join-tab.png
close-x.png

Help Shape the Future of Space Exploration

Join The Planetary Society Now  arrow.png

enews-tab.png
close-x.png

Join our eNewsletter for updates & action alerts

    Please leave this field empty
Explore

Pluto's Neighborhood

Pluto shares its part of the solar system with more than 1500 other icy worlds that we know about and countless ones that have, so far, evaded our detection. The shapes of their orbits are clues to a tumultuous history that hinges on the motion of Neptune.

Neptune formed in a location much closer to the Sun than it is now, but migrated outward from the Sun over time. As it moved, it herded and scattered the objects in the Kuiper belt. Neptune trapped some of them -- like Pluto, Orcus, Haumea, and Makemake -- in orbital resonances, locked in motion synchronized to the giant planet's. Others -- like Eris and 2007 OR10 -- it scattered to extremely elliptical or highly inclined orbits. Others, it tossed inward into the solar system, to bombard the other planets or to orbit among them as Trojans, centaurs, or irregular moons. And one -- Triton -- it captured as its own moon.  There is a belt of objects so far unaffected by Neptune's motion -- like Quaoar -- called the cold classical belt. Finally, there is Sedna, whose orbit is so distant from Neptune's that it may represent the first-discovered member of a wholly unexplored part of the solar system.

Eris, Orcus, Haumea, Makemake, 2007 OR10, Quaoar, Sedna, and Triton are the largest worlds in Pluto's neighborhood, and the little that we have learned to far about their surfaces proves that each is unique. More than a hundred others are probably large enough to be called "dwarf planets." And there may yet be even larger, Mars or even Earth-sized worlds beyond these, awaiting discovery.

There is only one mission that has ever been launched to study Pluto: New Horizons.

Recent Blog Articles About Pluto and Its Neighbors

Where are the big Kuiper belt objects?

Posted by Emily Lakdawalla on 2012/02/16 05:35 CST | 6 comments

Earlier today I wrote a post about how to calculate the position of a body in space from its orbital elements. I'm trying to get a big-picture view of what's going on in trans-Neptunian space.

Read More »

When will New Horizons have better views of Pluto than Hubble does?

Posted by Emily Lakdawalla on 2013/02/18 04:22 CST | 7 comments

Last week, I posted an explainer on why Hubble's images of galaxies show so much more detail than its images of Pluto. Then I set you all a homework problem: when will New Horizons be able to see Pluto better than Hubble does? Here's the answer.

Read More »

Visiting the San Diego SpaceUp Unconference

Posted by Mat Kaplan on 2012/02/14 08:38 CST

Emily Lakdawalla and I drove down to the 3rd annual San Diego SpaceUp Unconference on February 4. We had great fun hanging out with the other space geeks.

Read More »

The Discovery of a Planet, Part 6: From Pluto to Sedna

Posted by Amir Alexander on 2005/02/17 11:00 CST

74 years after Clyde Tombaugh discovered Pluto as a faint dot on a pair of photographic plates, a modern group of astronomers made another remarkable discovery. On March 15, 2004, Michael Brown of Caltech, Chad Trujillo of the Gemini Observatory, and David Rabinowitz of Yale announced the discovery of Sedna – the furthest object ever detected in the Solar System.

Read More »

The Discovery of a Planet, Part 5: The Aftermath

Posted by Amir Alexander on 2005/02/16 11:00 CST

The discovery of Planet X was announced to the world on March 13, 1930, which marked the anniversary of William Herschel’s discovery of Uranus in 1781 as well as Percival Lowell’s birthday. The observatory’s communiqué emphasized that the discovery was no coincidence, but the vindication of Lowell’s predictions made years before.

Read More »

The Discovery of a Planet, Part 4: Clyde's Search

Posted by Amir Alexander on 2005/02/15 11:00 CST

Since his teenage years Clyde Tombaugh had been an avid amateur astronomer and a gifted telescope builder. Based on instructions contained in an article from a boy’s Sunday school paper, he built a series of telescopes of increasing power and quality on the family farm.

Read More »

The Discovery of a Planet, Part 3: Planet X

Posted by Amir Alexander on 2005/02/14 11:00 CST

The discovery of Neptune accounted for nearly all the unexplained motions of the outer planets of the Solar System. Nevertheless, several astronomers insisted that some unexplained residual motions remained, pointing to the presence of a ninth planet beyond the orbit of Neptune.

Read More »

The Discovery of a Planet, Part 2: Out of the Six-Planet World

Posted by Amir Alexander on 2005/02/13 11:00 CST

Since humans first set their eyes to the stars, they noticed that a few of these bright objects behaved differently from the others. Whereas all the stars moved together, revolving around the Earth once every 24 hours, five appeared to move within the firmament among the other stars. Accordingly, they were named “planets,” meaning “wanderers” in Greek.

Read More »

The Discovery of a Planet, Part 1: The Blinking Image

Posted by Amir Alexander on 2005/02/12 11:00 CST

February 18, 1930, was a cloudy day at the Lowell Observatory, on top of Mars Hill in Flagstaff, Arizona. 22 year old Clyde Tombaugh was hard at work, peering through the lens of an ancient-looking brass-colored device. The instrument, known as a “blink comparator,” mounted two large photographic plates.

Read More »

South of the Border

Posted by Meg Schwamb on 2011/05/25 08:30 CDT

The last decade has seen an explosion in our understanding of the solar system with the discovery of the largest Kuiper belt objects (KBOs) of comparable size to Pluto.

Read More »

Salacia: As big as Ceres, but much farther away

Posted by Emily Lakdawalla on 2012/06/26 12:27 CDT | 10 comments

A newly published paper shows trans-Neptunian object Salacia to be unexpectedly large; it's somewhere around the tenth largest known thing beyond Neptune. It has a companion one-third its size, making it appear similar to Orcus and Vanth.

Read More »

Pluto: The Discovery of a Planet

Posted by Amir Alexander on 2005/02/18 11:00 CST

To mark the 75th anniversary of the discovery of the planet Pluto, The Planetary Society presents to its readers the remarkable story of the discovery.

Read More »

Pluto's seasons and what New Horizons may find when it passes by

Posted by Emily Lakdawalla on 2013/05/02 03:42 CDT | 2 comments

New Horizons might see a Pluto with a northern polar cap, a southern polar cap, or both caps, according to work by Leslie Young.

Read More »

New Horizons workshop, day 1: Chemistry & climate on Pluto & other cold places

Posted by Emily Lakdawalla on 2011/08/30 11:27 CDT

New Horizons workshop, day 1: Chemistry & climate on Pluto & other cold places

Read More »

New Horizons Day 2: Tectonic features on icy worlds

Posted by Emily Lakdawalla on 2011/09/09 01:05 CDT

New Horizons Day 2: Tectonic features on icy worlds

Read More »

New Horizons Day 2: Liquids on Pluto's surface?

Posted by Emily Lakdawalla on 2011/09/13 01:27 CDT

Jeff Moore's presentation was cool because of the discussion it stimulated. He considered what exogenic processes might be operating on Pluto's surface. What's an exogenic process? It's something that modifies the shape of the surface from the outside, and doesn't require the body to be geologically active inside.

Read More »

New Contest: Name the Moons of Pluto!

Posted by Emily Lakdawalla on 2013/02/11 11:41 CST | 15 comments

The discoverers of Pluto's fourth and fifth moons are inviting the public to vote on (and write in candidates for) their formal names. Voting closes in two weeks.

Read More »

Kuiper Belt Objects Submitted to Minor Planet Center

Posted by Alex Parker on 2013/01/25 03:30 CST | 2 comments

Recently, several of the Kuiper Belt Objects our team has discovered while searching for New Horizons post-Pluto flyby candidates have been submitted to the Minor Planet Center (the organization responsible for designating minor bodies in the solar system) and their orbital information is now in the public domain.

Read More »

Full Free Intro Astronomy Class Now Online

Posted by Bruce Betts on 2012/05/22 02:57 CDT

Bruce Betts' complete CSUDH Intro Astronomy and Planetary Science class is now available online. Find out how to access it, and go behind the scenes.

Read More »

Ever Plan Ahead? How About Six Years Ahead?

Posted by Alan Stern on 2009/05/19 07:05 CDT

Despite still being more than six years and just over 18 Astronomical Units from the Pluto system, the project team for New Horizons is conducting the second and final portion of our Pluto Encounter Preliminary Design Review (EPDR) tomorrow and the next day.

Read More »

Facebook Twitter Email RSS AddThis

Support our Asteroid Hunters

They are Watching the Skies for You!

Our researchers, worldwide, do absolutely critical work.

Asteroid 2012DA14 was a close one.
It missed us. But there are more out there.

I want to help

Save Our Science

Become a Space Advocate

We are at a crucial turning point in the history of planetary exploration.

You can help.

Together, we can get the budget we need to support our planetary endeavors and Save our Science.

We've done it before. Let's do it again.

I want to help!

Fly to an Asteroid!

Send your name and message on Hayabusa-2.

Send your name

Join the New Millennium Committee

Let’s invent the future together!

Become a Member

Connect With Us

Facebook! Twitter! Google+ and more…
Continue the conversation with our online community!

facebook.png twitter.png rss.png youtube.png flickr.png googleplus.png