Astrophoto Friday - Eris Discovery

Astrophoto Friday returns today with an animated gif of the discovery photos of dwarf planet Eris. Can you spot it?

Eris is the moving object near the left-hand side of the image.

The discovery of Eris was made by Caltech's Mike Brown and his partners. They first imaged this distant world of the Kuiper Belt using Palomar's 48-inch Samuel Oschin Telescope. The discovery rocked the astronomical world and helped to bump Pluto out of its planetary status. Both Pluto, Eris and some other worlds discovered by Mike at Palomar share a new category, that of dwarf planet.

The discovery and the turmoil that followed is the subject of a new book by Mike Brown which will be available on Tuesday, December 7 (both Gerard Kuiper’s birthday and Pearl Harbor day).


Of course, Palomar Observatory's gift shop will be stocking the book - which happens to make a great gift.

Palomar Observatory on TV this week

Look for Caltech's Mike Brown and Palomar Observatory to be featured in this Thursday's episode of Known Universe on the National Geographic Channel. Check your local listings.

Check out the preview embedded below (and please accept our apologies for the commercial that runs first).




Filming at the Hale Telescope was done last summer. In the episode Mike Brown talks about dwarf planet Eris, a member of Kuiper Belt, discovered by him with images taken with Palomar's 48-inch Samuel Oschin Telescope.

Keeping Up With the Outer Solar System

In late March I mentioned that Caltech's Mike Brown was looking for a name for the satellite of Pluto. He's picked one so be sure to visit Mike Brown's Planets to find out what name was chosen and why.
Speaking of Mike Brown, he has been looking for more objects like Sedna but none have been found yet and that is telling about the solar system. He has also published some work on Haumea and its satellites.

The Great Planet Debate

It is a huge understatement to say that there has been some controversy about how astronomers have handled the status of Pluto and the definition of a planet in recent years. The 2006 decision by the International Astronomical Union that defined a planet and created the new term "dwarf planet" confused and angered some members of the general public. Many astronomers were not pleased either.

It has been two years and the controversy has not gone away. It is manifesting itself this week in the form of The Great Planet Debate. Astronomers Mark Sykes, director of the Planetary Science Institute, and Neil deGrasse Tyson, director of the American Museum of Natural History, will square off on Thursday, August 14 from 1:30 to 2:45 p.m. (PDT) in a debate that will be carried live over the Internet. To watch the event you must register online in advance.

Sykes is proposing that our solar system has 13 planets (Mercury, Venus, Earth, Mars, Ceres, Jupiter, Saturn, Uranus, Neptune, Pluto, Charon, Eris, and Makemake), while Tyson, as you might imagine has a different idea (just 8 planets like the IAU put forward). No matter which side of the debate you come in on, this is an interesting time where people can see how the scientific process moves along and how new discoveries can make us re-think our ideas.

The Biggest Worlds of the Kuiper Belt

As reported earlier the I.A.U has decided that Makemake is joining Eris and Pluto as Dwarf Planets of the Kuiper Belt. Here's a look at the biggest known objects of the Kuiper Belt. Eris, Makemake, 2003 EL61, Sedna, Orcus, and Quaoar were all discovered here at Palomar. Six out of eight isn't bad.

The Punisher

Just a short post today. Four years ago today 90482 Orcus was discovered using the Palomar 48-inch Samuel Oschin Telescope. Orcus (aka 2004 DW) is a Kuiper Belt Object with a 247-year orbit. In mythology Orcus was the punisher of broken oaths.

Here's the discovery images:


More information is available from Wikipedia and Chad Trujillo's 2004 DW page.

World of Strife

Ok, just the other day I told you something about Eris, but today, January 5th, is the third anniversary of its discovery so I'm posting a bit about that event. Mike Brown (Caltech), Chad Trujillo (Gemini Observatory), and David Rabinowitz (Yale University) were and still are running a search for slow moving (i.e. distant) objects in the outer solar system. The search makes use of the 161-megapixel QUEST camera on the Palomar Observatory's 48-inch Samuel Oschin Telescope. Data gets transferred from Palomar to Pasadena via the High Performance Wireless Research and Education Network (HPWREN).

Dr. Brown and his team actually collected the data for the discovery on October 21, 2003, well over a year before the big find. They fine tuned their software, which culls through the vast amount of data for moving objects. They were in the midst of a reanalysis of the data when this bright, slow moving object turned up.

Can you spot it in these discovery images? It is the moving object just above center on the left side of the image.

The world was officially called 2003UB313, but it was given the nickname of "Xena" - A nice name starting with "X" as in "planet X" or even the Roman numeral "X" for 10, as in the tenth planet.

An official name couldn't come until it status as a planet, Kuiper Belt Object or other was sorted out. It wasn't until 2006 that the International Astronomical Union gave the object its "dwarf planet" status and it was allowed to get a name.

So what does Eris mean? From Greek mythology, Eris is the goddess of warfare and strife. It is a fitting name as there was plenty of strife in the astronomical community over this world.

A Look Back

2008 will mark the 60th anniversary of the dedication of the Hale Telescope (1948 - 2008). Over the course of the year I'll be presenting some historical highlights from the observatory's past.

January 1, 1801 —Long before the birth of the Palomar Observatory Ceres, the first asteroid, was discovered by Guiseppe Piazzi. For a time Ceres was thought to be a planet. With the discovery of other asteroids, and the asteroid belt, it was eventually realized that Ceres is better described as the largest member of the asteroid belt.

This same sort of sequence was repeated with Pluto. It was discovered in 1930 and classified as a planet. In the 1990s came the eventual discovery of the Kuiper Belt, a collection of icy bodies in the outer solar system. 2005 brought the discovery of distant Eris, a world larger than Pluto. Eris was discovered using the Palomar Observatory's Samuel Oschin Telescope. Its discovery called into question the planetary status of Pluto.

In 2006 Ceres, Pluto and Eris were re-classified and given a new status —dwarf planet. The International Astronomical Union (IAU) dropped down to just 8 planets.


Some people are still upset by the IAU's decision to demote Pluto. Others see it as just another step in our understanding of our back yard, the solar system.