Did Lomonosov see the Venusian atmosphere?

Abstract

Vladimir Shiltsev (Physics Today, February 2012, page 40) properly credits Mikhail Lomonosov with a wide range of scientific achievements. But we have been corresponding with Shiltsev for some months about our realization1 that Lomonosov did not discover the atmosphere of Venus. One of us (Pasachoff) analyzed spacecraft observations of the Cytherean atmosphere at the 2004 transit of Venus,2 and we realized that what Lomonosov reported did not match actual atmospheric observations. NASA’s Transition Region and Coronal Explorer spacecraft detected Venus’s atmosphere for about 20 minutes as Venus’s silhouette entered the Sun’s limb, and again for the first 20 minutes of its exit from the solar disk. Lomonosov saw only a bulge of light—shown in figure 4a of Shiltsev’s article—and a brief flash of light. We think that what he saw was an artifact of his relatively primitive and small telescope rather than the aureole that is sunlight refracted toward Earth by Venus’s atmosphere. Our conclusions were reinforced by observations made during the 2012 transit of Venus.