Solar System in fiction close to the Sun and its surface was exposed to extremes of temperature. The asteroids were too tiny and airless. By the early 20th century, prospects for life in the Solar System focused on Venus, the larger moons of Jupiter and Saturn, and especially Mars. With the onset of the Space Age, planetary probes cast increasing doubt on the likelihood of extraterrestrial life in the Solar System, at least life of any magnitude greater than organisms such as bacteria. By the mid-1960s, it was firmly established that life could have no foothold on the hostile surfaces of Mercury or Venus,
Wonders of the Solar System greenhouse planet Venus, a planet often referred to as "Earth's twin", and compares it to the vulcan geology of the Deccan Plateau. An example of Earth's interconnectivity with the solar system reveals that Jupiter's gravitational effect could potentially send an asteroid through the Asteroid Belt on a collision course with Earth, as evidenced by Meteor Crater. The same gravitational force is also shown to give the Jovian moon Io geological life (given the absence of meteor impact evidence there) as paralleled by the volcanism of Erta Ale in Ethiopia. All in all, with the universal laws of physics at play