Leaving Earth cover

In 2019 I obtained from my former publisher the last 30 copies of the now out-of-print hardback of Leaving Earth. I sold about half of these, and with only a handful left in stock I have raised the price. To get your own autographed copy of this rare collector's item please send a $75 check (includes $5 shipping) payable to Robert Zimmerman to

Behind The Black, c/o Robert Zimmerman
P.O.Box 1262
Cortaro, AZ 85652

I will likely raise the price again when only ten books are left, so buy them now at this price while you still can!

Also available as an inexpensive ebook!

Leaving Earth: Space Stations, Rival Superpowers, and the Quest for Interplanetary Travel, can be purchased as an ebook everywhere for only $3.99 (before discount) at amazon, Barnes & Noble, all ebook vendors, or direct from my ebook publisher, ebookit.


Winner of the 2003 Eugene M. Emme Award of the American Astronautical Society.

"Leaving Earth is one of the best and certainly the most comprehensive summary of our drive into space that I have ever read. It will be invaluable to future scholars because it will tell them how the next chapter of human history opened." -- Arthur C. Clarke

IAU once again sticks it to an American scientist, devaluing Edwin Hubble

In what is already seen by many scientists as an inappropriate action, the International Astronomical Union (IAU) this week voted to change the name of Hubble’s Law to the Hubble-Lemaître Law.

Hubble’s Law, a cornerstone of cosmology that describes the expanding universe, should now be called the Hubble-Lemaître Law, following a vote by the members of the International Astronomical Union (IAU), the same organization that revoked Pluto’s status as a planet. The change is designed to redress the historical neglect of Georges Lemaître, a Belgian astronomer and priest who in 1927 discovered the expanding universe—which also suggests a big bang. Lemaître published his ideas 2 years before U.S. astronomer Edwin Hubble described his observations that galaxies farther from the Milky Way recede faster.

There are so many things about this that are wrong it is hard to keep count. First, the IAU was never given the right to change the name of a scientific concept. It’s original job was merely to systemize the naming of astronomical objects, and that alone.

Second, it appears to be based on a misunderstanding of basic science.

The resolution has also come under fire for confusing two different issues: the expansion of the universe and the distance-velocity relation for galaxies, which is also known as the Hubble constant. Hubble never claimed to have discovered cosmic expansion, but did do much of observing work to nail down how fast the universe was expanding. “If the law is about the empirical relationship, it should be Hubble’s Law,” Kragh says. “If it is about cosmic expansion, it should be Lemaître’s Law.”

Third, it relies on bad history.

The text of the IAU resolution, circulated to members ahead of the vote, asserts that Hubble and Lemaître met in 1928, at an IAU general assembly in Leiden, the Netherlands—between the publication of their two papers—and “exchanged views” about the blockbuster theory. Kragh says that meeting “almost certainly didn’t take place” and that IAU’s statement “has no foundation in documented history.”

There are other problems, including the method by which the IAU conducted its vote. The bottom line is that this organization has no business sticking its nose into this issue, and it illustrates again, as happened when it tried to push a bad definition of “planets” on the planetary community in order to devalue the discovery of Pluto by an American, that there is a strong anti-American streak within it.

Pioneer cover

From the press release: From the moment he is handed a possibility of making the first alien contact, Saunders Maxwell decides he will do it, even if doing so takes him through hell and back.

Unfortunately, that is exactly where that journey takes him.

The vision that Zimmerman paints of vibrant human colonies on the Moon, Mars, the asteroids, and beyond, indomitably fighting the harsh lifeless environment of space to build new societies, captures perfectly the emerging space race we see today.

He also captures in Pioneer the heart of the human spirit, willing to push forward no matter the odds, no matter the cost. It is that spirit that will make the exploration of the heavens possible, forever, into the never-ending future.

Available everywhere for $3.99 (before discount) at amazon, Barnes & Noble, all ebook vendors, or direct from the ebook publisher, ebookit.


  • Phill O

    Anti-Americanism and antisemitism go hand in hand.

    There is little wonder that Obama went to Europe before he was elected president. He shared their sentiments!

    Personal opinion is that the third class of planets should be Plutanoids, after the terrestrials and gas giants.

  • Andrew_W

    “. . .in order to devalue the discovery of Pluto by an American,”

    So Pluto’s status as a planet was removed not because it’s one of many relatively small objects of similar size in the Kuiper Belt but because it was discovered by an American? If it had been discovered by an Italian or a Norwegian it’s status would have remained as a planet?
    Paranoid much?

  • Andrew_W

    “If the law is about the empirical relationship, it should be Hubble’s Law,” Kragh says. “If it is about cosmic expansion, it should be Lemaître’s Law.”

    As I interpret it, the law is about the empirical relationship in cosmic expansion, so I think we should call it the Hubble-Lemaître Law.

  • vonmazur

    Eurocentric conceits from the usual suspects…I agree, the IAU has been like this for some time, starting in the 1960’s with a gradual build up over the years.

  • Phill O

    IUPAC is International Union of Pure and Applied Chemists. They set the rules for chemical nomenclature. Interesting that Chemical Abstracts and the organic chemist as a whole, use many trivial names because it makes perfect sense as the IUPAC names can become cumbersome. I pointed this out to my Ph.D supervisor. That was putting my foot in my mouth. He was on IUPAC. Easy to laugh now.

    However, the astronomical society which votes stuff in are as bad as this topic points out. Best to leave it as it is: Hubble’s Law. There is always some argument to change but they get lost in politics as this is!

  • Andrew_W: No, my statement is based on many interviews with many planetary scientists, who participate with the IAU and were quite frank about the anti-American factions within it.

    If you wish to ignore reality, go ahead.

  • Andrew_W

    Mr. Zimmerman, so you talk to some like minded people and they agree with you, those that don’t share your paranoia just nod in agreement with you and so you see your beliefs confirmed.

  • Andrew_W: As usual, you dismiss any evidence you don’t like. I have spent the last few decades as a science journalist, talking to a lot of scientists. I report what they tell me. You don’t like it, or don’t want to consider it as possible, so therefore it must be because I am biased.

    As Cromwell said, “I beseech you, in the bowels of Christ, think it possible you are mistaken.”

  • Robert Pratt

    IAU = Typical bureaucratic mission creep and credentialed hubris.

  • Andrew_W

    Mr. Zimmerman, apparently you think acting as a journalist is evidence of being unbiased, riight. Have you even worked out that your Cromwell quote cuts both ways?

    It’s human nature to be biased in anything political, especially if it’s something important to us. In the definition-of- a-planet debate it evidently has become important to some American astronomers that Pluto remain a planet, because 1. It’s the only “planet” in our solar system discovered by an American, and 2. There’re a lot of US astronomers whose work in centered on Pluto (especially with the data from New Horizons being evaluated) the decline in Pluto’s status endangers the financing for that study, so there are both patriotic and financial reasons for American astronomers to oppose Pluto’s reclassification.

    On the other hand the wider international astronomy community, in your evaluation, is in favor of the reclassification, not for the obvious reason that there are TNO’s and KBO’s of similar size to Pluto with many more likely to be discovered (all tiny objects compared to Mercury) but because the rest of the world hates Americans. You actually offer that as a serious explanation for the wider astronomy communities position. Like I said, paranoia.

  • Andrew_W: I never said I was unbiased. The reason I like having contrarians like you, who get pleasure out of playing devil’s advocate, is that it keeps me on my toes, and makes me aware that I could be wrong. Unfortunately, you are not that useful in this regard, because you so rarely argue from the entire set of facts. You like to pick and choose.

    As for the definition of planet, the public and the community of planetary scientists has repeatedly and continuously rejected the IAU’s definition, since the day it was approved. And note also that this definition was approved of by a very tiny percentage of the IAU membership and was changed from a different recommended definition written by the very committee the IAU put together to address this question.

    These facts bother you I know, but there they are. It wasn’t “the wider international astronomy community” that approved the IAU planetary definition, but the small number of remaining attendees that stood around until the last few hours of an IAU conference. This small group then voted on an definition that had been quickly rewritten by god knows who, changed to make sure Pluto would not qualify as a planet.

    The IAU was especially criticized for this maneuver, which is why this most recent proposed change was presented to the entire membership. That it passed, based as it does on faulty logic, bad history, and the fact that such things were never ever intended to be decided by the IAU, suggests that the IAU membership had other motives for the change. (One positive motive could have been to give Lemaître more credit. This however could have been done in many other ways, without diminishing Hubble. That they went out of their way to diminish Hubble once again suggests other motives.)

    Considering the amount of hate I see repeatedly these days in the modern global international community for the United States, it seems quite reasonable to consider this as a factor. Is it the whole story? Probably not, but in cases of the IAU and of what I know about it, I cannot dismiss it as a minor component.

    Finally, to repeat a most important point, the IAU was never ever supposed to do this. Its mandate from the beginning was simply to organize and systemize the naming of astronomical objects. Like all bureaucratic institutions, however, they have pushed for mission creep, attempting to expand its power into places it has no business being. And some of that creep apparently has political overtones that are especially odious.

    None of these factors should be ignored, if one desires to be intellectually honest.

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