The goal of comparative planetology is to discover the commonalities among the ways that planets form and evolve. The planets that have been discovered differ substantially from one another when viewed as individual, isolated systems, but astronomers believe that there are universal principles that apply to them. By comparing the properties of different planets, scientists hope to spot these universal principles and gain greater insights.Know More
There are many factors that separate each planet in Earth's solar system from one another, and that is only within one solar system. Scientists have discovered many planets orbiting other stars, some quite different from the ones near Earth. The biggest division in comparative planetology is between the rocky planets, like Mercury, Venus, Earth and Mars, and the gas giants, Jupiter, Saturn, Uranus and Neptune. In comparative planetology, scientists look for commonalities both within and between these major groups.
Even within this solar system, comparative planetology is in its infancy. The ability to send probes beneath the outer atmospheres of other planets is relatively new and still extremely limited. Even relatively close planets with known solid surfaces, like Venus, contain conditions that are incredibly hostile to most equipment. Even worse are the gas giants, with their immense gravity, thick atmospheres and extreme weather.Learn More
Mercury, Venus, Mars, Jupiter and Saturn have been known since prehistory. According to NASA, only two non-dwarf planets in the solar system have official discoverers and dates of discovery. These are Uranus and Neptune. Other worlds, such as moons and dwarf planets, were also discovered after the invention of telescopes.Full Answer >
The eight described planets all orbit the Sun at different distances; Mercury is the closest planet to the sun, followed by Venus, then Earth, Mars, Jupiter, Saturn, Uranus and Neptune. The distances of the planets are normally measured in kilometers, because scientists use metric measurements. However, scientists also use a unit called an “astronomical unit,” which is equal to the distance between Earth and the sun.Full Answer >
All four of the gas giant planets in the solar system have rings. These are Saturn, Jupiter, Neptune and Uranus. The rings of Saturn are so prominent that they can be seen with binoculars on clear nights. The rings of the other planets are much more faint.Full Answer >
The next time any of the planets will align with each other is predicted to be in October 2015. The last time at least three planets aligned was in 2011.Full Answer >