University of Arizona, Tucson | 2019 Sep 24
Volcanism has always intrigued humanity. Less than 50 years ago, scientists discovered cryovolcanism – ice volcanoes on other worlds. Now, researchers may have identified volcanoes of molten metal.
The metallic asteroid Psyche has mystified scientists because it is less dense than it should be. Now, a new theory by researchers including scientists at the University of Arizona, could explain Psyche’s low density and metallic surface.
Psyche, the largest known metallic asteroid in the solar system, is located in the asteroid belt between Mars and Jupiter. Psyche appears to be composed largely of iron and nickel, rather than rocky rubble, like most asteroids, yet its density is estimated to be only about half that of an iron meteorite.
Metal-rich asteroids are thought to have formed when primordial planetesimals collided, stripping away much of the outer material and leaving behind the inner metallic cores, which then cooled and solidified from the outside in. During this cooling process, an alloy of residual melted pockets of iron, nickel and lighter elements like sulfur, might have flowed to the surface through fluid-filled cracks called dikes, coating a topmost, rocky layer. ...
Ferrovolcanism on Metal Worlds and the Origin of Pallasites
~ Brandon C. Johnson, Michael M. Sori, Alexander J. Evans
- Nature Astronomy (online 16 Sep 2019) DOI: 10.1038/s41550-019-0885-x
- arXiv.org > astro-ph > arXiv:1909.07451 > 16 Sep 2019