## Fractint

*Fractint*still exists, and is actually still maintained! The program…

When I was writing an article on the Mandelbrot set, I looked for software to generate illustrations. Needless to say that there is lots of stuff available for a colorful subject like that. But, lo and behold, I discovered that the venerable *Fractint* still exists, and is actually still maintained! The program…

If you want to launch a rocket into space, as I’m sure practically all of you are at least contemplating, where should you do that? The main thing is of course to avoid populated areas, to limit the damage if the thing blows up. The launch pad itself should be located away from people, and there should be a large uninhabited region to the *east* of the launch site…

If you think about a set with an infinite number of elements, you might conclude that there is not much to say about the number of elements anymore. Infinite is infinite, right? Well, it turns out that not every infinity has the same “value”, and that there’s actually quite a lot to say about it. Take the natural numbers…

Euler’s identity, \(e^{i\pi}+1=0\), must be the most beautiful formula in the whole of mathematics. The expression establishes an amazing relation between five important numbers…

Color is a straightforward way to make those boring QR codes special. This seems to have caught on with quite a few people, as a quick Google image search reveals. But, there’s a problem. Deviating from the ideal black-and-white makes the QR code more difficult to scan. In this article, I show a way to…

The Mars Science Laboratory (MSL) is one of the most spectacular planetary missions ever. The MSL homepage gives lots of details, and includes a countdown clock to the landing in…

After the fun with the “doctored” photo from a previous article, I thought it would be nice to show another example of a photo that “fades to gray” if you’re not careful. This time the image disappears if it is converted to grayscale in the wrong way. This is…

You have probably already encountered a few *QR codes*. These codes are becoming more and more common, and can be found on business cards, ads, historical buildings, T-shirts, etc. You're meant to scan them using your smartphone. They can contain all sorts of information, the most common being plain text, URLs, and contact information. The information is… *[This article contains a demo in which you can create your own QR codes!]*

This article points out the danger of assuming that astronomical images are encoded using linear intensity. It is meant for the many people that are performing astronomical observations using regular cameras. Not because there’s something wrong with that, but because those cameras are optimized for “normal” photography and video, not for numerical calculations on their images. The illustration below…

The distance between two points is a concept that is, in every day use, clear and unambiguous. Mathematically, the normal (every day) distance between two points is called the *Euclidean distance*, but mathematicians generalize this definition. I show how, and I try to make you think by showing how circles look using some of these alternative definitions…