, sadly, end up being something political again (I'm sure the moon landing was just scientifically motivated :)
Well, there's my rant for today :)
If you say that this experiment "confirms" GR, then it also "confirms" many theories that otherwise wildly disagree with GR.
I would concur.
The assumption is often that, since a particular mechanism was proposed along with a particular equation, that if the equation is right, the mechanism has to be.
That simply doesn't have to be the case, any more than deriving an equation describing the falling activity of Slashdot threads would lend 100% credence to my hypothesis that the light from the Slashdot home page casts light evenly on the topics, and thus causes activity, until they pass beyond the Oldnewsii Shell at some distance and get progressively more shielded from the light by other articles. :)
There are plenty of means to get to the same sorts of relationships as GR presents in terms of light bending. Etheric, tired light, and other particle, flux, or field-based theories can arrive at the same observations.
Sometimes it's a primacy (who got there first) or popularity contest. That's perhaps sad in a way, but the devil is really in the anomalies - sometimes brushed away as 'error', other times requiring some other body acting on it (that can lead to discovering Pluto, or a need for dark matter). The anomalies are where alternate explanations might really prove their mettle.
Here's an example:
There are anomalies in the in-track acceleration of the LAGEOS satellites.
Do you try for the General Relativity solution (section 3.7.3)? Or something "wilder" (near the bottom)?
I guess it's easier to say "X confirms GR" than "X confirms list of equations here", but it does imply that much more in physics has been 'set in stone' than actually has been.
Protesting is one possibility. Another is to make sure there's a corresponding event for every road show stop they're making.
If you could get Kenny G concert booked and a Hooters swimsuit pageant going at the same time, you'd probably chop attendance by 90%.
Deepness in the Sky was a pretty good novel as well.
Joan D. Vinge, his ex-wife, wrote the Catspaw series, as well as the Snow Queen series. She brushes on fantasy a little in style, but with science fiction underpinnings, and they deal nicely with topics such as racism, questioning the status quo, rising above your station, and the limits on freedom when you're at the very top.
...of course, during the time it took me to write this, Stephen King came out with another book... doh! :)
I've read a few accounts of how the shortening of the telomeres causes troubles. A lot of them seem to have to do with "unravelling" as though the ends were aglets (plastic bits on the end of a shoelace). I believe it was Ben Bova's Immortality (a decent read, although Ben Bova isn't necessarily the be-all end-all of references) talking about how when the telomere is down to its last few hundred base pairs, it attracts a protein that stops cell death transcription in much the same manner as "too much mutation" does, shutting the cell down.
There's likely an electrical explanation to it somehow as well - strings of G-C have a unique electrical signature. It's posited that pairs and triplets of G-C attract the electron holes that result from chemical/thermal attacks on DNA. Artifical DNA created solely from G-C can actually wind the other way - a form called z-DNA (from a textbook a fair while back). Since the telomere is a repeated TTAGGG, it's possible that it's not just recognized as a starting point for DNA replication, but may act as a 'sacrificial anode' as well.
New Scientist has an issue this past while with a good series of articles on electrical activity in DNA.
...
So what are we going to do if they succeed? Francis Fukuyama's Our Post-Human Future has some interesting if not terribly "far out" views on the political and human landscape in a life-extended world.
Personally, I'd be quite happy to celebrate my 200th birthday party, by hook or by crook! You're all invited... if I can afford it by then ;)
I sure hope antiagathics arrive soon... and get cheap in a hurry :)
I prefer Ada's treatment of generics for the way it makes the use of the generic explicit. To make an integer-based stack, you'd declare a new type based on the Stack generic with an Integer as a type.
I remember when C++ got its templates (IIRC, that was in the 2.0 specification); it took compiler developers a long time to integrate the features. Before that, we'd put together token-pasting (##) macros.
Trying to track down troubles in a C++ template used to be utterly atrocious; define-at-first-use (e.g. first time the compiler encounters Stack<int> per target file) combined with the way the compile/link actually generated the templates behind the scenes made for... to put it mildly... a cryptic experience in a very long error log, usually at link-time. *laugh* Based on some more recent MSVC error listings I've seen, I don't think it's gotten much better ;)
(P.S. Does anyone know whether IBM has removed all the unnecessary #pragmas from their 'STL' implementation? :)
I'm personally interested in generics in any given language for a few reasons:
- Less typing
- Less typecasting
- Changes to the algorithm occur in one spot
- Type-safety at compile-time
None of those reasons make or break using a language. I've survived with and without generics for years on end.Java should do quite well by generics. They will be useful. C++ got along famously without them, but did better with them. Indeed, lack of them in a language is no indication that the language wouldn't be useful with them.
Delphi has no official generics, either, but just like C++'s old token-pasting, there are ways to do generics in Delphi, too.
One of the alternate theories to General Relativity is Lorentzian Relativity. It doesn't require (or indeed, perhaps, allow) time to run backwards, or time to stop, which also doesn't leave us in the lurch the same way trying to imagine what a 0 or -n result from General Relativity means.
Tom Van Flandern uses it to postulate FTL behavior of gravity and electromagnetic effects. Electromagnetic effects include the deflection of particles based on the other particle's "actual location" (as would be based on a much faster than light propagation) as opposed to their "apparent location" (which would be based on a propagation of the field at the speed of light). He proposes something similar for gravity.
Far-flung, perhaps, but objecting to it solely on the grounds that GR is "right" would fly in the face of the whole research process.
The attenuation of gravity, according to one of the papers I ran across is about a kiloparsec, or about 3,300 light years from each single source.
It can help get around the apparent contradiction that intact spiral galaxies present.
Regardless, the attenuation is one of the predictions of one of the theories, and can be used to prove or disprove it. Currently, very little resources are being expended on such observations. Even Majorana's careful gravity shielding experiments have not yet been redone.
Other LeSagian-type theories make no such assertion at a distance, but still modify the Newtonian equation for the insides of bodies. They establish upper and lower bounds on the strength of gravity with a 'weak' solution (negligible graviton absorption) to a 'strong' solution (complete graviton absorption).
Gravity at long distances is still open to interpretation. You have some of the more recent cosmological theories posit cosmos-wide antigravity to 'speed up the expansion of the universe', and other more mundane Big Bang interpretations assuming that the universe is flying apart, there's the "Great Attractor" purportedly pulling us towards it, but is still red-shifted.
As to the anomalous acceleration of the Pioneer probes, there's another potential explanation with some good links to various other explanations.
We're unfortunately a bit hamstrung in that we can rarely ever see phenomena happen, so a lot of interpretation of what we see - and those are what frequently get overturned.
On a more personal note, I'm just a little shocked at how much the 'party line' is expected to be followed in most fields of physics. In biology, there's not nearly the same embarrassment about being wrong, and it's a vibrant field. In physics, most work outside of quantum physics and computing seems (on a relative scale) practically dead.
So, a special plea from me to revive the field.
("No, sir, it's not dead, it's resting" :)
Black holes rely on an assumption that gravity has no limits on its strength, and to some extent on it following a strict Newtonian curve.
Thinking of "curves" in space-time is an interesting analogy for gravity, but still doesn't address the mechanism - sure, the planet may be on a "45 degree" incline in spacetime, but what forces it down... and not up? You would nearly have to posit the existence of some constant stream of gravitons coming at 'right angles' to three-dimensional space in order to actually push things 'down the well'.
There are alternate corpuscular (i.e. caused by particles; "quantum") models of the mechanism of gravity. There's the LeSagian model, with modern reworks that range from the bizarre-yet-possible theories of Tom Van Flandern, to the more "moderate" theories of Paul Stowe explaining how the "drag" factor that detractors expect doesn't show up, in exactly the sort of way that Feynman expressed it for electromagnetism.
The LeSage-type theories are, in general, "push" theories, which operate in a medium filled with gravitons (just as space is filled with photons) that are deflected/absorbed near bodies and cast 'shadows' that create a low "pressure" area close to surfaces and, to a lesser extent, between bodies.
The formulae calculate out approximately to Newton's/GR's gravity equation, but with some interesting exceptions:
This upper limit on the strength of gravity may prevent the ultimate collapse that black hole theory requires.
Black holes are still a theoretical construct. Even the jets, now often taken as a 'sign' of a black hole, are still a largely unexplained phenomenon, one that is also associated with accretion disks for newly-forming stars.
So if something's singing in that cloud, it may not be as dense as it's accused of being.
I apologize for all the jargon. I shall go read another thread on SCO as just punishment :)
I can't resist...
"Hmmm, well isn't that special. Posting links to church secrets. Who could be behind this? I just can't imagine who...
Could it be... THETANS?"
Props to the Church Lady :)
One thing unit testing is often spectacularly good at is pointing out where assumptions have been made and not spelled out. This often takes the form of "negative testing". (What happens if you add a NULL to that list? What happens if you try to access the -1th element in an array? What happens if you neglect to set an IP address?)
What you'll likely find is that, in a number of spots, the refusal or assertion is not spelled out. Occasionally, it can take some mulling to figure out how to deal with those edge cases (could NULL be valid in some circumstances? Should we make a different derivative or member variable to determine that behavior?)
There's much positive testing to do, too.
Don't bother with testing the extremely simple stuff. If it's to the point where you might as well be questioning whether the compiler can do its job, you won't gain value from it, and it will bore you to tears. (Mind you, if you have one of "those" compilers whose very foundations you question... :)
If you have classes that produce output lists/objects, one nice technique to use is, instead of checking the output manually, is to create an equals/== method for your output, then create the expected output in your test and compare it (via your equals) with the output from the class.
Some other miscellaneous observations I've made:
One of the hardest things about writing unit tests is trying to interface to the outside world. Whenever you can, avoid it. You can fake things to a point (using 127.0.0.1 as an IP address in some tests, for example), but you'll have to fall back on functional testing at some point. That's another good reason for keeping as much logic out of the view as you can.
One note of hope: the most difficult part of unit testing is getting started. Honestly. Once you "get it", you will always "get it", so hang in there :)