Dallas shows an orrery – a mechanical model of the solar system. Before the 17th century most people believed in a geocentric model of the solar system. Dallas explains the geocentric model and ...

with the ancient Greek scholar Ptolemy formalizing this "geocentric" model in 150 B.C. Then, in 1543, Nicolaus Copernicus described a heliocentric (sun-centered) model of the solar system ...

In the coming decades, Voyager 1 will be joined by other craft sent along solar ... Solar System. To put the challenge of interstellar travel in perspective, let’s build a scale model of our ...

An Egyptian astronomer called Ptolemy (AD100-168) described one of the earliest ideas for how the Solar System is structured. Ptolemy’s model and many earlier ideas of the Solar System had the ...

This model of solar system formation is known as the nebular hypothesis. The solar system is structured in a roughly flat plane called the ecliptic, with most planets orbiting the sun in the same ...

According to the team, the gravitational pull of our solar system's planets and passing stars do not have much of an effect on the Oort Cloud. The team's new model was plotted from "a viewpoint of ...

The Oort cloud — the mysterious shell of icy objects at the edge of the solar system — might sport a pair of spiral arms that ...