The spinthariscope, invented and beautifully named by William Crookes in 1903, is a device for seeing individual atoms. Or at least, seeing the death of individual atoms.

A spinthariscope consists of a needle, similar to a watch hand, positioned in front of a zinc sulfide luminous screen, with a magnifying glass focused on the screen. At the end of the needle is a small patch of radioactive material. Originally radium was used; more recently polonium, uranium, and americium have been found to be safer.

More »

“And although it will no doubt be very difficult to prove, it seems likely that this Turing machine will in the end turn out to be universal.”

So I wrote on page 709 of A New Kind of Science (NKS).

I had searched the computational universe for the simplest possible universal Turing machine. And I had found a candidate—that my intuition told me was likely to be universal. But I was not sure.

And so as part of commemorating the fifth anniversary of A New Kind of Science on May 14 this year, we announced a $25,000 prize for determining whether or not that Turing machine is in fact universal.

I had no idea how long it would take before the prize was won. A month? A year? A decade? A century? Perhaps the question was even formally undecidable (say from the usual axioms of mathematics).

But today I am thrilled to be able to announce that after only five months the prize is won—and we have answer: the Turing machine is in fact universal!

Alex Smith—a 20-year-old undergraduate from Birmingham, UK—has produced a 40-page proof.

I’m pleased that my intuition was correct. But more importantly, we now have another piece of evidence for the very general Principle of Computational Equivalence (PCE) that I introduced in A New Kind of Science.

We are also at the end of a quest that has spanned more than half a century to find the very simplest universal Turing machine.

Here it is. Just two states and three colors. And able to do any computation that can be done.

More »

My announcement last Thursday that you can publish almost any Mathematica notebook so it’s interactive in our free Player brings about much more of a change than you might first think.

In my Technology Conference talk, I explained how this new Publish for Player service removes one of the last hurdles to making new applications as everyday as new documents. And in turn that initiates a new era of communicating technical ideas.

More »

This is one of the busiest–and most satisfying–times of year for me. Later this week is the annual Wolfram Technology Conference. And in addition to bringing together a fascinating group of Mathematica users and developers, it’s also a time when many of our key corporate partners come to visit and interact.

Here’s this year’s group:

More »

The Demonstrations team has been very busy behind the scenes lately. Even though I work on The Wolfram Demonstrations Project every day, it amazes me to see that we’ve published nearly 2,000 Demonstrations already. And we’re working hard to add site features (many of which are user-suggested) at the same time.

More »