While economists have been taking a beating for not predicting the future correctly, it is useful to remember that when you take a physicist to the real world, he too has little to say. Consider our understanding of our solar system, a seemingly straightforward issue.
Mercury: Has an abnormally large iron core. For its size, its density seems too high. This is a puzzle. Leading theory: hit by asteroid.
Venus: Venus rotates in a clockwise fashion, in contrast to other planets. Leading theory: an asteroid hit it to spin the other way
Earth: No one knows where the water came from. Leading theory: snow comets hit us. The moon's origin, also, is not obvious, because it doesn't have enough iron, and if it just spun out of a really fast spinning earth, the earth would still be spinning fast or the energy release needed to slow the earth down would raised the temperature to 1000 degrees Celsius. Nebula forming two planets, or planetary capture, don't work. Leading theory: an asteroid hit the early Earth, creating the moon.
Mars:There appears to be evidence that Mars used to have water, as it seems to have lots of old lake beds and dry river beds. Why did the water leave? The atmosphere is currently about 0.3% of the earth's, so currently water goes immediately from ice to water vapor and then floats into space. So where did the atmosphere go? Solution: solar winds, or an asteroid hit it and pulled away the atmosphere.
Jupiter: Jupiter is 1300 times the volume of the earth, yet spins around once every 10 hours. Puzzling.
Saturn: Where did the rings come from? At some point in Saturn's early history, a moon about 300 km across got too close to Saturn and was torn into pieces. Or, it's also possible that two moons collided together, or a moon was struck hard enough by an asteroid that it just shattered.
Uranus: Uranus spins on its side, rolls around like a ball, unlike the other planets. This is a puzzle, because in theory, the solar system started as a spinning nebula of debris that generated a similar spin to it agglomerated parts, and also because its moons circle the planet on a different axis. Solution: an asteroid hit it. The moon Miranda has a very strange surface. There are huge faults, smooth plains, and curiously shaped rifts, smooth in some areas, rocky in others, that make it seem like it has different parts. A leading explanation: hit by asteroids.
You can only use the 'hit by an asteroid' explanation so many times, before it starts sounding like a filler for 'we have no good theory'.
We have a lot of work to do figuring out lots of prosaic stuff. Nobel physicist Robert Laughlin points out, much interesting physics are emergent phenomenon, they are not derived from basic forces. Very little, if any, collective organizational phenomenon, such as crystallization and magnetism, has ever been deduced from its lower lower-level parts.Those predicting the End of Physics are ignoring all the interesting problems that are not potentially generalizable to everything.
A physicist's ability to predict the terminal velocity of rocks falling from the Tower of Pisa, is like an economist predicting that when you subsidize something you get more of it. True in itself, but few are interested in such isolated phenomena.
17 comments:
None of your examples have anything to do with prediction. Ask a physicist about the future of the solar system and they can give you stunningly accurate answers.
The problem for economists is that they can't perform experiments, not that they are stupid.
I kind of agree with the first commenter, but I am amused by the example you constructed, and think it could be applied to other arguments - did you come up with this by yourself? Clever.
I disagree... A physicist is as unlikely to produce "stunningly accurate answers" about the FUTURE in the solar system as they are to produce stunningly accurate explanations for observations, as the blogger so noted. Ask how long the universe will last and you will get 100 to 200 trillion years. How accurate is that? Not very, and if they were off by 1000% how could you tell?
"None of your examples have anything to do with prediction. Ask a physicist about the future of the solar system and they can give you stunningly accurate answers."
Yea as in "the earth will end up eaten by a gigantic turtle".
What's the point of making predictions that none of us are able to check ?
Economists are not scientists. They're more like Astrologists.
A physicist can tell you with accuracy where the moon will be in two years, an economist can't tell you what the US/Euro exchange rate will be at that time.
The physicists sound like my contractor ... but his answer to everything is "just needs a little caulk".
Mathematicians are smarter than economists. I read it somewhere.
"A physicist can tell you with accuracy where the moon will be in two years, an economist can't tell you what the US/Euro exchange rate will be at that time."
Again - you have to frame it in comparable units. How much standard deviations better than the layman's prediction will the physicist's be ?
You push as economist off the Tower of Pisa. Does he fall faster than a banker who jumped?
well Jamougha - that is quite a simple question. But please try to answer something that has about 1000 parameter that combine or might not. Economy depends on reaction of the concerned subjects. I don't think there is much free will in the suns behaviour
You restrict your definition of astronomy to solar system formation and evolution, which is all about big chunks of matter interacting and slamming together, and you complain that it's all about big chunks of matter interacting and slamming together?
You terribly misuse the word asteroid, by the way. For example, the object which presumably hit Earth, to form our moon, is thought to have been Mars-sized (7000km across), which is not at all what we'd call an "asteroid". The largest asteroid is something like 1000km across, and it's a freak thing -- probably 5 times larger than most asteroids, and 100 times larger than the smallest ones!
Where on this scale would you put economics?
http://forums.xkcd.com/viewtopic.php?f=7&t=23609
There are over 1 million asteroids in the solar system today over 1 km in diameter.* And so wouldn't it be expected that asteroid collisions with planets would be relatively frequent? Look at the moon, those pits weren't caused by gophers.
* http://www.spaceref.com/news/viewpr.html?pid=7925
Over the past 50 years I have personally witnessed the demise of space physics, as experimental data pointed to conclusions that were opposed by those distributing federal funds for space studies. Modern text books and literature on astronomy, cosmology, astrophysics, climatology, solar and nuclear physics still promote these FABLES that have been experimentally discredited by these empirical FACTS:
1. FACT: Neutrons strongly repel each other.
1. FICTION: Neutrons strongly attract each other.
2. FACT: Neutron-emission and decay make the Hydrogen that fills interstellar space.
2. FICTION: A "Big Bang" filled the universe with Hydrogen.
3. FACT: Neutron repulsion powers the Sun.
3. FICTION: Hydrogen fusion powers the Sun.
4. FACT: The core of the Sun is a neutron star.
4. FICTION: The core of the Sun is a fusion reactor.
5. FACT: Elements are layered by mass in the Sun.
5. FICTION: Elements are well mixed in the Sun.
6. FACT: Hydrogen fusion produces ~35% of solar luminosity.
6. FICTION: Hydrogen fusion generates ~100% of solar luminosity.
7. FACT: Neutron-emission/ decay produce ~65% of solar luminosity.
7. FICTION: ~65% of solar neutrinos oscillate away before detection.
8. FACT: Iron (Fe) is the most abundant element in the Sun.
8. FICTION: Hydrogen (H) is the most abundant element in the Sun.
9. FACT: Solar-planetary interactions and inertial motion produce solar cycles and changes in Earth's climate.
9. FICTION: Anthropologic carbon dioxide, CO2, controls Earth's climate.
The experimental basis for the above FACTS are summarized in two papers:
1. "The Sun is a plasma diffuser that sorts atoms by mass", Physics of Atomic Nuclei 69, number 11, pp. 1847-1856 (2006); ISSN 1063-7788; Yadernaya Fizika 69, number 11 (2006); PAC: 96.20.Dt
Popular version: http://xxx.lanl.gov/pdf/astro-ph/0502206
Overheads: http://www.omatumr.com/Overheads/Overheads.htm
Manuscript: http://arxiv.org/pdf/astro-ph/0609509
2. "Fingerprints of a local supernova," in SUPERNOVA RESEARCH (Nova Science Publishers, Inc., Hauppauge, NY, in press, 38 pp., 2009).
http://www.omatumr.com/abstracts2007/20071202_Manuel_and_Ratcliffe.pdf
With kind regards,
Oliver K. Manuel
Emeritus Professor
Nuclear & Space Science
http://myprofile.cos.com/manuelo09
||You can only use the 'hit by an asteroid' explanation so many times, before it starts sounding like a filler for 'we have no good theory'.||
In the early days of the solar system, there was a lot of stuff flying around and smacking into things. One only needs to look at the surface of the moon. It does not strike me as unreasonable to consider all major planets in the solar system have been hit by something large billions of years ago and this would have affected their spin and composition in important and distinct ways.
||Leading theory: an asteroid hit the early Earth, creating the moon.||
You should probably read the pages you link to. Nowhere does it claim the moon was formed by an asteroid.
"Astronomers believe that the Moon was formed when a Mars-sized body smashed into the Earth..."
http://genomicron.blogspot.com/2009/09/does-evolutionary-biology-make.html
Five predictions made and confirmed by evolution.
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