1071: "Exoplanets"

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Re: 1071: "Exoplanets"

Postby gmalivuk » Thu Jun 21, 2012 10:39 pm UTC

nykevin wrote:Perhaps they think a cell is an irreducible complexity?
That, and maybe they remember elementary school biology, when they were told something like "all cells come from other cells".
Unless stated otherwise, I do not care whether a statement, by itself, constitutes a persuasive political argument. I care whether it's true.
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Re: 1071: "Exoplanets"

Postby chenille » Fri Jun 22, 2012 12:40 am UTC

DVC wrote:2) Even if if the definition was changed to say orbit a star, we'd have no idea if these bodies had 'cleared their orbits of debris,' and so couldn't say whether they were planets or not by the IAU's definition.

Most of the objects we've found around other solar systems have been based on radial velocity, so if there were other objects of comparable mass in the same orbit, you would know. There is a bit more room for variation in the transit method, but seeing as how we've found a star with several similar companions at the same distance, we obviously get some idea about it.

Ultimately, objects that have cleared their orbits are one of the easiest things to recognize at a distance. Everything else, even whether they are gaseous or rocky, takes a lot more work to find out.

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Re: 1071: "Exoplanets"

Postby doneloquente » Fri Jun 22, 2012 5:33 am UTC

I looked over the alternate text about how the chart would have to be nested into itself three layers deep to display all the planets in the galaxy. (786^3 planets = 485,587,656 planets). A little research revealed that the current estimated number of planets in our galaxy is 160 billion planets, at least one for every star. Am I missing something or is this an oversight on randall's part?




http://cosmiclog.msnbc.msn.com/_news/2012/01/11/10115679-160-billion-planets-in-the-milky-way?lite

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Re: 1071: "Exoplanets"

Postby DVC » Fri Jun 22, 2012 11:28 pm UTC

Yes, I know, I work in the field.

My point, and not all my colleagues agree, is that being able to infer with a good degree of certainty that the objects have cleared their orbit is not the same as knowing that they have, and that for some objects that we might label exoplanets confirming the orbit is clear of debris is a more difficult measurement, and (here is the kicker) not that important because it doesn't change the nature of the body.

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Re: 1071: "Exoplanets"

Postby gmalivuk » Sat Jun 23, 2012 12:03 am UTC

doneloquente wrote:Am I missing something
Yes, I think by "three layers deep" it means one repetition of this chart inside each planet is 1 layer, so the total is 786^4, or about 380 billion.
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Re: 1071: "Exoplanets"

Postby chenille » Sat Jun 23, 2012 7:57 am UTC

DVC wrote:My point, and not all my colleagues agree, is that being able to infer with a good degree of certainty that the objects have cleared their orbit is not the same as knowing that they have, and that for some objects that we might label exoplanets confirming the orbit is clear of debris is a more difficult measurement, and (here is the kicker) not that important because it doesn't change the nature of the body.

Fair enough, but it does mean a lot to the structure of the planetary system. As someone who doesn't work in the field, I've found seeing how different planets and belts relate to one another has been the most interesting thing so far, if only because the nature of the bodies is even more of an inference. As you know, there are tons of cases where the orbital inclination hasn't been measured, so even the masses are really just what is statistically likely.

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Re: 1071: "Exoplanets"

Postby mfb » Sat Jun 23, 2012 2:10 pm UTC

Another issue: "cleared their orbit" is not so clear as it might look like. Has earth cleared its orbit? Sure, but there are still some objects near this orbit, and we even have trojans with basically the same orbit (just a different phase).
Where is the border?

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Re: 1071: "Exoplanets"

Postby chenille » Sat Jun 23, 2012 3:40 pm UTC

On that you can see wikipedia for some numerical measures. Right now the IAU only covers our solar system, where there are many orders of magnitude difference between the eight main objects and the others, so there's no need for a fast limit. So far it looks like most other planetary systems are probably similar, but we have found some intermediate cases which means the definition would have to be refined.

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Re: 1071: "Exoplanets"

Postby salty » Sun Jun 24, 2012 9:01 pm UTC

ehem...

I don't want to be a pain in the ass but I really would like to know how Randall did the chart (assuming he did it with automation).

Come on guys!
Someone has to know how you can find the optimal composition of this image algorithmically.

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Re: 1071: "Exoplanets"

Postby Hafting » Mon Jun 25, 2012 11:31 am UTC

MotorToad wrote:"That's no moon...."

I can't imagine that we'll know anything about the make-up of these planets in our age. It's going to take more than telescopes and reflected light.

What tools would give us anything but the mass compared to the star it's around?


A sufficiently big telescope will let us see some of the planets well enough. If the atmosphere is clear, we can make map continents and look for signs of life. That might be very expensive to build, but there is more motivation now that we know the planets are there. After all, a failed mission to an uninteresting planet will cost much more.

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Re: 1071: "Exoplanets"

Postby Just a Geologist » Mon Jun 25, 2012 4:58 pm UTC

Sadly, we now have one less of a planet due to new discoveries within our solar system.

Speaking on planet updating, how could we update our information in Voyager 1 and Voyager 2?

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Re: 1071: "Exoplanets"

Postby Just a Geologist » Mon Jun 25, 2012 10:07 pm UTC

Hafting wrote:
MotorToad wrote:"That's no moon...."

I can't imagine that we'll know anything about the make-up of these planets in our age. It's going to take more than telescopes and reflected light.

What tools would give us anything but the mass compared to the star it's around?


A sufficiently big telescope will let us see some of the planets well enough. If the atmosphere is clear, we can make map continents and look for signs of life. That might be very expensive to build, but there is more motivation now that we know the planets are there. After all, a failed mission to an uninteresting planet will cost much more.


Most additions to telescopes are in space.

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Re: 1071: "Exoplanets"

Postby eran_rathan » Tue Jun 26, 2012 12:20 pm UTC

Just a Geologist wrote:
Hafting wrote:
MotorToad wrote:"That's no moon...."

I can't imagine that we'll know anything about the make-up of these planets in our age. It's going to take more than telescopes and reflected light.

What tools would give us anything but the mass compared to the star it's around?


A sufficiently big telescope will let us see some of the planets well enough. If the atmosphere is clear, we can make map continents and look for signs of life. That might be very expensive to build, but there is more motivation now that we know the planets are there. After all, a failed mission to an uninteresting planet will cost much more.


Most additions to telescopes are in space.


I'm pretty sure he means the atmosphere of the exoplanets. However, I sincerely doubt that we'd be able to do that without a telescope/interferometer in the (seriously ridicious size) baseline range.
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Re: 1071: "Exoplanets"

Postby mfb » Tue Jun 26, 2012 3:14 pm UTC

Just a Geologist wrote:Speaking on planet updating, how could we update our information in Voyager 1 and Voyager 2?

It is outdated anyway: Image. There, it has earth-like parameters (14000km diameter, 90% mass of earth, ~16h rotational period). The modern numbers are 2390km, 0,2% mass of earth, 6d rotational period.

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Re: 1071: "Exoplanets"

Postby Crosshair » Sat Jun 30, 2012 3:03 am UTC

SamSam wrote:Nonsense. "Darwinism," as you so dismissively call it, works on anything that is able to copy itself.


Please elaborate on how is that dismissive? Natural selection acting on random mutation as an explanation for the wide diversity of life we see today is refereed to by almost everyone as Darwinism. Are you saying that Richard Dawkins is dismissive of Darwinism? He uses the term too. Aristotle may have been wrong about a lot of stuff, but one thing he was right about is the following, "It is the mark of an educated mind to be able to entertain a thought without accepting it."

Also, your point is nothing more than an assertion.
If I put the front page of the local newspaper into the photocopier, copy it,then put that copy into the copier and repeat, how long before I get the front page of that days New York Times?
If I tell a computer to copy its install of Windows 95 from one hard disk to another continually, how long until random copying errors result in a copy of Windows 7?

Whether it's an organic polymer or a peptide structure, once it copies itself it's subject to evolutionary pressures.

This is an assertion.
What evidence do you have that this works anywhere outside the lab?
What evidence do you have that self-replicating organic polymer or a peptide structures can self arrange into a simple life form?
Not conjecture, not theory, evidence.

The Natural Chemical Origin of Life I would agree is a perfectly valid theory, with many ideas, and much conjecture, but precious little evidence. Science demands evidence. That evidence doesn't have to be 100% certain or explain everything 100%. We still have no idea what the hell gravity is and have no theory of quantum gravity that works all that well, but we can be relatively certain about other parts of quantum physics.

The Natural Chemical Origin of Life Theory is fraught with problems that need answers. You are not the first person who has raised that explanation. While I would agree that it has not been disprove, the evidence is far from convincing.

1. While you are correct that self-replicating molecules have been created in a lab, none are stable replicators that can exist outside the lab in anything resembling earth at any time in its past that also show any possibility to do anything except break and stop self replicating.
2. The theory still cannot explain the information required to build a genome of even the simplest organism. Prior to the origin of life, self-replicating organic polymer or a peptide structures could only rely upon the basic laws of chemistry. But how could the basic laws of chemistry and physics create the information present in life? The Natural Chemical Origin of Life Theory falls for the simple reason that you do not have enough monkeys or enough time for a brute force attack at the problem. You keep smuggling intelligence into the equation because YOU, with your intelligence, can, or think you can, see the path, but fail to see the problems an unintelligent process would have doing the same.

Example, take the most basic 1 mph bumper bot, one with no search patterns or anything programed in, since random mutations are in no particular direction. Just a bot that back up when it hits something, turns a random direction, and goes forward again. Then let it lose in a random location in the continental US. Then randomly put a 1" by 1" target somewhere in the continental US and see how long it takes the bumper bot to hit that target. Note that the continental US only has an area of 1.5x10^16 inches square.

3. The Miller-Urey experiment shows how one might get amino acids out of non-organic chemicals. Leaving aside the problem that he used the wrong gasses that we now think existed on the early earth, further research showed that while you CAN get amino acids, you don't get anything else regardless of how long you run the experiment. No increasing complexity forming proteins useful for life, no self arranging cell walls, nothing. The same here. Someone creates self-replicating molecules created in a lab, good for them, it is an interesting accomplishment. As far as I have found, that is about ALL you get. People have lots of conjecture of what they MIGHT be able to do with them. I have lots of conjecture of what I might be able to do with a pallet of duct tape. Until ones physically shows that it is possible, it remains conjecture and theory.

Accepting the Natural Chemical Origin of Life Theory as true, rather than a theory in need of further research, is nothing more than blind faith on your part.

If you're going to argue against evolution in a room full of xkcd readers, at least understand the basic science, please.

If I ask you an honest question, will you give me an honest answer? How many books have you seriously read that are critical of Darwinism? Which ones? Did you go investigate the claims afterwards and read the counter arguments and the counter counter arguments? They are there on the internet and Amazon. Yes I may be a very boring person to do all this reading, but I'm interested in questioning things and following the evidence. How can a person know that Pepsi is better than Coke when they have never tasted Coke?

Many people on the XKCD are very knowledgeable on issues of science, unfortunately, many of those same people are very stupid when it comes to philosophy and how ones worldview can contaminate the evidence and close certain avenues of investigation. As I quoted earlier, "It is the mark of an educated mind to be able to entertain a thought without accepting it." How many people can and do? My worldview allows both possibilities, does yours?

Could Darwanisim be true, yes. The problem is that the last 50 years of biology have raised questions that many are pretending do not exist. Those questions COULD have answers, who knows. Perhaps there is something there that makes this all possible that we just haven't found yet. Would Geocentric theory be any-more true if astronomers ignored the problems it had? The only reason people considered heliocentric theory was because astronomers were honest enough to admit that Geocentric theory had problems. Scientists found that they had the right idea, they just had things in the wrong order. Scientists of the day back then demanded evidence, people in Galileo's day had no problems with heliocentric theory as a theory and many would admit that it would explain planetary motions better than geocentrism. The problem for Galileo was that there were two fatal scientific objections to the theory that had to be dealt with and he could answer neither. The first, the lack of perceived planetary motion, was answered when Newton published Philosophiæ Naturalis Principia Mathematica in 1687. The second was not answered until 1829 when stellar parallax was first observed. (Galileo instead went the Greater Internet Fuckwad route and ridiculed everyone who disagreed with him in print.) He found out that ridiculing the Pope, who was also a personal friend of Galileo and who had written poetry about his discoveries, when your research activities are FUNDED by the church is not the way to have your research funding continue. Especially after being given about 10,000 passes.

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Re: 1071: "Exoplanets"

Postby ijuin » Sat Jun 30, 2012 6:44 am UTC

The problem with assuming that God will or will not intervene at His own discretion is that once one makes this assumption, then how is one to tell when God is intervening or not? It becomes trivially easy to say "God intervened" every time a data anomaly shows up.

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Re: 1071: "Exoplanets"

Postby Pfhorrest » Sat Jun 30, 2012 7:05 am UTC

Crosshair wrote:If I put the front page of the local newspaper into the photocopier, copy it,then put that copy into the copier and repeat, how long before I get the front page of that days New York Times?
If I tell a computer to copy its install of Windows 95 from one hard disk to another continually, how long until random copying errors result in a copy of Windows 7?


This question belies an important misunderstanding of evolution: that it is some kind of directed process toward something objectively better in some way. It isn't. Replication with mutation under selection produces a variety of things better fit for surviving whatever selection criteria you have, that's all. You haven't specified any selection criteria for the copying of a newspaper or software, so who is to say that the New York Times or Windows 7 are "more evolved" in any way? We would expect, just by sheer random mutation without any selection, that enough (that that's a really big "enough") copying would eventually produce those results, but it will eventually produce any and every result too so that's not really notable. If we accept a selection criteria by which the New York Times is better than the local paper and Windows 7 is better than Windows 95, then almost any mutation in the early copies will be less fit by that criteria, and the newspapers or software would be stuck in their present form in that niche, as mutants would quickly die off and cease to reproduce. To get to Windows 7 or the NYT would require either some strange migration into different niches (a slow shift in selection criteria) allowing mutations to somehow be useful for other purposes than our initial criteria before eventually becoming more useful for the original criteria than the original thing, displacing it when reintroduced to that niche; or, a long relaxing of the selection criteria to allow a large accumulation of generally less-fit (by that old criterion) mutants to build up, including the NYT and Windows 7, and then a reapplication of those criteria to weed out all the mutants which aren't those better-fit ones. These are the kinds of processes by which biological organisms evolve too.

Materialism is NOT science, it is a philosophy, a worldview. Science only concerns itself with the study of the physical world.

But that is itself taking a philosophical position -- at least an instrumental, methodological naturalism, materialism, physicalism. Science as such does not admit of supernatural explanations, just like your quote said. Some people who accept some results of science may nevertheless admit of supernatural explanations in other parts of their lives, but that's just doublethink and the selective abandonment of science, not any compromise on the part of the science itself. To the extent that one is being scientific, one is also being materialistic. You can selectively abandon materialism, sure... but you're selectively abandoning science with it.

It is agnostic about there being anything outside the physical world that may or may not interact with the physical world. That realm belongs to philosophy.

Anything which interacts with the physical world has some effect on the physical world and thus has a physical effect and is a physically observable phenomenon capable of being studied scientifically. Anything which doesn't have such physical effects should be ignored by science, sure... and everything else as well.
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Re: 1071: "Exoplanets"

Postby chenille » Sat Jun 30, 2012 8:47 am UTC

Crosshair wrote:Scientists of the day back then demanded evidence, people in Galileo's day had no problems with heliocentric theory as a theory and many would admit that it would explain planetary motions better than geocentrism. The problem for Galileo was that there were two fatal scientific objections to the theory that had to be dealt with and he could answer neither. The first, the lack of perceived planetary motion, was answered when Newton published Philosophiæ Naturalis Principia Mathematica in 1687. The second was not answered until 1829 when stellar parallax was first observed. (Galileo instead went the Greater Internet Fuckwad route and ridiculed everyone who disagreed with him in print.) He found out that ridiculing the Pope, who was also a personal friend of Galileo and who had written poetry about his discoveries, when your research activities are FUNDED by the church is not the way to have your research funding continue. Especially after being given about 10,000 passes.

Ha. Galileo was tactless about presenting his theory, but it takes some serious victim-blaming to think this makes it reasonable that a theocracy curtailed his speech and placed him under house arrest. Which I notice you don't mention, in favor of framing it as a mere funding dispute. Then if you look up the text of the church's decision, it actually rules the heliocentric model as not unsubstantiated but heretical by itself, so acting as if people had no problem with it except scientific objections is simply wrong.

Not to mention that Copernicus' book was published near his death, dedicated to the pope by a different author who added a note that it was only a mathematical and not a physical model, and still subsequently placed on the Index of Forbidden Books pending corrections. Not something you'd guess from your comic, huh?

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Re: 1071: "Exoplanets"

Postby mfb » Sat Jun 30, 2012 2:08 pm UTC

Crosshair wrote:2. The theory still cannot explain the information required to build a genome of even the simplest organism. Prior to the origin of life, self-replicating organic polymer or a peptide structures could only rely upon the basic laws of chemistry.

And afterwards, life modified the laws of physics to have more than that? ;)

Self-replicating organic polymers have replication, selection (stability and reproduction rate) and mutation, this is sufficient for evolution.

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Re: 1071: "Exoplanets"

Postby philip1201 » Sat Jun 30, 2012 6:26 pm UTC

Crosshair wrote:The problem for Galileo was that there were two fatal scientific objections to the theory that had to be dealt with and he could answer neither. The first, the lack of perceived planetary motion, was answered when Newton published Philosophiæ Naturalis Principia Mathematica in 1687.


Do you mean the motion of the heavier object? Because we do see planets moving. And when geocentrism puts an unmeasurably greater mass on every counterweight in their "crystal spheres", opposite the planets, I don't see why putting an unmeasurably greater mass on the sun, and an unmeasurably smaller mass on the Jovian moons. It's a good first-order approximation (neglect lesser mass) of a good first order approximation (assume circular orbits) of the actual orbits, even when explicitly calculating things, which neither Galileo nor the Aristoteleans could do because, as you say, Newtonian physics hadn't been invented yet.

With your standards, the only way Galileo could have made a proper discovery is if he derived Kepler's laws and Newton's laws while he was at it, which is absurd. Scientific advancement goes with small steps.

The second was not answered until 1829 when stellar parallax was first observed.


This is either double, or you are somehow claiming that planets had not been observed to move until Newton's time.


(Galileo instead went the Greater Internet Fuckwad route and ridiculed everyone who disagreed with him in print.) He found out that ridiculing the Pope, who was also a personal friend of Galileo and who had written poetry about his discoveries,


Do you even know what "Greater Internet Fuckwad [Theory]" means? It's about what you do when you're anonymous. As for "ridiculing the pope", he wrote a book with a neutral character, a heliocentric smart guy and a geocentric dumbass. Then the pope said he had to write the pope's own argument in his book, so he let the geocentric character say it. A bit socially blind, perhaps, but understandable.

when your research activities are FUNDED by the church is not the way to have your research funding continue. Especially after being given about 10,000 passes.


Also, are you suggesting that if, say, a scientist funded by a drug company discovers their drug doesn't work, that the drug company has the right to fire them, imprison them, and forbid their results from being published? Or, at least, that it counts as "being given a pass" when they aren't fired, and that they can be imprisoned etc. for insulting their employer?

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Re: 1071: "Exoplanets"

Postby prosfilaes » Sat Jun 30, 2012 7:24 pm UTC

dp2 wrote:"Solar System" has a meaning in English. The meaning is not "a group of planets orbiting a star". The word for that, again in English, is "planetary system". "Solar System", in English, is a proper noun referring to the planetary system that Earth is in. That's the point.


L'Académie française has neglected to rule on English, so we're left studying how speakers (especially but not exclusively native speakers) use the language. http://books.google.com/books?q="alien+solar+system" shows a number of hits for "alien solar system", from many science fiction authors, to the Economist, to the New Scientist, to the New York Times Book Review, to the Twayne Companion to Contemporary Literature in English. It seems like writers in many fields, popular, scientific and literary, agree that this is an acceptable use of the term.

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Re: 1071: "Exoplanets"

Postby gmalivuk » Sat Jun 30, 2012 7:36 pm UTC

Crosshair wrote:
Whether it's an organic polymer or a peptide structure, once it copies itself it's subject to evolutionary pressures.
This is an assertion.
What evidence do you have that this works anywhere outside the lab?
What evidence do you have that self-replicating organic polymer or a peptide structures can self arrange into a simple life form?
Those things you want evidence for are completely irrelevant to the assertion you quoted. The assertion is that once it copies itself it is subject to evolutionary pressure. It says nothing whatsoever about which things are, in fact, able to copy themselves.
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Re: 1071: "Exoplanets"

Postby ijuin » Sun Jul 01, 2012 8:53 am UTC

philip1201 wrote:
Crosshair wrote:The problem for Galileo was that there were two fatal scientific objections to the theory that had to be dealt with and he could answer neither. The first, the lack of perceived planetary motion, was answered when Newton published Philosophiæ Naturalis Principia Mathematica in 1687.


Do you mean the motion of the heavier object? Because we do see planets moving. And when geocentrism puts an unmeasurably greater mass on every counterweight in their "crystal spheres", opposite the planets, I don't see why putting an unmeasurably greater mass on the sun, and an unmeasurably smaller mass on the Jovian moons. It's a good first-order approximation (neglect lesser mass) of a good first order approximation (assume circular orbits) of the actual orbits, even when explicitly calculating things, which neither Galileo nor the Aristoteleans could do because, as you say, Newtonian physics hadn't been invented yet.

I think by "lack of perceived planetary motion" he meant that we, riding along with the Earth, have no perception of the movement of the Earth itself. We feel none of the vibrations that we would feel when moving along the ground on foot, horseback, or a sled/wheeled/tracked vehicle, and none of the rolling movement that we would feel when moving through water or air--the Earth's motion is too smooth to perceive directly (earthquakes notwithstanding). All we see is the lights in the sky changing position relative to us.

What we really needed in order to fully apprehend the motion of the Earth was a sense that "down" is not an absolute direction. If gravity's tendency were, as Aristotle proposed, to pull things toward the center of the universe rather than to pull all masses toward each other, then the Earth being anywhere other than the center of the universe would mean that you could "fall off" of it, because the direction toward the center of gravity and the direction toward the ground would be different from each other. Thus, you need a concept that gravity will keep pulling you toward the center of the Earth no matter where the Earth may move to.

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Re: 1071: "Exoplanets"

Postby Max™ » Mon Jul 02, 2012 1:36 am UTC

I am offended at the implication that Windows 7 is in any way a positive evolutionary outcome, if anything it's like wisdom teeth or an appendix, it may have served a purpose at some point, but nowadays it's best removed before it becomes infected.
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Re: 1071: "Exoplanets"

Postby SerMufasa » Mon Jul 02, 2012 4:26 am UTC

Max™ wrote:I am offended at the implication that Windows 7 is in any way a positive evolutionary outcome, if anything it's like wisdom teeth or an appendix, it may have served a purpose at some point, but nowadays it's best removed before it becomes infected.


But it's non-Hitlery!

EDIT: I also find it weird that someone is citing the Catholic repudiation of Galileo while simultaneously calling into question Evolution ... when the Catholic Church accepts and teaches Evolution.
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Re: 1071: "Exoplanets"

Postby philip1201 » Mon Jul 02, 2012 8:39 am UTC

ijuin wrote:
philip1201 wrote:
Crosshair wrote:The problem for Galileo was that there were two fatal scientific objections to the theory that had to be dealt with and he could answer neither. The first, the lack of perceived planetary motion, was answered when Newton published Philosophiæ Naturalis Principia Mathematica in 1687.


Do you mean the motion of the heavier object? Because we do see planets moving. And when geocentrism puts an unmeasurably greater mass on every counterweight in their "crystal spheres", opposite the planets, I don't see why putting an unmeasurably greater mass on the sun, and an unmeasurably smaller mass on the Jovian moons. It's a good first-order approximation (neglect lesser mass) of a good first order approximation (assume circular orbits) of the actual orbits, even when explicitly calculating things, which neither Galileo nor the Aristoteleans could do because, as you say, Newtonian physics hadn't been invented yet.

I think by "lack of perceived planetary motion" he meant that we, riding along with the Earth, have no perception of the movement of the Earth itself. We feel none of the vibrations that we would feel when moving along the ground on foot, horseback, or a sled/wheeled/tracked vehicle, and none of the rolling movement that we would feel when moving through water or air--the Earth's motion is too smooth to perceive directly (earthquakes notwithstanding). All we see is the lights in the sky changing position relative to us.

What we really needed in order to fully apprehend the motion of the Earth was a sense that "down" is not an absolute direction. If gravity's tendency were, as Aristotle proposed, to pull things toward the center of the universe rather than to pull all masses toward each other, then the Earth being anywhere other than the center of the universe would mean that you could "fall off" of it, because the direction toward the center of gravity and the direction toward the ground would be different from each other. Thus, you need a concept that gravity will keep pulling you toward the center of the Earth no matter where the Earth may move to.


Enter Galileo's experiment where he showed that the gravitational acceleration is constant with respect to mass. Though he never used it explicitly, this does necessarily cause subjective gravity for people on earth in the limit of zero distance between the Earth's and the observer's center of mass, regardless of the way the gravitational force is dependent on radius.

Given only that observation and that approximation, it is necessary that the earth+observer system experiences no internal forces due to external gravity (so no tides are predicted in this approximation*). Therefore in the earth-centered frame, the observer and the earth would be attracted to each other in the same way as there were no external forces at all. This holds true both in Newtonian and in Aristotelean physics.

Regardless of whether Galileo thought it through this way, the "crystal spheres" on which the geocentric planets moved were commonly held to be frictionless, and there wasn't any established dogma that I know of which made any statement about the subjective experience of extraterrestrial gravity, so there really was no expectation to replace in that regard.


(* if we slowly turn tidal forces back on again, the oceans turn out to be far more sensitive to them than people, because they extend over a much larger range).

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Re: 1071: "Exoplanets"

Postby PolakoVoador » Mon Jul 02, 2012 3:56 pm UTC

Crosshair wrote:
2. The theory still cannot explain the information required to build a genome of even the simplest organism. Prior to the origin of life, self-replicating organic polymer or a peptide structures could only rely upon the basic laws of chemistry. But how could the basic laws of chemistry and physics create the information present in life? The Natural Chemical Origin of Life Theory falls for the simple reason that you do not have enough monkeys or enough time for a brute force attack at the problem. You keep smuggling intelligence into the equation because YOU, with your intelligence, can, or think you can, see the path, but fail to see the problems an unintelligent process would have doing the same.

Example, take the most basic 1 mph bumper bot, one with no search patterns or anything programed in, since random mutations are in no particular direction. Just a bot that back up when it hits something, turns a random direction, and goes forward again. Then let it lose in a random location in the continental US. Then randomly put a 1" by 1" target somewhere in the continental US and see how long it takes the bumper bot to hit that target. Note that the continental US only has an area of 1.5x10^16 inches square.


Either I'm totally failing to see the point in your bumper bot example, or you fail to understand evolution's concept once again: remember, evolution doesn't have a defined objective. If you said: "Earth had 4.5 billion years to produce dragons, but we're not seeing any of those." you would have made just as much sense.

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Re: 1071: "Exoplanets"

Postby Pfhorrest » Mon Jul 02, 2012 5:54 pm UTC

Or to bring the analogy back to organisms: the odds of the exact life that we know being around right now are fantastically small, just like the odds of the bumper bot being at any given place in the country is. But the odds that some life or another will be humming along even in the face of selective pressures, given replication with mutation, are very good, just like the odds that the bumper bot is chugging along somewhere and not stuck nose first in a corner are pretty good, despite all the obstacles in its way, given its back-up-and-go-another-route behavior.
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Re: 1071: "Exoplanets"

Postby Max™ » Mon Jul 02, 2012 7:05 pm UTC

Release a few bumper bots into different locations in the country, if one manages to bump into a wall and go another route, release another one.

If two bots meet, the one that doesn't turn is eliminated (i.e. if one bumps the side of another), if a bot goes into the ocean or another body of water it is eliminated.

Natural accidents can eliminate them, cliffs, fires, volcanic activity, being hurled around by a tornado, and so forth. If one becomes stuck, eliminate it.

How likely is it to find a bot at the location you wanted to find one at?

How likely is it to find any bots at all?
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Re: 1071: "Exoplanets"

Postby prosfilaes » Mon Jul 02, 2012 7:49 pm UTC

Max™ wrote:How likely is it to find a bot at the location you wanted to find one at?


Again, evolution says nothing about finding a bot at the location you wanted to find one at. Given berries on a large enough island, evolution can tell you that it's likely that's something is eating them, but that something could be reptilian, canine, ursine, primate, bat or any number of possibilities.

How likely is it to find any bots at all?


We know that some cases of self-replication, in theory and in practice, can sustain and increase their populations. Known facts trump vague analogies any day.

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Re: 1071: "Exoplanets"

Postby PolakoVoador » Mon Jul 02, 2012 8:07 pm UTC

prosfilaes wrote:
Max™ wrote:How likely is it to find a bot at the location you wanted to find one at?


Again, evolution says nothing about finding a bot at the location you wanted to find one at. Given berries on a large enough island, evolution can tell you that it's likely that's something is eating them, but that something could be reptilian, canine, ursine, primate, bat or any number of possibilities.


We can make our bumper bot example better, let's take Max™ definitions, and add one more:
- Make that the bots which go somewhat closer to the general direction of the Dot have higher chances of releasing a new (similar) bot whenever they bump into something and change direction

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Re: 1071: "Exoplanets"

Postby Max™ » Mon Jul 02, 2012 8:50 pm UTC

prosfilaes wrote:
Max™ wrote:How likely is it to find a bot at the location you wanted to find one at?


Again, evolution says nothing about finding a bot at the location you wanted to find one at. Given berries on a large enough island, evolution can tell you that it's likely that's something is eating them, but that something could be reptilian, canine, ursine, primate, bat or any number of possibilities.

That was sort of my point, you might find one at a given point you intended them to reach, but it would be more of a coincidence than an expected outcome.

How likely is it to find any bots at all?


We know that some cases of self-replication, in theory and in practice, can sustain and increase their populations. Known facts trump vague analogies any day.

Well, the example that I gave should produce a stable population, as the basic "bump and reproduce" rule would give a fairly random but sustained rate of growth versus the "collision and inability to move" rate of removal.
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Re: 1071: "Exoplanets"

Postby mfb » Tue Jul 03, 2012 10:03 pm UTC

Max™ wrote:That was sort of my point, you might find one at a given point you intended them to reach, but it would be more of a coincidence than an expected outcome.

This just tells us that your model is unrealistic. You try to find a single target, where the surrounding area is not different from anything else. The replicating things found one of many local maxima of the fitness function*, after climbing up the corresponding "fitness hill".

*of course, this was not a static point, the map is extremely high-dimensional and depends on the changing environment, too.

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Re: 1071: "Exoplanets"

Postby Max™ » Wed Jul 04, 2012 12:39 am UTC

I wasn't saying that expecting it to be at a given point is consistent with evolution, and illustrating that while you can see if something evolves "towards" any given state, in general evolution is merely away from one state with no real direction otherwise.
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Re: 1071: "Exoplanets"

Postby EchoRomulus » Mon Jun 17, 2013 8:30 pm UTC

I just checked wikipedia now that this comic is about a year old.

We are not at 899 exactly including the 8 around Sol.

do you know what that means?

We're UNDER NINE HUNDRED!!!
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Re: 1071: "Exoplanets"

Postby jewish_scientist » Wed Nov 29, 2017 3:33 pm UTC

Wait, Project Orion allows interstellar travel? Just how fast can these ships suppose to go!

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Re: 1071: "Exoplanets"

Postby Soupspoon » Wed Nov 29, 2017 7:18 pm UTC

jewish_scientist wrote:Wait, Project Orion allows interstellar travel? Just how fast can these ships suppose to go!

Do you mean "allows interstellar travel within a reasonable length of voyage time?"? We already got some Voyagers/Pioneers escaping the Solar system gravity well, and they're just drifting slowly now, but they'll probably get somewhere, sometime, if there's not too many hazards like Oumuamua or bored Klingons out there to destroy them.

(But putting a nominal 1G ac(then de)celeration and a stellar distance of your choice into this might be useful. Alpha Centauri within 6 years, or 3.5 in ship-time, assuming you can pack the bomb-fuel necessary to do that.)

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Re: 1071: "Exoplanets"

Postby orthogon » Wed Nov 29, 2017 10:07 pm UTC

Soupspoon wrote:
jewish_scientist wrote:Wait, Project Orion allows interstellar travel? Just how fast can these ships suppose to go!

Do you mean "allows interstellar travel within a reasonable length of voyage time?"? We already got some Voyagers/Pioneers escaping the Solar system gravity well, and they're just drifting slowly now, but they'll probably get somewhere, sometime, if there's not too many hazards like Oumuamua or bored Klingons out there to destroy them.

(But putting a nominal 1G ac(then de)celeration and a stellar distance of your choice into this might be useful. Alpha Centauri within 6 years, or 3.5 in ship-time, assuming you can pack the bomb-fuel necessary to do that.)

Are the Voyagers likely to ever enter another solar system?

Pseudo-edit: I just googled it and it seems like they're eventually going to pass within a few light years of some stars. It seems that the Milky Way is dense enough that if you drift for long enough you'll get close to things from time to time. A lightyear is a long way though - they're not even a light-day away yet.

On the way I found this page, which I find kind of calming and uplifting at the same time. (No, it's not zombo.com). The idea that, as a species, we did this, gives me hope.
xtifr wrote:... and orthogon merely sounds undecided.

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Re: 1071: "Exoplanets"

Postby rmsgrey » Wed Nov 29, 2017 11:52 pm UTC

orthogon wrote:Are the Voyagers likely to ever enter another solar system?


Depends where you put the boundaries of a solar system - it's not like there are picket fences at 1 light-month out or anything...

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Re: 1071: "Exoplanets"

Postby orthogon » Thu Nov 30, 2017 7:39 am UTC

rmsgrey wrote:
orthogon wrote:Are the Voyagers likely to ever enter another solar system?


Depends where you put the boundaries of a solar system - it's not like there are picket fences at 1 light-month out or anything...

Well, of course, but there are magnetoshocks, heliopauses and whatnot. My question is, I guess, whether they could enter another solar system in the same sense that they've left ours. Actually, I could relax it to say: would they enter another solar system according to the outermost definition of the edge of a solar system?
xtifr wrote:... and orthogon merely sounds undecided.


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