article_snippet: For Earth-bound optical telescopes, the surface of Venus is shrouded beneath thick clouds made mostly of carbon dioxide.
article_snippet: Venus is slightly smaller than Earth but has a similar mass.
article_snippet: It is the second closest planet to the sun at a distance of about 67 million miles (108 million kilometres), and takes about 225 days to orbit the sun.
article_snippet: One day on Venus lasts as long as 243 Earth days.
article_snippet: One day on Venus thick and toxic atmosphere is made up mostly of carbon dioxide and nitrogen, with clouds of sulphuric acid droplets.
article_snippet: One day on Venus's believed that One day on Venus atmosphere contributed to a runaway greenhouse effect that made the planet inhospitable.