This Week's Amazing Sky

Looking for Planet Nine

Bob Berman

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Planets Orbiting

Find out more about the so-called discovery of Planet Nine and win brand-new binoculars in our Name That Planet Contest!

Name That Planet Contest

Win New Celestron Binoculars! For FIVE lucky winners!


There’s been a lot of news about a possible new planet in our solar system. IF this new planet is discovered, it will need a name. So, let’s have fun naming it! Legally, anyone can name anything. (Which official agency will accept a given name is another story!)

If it’s catchy enough, it has a good chance of gaining global reputation, and, who knows, official recognition.

So go ahead—name the new planet.

Enter to Win Here!


The Prize

The Almanc is giving away FIVE Celestron G2 Upclose 8x40 Binoculars* for spying the night sky. View the Moon, nearby planets, and the Milky Way Galaxy!

Deadline: The deadline is March 1, 2106. Winners will be announced on this page, in our Almanac Companion newsletters, and on our Facebook page.

What Is Planet Nine?

Everyone likes planets.  They’re familiar.  We live on one.  Ask your Aunt Lucie to name a few of the solar system’s Moons or to recite five stars, and you’ll probably get a blank stare.  But ask her to name all the planets, and no problem.

It’s been a while since anyone found a new planet in our solar system.  The world was amazed at the discovery of Uranus in 1781 and Neptune in 1846. 

Pluto’s discovery in 1930 also generated global excitement. It didn’t hurt when Walt Disney named his only nonspeaking character after it a year later. (The dog had been “Rover” in an earlier cartoon). 

But as we all know, Pluto was demoted in 2006—officially designated a “dwarf” like so many other Disney characters. See definition of a dwarf planet.

Image: NASA. Dwarf planets Pluto and Eris oribiting through the Kupiter Belt, beyond Neptune.

We’re ready for a new one.  And we may get it.  Researchers recently discovered that the weird orbits of six very distant icy objects can be explained if they’re being tugged by a huge unseen world far away.

IF a planet is discovered, it would have to be several times larger than Earth.  And achingly distant.

If Earth’s distance from the Sun is 1 astronomical unit or AU, and Pluto averages 40 AUs from the Sun, a new planet would have to have a highly eccentric non-round orbit that comes as close as 200 and goes as far away as at least 500 AUs. That’s way out there.

Image: NASA. If Planet X exists its orbit might exist in the frozen Kuiper Belt region of our outer solar system, counterbalancing the orbits of the other Kuiper objects with its gravitational pull.

Hypothetically, it would be at its farthest away right now. That would make it incredibly dim, something like magnitude 22, or a thousand times fainter than Pluto. Tough to find.  So far, it’s being called Planet Nine.  No doubt, if it exists, it will be named after some Roman god, to match the other planets.

Image: The imaginary Planet Nine.

At a time when all the naked-eye planets are visible at the same time, it’s exciting to think that our solar system might have a large, mysterious new member.  Aren’t we all kind of rooting for Planet Nine?

*Now, if you don’t happen to win the Name That Planet Contest, I highly recommend the Celestron G2 model. I’ve personally tested the G2, and they’re impressive, with wonderful images for the money. Amazing, really. I’ve tested for sharpness, color fringing, edge of field focus, and whether or not blacks were deep as opposed to milky. Using them gave a “being there” feeling which is rare at this reasonable price point. Good luck!


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