THE biggest smoke ring ever seen has been identified in an image from the Hubble Space Telescope.
Smoke rings are a form of soliton, a type of wave discovered in 1834 by John Scott Russell, a Scottish engineer. While riding on horseback along the Union Canal at Glasgow, Russell saw a canal boat stop and noticed that the boat鈥檚 bow wave maintained its shape and energy for a long distance. The phenomenon was largely forgotten until the 1960s when the American physicist Martin Kruskal rediscovered Russell鈥檚 solitary wave and called it a 鈥渟oliton鈥�.
The cosmic smoke ring is a bizarre galaxy called Hoag鈥檚 Object () first seen in 1950. Like a giant wheel without spokes, it consists of a bright ring of hot blue stars surrounding a nucleus of yellow stars.
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According to George Pronko of the Institute for High Energy Physics in Protvino in Russia, Hoag鈥檚 Object is similar to a three-dimensional soliton that usually forms in a gas, but consists instead of stars moving under the influence of gravity. 鈥淭he simplest example of such a soliton is a tornado,鈥� he says.
And if you think that finding one such galaxy is amazing, Pronko says to look in the background of the image, just above the core 鈥� it鈥檚 another soliton galaxy.
