Archives for the 'planets' Category
Defining Planets (Part III)
Published on 7 Feb 2009 at 2:19 pm.
10 Comments.
Filed under planets.
Pluto was an oddity among the planets for much of the Twentieth Century. As I said in my last post, it just didn’t seem to fit with the other eight planets. There was debate for decades on whether or not Pluto should really have been on the list. In the end, most […]
Read ‘Defining Planets (Part III)’
Defining Planets (Part II)
Published on 4 Feb 2009 at 11:43 am.
7 Comments.
Filed under planets.
In my last post, I gave a sort of history of how we got to having 9 planets in the Solar System, according to science textbooks for most of the Twentieth Century. But, Pluto was a problem from the very beginning.
Already, by the beginning of the Twentieth Century, astronomers knew that there was a […]
Read ‘Defining Planets (Part II)’
Defining Planets (Part I)
Published on 2 Feb 2009 at 4:48 pm.
6 Comments.
Filed under planets.
In 2006, the International Astronomical Union voted on a new definition of the word planet. I wrote about the matter at the time, but I now feel that I should revisit that discussion. Last week I wrote about an asteroid sharing Earth’s orbit and that this asteroid raised issues with the IAU definition of […]
Read ‘Defining Planets (Part I)’
Naming craters on Mercury
Published on 22 Dec 2008 at 9:03 am.
2 Comments.
Filed under planets.
There are rules for naming things in astronomy. The only body whose names astronomers consider official is the International Astronomical Union (not various private entities who sell star names, particularly at this time of the year). For the planet Mercury, the rules are that the craters are named for people who have made […]
Read ‘Naming craters on Mercury’
Plutoids
Published on 11 Jun 2008 at 12:40 pm.
10 Comments.
Filed under planets, solar system.
We have yet another new word to describe some of the things out there beyond Neptune: Plutoids. As you may recall, a couple of years ago, the International Astronomical Union finally defined the word “planet.” It was something of a shock to many people in the public, but astronomers had never actually […]
Neptune in Conjunction
Published on 10 Feb 2008 at 6:28 pm.
2 Comments.
Filed under astronomy, planets.
According to my Observer’s Handbook, Neptune will be in conjunction with the Sun in less than two hours. So, I thought that I’d take a moment to explain what we mean by the terms conjunction and opposition when we are talking about planets. For this discussion, I’ll focus on superior planets, which are […]
Hellas Planitia
Published on 4 Feb 2008 at 3:35 pm.
7 Comments.
Filed under Mars, planets.
A few days ago, I wrote about Mercury’s Caloris Basin. It is mind boggling huge. Naturally, as Darnell Clayton of Colony Worlds asked, it is natural to wonder if this is the largest impact basin in the Solar System. As it turns out, there are larger impact structures. The largest may […]
