Category Archives: Astronomy
This is a nice little book about the process that resulted in the downgrading of Pluto from full planethood to a status of Dwarf Planet by one of my favorite people, Neil deGrasse Tyson. From his perspective as the Director of the Hayden Planetarium, and as one of the scientists involved in the reclassification of Pluto Tyson gives us a nice, easily readable and humorous account of this process. It was one of those rare times that what should be a strictly scientific process got caught up with tradition, history, culture and public opinion.
Tyson does a very nice job placing Pluto in our culture as the most popular of the planets. As the runt of the solar system it was often used as a metaphor for over achievment. It’s mystery provided the fodder for dozens of science fiction works, mainly aimed at kids…and even Disney named one of its characters Pluto.
The outcry when it was discovered a change to its classification was being contemplated was fairly stunning, with the public firmly supporting retaining its planethood, while astronomers and planetary scientists were surprisingly divided on the question. At it’s heart the debate revolved around what the definition of a planet was. That term had never really been defined before.
If we consider planets to be round bodies, with a regular orbit around the sun and not orbiting another object then Pluto qualifies. If size is taken into account, well there are several moons in our solar system larger than Pluto so the answer is less clear. It is out of place in the solar system, with the inner planets (Mercury, Venis, Earth and Mars) being rocky worlds, and the outer planets (Jupiter, Saturn, Uranus and Neptune) being large gas giants. Pluto does not fit into either of these categories. Analysis suggests it is largely an icy world, closer in composition to a comet than any of the other planets.
Pluto lies in what is called the Kuiper Belt, a belt of objects extending from the orbit of Neptune outward. It basically contains the leftovers from the formation of our solar system. Pluto is a Kuiper Belt object. One of the proposed criteria for classifying an object as a planet was whether it was large enough to clear out its orbital path. In other words as the object circled the sun did it accumulate enough of the debris in its orbit to basically remove everything but itself. Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune all do this. Pluto does not. It is only one of thousands of objects in the Kuiper Belt, albeit one of the largest. Those wishing to keep Pluto classified as a planet advocated ignoring this requirement due to Pluto’s size. The question then arose; what would happen if another Kuiper Belt object was found that exceeded Pluto in size? Would it then be a planet as well? And in fact this did happen with the discovery of Eris in 2005 as this debate was taking place. Eris is 27% larger than Pluto, and for a year was considered the solar system’s 10th planet.
Finally, in 2006 it was decided Pluto, Eris and similar worlds would be classified as Plutoids or “dwarf planets.” As Tyson points out however, this will do little to diminish people’s affection for Pluto. After all a dwarf human is still a human…so for most people, Pluto remains a planet.
If you have a few hours to kill and have any affection for or interest in Pluto…or are a Neil deGrasse Tyson fan, you will enjoy this!
Note: The New Horizons space probe, the fastest object ever launched by human beings humming along at 37,00 mph, is scheduled to reach Pluto in August of this year. It should provide many of the answers to questions we have had about Pluto since its discovery, including its exact size, the compostion of its atmosphere etc!
Just read this again after having read it the first time about 20 years ago. It really is a beautiful book that hasn’t lost any of its relevance even with 20 years of additional discovery (which it deals with in an afterwards).
It tells the story of the Universe while also telling the story of telling the story of the Universe, from the first decipherable cave paintings to up to date discoveries in the field of particle physics – all in a way that can be understood by folks like me that have an interest in science and discovery but have no aptitude for it!
Pretty workmanlike autobiography of Apollo 15 astronaut Al Worden. Interesting but not overwhelmingly so. Two parts did stand out though. First, his description of the moon mission he participated in was very well written and did an effective job of putting the reader in that place and time. And second, his recounting of the postal cover scandal was interesting and provided a perspective that did not get much play at the time. If you are a space buff like me you will enjoy this…if not it is a bit of a slog.
I had mixed feelings about this book.
On one hand it is really well written, flowed really well, didn’t get bogged down in the techno babble that dooms so many other books on space and space exploration, and at times was funny and poignant. It gives a very good behind the scenes look at the Shuttle program, its management, and most importantly the personalities of the astronauts themselves. His recounting of the flights he participated in were particularly good, including exceptionally well written sections on the times he spent simply watching the Earth go by beneath him. Best of all it is a very easy read!
On the other hand, Mullane tries too hard to come off as the typically over-sexed, right wing, hot shot rocket jock everyone assumes test pilots are. It seems contrived. The constant stream of digs at N.O.W., Gloria Steinem, Ted Kennedy and “commies” grew kind of tiresome. And I am convinced he doesn’t actually know what the term “political correctness” means. He seems to think every time someone pushed back on some sexist and/or inappropriate thing he said or did they were being “politically correct.” In actuality they were just pointing out he was being a jerk.
He was also unnecessarily critical of non-astronauts who either flew the shuttle or had some other role astronauts with a military background disapproved of. In what seems like a requirement for test pilots he apparently believed the Shuttle Program was there exclusively so he could fulfill his dream of getting into space. Any accommodation made to non-astronauts that delayed that goal was viewed with disdain.
His criticisms of John Glenn and Christa McAuliffe were notably off base…referring to their role in the shuttle program as immoral. He seems not to have a grasp of the larger purpose for manned space exploration, nor the fact that its funding is dependent on the support of the American people.
In the epilogue he included a moving tribute to the professional astronauts who were killed in the Challenger disaster; omitting part timers Christa McAuliffe and Greg Jarvis from his tribute. An unnecessary and petty omission in my opinion; one that ignores the inspiration McAuliffe has been to younger generations.
These criticisms aside however, I really did enjoy this book. The folks that decide to risk their lives doing this work will always get slack from me.