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mattbrowne's avatar

Humility versus hubris - Does science have the potential to answer any question?

Asked by mattbrowne (31580points) May 27th, 2009

Okay, here’s just one question:

Where exactly will all the planets in our solar system be in 100,000 years from today May 27, 2009 at 5 pm GMT? We allow a margin of error of 10 feet.

The question is somewhat related to asking: Is the solar system stable or will one planet, say Mars, leave our solar system entering interstellar space?

What do you need to answer the question? Here are a couple of options. Please pick one:

1) A small personal computer and an astronomy program
2) A high-end computer with 16 processors
3) A data center full of high-end computers
4) A computer the size of Jupiter

Or does the question require a computer that consists of more than 10^85 atoms? If our universe is too small for that, does this mean science does not have the potential to answer any question?

Here’s the definition of the problem:

The n-body problem is the problem of finding, given the initial positions, masses, and velocities of n bodies, their subsequent motions as determined by classical mechanics, i.e., Newton’s laws of motion and Newton’s law of gravity.

http://en.wikipedia.org/wiki/N-body_problem

Any opinions?

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16 Answers

Fyrius's avatar

I’m no expert, but couldn’t a more moderately sized computer solve that problem if you just let it compute for ages on end? Of course that way it may take longer to compute it than the planets would take to arrive at the positions we’re trying to find out, but technically that would make it possible to find out. Without waiting and seeing.

Besides, a margin of error of just ten feet for the movements of planets is surrealistically much to ask.

skfinkel's avatar

Without answering your question specifically at this time (...), I would like to say that I am generally in favor of humility over hubris. Although I know there are times when hubris is really important (eg just saw a great program about a physicist/genius named Gold, who seemed to be right on just about everything he studied—from hearing to astronomy—many years ahead of his time, often couldn’t get his stuff published, and had a strong ego that let him go on in spite of the philistines of his day—he died in 2004, with most of his ideas finally accepted). So, there is a place for healthy hubris, but most hubris is from people who don’t have a clue.

Ivan's avatar

Science has the potential to explain any phenomenon. You have, admittedly, convinced me that my language was misleading, but my opinion is unchanged.

Zaku's avatar

Main question: No, science can’t answer “any” question, at least not accurately. If you just meant, can it offer an answer, then sure. One test: Have science answer: what Julius Caesar first thought as he awoke on his third birthday?

Also, your example and question are in the present tense, and we don’t have the data to solve your problem in the present tense.

Taking on your problem, one missing involves missing data about what will happen, say, inside stars, in the future, and when exactly.

Also, current models of astronomy acknowledge that we lack much of the data on what objects are where. We don’t even know if and when a large asteroid might come and smash our own planet.

Assuming we knew everything, and were just doing a motion model, it’s still a massive problem to model accurately because every object pulls on every other object, but in theory, I suppose it’s soluble. With current technology, I’d want the Jupiter-sized computation center (and who wouldn’t, if it works and doesn’t gravitationally crush itself, and especially if it has some great computer games!). It currently takes a bunch of very smart trained people and a data center to try to get one rocket to Mars, and sometimes they goof up…

bomyne's avatar

Science can predict where the planets will be, but there is a lot that could change over that period. A black hole, for example, would adjust our solar system’s alignment. Our sun going super nova would destry half the planets.

Science is good with predicting things, but you need to allow for the unexpected.

Fyrius's avatar

@bomyne: I think your examples are a bit far-fetched.

Black holes do not suddenly pop into existence out of nowhere. They’re former stars that have burnt up and collapsed. And science already knows quite a bit about all stars reasonably close to us, and could presumably tell how much longer each is going to last.
Moreover, a black hole has the exact same gravitational pull as the star it used to be, having the same mass; the only difference is that it’s smaller, so that the gravitational pull at its surface becomes immense, simply because the surface will be closer to the core. So a star turning into a black hole would not affect the orbital trajectory of anything one iota.

Nor do stars turn into supernovae except for very good reasons that science would see coming many millennia away. Surely our own sun should be familiar enough to us to detect the steps that lead to supernovahood the moment they manifest themselves.
I’m not even sure if our sun is large enough to be able to turn into one at all.

FireMadeFlesh's avatar

Perfect science can answer any question perfectly, and imperfect science can answer any question imperfectly. Since we will never have a complete theory of everything, and never have the computing power to calculate the results of the equations, some questions will always remain unanswered, though they have the potential to be answered.

Computing power is very limited. The Bekenstein Bound limits the information content of a certain volume, and computing power is limited by physical size if we ever reach this bound. It has also been calculated that with conventional computing, if Moore’s Law holds true for the next 410 years, we will have used all the energy and matter in the observable universe – and I’ll be willing to bet that it still could not completely solve the Quantum Mechanics equations for a single Uranium-235 atom.

mattbrowne's avatar

@Ivan – I like the statement “science has the potential to explain any phenomenon” and this is probably true except in at least one case: The meta-phenomenon that there are phenomena for us to observe and explain.

mattbrowne's avatar

@Fyrius – What about

http://en.wikipedia.org/wiki/Primordial_black_holes ?

@bomyne – Suppose we leave out all outside influences and just look at the 8 planets of our system. They all influence each other. How can science predict the future? How would the computation look like?

Fyrius's avatar

@mattbrowne:
“A primordial black hole is a hypothetical type of black hole that is formed not by the gravitational collapse of a star but by the extreme density of matter present during the universe’s early expansion.
According to the Big Bang Model, during the first few moments after the Big Bang, pressure and temperature were extremely great. Under these conditions, simple fluctuations in the density of matter may have resulted in local regions dense enough to create black holes. Although most regions of high density would be quickly dispersed by the expansion of the universe, a primordial black hole would be stable, persisting to the present.”

Apparently all primordial black holes formed at the beginning of time as we know it. That means primordial black holes have been around since long before the planets were around, and have been exerting their gravitational influence on the planets’ movement since the moment they came into existence.
That means these black holes too cannot suddenly and unexpectedly meddle with the trajectories of the planets.

If they exist in the first place.

mattbrowne's avatar

@Fyrius – Suppose they exist and suppose they populate intergalactic space and on a smaller scale interstellar space as well. Suppose they get close to a star once every 5 billion years. Suppose one enters the solar system in 2012. In this case I would not called this sudden and unexpected. It’s rare, granted. By the way, in 1.4 million years Gliese 710, a red dwarf star, might pass our solar system at a distance of only 1.1 light years. What will it do to the Oort Cloud?

Fyrius's avatar

I know this would be nitpicking, but: In 2012? Just three years from now? That would be a bit soon.
Black holes are necessarily immensely heavy object that exert much more gravitational pull than our own sun, otherwise they couldn’t have collapsed into a singularity (even if they don’t derive from a star). That means a black hole coming our way would significantly distort the movements of the stars our astronomist friends look at all the time. Surely its approach would be noticed ages before it comes anywhere near us.
If one is underway to pay a visit to our very own solar system in 2012, and we still can’t see it now, I dare say this primordial black hole must move insanely fast.
Even though the starlight that reaches us is delayed by one year per lightyear of distance covered, if the difference between light speed and the speed of this black hole is not big enough to ensure the news reaches us more than three years before the thing arrives, I would still dare call that insanely fast.
I think it serves to illustrate this point that, as you mentioned, we already know now that Gliese 710 could pass us by 1.4 million years from now.
Disclaimer: I’m just speculating, though. I haven’t done the math and have only the popular science book reader’s kind of grasp of astronomical physics.

More on-topically: Yes, I do suppose extrasolar bodies dropping by for a cup of tea unannounced could influence where a given planet will be in the far future, without science having the knowledge required to take it into account. But then again, that bears more on the question whether there are question science can’t answer now than it does on the question whether there are questions science can never answer at all.

What will Gliese 710 whizzing by do to the Oort cloud? Heck if I know. Some of the debris there would probably err in its orbit and maybe end up leaving the cloud, or even falling into Gliese 710.
Again, if it exists in the first place. The Oort cloud is still hypothetical too, apparently.

mattbrowne's avatar

@Fyrius – Well, it was my understanding that primordial black holes would be very small with event horizons e.g. the size of a fridge. Suppose it has 0.00001 solar masses traveling in interstellar space. How would it distort the movements of our nearby stars for us to detect?

Fyrius's avatar

Is that so?

Well, in that case, why are we talking about it in the first place? How much gravitational influence could a black hole with an event horizon the size of a fridge exert on the movements of the planets?
Besides a rhetorical question, that is in part also a serious one. I don’t know. I would guess not much, because although one needs a lot of gravitational force to get an event horizon at all, a refrigerator is negligibly small on the scale we’re talking about here. Astronomically small, even.
I wonder how large the event horizon of our own sun would be if it were to collapse into a singularity. Or that of the earth.

Anyway, it would be more interesting if a black hole of a size somewhere in between would head our way – too small to sway the stars visibly, but large enough to bend the orbital trajectories of our planets.

mattbrowne's avatar

0.00001 solar masses is quite serious if it’s headed for the inner solar system. Or suppose it’s 10 times as heavy?

Fyrius's avatar

In that case, yes, I suppose.

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