I presented three options:
1) Some experimental test would require a little improvement in current technology in order to test. This can sometimes take just a few years, or it could take many decades.
2) If the predictions are far beyond the capability of current, or even near-future technology, one can find other ways to test the theory that may not be as direct. Assume the theory is valid until real evidence can be found to the contrary.
3) Declare any aspect of the theory beyond immediately testable in the laboratory as unknowable and open to explanations at any level of crackpotism.
I opened the door to suggestions from others in the event there were more possibilities, but have yet to receive any responses or suggestions beyond these.
Mainstream science generally chooses option (1 & 2). Many pseudo-sciences insists the only choice is option (3).
Most of the examples below are described in more detail, with detailed references, in my paper, “The Cosmos In Your Pocket. How Cosmological Science Became Earth Technology. I.” I've even tossed in one example that will have more detail in paper II of the series.
There are many examples of option (1) throughout scientific history. I'll examine a couple here.
* One of the best known examples of astronomy's contribution to chemistry is in the discovery of helium. First identified by spectroscope during a solar eclipse in 1868, it would not be successfully isolated in Earth laboratories until 1895, an interval of 27 years.
* In 1868, W.H. Huggins was one of the first astronomers to point the newly-invented spectroscope at astronomical objects. Among his first discoveries (though Huggins didn't fully realize it at the time) were spectral lines emitted by planetary nebulae that did not correspond to any of the known chemical elements. The discovery of new chemical elements over the next almost 60 years did not solve the mystery. Huggin's wife would suggest the name 'nebulium' for the element which created these spectral lines. With the development of quantum theory in the 1920s, the understanding of how atomic spectral lines were created provided one of the key missing pieces. In 1927, Ira Bowen would realize that the spectral lines corresponded to differences in a unusual type of atomic energy levels, called metastable states. Metastable states had been detected in laboratories but did not appear to transition and produce a spectral line. This property of the transiton earned the lines the name 'forbidden lines'. But Bowen realized that these lines didn't appear because electrons could not stay in the metastable states at gas densities available in laboratory discharge tubes. It would be a few years later, 1931, before a laboratory experiment could be conducted that had sufficient sensitivity to detect the so-called 'forbidden' spectral lines.
For more details and references on this part of scientific history, see Section III of “The Cosmos In Your Pocket”.
The Fuzzy Border between Option 1 & Option 2
Now, the boundary between option (1) and option (2) can be quite fuzzy, largely because it is rarely clear when technology will improve to the point that something that is otherwise option (2) could become an option (1).
* By far the best example of this would be Newton's theory of gravity. For over two hundred years, the inverse-square dependence of gravitational force with distance could only be subjected to indirect testing, through observations of planets, asteroids, comets as well as distant stars and galaxies. In Newton's day, only the equivalent of science fiction writers actually regarded travel to other planets as a potential reality. At the time we launched the first satellites into orbit in 1957, these were the FIRST controlled test of the Newtonian gravity, where we knew the detailed kinematics of the object we were observing. We would not be able to verify the inverse-square law nature of gravity in the laboratory until the 1990s. For more details of this history, see Section II of “The Cosmos In Your Pocket”.
* With the discovery of the positron in 1932, we had experimental verification of the process of matter-antimatter annihilation. An electron and positron would collide, producing two photons. One basic principle of physics is that all sub-atomic processes are reversible in time. This principle of time-reversibility has been tested in many reactions, but not all reactions. If an electron and position can produce two photons, the reverse reaction should occur as well -- we should also be able to collide two photons together and produce an electron and positron. The probability for such a reaction was first calculated in 1934 by Breit and Wheeler[1,2]. Astrophysicists, studying high-energy processes, would examine the kind of electromagnetic spectrum could be emitted from a plasma where densities were high enough that photon-photon collisions would produce electron-positron pairs which would then recombine into photons. Such plasmas are called pair plasmas. I did some theoretical work on pair plasmas while I was a graduate student. Yet at that time, the production of positrons and electrons from two-photon collisions had not been reproduced in the laboratory! An actual laboratory demonstration of the process would finally be achieved by SLAC (Stanford Linear Accelerator) in 1997 .
More to come...
- G. Breit and J. A. Wheeler. Collision of Two Light Quanta. Physical Review, 46:1087–1091, December 1934. doi: 10.1103/PhysRev.46.1087.
- M. S. Plesset and J. A. Wheeler. Inelastic Scattering of Quanta with Production of Pairs. Physical Review, 48:302–306, August 1935. doi: 10.1103/PhysRev.48.302.
- D. L. Burke, R. C. Field, G. Horton-Smith, J. E. Spencer, D. Walz, S. C. Berridge, W. M. Bugg, K. Shmakov, A. W. Weidemann, C. Bula, K. T. McDonald, E. J. Prebys, C. Bamber, S. J. Boege, T. Koffas, T. Kotseroglou, A. C. Melissinos, D. D. Meyerhofer, D. A. Reis, and W. Ragg. Positron Production in Multiphoton Light-by-Light Scattering. Physical Review Letters, 79:1626–1629, September 1997. doi: 10.1103/Phys-RevLett.79.1626.