Friday, June 14, 2013

A Very Brief History of Time Paradoxes

I've been reading up on the twin paradox for the last year or so.  This is the paradox where one twin flies away from another at relativistic speeds and when they get back, they find that they're younger than their sibling who stayed home.   It amounts to time travel into the future.

Last night when I got too tired to do anything productive I made a histogram, (shown in picture 2 below), using Google Scholar data of the number of citations containing the phrase 'twin paradox' over the years.  The first reference I found to the twin paradox was in 1956.  Prior to that it seems to have gone by the moniker of "Clock Paradox".  As I perused through the references, (there were a total of 2,393 between 1956 and 2013 by the way), one caught my eye because it was published by the U.S. Naval Research Laboratory in 1959[3].  As I've mentioned before, their was a push for anti-gravity in the late '50s and early '60s[8].

The document turned out to be a bibliography compiled by Mildred Benton[5], (picture 1 above)[6], of the library branch of the technical information division.  Mildred served as the librarian at the Navy's Ruth H. Hooker[4] library between 1951 and 1954.  This in and of itself looks really interesting.  Ruth Hooker was a physicist and judging from the bibliography it looks like Mildred Benton may have known more than a little physics herself.  But I'm digressing into a whole other post here :)

You should really, really look into this bibliography.  The references are fascinating.  I've listed a couple of them below.  The most colorful reference I've found so far is to an article from the October, 1957 issue of Popular Science, "Will Space Travel Lengthen Life?"[7].  The article asks why Martin, (soon to become Martin-Marietta), would place an employment ad in Time Magazine at the expense of $12,500 positing the possibility of time travel.  For the folks that are wondering how to attract youth into the STEM fields, this ad has a pretty good solution.  I've included it here as picture 3, but it's a bit of an eye chart, so here's the text:
"Anything that can be postulated is possible, says  science - including timelessness.
The latest table-talk among the rocket and missile men has to do with the physics (and meta-physics)  of photon propulsion: thrust for a space vehicle derived by shooting incredibly concentrated beams of light (photons) from its tail.  Result - speeds approaching that of light!  Round trips to distant galaxies could thus be accomplished in a single generation of the crew.  Meanwhile, however, the Earth would have passed through a billion years - possibly into cosmic oblivion!
The space-time is increasingly a factor in the calculations of a brand new field of science known as astronautics... Work in this field at Martin is already at the threshold of tomorrow."
Now that should get the kids... pssht, actually just about anybody interested!

Here are the few references I mentioned above.

Purports to be the first experimental verificaiton of time dilation.  High speed 'mesotrons', (now known as muons), are seen to have a longer lifetime before they decay.
"189.  Rossi, Bruno; Hilberry, Norman and Hoag, J.B. THE VARIATION OF THE HARD COMPONENT OF COSMIC RAYS WITH HEIGHT AND THE DISINTEGRATION OF MESOTRONS. Phys.Rev. 57:461-469,Mar.15,1940.
F.S. Crawford (See Item 45) states that the first quantitative check of the assumption that the time dilation of special relativity holds for uniform motion is contained in the combined experiments of Rossi, Hilberry and Hoag; Rasetti; and Blackett (See also Items 184 and 14)."

This one may be applicable to my work at the moment.  We're trying to determine the spacetime metric of an infinite sheet of constant density matter.

Various definitions of uniform acceleration are possible in relativity theory. Two of these are considered with particular reference to their physical realizations."

Minguzzi E. (2005). Differential aging from acceleration: An explicit formula, American Journal of Physics, 73 (9) 876. DOI:

1.a. Open Access version
E. Minguzzi (2004). Differential aging from acceleration, an explicit formula, Am.J.Phys. 73 (2005) 876-880, arXiv:

Schild A. (1959). The Clock Paradox in Relativity Theory, The American Mathematical Monthly, 66 (1) 1. DOI:

3.  U.S. Navy Twin Paradox Bibliography

4.  Ruth H. Hooker Research Library

5. Also by Mildred Benton,44

6.  Mildred Benton historical image

7.  Popular Science article, (open access)

8.  References from Copasetic Flows regarding the push for anti-grav in the '50s

1 comment:

Nicholas said...

On the one hand, the empirical data supports the contention that (absolute) velocity causes clocks (including human metabolism) to slow down. However, I agree with the thousands of physicists who contend that Special Relativity, which is built on the construct of RELATIVE velocity, is NOT the correct theoretical basis for this phenomenon. Instead, Special Relativity's predecessor, Lorentz Relativity is the appropriate theory.

Since Special Relativity is built on the construct of RELATIVE velocity, its prediction must be inherently symmetric and it cannot logically be claimed to produce an asymmetric effect such as a net proper time difference. This was the essence of both the Clock Paradox and the Twin Paradox.

For those who are interested in exploring this view more, please see the Home Page at, entitled "Data Does Not Match Special Relativity Time Dilation". I'd also recommend the following easy to read pages: "Open Letter On Twin Paradox", "Report", and "Mainstream Response". Much of the rest of the site goes into a detailed analysis of the logic of the Twin Paradox Debate, however, that issue seems obsolete now that GPS data has proved what the logic contended.