Discussion Board

Topic: A hope of Marsian gravity.

From: Amy Jording
Location: Trout Lake, WA
Date: 10/12/2011

Hi Greg,

My boyfriend and I are fans of your books. At this moment, he is reading Anvil of Stars and just finished Forge of God, he's hooked and loving how ahead of times you were with the Forge of God. It's like you predicted all that has come to be.

I read your book, Halo Cryptum, and thoroughly enjoyed it.

I am working on my own story and wanted to ask for some advice about a specific obstacle that was thrown at me.

In my story, I want to terraform Mars and have cities and modern (4000 ad) society thriving on the planet. The problem I am having right now is that I am trying to make the story quasi-believable. What I mean by that is, the universe I'm writing in is similar to Cowboy Bebop, and it sits within the confines of the Solar System.

In this story, the focus is on this stage of mankind, branching out to the various planets of the solar system. Some of the adaptation is voluntary evolution of man, and yet, on Venus and Mars, I wish to keep humans looking as "normal" to Earth humans as possible.

The issue I'm having right now with Mars is that I've been reading a lot on Terraforming the planet and there are a lot of grim outlooks on the issue of a Magnetosphere, keeping an Atmosphere and most importantly, creating enough gravity.

I know you're no stranger to writing about Mars, so I wonder, with your excellent foresight, if you can think of a plausible, and convincing way that Mars is able to have perhaps a "synthetic" gravity, enough for the common man to find believable?

I've read about a black hole in the middle of Mars or having to make Mars bigger in mass by throwing a bunch of asteroids into it, but I'd rather do something more graceful than that. I would imagine that you've thought about these things in context of a good sci-fi story.

Thank you for your wonderful stories.


Re: A hope of Marsian gravity.

From: Greg Bear
Date: 11/09/2011

Hello, Amy! The problem of not enough gravity to hold an atmosphere is real--but may not be important except over thousands or hundreds of thousands of years, if some method of creating an atmosphere works on Mars. The magnetosphere issue likely has to do with a cooling interior. Slipping a black hole into the mix is interesting--but one sufficiently large to add to the gravity would easily swallow the rest of the planet! How do you keep it from gobbling up everything?

I'd say that terraforming is great fun, but unlikely to affect Mars short term, or last long term. Which is why in MOVING MARS I put colonists underground. Upsetting the planet's stable interior eventually recreates an atmosphere of sorts, and rain, but that's not something our level of engineering is likely to accomplish in the foreseeable future. (And where would you procure that black hole? Costco has them, for sure, but in bundles of six--and the packaging is extreme!)

Let me know how you work this out! It's an intriguing idea, would take some super physics to solve, and could be great fun to write about. (In essence, you'd be transforming Mars into a gigantic artificial station in space!)

Re: A hope of Marsian gravity.

From: Kelly Marsh
Location: Camano Island, WA
Date: 11/26/2011


I must say I have been quite disappointed in Costco of late. On each of my last three visits, their black hole shelves have been completely empty, and on my last visit even the endcap display was gone. When I finally asked one of the employees why this was so, he looked at me rather oddly, (I didn't like him, he had shifty eyes) then said something about how they were trying to find a new supplier due to problems with packaging. According to him, the last shipment had what he called "bad shielding," and swallowed an entire forklift along with the driver, then a few other items of their stock, and part of the building before they were able to get it under control. I told him (quite rightly, I thought) I had little sympathy for this; either they were in the business of selling black holes or they were not. I must admit I was quite unprepared for the rudeness of his reply. No retail employee should ever speak to a customer in such a fashion, and really, how was I to know the forklift operator was his brother, anyway?

Seriously, though, regarding "...one sufficiently large to add to the gravity would easily swallow the rest of the planet," isn't it a question of degree? Couldn't a tiny black hole merely augment planetary gravitation sufficiently to hold an atmosphere without sucking in the planet in the bargain? Admittedly I am no physics genius, but it seems to me that if we were able to create black holes to order, we might be able to also control the degree of gravitational force they, er, emit? Or am I missing something basic, here?

Re: A hope of Marsian gravity.

From: Greg Bear
Date: 01/16/2012

Indeed. Black holes are rarely the solution. In packs of six, they are definitely an accounting problem.

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