The physics behind Interstellar — Christopher Nolan’s space drama

As a man of physics, Interstellar is a film I would not miss for the world; if not for the physics, for the images — and director Chris Nolan’s images have always been powerful. Interstellar does not fall short on that. However, it helps for the layperson to learn a thing or two about physics before watching the film, which is why I wrote this article — and made sure there are no spoilers.

The film is really very small, but dressed as an operatic journey through space and time. The use of physics is interesting, almost exciting, and what holds the audience’s attention is (surprisingly) as much the science as the story of a parent-child relationship.

And yet, like so many films before it, Interstellar falls short merely because it was hyped far too much and it set itself an unrealistically high barrier.

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Presentation: On theories

This presentation was made to explore what a theory is, how it is developed, what makes a good theory as well as related topics such as the concepts of accuracy and precision, the scientific method, Karl Popper’s requirements of a theory, Occam’s razor, the ideas of  provability v. unfalsifiability etc.

Download the PDF file .

You are free to download a .pdf version of this presentation and use it according to the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International license.

Abraham Lincoln’s unitary method problem

They say Lincoln had very little or no formal education. The former US president himself is known to have spoken few good things about his childhood schooling.

However, sometime back in June last year two mathematics professors in Illinois confirmed the discovery and authenticity of two papers believed to have been part of Linoln’s cyphering book — that is a 19th century term for “workbook”, in case you are wondering.

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On projecting an octahedron onto ellipses

I recently came across an interesting animation that was shared with a rather poor choice of words: “Dots that are moving around in a circle! Connect them and you’ll get a moving octahedron…”

I find that this statement is faulty for reasons I will explain below; but first, the animation in question:

I will try to limit the mathematics to the necessities; generally, neither is this a two-dimensional figure, nor are those circles. I think the animation, in its present form, merely benefits from a rather tricky choice of perspective.

Before we actually talk about this, I hope to clear up a few things (read, prove a couple of lemma) regarding the construction and structure of an octahedron.

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Dark energies, Higgs boson seesaws and the tiny Grand Unified Scale

ONE OF THE BIGGEST PROBLEMS in contemporary theoretical physics is the dark matter-dark energy duo. Back when Einstein forced himself to tailor his theory of general relativity to a static universe, he had come up with what was termed the cosmological constant; it was, for all practical purposes, a sort of correction parameter which made sure his famous field equation worked in a static universe. Once turned off (i.e. the Lambda in the equation below (the upside-down V) once set to zero) one term is knocked off the equation once again returning it to a state of satisfying a changing universe.

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Quantum fluctuations and the cosmological constant

The entire elaboration that was the cosmological constant has since died and been resurrected. Physicists are now toying with the idea that the value-equivalents of temporary fluctuations of energy in space (as a result of Heisenberg’s uncertainty principle) called quantum vacuum fluctuations is nothing but the cosmological constant.

Click here to read an interesting paper introducing the cosmological constant pedagogically. Or you can read Steven Weinberg’s slightly denser paper instead.

A lot of hope was stacked on the Higgs Boson prior to its discovery, and if anything, that has all be trebled after the fact. Now, the latest attribution to the so-called God particle, is the mysterious behaviour of dark matter (no, not the comic,) and dark energy and, in turn, the cosmological constant itself.

Ride the Higgs boson seesaw?

In their PRL paper, “A Higgs seesaw mechanism as a source for dark energy,” physicists Lawrence Kraus and James Dent propose using the seesaw mechanism (which was originally used to understand neutrino masses which are a mere millionths of, say, particles in the Lepton family) to understand how the Higgs particle can create an energy density in the Grand Unified Scale (about 16 orders smaller than a proton) at which the three known energies are believed to tie to form a unification à la Einstein’s Grand Unification Theory — quite aptly shortened to GUT.

Promises of a minuscule order

The discovery of the Higgs boson has provided a much needed injection of fact into what was otherwise turning out to appear like a lot of wild conjecture.

Dark matter is what occupies a majority of the mass on any given galaxy, but can only be detected indirectly (by its gravitational influence) since it does not interact with light (things such as light shining off it do not occur.) Such an energy, called dark energy for obvious reasons, appears to have a magnitude of electroweak physics’ GUT order.

This webpage explains the neutrino seesaw mechanism in (once again) a pedagogical manner better than I care to elaborate here. It is a fairly typical but more fluid treatment by one, Robert Klauber.

Kraus and Dent’s theory of Higgs coupling along the lines of the Neutrino seesaw explanation arrives at precisely this order of magnitude of energy contribution, as it were, to a quantum vacuum. The duo calls this an “extension of the standard model” — another promising, if not fully proven, foundation on which to explain their ideas.

The pith of this paper is that by operating on a factual entity (the Higgs boson,) using, analogously, a previously tested approach (the neutrino seesaw,) treated on the platform of a well-accepted idea (the standard model,) we end up with energies of exactly the same minuscule order of magnitude as the one we found hard to explain convincingly.

Perhaps this paper is more of a nudge in the right direction than a revelation itself, but sometimes in physics nudges are exactly what we need.

 Cover image: Rosette nebula via Flickr/bobfamiliar 

Does laser eye-surgery last indefinitely?

Laser eye surgery is without doubt an amazing procedure, giving people the opportunity to throw away their glasses and contact lenses. Laser eye surgery has actual been around a lot longer than most people realise and it was first carried out over 20 years ago, admittedly not with the same impressive results as we expect today.

In the early days, laser eye surgery was far more invasive than it is today, leaving people with extensive corneal scarring and variable results. Laser eye surgery risks were also far higher and they also tended to be more serious.

Today however, laser eye surgery is minimally invasive and the results are extremely impressive. Around 95% of people having the procedure will end up with 20:20 vision and almost 100% will have driving standard of vision or better. Laser eye surgery is the most common elective surgery available and is far more popular than even the most common cosmetic surgery procedures.

For those deciding whether or not to have laser eye surgery then one of the most commonly asked questions is just how long the visual results are likely to last. This article is going to outline the most important points you need to know about this aspect of laser eye surgery:

Laser re-treatments

Around 6% of all laser eye surgery procedures will have to be repeated with a ‘top up’ treatment. This is normally done for free by the clinic that carried out the original procedure and it may only be required for one eye. To illustrate how laser re-enhancements work, it is best to use an example.

Imagine your prescription was -7.00 Dioptres prior to your surgery and then after surgery your prescription was completely eliminated to zero, meaning you had perfect vision. Then over the course of the next year your prescription slowly regressed to -1.00.

This is obviously only a fraction of what your prescription was before you had the surgery but it is enough to affect your vision. The laser is then re-applied to re-correct this remaining prescription.

Long sighted prescriptions

Long sighted prescriptions (plus e.g. +5.00) are more likely to regress than short sighted (minus e.g. -3.00) prescriptions.

Higher prescriptions

The higher the prescription the more likely you are to need a laser re-enhancement. The reason for this is that the more something has changed, the more likely it is to return back to its original state.

Reading glasses as you get older

Regardless of whether you have had laser eye surgery or not, you are still going to need reading glasses as you reach your mid 40’s. This is related to the lens in your eye that slowly loses its power which is a condition called presbyopia.

Eye diseases

As we get older so the chances of us getting age related conditions such as cataracts increases. Cataracts typically start affecting us aged around 70 years old and they can cause a change in our prescription. So even though you may have had laser eye surgery previously the cataracts could mean you end up needing glasses as you get older.

So, as you can see, having laser eye surgery does not guarantee that you will be free from glasses/contact lenses for life but for most people they will at least have perfect distance vision for a prolonged period of time.

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Tim-HarwoodTim Harwood is an optometrist with over 8 years in practice with a specialist interest in both laser eye surgery and contact lenses. He has worked both in the United Kingdom as well as Australia and has worked for both multiple and independent opticians. Tim also provides useful information on his own website, TreatmentSaver.com.

[/sws_blue_box]  Cover image: Flickr/Peretz Partensky