The number of planets that orbit the sun depends on what you mean by “planet,” and that’s not so easy to define ...

And being so close to the sun, it will be difficult to see. With eight planets in our solar system, they all have some very interesting traits. Here's a quick look at the planets aligning on this ...

Mercury will join them in late February. NASA / JPL-Caltech The eight planets in our solar system all orbit the sun in roughly the same flat plane, known as the ecliptic—but they move at ...

While the planets won’t be perfectly aligned, their placement will follow the orbital plane of our solar system. Which planets are parading in January and February? The January planetary ...

Scientists believe that two asteroids might be fragments of long-lost "planetary embryos" from the early solar system.