There are many planetary systems like ours in the universe, with planets orbiting a host star Our planetary system is called “the solar system” because we use the word “solar” to describe things related to our star, after the latin word for sun, solis. The star nearest to the planet earth is the sun The sun’s diameter is 1.4 million kilometers and its distance from earth is 150 million kilometers But what do numbers that big really mean To get an idea of size, use a grapefruit to represent the sun
Set it down and walk a dozen steps away. Lesson overview ot only the physical sizes of the sun an planets, but also the distances between them Planets are tiny worlds in a vast space In october 2001, the voyage scale model solar system opened in washington, dc, displaying a one t ten billion scale of the sizes of the sun and planets, and the distances between them Scientists think it's likely some other force is responsible, such as an undiscovered giant planet (in a very distant orbit), the gravity of passing stars, or gravitational perturbations as the kuiper belt was forming long ago. The sun formed from a swirling disk of gas and dust, billions of years ago
Most of this ancient space rubble can be found orbiting our sun between mars and jupiter within the main asteroid belt Halley's orbit period is, on average, 76 earth years This corresponds to an orbital circumference around the sun of about 7.6 billion miles (12.2 billion kilometers) The period varies from appearance to appearance because of the gravitational effects of the planets.
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