# The Gömböc, the Sphere and the Pebbles of Mars

Everyone thought it was just a mathematical curiosity, but when the Gömböc turned out to be involved in the explanation of the shape of pebbles on Mars, both mathematicians and geophysicists had to think again. Lecture by Professor Gabor Domokos, Budapest University of Technology and Engineering.

Foto: NASA / Domokos

The mathematical object called the *Gömböc*, the mathematical equivalent of a weeble toy, was first described in 2006 in an article by speaker Domokos and his colleague Varkonyi in the renowned journal Mathematical Intelligencer [1]. The Gömböc was their constructive proof of a conjecture by the great mathematician Arnol'd, whom in 1995 claimed that convex, homogeneous three dimensional objects with only two static balance points exist.

The Gömböc is an intricate object, and it appeared at first to be yet another mathematical curiosity. Therefore, it was a great surprise when images from Mars in 2012 showed rounded pebbles that could be explained by the Gömböc [2]! Even though it at first seemed like a far-fetched idea to link the Gömböc to pebbles on Mars, the laboratory- and field data has complied with the theoretical model, where the Gömböc is* the* key [3].

The Gömböc was on the list of the 70 most interesting discoveries in The New York Times in 2007, it has been on BBC'ss "QI"-talkshow, and it was the main exhibition at the Hungarian pavillion during World Expo in Shanghai in 2010.

Don't miss this talk, that ties mathematical objects to observations on Mars and models in geophysics! Hear the amazing story from one of the men behind it, Professor and mathematician Gabor Domokos from Budapest University of Technology and Engineering.

**References:**

[1] P.L. Varkonyi and G. Domokos: Mono-monostatic bodies: The answer to Arnold’s question. The Mathematical Intelligencer, 28(4) pp 34-38. (2006)

[2] R.M.E. William et al.: Martian fluvial conglomerates at Gale crater. Science 340 (6136) 1068-1072

[3] T. Szabó, G. Domokos, J.P. Grotzinger & D.J. Jerolmack: Reconstructing the transport history of pebbles on Mars. Nature Communications 6, Article number: 8366 (2015) doi:10.1038/ncomms9366