Label: Pluto

July 12, 2012

Today, astronomers using the Hubble Space Telescope announced that they have discovered Pluto’s fifth moon. Scientists have been looking closely at the space around Pluto because they are preparing for the 2015 Pluto flyby of NASA’s New Horizons spacecraft. New Horizons is going to give us our closest look yet at the dwarf planet, so NASA engineers want to map as many potential crash hazards as they can and design the safest possible course for the probe.

For the moment, the new moon is simply called S/2012 (134340) 1, or "P5" for short. Eventually, the International Astronomical Union will give names to P5 and P4, the fourth moon that was discovered late last year, and they will probably be names from Greek mythology. Pluto’s first three moons were named after mythological characters associated with the underworld. Greeks believed Charon was the ferryman who carried souls across the river to the underworld. Hydra was the serpentine monster that guarded the gates of the underworld, and Nix is named after the Greek goddess of the night.

The team is waiting awhile before naming P4 and P5, in case a P6 comes along. One thing for sure is that we’re going to learn a lot more about Pluto and the objects orbiting it in the next three years.

The timing of this discovery is good for one of my new eBooks. We are updating SPACE WORDS: A DICTIONARY for publication as an eBook, and my editor just changed the Pluto entry to state that it has five moons. Surely this will be the most up-to-date reference out there when it is published in late July!


Photo: M. Showalter / SETI Institute / NASA / ESA

Posted by: Seymour Simon

(3) Comments  •   Labels: space, Solar System, Space Travel, Exploration, Pluto   •  Permalink (link to this article)

February 11, 2012

This week we ran a contest called 3 CHEERS FOR PLUTO! for students at schools that I visited in Wayne, New Jersey, Skillman, New Jersey, and Newtown, Pennsylvania.  I asked students to do some research about Pluto, and write three facts about the dwarf planet. 163 students and classes left comments on the blog with their answers. Wow!

How did I come up with a winner among the many correct answers? The winner was randomly chosen by a true random number generator on the website First we listed all the entries on page after page, in order of when they were received. Then we used the random number generator, first to pick a page number and then to pick a number on the page. The winning pick was Ainsley, in Mrs. Rodgers’ Class, at Sol Feinstone Elementary School.


Ainsley wrote: 

1. The region of its orbit is known as the Kuiper

2. Puto’s distance from the sun is about 3,670,050,000 miles [5,906,380,000 kilometers] smile

3. Pluto’s surface is one of the coldest places in our solar system. smile


The class pick, for Kindergarten through second grade, was a little different. We put each class entry on a small slip of paper, put all of the class entries into a paper bag and then I put my hand into the bag and picked up one of the slips of paper without looking. The winning slip of paper was Mrs. Doheny’s 2nd grade class at Sol Feinstone Elementary School. They wrote:

smileOn August 24th, 2006 Pluto’s status was changed from planet to dwarf planet. 

smilePluto is the only planet named by a kid.

smilePluto has three moons.

 Our second grade class had so much fun researching facts about Pluto this afternoon.  The children can’t wait until Seymour Simon comes to visit us tomorrow!!! 

See you soon,

Mrs. Doheny’s Second Grade Class 

Congratulations to both winners. Ainsley will receive an autographed copy of OUR SOLAR SYSTEM, and Mrs. Doheny’s class will receive an autographed copy of PLANETS AROUND THE SUN.

Now, some of you very advanced planet studiers may have noticed that just a few months ago, astronomers identified a fourth moon orbiting Pluto. For now, it is just being called P4 - it is so new that it has not been given another name yet. Since it is so new, we did not disqualify any entries that said that Pluto has three moons, Charon, Nix and Hydra.


For those of you who are interested, here is a recent diagram from NASA, showing Pluto’s satellite system, which includes all four moons.

Congratulations to everyone who entered the contest! All of your entries have been posted as comments on my blog. Look for your name and your entry on my website, Some of you put your comments on stories other than the contest story, so if you don’t see it there, you’ll probably find your comment under another blog story.

Please keep in touch by telling me about what book of mine you’re reading, and what subjects you like the most!

I had so much fun meeting you all last week. Thank you for your enthusiasm for paper airplanes, strange mysteries, and Pluto!

Posted by: Seymour Simon

(2) Comments  •   Labels: School Visits, Contests, Pluto   •  Permalink (link to this article)

February 9, 2012


Did you know that Seymour Simon’s SCIENCE DICTIONARY is available on his website for you? Here is an interesting definition from the Science Dictionary that may have come up in the research that many of you have been doing this week for your contest entries. Have you come across these words - Kuiper Belt? This is what the Kuiper Belt looks like.

Now click here for Seymour’s definition, to help you understand what Kuiper Belt means. 

Posted by: Seymour Simon

(2) Comments  •   Labels: space, Solar System, Science Dictionary, Pluto   •  Permalink (link to this article)

January 14, 2011

Alas, poor Pluto is no longer considered to be a planet by the scientists of the IAU (International Astronomical Union).  Astronomers use three criteria for a body to be called a planet: 1) it has to be in orbit around the Sun. 2) it has to have enough mass to pull together so that it becomes nearly round. And 3) it has to have enough mass and gravitational pull to clear out other bodies in the space around it. Pluto meets the first two tests, but it does not have enough mass to clear the space around it (for example, if it had enough mass its gravity would pull a meteorite down so it crashes to the surface). So Pluto has been renamed a Dwarf Planet. All you kids who have memorized the planets in order from the sun will now have to stop at Neptune, the eighth planet from the sun.

Here’s some more information about Pluto from, a really neat site that you can use to find out all kinds of interesting facts about what’s out there. 

Posted by: Seymour Simon

(7) Comments  •   Labels: Astronomy, Solar System, planets, Pluto   •  Permalink (link to this article)

August 26, 2010

Dear Neil DeGrasse Tyson,
I’ve been wanting to write to you for sometime now after I read your autobiography a number of years ago, and finally decided to do so. (My autobiography, From Paper Airplanes to Outer Space, is published by Richard C. Owen.)First of all, I’d like to tell you some of the common background we share. I’m also a graduate of Bronx HS of Science and was an amateur astronomer all through my HS years and beyond. During HS years, the AMNH hosted an office (in the basement) for the Junior Astronomy Club. I was at different times,  Editor of their magazine (JAC NEWS), Vice President and then President. We used to have observation meetings in Central Park and some of us (including me) had passes to get into the Museum at off hours to use our office and to work on the magazine. After graduating HS, most members went on to become members of the adult group, The Amateur Astronomy Association. It was a very good time to be a Junior Astronomer in NYC.
I went on to become a writer of science books for children. I’ve written over 250 books, currently they are copublished by Collins/Smithsonian. My website is
Here are of my current blogs about astronomy.  Please come by and take a look. I’d love for you to grant me permission to post one of your pieces about Pluto on my site. Is that at all possible?
In any event, I wanted to say hi and to also say that I’m very proud that we’re both graduates of Bronx Science (despite the fact that I’m sentimental about Pluto)!
P.S. I can’t find your current email address anywhere! If you get this post, please write to me. Seymour Simon

Posted by: Seymour Simon