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

Oblique mosiac of bright spot on Ceres

Cerealia Facula on Ceres

Cool image time! With the Dawn spacecraft now swooping with 22 miles of the surface of Ceres every 27 hours, the science team has assembled a spectacular oblique image of Cerealia Facula, one of the dwarf planet’s bright spots thought to be brine deposits that at some point erupted up from below the surface.

The image on the right, reduced in resolution to show here, shows that mosaic. If you click on the image you can see the full resolution version. From the image webpage:

This mosaic of Cerealia Facula combines images obtained from altitudes as low as 22 miles (35 km) above Ceres’ surface. The mosaic is overlain on a topography model based on images obtained during Dawn’s low altitude mapping orbit (240 miles or 385 km altitude). No vertical exaggeration was applied.

There are a lot of intriguing details in the full resolution image. I have highlighted one feature, indicated by the white box and shown in full resolution below.

Detail from mosaic

The white material very clearly appears to be a flow going downhill, though the feature has some puzzling aspects. For example, the edges of the deposit are its brightest, as if the center area is the oldest and has faded with time. Moreover, the bottom edges are the brightest of all, and the faded center area seems depressed relative to its edges.

We know that many of these bright spots are in depressions. It has been theorized that they might have once been brine volcanoes that after the eruptions died out the volcanoes slumped, collapsing into a sink.

This detail as well as the full image of the entire bright spot suggests something different to me. Instead of a brine volcano, it appears that the seep comes up slowly from below, and causes a sink, not a volcano, as it does so. The detail shows that new material does not necessarily break the surface initially, but seeps downhill to break out at the edges, thus creating those brightest sections.

All guesses on my part. Greater certainty of the make-up of the white material and the surrounding darker material, combined with a lot of calculations based Ceres’s weak gravity, will be needed to get a better understanding of what is happening here.

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.


  • Very nice. Thank you for posting this.

  • danae

    Being able to distinguish differences in elevation of surface features is a major improvement over the straight-on photos of these bodies we’re so accustomed to seeing. Much respect to the science team for creating a strategy of combining images to produce this first-rate effect.

  • mpthompson

    Could the brighter material that appears around the edges travel through the equivalent of lava tubes that form underneath the older hardened surface?

  • Charlie

    I guess the brighter material is underlying material being exposed as it moves downhill. What has my eye is what looks like a vent hole at the top of the white area with what appears to be a ring around it.

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