UK chemistry teacher Andy Brunning has put together a very sharp looking infographic that explores the atmospheric compositions of our solar system's planets. When you look at it this way, it's pretty obvious why visiting other worlds is going to be a dangerous proposition.
Like a lab experiment, different chemical elements give rise to particular effects. For example, and as Brunning writes:
Venus is similar to Earth in several respects: its density, size, mass, and volume are all comparable. The atmosphere is where the similarities end, however. The atmospheric pressure is around 92 times that found at sea level on Earth, with the main gas being carbon dioxide - the result of previous volcanic eruptions on the planet's surface. Higher in the atmosphere, the planet also has clouds which are a mixture of sulfur dioxide and sulfuric acid. There is a thick layer of carbon monoxide below these clouds, which subjects the surface of the planet to an intense greenhouse effect. Surface temperature on Venus is around 480˚C – much too hot to sustain life as we know it.
Whereas on Mars:
The atmosphere of Mars is, much like Venus, composed primarily of carbon dioxide. Having mentioned the extreme greenhouse effect present on Venus as a consequence of the high carbon dioxide levels, it may seem puzzling that the surface temperature of Mars reaches a maximum of 35˚C. This is because the atmosphere of Mars is significantly thinner than that of Venus, so although the proportion of carbon dioxide is comparable, the actual concentration is much lower. The dustiness of the atmosphere gives Mars its characteristic appearance.
Much more at Brunning's original blog post, including a special graphic for Pluto.
Via Universe Today.