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.

Eris Anniversary

Four years ago today the discovery of dwarf planet Eris was announced. Eris was found using Palomar's Samuel Oschin Telescope. Of course back then it didn't even have a proper name. Eris helped to push the issue of Pluto's planetary status forward and nearly three years ago the International Astronomical Union (IAU) decided to create the new dwarf planet category and put both Pluto and Eris into to it (along with the asteroid Ceres).

The IAU meets again this summer. While the issue of Pluto may not come up again there, it certainly hasn't gone away. NewScientist has as story Is Pluto a planet after all? that is worth reading if you are interested in this issue.

Also Mike Brown, the discoverer of Eris, has some book reviews on his blog that cover the events related to the whole dwarf planet / Pluto issue. Click on over to see what he has to say about The Pluto Files: The Rise and Fall of America's Favorite Planet by Neil DeGrasse Tyson and The Hunt for Planet X: New Worlds and the Fate of Pluto by Govert Schillng. Both books are on my reading list, but I haven't gotten around to them yet.

Podcast on Sky Surveys

My latest podcast for the 365 Days of Astronomy is up. You can check it out from their site directly or download it via iTunes too.

Error Correction: For some reason in the podcast I said the QUEST camera was 196-Megapixels. It was really only 161-Megapixels. Sorry about that.
Here are some links to go with the show:
Palomar's Samuel Oschin Telescope - Where it all happens

Second Palomar Observatory Sky Survey (aka POSS II) - some details on the second survey.

Google Sky & WorldWide Telescope - two ways to surf the sky from your desktop.

SkyFactory - home of some great images produced from the Second Palomar Sky Survey

High-Performance Wireless Research and Education Network - The high-speed network that allows astronomers to work remotely, far from Palomar.

Palomar-QUEST Survey - info on the survey completed last fall

Dwarf Planet Eris - Mike Brown's page on the world that "killed" Pluto

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.

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.