Sentence examples for major planet from inspiring English sources

But then, out of the blue, the same astronomer whose original research prompted the demotion of Pluto announces that he's discovered evidence of Planet Nine, a major planet somewhere between the size of Earth and Neptune, that could take the place of Pluto – the original ninth planet – in the known planetary system.

Choice of a suitably fiddled threshold (say, 1,000km) would then make Pluto, but not Ceres, a major planet.

When the Voyager 2 probe flew past Neptune and its moons in August 1989, every known major planet had been explored by spacecraft.

So how can the International Astronomical Union (IAU), which decides on such matters, square Pluto's historical status as a major planet with all the modern evidence to the contrary?An astronomical fudgeOne approach might be to say that in order to be considered a major planet, a body needs to be larger than a certain diameter.

Pluto, discovered in 1930 after a search for a planet predicted to lie beyond Neptune, was considered a major planet until 2006, when it was redesignated a dwarf planet by the International Astronomical Union.

And whilst Pluto is large enough to have collapsed under its own gravity into a spherical shape, that, too, is not a sufficient claim to full planethood, or Ceres would also be a major planet.

The orbits of all the major planets, including Earth's, lie well within the heliopause.

In addition to Earth, five major planets (Mercury, Venus, Mars, Jupiter, and Saturn) have been known from ancient times.

All asteroids orbit the Sun in elliptical orbits and move in the same direction as the major planets.

In 2006 the International Astronomical Union demoted Pluto from being one of the nine major planets to one of the tens of thousands of minor planets.

Minor planets and asteroids are among the smallest members of the solar system, along with comets and some of the moons of the major planets.