First Indications of Geological Activity on Triton

Abstract

In his News of the Week article “Neptune's icy cold satellite comes to life” (15 Oct., p. [383][1]), Richard A. Kerr reports on new work that has led to a “startling” realization that Triton “is still showing signs of [geological] life,” and he mentions observations hinting that Triton's “geological activity has made itself evident in recent years.” The article also has quotes from scientists talking about “real surprises” and that the implication of the new work is that Triton “probably still is active.” However, the article does not mention the discovery from the Voyager 2 mission 10 years ago of active smoking vents on Triton, which led the Voyager team to conclude (Reports, 15 Dec. 1989, p. 1417) that sparsely cratered Triton has “a geologically young surface…and at least two geyser-plumes.” What appears to be new in the work Kerr reports about is not the youthful surface or the geologic activity, but interesting constraints on the resurfacing parameters, global spectral changes, and impactor environment of Triton. # Response {#article-title-2} As Hartmann notes, the Voyager team concluded that Triton has “a geologically young surface,” but, at the time, geologically young meant that the average age of the surface was perhaps 1 billion years, and even the youngest surfaces could have been half a billion years old (p. 1448 and Table 5 in Reports, 15 Dec. 1989, p. 1422). The recent drop in perceived average surface age to 100 million years and perhaps much lower has let some planetary scientists conclude that geological activity driven by internal heat (not solar-driven geysers) is resurfacing Triton. [1]: /lookup/doi/10.1126/science.286.5439.383