Sent in by Gary, and also by Robert – see for example https://phys.org/news/2021-05-heavy-metal-vapors-unexpectedly-comets.html … and www.dailymail.co.uk/sciencetech/article-9592913/ … a new study by a Belgian team using data from the European Southern Observatory, have shown that iron and nickel exist in the atmospheres of comets – throughout the solar system. Even those far from the Sun and assumed to be very cold and inhospitable. A similar study by a Polish team report nickel in the upper atmosphere of comet 21/Burisov [thought to be an interstellar interloper]. Metals are usually associated with hot environments rather than in comets originating in the cold nether regions of the far solar system. We are told, it was a big surprise. Iron and nickel atoms have been found in the atmosphere of some 20 coemts. Astronomers are said to know heavy metals exist in comet interiors but did not think their properties would sublimate [become gaseous]. Hence, we are looking at mainstream being forced to revise once again, the beauty of the space age and all those missions [and telescopes]. Sublimation does not seem to be as simple as thought. What else is going on. Why do comets sublimate long before they get anywhere near the Sun?