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There’s something happening right now that many of you might not have heard about. It’s a step towards the future of energy, known as ITER (International Thermonuclear Experimental Reactor). The project is an attempt to recreate experimental studies of plasma physics in a full-scale, electricity-producing fusion power plant at the Cadarache facility in the south of France. It promises to be the world’s largest and most advanced experimental tokamak nuclear fusion reactor, surpassing the Joint European Torus. A tokamak is basically a device using a magnetic field to confine plasma in the shape of a torus. The theory behind the toroidal design is a little complicated and besides the point so I’ll just stick this picture in here I got off Wikipedia to help you visualise a torus.

 

For those of you who know about fusion, it’s the opposite principle of current nuclear power reactors, which use fission. Fusion fuses two or more atomic nuclei together into a heavier nucleus. The process releases a large amount of energy (more than fission, which is the splitting of atoms).

The project is being funded by seven members – the European Union, as the host, contributing 45% of the cost, while India, Japan, China, Russia, South Korea and the United States are contributing 9% each.

Research into fusion technology has existed for a long time, but there’s always been a problem with its feasibility. Fusion inherently requires a large amount of energy. The Joint European Torus peaked at 65% of its input power in 1997 (meaning it produced less power than it took), but the ITER project hopes to produce ten times more power than its input. Unfortunately, this project will take a long time to complete. The current timeline for the project is:

2006 – Funding agreed upon by seven members

2008 – Site preparation and ITER itinerary begun

2009 – Site preparation completed

2010 – Tokamak complex excavation begun

2013 – Projected start of tokamak complex construction

2015 – Projected assembly of tokamak

2019 – Projected completion of tokamak assembly and start of torus

2020 – Projected achievement of first plasma

2027 – Projected start of deuterium-tritium operation

2038 – Projected end of project

The cooling of the reactor will be through a combination of a water cooling loops, as well as liquid nitrogen and a liquid helium system.

There are a number of criticisms for the project, generally focused on the practicality of containing the fusion project. As Pierre-Gilles de Gennes said on the topic of fusion, “We say that we will put the sun into a box. The idea is pretty. The problem is, we don’t know how to make the box.” Concerns in this regard include contamination of the reactor walls due to intense neutron bombardment. However, ITER maintains that it has considered and addressed all these issues.

The dream of fusion power has been a long one, and ever since cold fusion had been conclusively shut down it seemed like a distant dream. I’ve always maintained that it would be a shame for me not to live through an amazing breakthrough in science. I sincerely hope this “man made sun”   will be successful within my lifetime.

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I remember as a kid we’d settle arguments by whoever could say the highest number (or multiply by it; such as “I hate you more times 100, or I’m 50 times better than you). At some point we all learned of the existence of infinity, and that would settle it. Whenever someone said “infinity plus one”, the other would object by saying “but infinity plus one is still infinity!” implying that infinity was as big as you could get, and that all infinities were the same size. Turns out they’re not.

This may sound counter-intuitive to some of you. After all, infinity alludes to an endless size right? How can two things that are endless be bigger or smaller than the other?

Well the properties of infinite sets have been studied for quite some time. I’m not sure if he was the first, but Galileo Galilei identified a conceptual problem with infinite sets in his final scientific work Two New Sciences. I’m not interested in giving a history lesson so I’ll keep this post short and let you do you own research if you don’t believe me (and by now, you should have much more faith in me than that!).

His work identified a property of infinite sets that is now known as Galileo’s Paradox. The gist of it is this:

  1. Some numbers are squares (2^2 = 4; 3^2=9; etc.) whereas some numbers are not (prime numbers and other non-square integers, etc.). Therefore all numbers must consist of both squares and non-squares, and thus be more numerous than just the squares alone.
  2. However, every square has exactly one positive number that is its square root (basically just reversing the square operation). Therefore, there are as many squares as there are square roots.
  3. For every number, there is exactly one squared value (you can square any number by multiplying it by itself). Therefore, there are as many square roots as there are numbers (because every number can be squared so every number has a square root). Since there are as many squares as there are square roots, and there are as many square roots as there are numbers, then there must be as many squares as there are numbers.
  4. However, our premise was that there are more numbers than there are squares. Therefore it is a “paradox”, the solution to which is that some infinities are larger than others.

Galileo simplified this in his work with a very apt analogy that I think will help people visualise this concept better. Imagine two lines, one longer than the other. You can say that both lines are made up of an infinite amount of infinitesimally small points, however, you can also clearly see that one is longer than the other.

Later on, the mathematician Georg Cantor provided mathematical proof and definitions for sets and trans-infinite numbers, to which a great deal of resistance was put up by the other mathematicians of the time. The existence of larger infinities was and is of great philosophical importance. You can Google more of Georg Cantor if you wish; this post is merely for me to show you that not all infinities are the same.

Also, here’s an 8 minute video explaining this concept with some different examples by Numberphile. The guy presenting has a creepy smile and is way too excited about maths, but it’s still quite informative: http://www.youtube.com/watch?v=elvOZm0d4H0

And a much faster explanation by MinutePhysics (about 2 minutes): http://www.youtube.com/watch?v=A-QoutHCu4o

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