The Moving Average as a Filter

Figure 1. Smoothing with a moving average filter.

The moving average is often used for smoothing data in the presence of noise. The simple moving average is not always recognized as the Finite Impulse Response (FIR) filter that it is, while it is actually one of the most common filters in signal processing. Treating it as a filter allows… read more

Submitted on 4 December 2015

The Diverging Color Map Is the New Rainbow Color Map

Figure 1. The diverging color map is the new rainbow color map.

I am not a visualization specialist, but I’m convinced that the often used rainbow color map is not well suited for scientific visualization. It might be attractive, but it is not effective. This post mainly introduces diverging color maps as a much better alternative… read more

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Submitted on 16 November 2015

The Hubble eXtreme Deep Field

Figure 1. The Hubble eXtreme Deep Field (XDF).

This image is the Hubble eXtreme Deep Field (XDF). It was created by combining many images taken between 2002 and 2012 by the Hubble Space Telescope. The total exposure time was 22.5 days (almost 2 million seconds), and the image contains… read more

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Submitted on 8 June 2015

Are there Infinitely Many Twin Primes?

Recently, there has been much progress towards proving the twin prime conjecture, one of the great open questions in number theory. There are infinitely many primes, a fact that was already known by the ancient Greek. A short proof, although not the… read more

Submitted on 25 May 2015

If You See a Fireball, Please Report It

Figure 2. Sightings of a single fireball that appeared on 2015-03-15.

If you have ever seen a fireball, which is an unusually bright meteor (or shooting star), then you know that they can be very impressive. But did you also know that reporting your observation can help to further science? Fireballs, and meteors in general, are like… read more

Submitted on 21 March 2015

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