In 1761, Russian polymath Mikhail Lomonosov discovered that Venus has an atmosphere. Its atmosphere is much denser and hotter than that of Earth. The temperature and pressure at the surface are 740 K (467°C, 872°F) and 93 bar, respectively. The Venusian atmosphere supports opaque clouds made of sulfuric acid, making optical observation of the surface impossible. Information about the topography of Venus has been obtained exclusively by radar imaging. The main atmospheric gases on Venus are carbon dioxide and nitrogen. Other chemical compounds are present only in trace amounts.