3. The Milky Way is the galaxy which is the home of our Solar System together with at least 200 billion other stars. The central region of the Milky Way, as those of many other galaxies, is more densely crowded with stars than the outer region, and contains a massive central object.

4. The Sun is the most prominent feature in our solar system. It is the largest object and contains approximately 98% of the total solar system mass. Solar energy passes through this region on its way out from the center of the Sun.

5. As such, it circles the sun faster than all the other planets. Mercury is the smallest planet it is only slightly larger than Earth's moon. Amazing, as close to the sun as Mercury is, ice may exist in its crater. Mercury speeds around the sun every 88 Earth days, traveling through space at nearly 112,000 miles per hour.

6. Venus is the second planet from the Sun and the sixth largest. Venus’ orbit is the most nearly circular of that of any planet, with an eccentricity of less than 1%. There are strong (350 kph) winds at the cloud tops but winds at the surface are very slow, no more than a few kilometers per hour.

7. Earth, our home planet, is the only planet in our solar system known to harbor life. Some facts are well known. For instance, Earth is the third planet from the sun and the fifth largest in the solar system. Earth's diameter is just a few hundred kilometers larger than that of Venus.

8. Most rocks on the surface of the Moon seem to be between 4.6 and 3 billion years old. The moon is 4.5 million years old. Member of our solar system, satellite of earth.

9. The planet probably got this name due to its red color. Mars is sometimes referred to as the Red Planet. The southern hemisphere of Mars is predominantly ancient cratered highlands somewhat similar to the moon.

10. Jupiter is the fifth planet from the Sun and by far the largest. Jupiter is more than twice as massive as all the other planets combined (the mass of Jupiter is 318 times that of Earth). Jupiter probably has a core of rocky material amounting to something like 10 to 15 Earth-masses.

11. Saturn is the sixth planet from the Sun and the second largest. Saturn is the only planet you can see without a telescope at night or day.

12. Uranus is the seventh planet from the sun and the third largest. Most of the planets spin on an axis nearly perpendicular to the plane of the ecliptic but Uranus' axis is almost parallel to the ecliptic. Largest (by diameter). Uranus is larger in diameter but smaller in mass than Neptune.

13. Neptune is the eighth planet from the sun the fourth largest (by diameter). Neptune is smaller in diameter but larger in mass than Uranus. Like Jupiter and Saturn, Neptune has an internal heat source -- it radiates more than twice as much energy as it receives from the sun.

14. The world was introduced to dwarf planets in 2006, when petite Pluto was stripped of its planet status and reclassified as a dwarf planet. A dwarf planet hasn't "cleared the neighborhood" around its orbit, which means it has not become gravitationally dominant and it shares its orbital space with other bodies of a similar size.

15. No one knows how many stars exist, but the number would be staggering. Our universe likely contains more than 100 billion galaxies, and each of those galaxies may have more than 100 billion stars.