Geology of solar terrestrial planets Earth, and Mars) have substantial atmospheres; all have impact craters and tectonic surface features such as rift valleys and volcanoes. The term "inner planet" should not be confused with "inferior planet", which refers to any planet that is closer to the Sun than the observer's planet is, but usually refers to Mercury and Venus. The Solar System is believed to have formed according to the nebular hypothesis, first proposed in 1755 by Immanuel Kant and independently formulated by Pierre-Simon Laplace. This theory holds that 4.6 billion years ago the Solar System formed from the gravitational collapse of a giant molecular
Akaa Solar System Scale Model Model was built in 2017 by amateur astronomer Kari-Pekka Arola. A walking tour of Akaa Solar System Scale Model starts from the Sun and all the planets are located northbound from the Sun. The walking route goes through the center of Toijala and towards the port of Toijala, where the furthest dwarf planet in the scale model, Eris is located. All the planets and most notable dwarf planets are included in the scale model. The current location (140 AU) of Voyager 1 -spacecraft in relation to our solar system is also presented in the scale model (as the most distant