You can read her (more technical) paper on a fundamental minimum length here, and follow her tweets at @skdh. 2MASS J0523-1403. Alas, it is hard to make sense of the romantic idea of universes in universes in universes mathematically, not that I didn’t try, and so the minimal length keeps coming back to me. Amit is a philosopher but he certainly knows his math and physics. Similarly very small numbers are written using negative exponents, e.g. For a full list of record titles, please use our Record Application Search. Since then, the idea that the Planck length may be a fundamental length beyond which there is nothing new to find, ever, appeared in other approaches towards quantum gravity, such as Loop Quantum Gravity and Asymptotically Safe Gravity. Corporate Social Responsibility activities & fundraising ideas, Community engagement & tourism marketing activities. But in position space, one either has to break Lorentz-invariance or deform it and give up locality, which has observable consequences, and not always desired ones. What makes a Guinness World Records title? Amit has made a considerable effort to address the topic of a fundamental length from as many perspectives as possible, and he covers a lot of scientific history and philosophical considerations that I had not previously been aware of. (Amit’s book is admittedly quite pricey, so let me add that he said should sales numbers reach 500, Cambridge University Press will put a considerably less expensive paperback version on offer. One of the main difficulties with these theories is that a minimal length, if interpreted as the length of a ruler, would not be invariant under Lorentz-transformations due to length contraction. This post was written by Sabine Hossenfelder, assistant professor of physics at Nordita. Or is there a fundamental limit, and if so, what is it, and what is it that dictates its nature? NASA Finally Contacts Voyager 2 After Unprecedented Seven-Month Silence. How to set or break a Guinness World Records title. The smallest hypothetical thing in the universe is not … Did A Black Hole Give Birth To Our Universe? Just as the non-commutativity of momentum and position operators leads to an uncertainty principle, the non-commutativity of position operators limits how well distances can be measured. This problem is easy to overcome in momentum space, where it is a maximal energy that has to be made Lorentz-invariant, because momentum space is not translationally invariant. Smallest Hypothetical Object in the Universe. Zeno’s famous paradoxa sought to shed light on the possibility of infinite divisibility. The question returned in the modern age with the advent of quantum mechanics, with Heisenberg’s uncertainty principle fundamentally limiting the precision to which we can measure. WHAT MAKES A GUINNESS WORLD RECORDS TITLE? Radius: 0.086 R. Mass: Less than 0.08 M. In … Ask Ethan: Did The Universe Have Zero Entropy At The Big Bang? It became only more pressing with the divergences inherent to quantum field theory, due to the necessary inclusion of infinitely short distances. The smallest possible size for anything in the universe is the Planck Length, which is 1.6 x10-35 m across. Science and philosophy in earnest is only a few thousand years old, but the question whether there is smallest unit has been a driving force in our studies of the natural world for all of recorded history. Meanwhile, the problem of quantizing gravity appeared on stage and with it, again, non-renormalizability. Great ideas start with a question that comes back to you. The Ancient Greeks invented atomism: the idea that there is an ultimate and smallest element of matter that everything is made of dates back to Democritus of Abdera. By using this site, you agree that we may store and access cookies on your device. I like to think that we can look infinitely close into structures and will never find a final theory, turtles upon turtles, or that structures are ultimately self-similar and repeat. The book is also noteworthy for including a chapter on quantum gravity phenomenology. Ask Ethan: Can We Find Out If Gravitons Exist? Heisenberg’s idea was forgotten for some decades, then picked up again and eventually grew into the area of non-commutative geometries. Heisenberg’s main worry, which the minimal length was supposed to deal with, was the non-renormalizability of Fermi’s theory of beta-decay. Mead’s argument was forgotten, then rediscovered in the 1990s by string theorists who had noticed that using strings to prevent divergences (by avoiding point-interactions) also implies a finite resolution, if in a technically somewhat different way than Mead’s. Many (if not most) endeavors to find observational evidence for quantum gravity today look for manifestations of a minimal length in one way or the other, such as modifications of the dispersion relation, modifications of the commutation-relations, or Bekenstein’s tabletop search for quantum gravity. The question of whether there is a smallest possible scale in the Universe is today a very active area of research. Good ideas start with a question. http://4.bp.blogspot.com/-jLtyTEMrKpQ/Tx_e2sF0sCI/AAAAAAAABIE/D1UbRkRcK0M/s200/gup4.jpg, Heisenberg’s main worry, which the minimal length was supposed to deal with, was the non-renormalizability of Fermi’s theory of beta-decay, http://1.bp.blogspot.com/--0vueKXZYb4/Tx_Qjxko0CI/AAAAAAAABGw/v5T4rbG8IXo/s400/heisenberg_microscope.jpg, Alden Mead reinvestigated Heisenberg’s microscope, http://hadron.physics.fsu.edu/~crede/quarks.html, modifications of the commutation-relations, Bekenstein’s tabletop search for quantum gravity. 0.0000001 is 10-7 (the “1” is seven places to the right of the decimal point). Why Is The Universe Fundamentally Left-Handed? All records listed on our website are current and up-to-date. Registered Office: South Quay Building, 77 Marsh Wall, London E14 9SH United Kingdom. In other words, the idea of a “minimum length” would suddenly imply that different observers (i.e., people moving at different velocities) would measure different fundamental minimum lengths from one another! Luckily, those smart enough to hunt down the occasional bear eventually gave rise to a human civilization that was sheltered enough from the harshness of life to let the survivors get back to watching and wondering what we are made of. Weigh in with your comments at the Starts With A Bang forum on Scienceblogs! Can we forever look closer and ever closer into space, time, and matter? Personally, I think it is a mistake to interpret the minimal length as the length of a ruler (a component of a Lorentz-vector), and it should instead be interpreted as a Lorentz-invariant scalar to begin with, but opinions on that matter differ. My only complaint about the book is its title, because the question of “discrete vs. continuous” is not the same as the question of “finite vs. infinite resolution.” One can have a continuous structure and yet be unable to resolve it beyond some limit, such as would be the case when the limit makes itself noticeable as a blur rather than a discretization.