probably dramatically, impact planetary bodies—pulling them out of a system, making them unstable over very long time periods, et cetera.”
He paused. No one interrupted.
“That is very important because we are looking for a planetary system with a very specific planet that is stable over a long period of time. It takes billions of years for evolution to run its course. If we are going to devote a lot of time and effort to analyze the course of one planet’s development, we should focus on a planet that isn’t going to fall prey to cosmic malfeasance.”
Everyone in the group had intense interest in what Don was saying, except Catherine. She was visibly upset.
Don continued, “Most importantly, our planet needs to be in the HZ—the habitable zone. Recently, there has been some debate on that, so we’re going to focus on what is now being called the AHZ—the animal habitable zone. Microbial life can probably develop much more widely, but it’s a lot less interesting. On the other hand, the AHZ is a very small band. For example, if Earth were five percent closer to the sun, the oceans would boil. Fifteen percent farther away, and Earth would freeze. Microbial life, however, would probably be OK. Obviously, this is not as interesting to observe. Oh, and ideally, the planet has to be in the middle or outer parts of the AHZ—since stars tend to get brighter over time, which moves the edge of the AHZ away from the star. For instance, our sun has gotten thirty percent brighter since Earth formed.”
“We need a giant planet, like our Jupiter, to provide some cover for this hypothetical Alpha planet—to suck up asteroids and comets and such as they bombard the stellar system. But the giant planet can’t be too hot or have a weird orbit, or it might take out our planet, too. The Alpha star also needs to be just right. Too much UV, and life is doomed. Growing or collapsing is bad, too. The planet itself will benefit from a moon because that stabilizes its tilt and tidal systems. Its tilt needs to be right, to make sure the seasons are not too extreme. The planet needs the right mass and elemental makeup. Carbon is critical for life, but too much can lead to a runaway greenhouse effect. All of that will likely lead to lots of liquid water—oceans—the final ingredient.”
“In short,” he concluded, “everything needs to be just right. Perfect, even.”
He paused. “OK, I can see some of you out there cringing.” He smiled. “Here is the good news: the list can be reasonably well defined.”
“And tracked,” Stephen jumped in. “We’ve been working on a program that can identify planetary systems, look at the makeup and activity of the star, the planetary configurations, and much more. It’s not quite done, but it’s very close. We have now taken Don’s laundry list of stellar and planetary requirements for a habitable planet and created a search algorithm. It won’t be very fast, but it should work.”
Thomas asked, “Why won’t it be fast?”
“Because it effectively has to render the universe as it goes so that the program can look at it.”
“Oh.”
“While it’s running, we won’t be able to render anything. Also, it will slow universe processing…dramatically.”
Thomas frowned.
“So, we don’t know how long it will take to find targets. But we can’t scan the whole universe because of the rendering requirements, so we will focus on a short list of target galaxies.”
“Which we’ve already identified manually, by the way,” Don added. “We were able to pick target galaxies visually and mark target regions for scanning.”
“Even so,” Stephen continued as he ran his hands across his rapidly thinning hair, “we will be limited. Don’t expect a giant list of target planets. If we find even one in a reasonable period of time, I’ll be ecstatic.”
The whole group, bar Catherine, nodded. Everyone stood up, ready to get back to work.
Stephen added, “Oh, also—if we
He paused. No one interrupted.
“That is very important because we are looking for a planetary system with a very specific planet that is stable over a long period of time. It takes billions of years for evolution to run its course. If we are going to devote a lot of time and effort to analyze the course of one planet’s development, we should focus on a planet that isn’t going to fall prey to cosmic malfeasance.”
Everyone in the group had intense interest in what Don was saying, except Catherine. She was visibly upset.
Don continued, “Most importantly, our planet needs to be in the HZ—the habitable zone. Recently, there has been some debate on that, so we’re going to focus on what is now being called the AHZ—the animal habitable zone. Microbial life can probably develop much more widely, but it’s a lot less interesting. On the other hand, the AHZ is a very small band. For example, if Earth were five percent closer to the sun, the oceans would boil. Fifteen percent farther away, and Earth would freeze. Microbial life, however, would probably be OK. Obviously, this is not as interesting to observe. Oh, and ideally, the planet has to be in the middle or outer parts of the AHZ—since stars tend to get brighter over time, which moves the edge of the AHZ away from the star. For instance, our sun has gotten thirty percent brighter since Earth formed.”
“We need a giant planet, like our Jupiter, to provide some cover for this hypothetical Alpha planet—to suck up asteroids and comets and such as they bombard the stellar system. But the giant planet can’t be too hot or have a weird orbit, or it might take out our planet, too. The Alpha star also needs to be just right. Too much UV, and life is doomed. Growing or collapsing is bad, too. The planet itself will benefit from a moon because that stabilizes its tilt and tidal systems. Its tilt needs to be right, to make sure the seasons are not too extreme. The planet needs the right mass and elemental makeup. Carbon is critical for life, but too much can lead to a runaway greenhouse effect. All of that will likely lead to lots of liquid water—oceans—the final ingredient.”
“In short,” he concluded, “everything needs to be just right. Perfect, even.”
He paused. “OK, I can see some of you out there cringing.” He smiled. “Here is the good news: the list can be reasonably well defined.”
“And tracked,” Stephen jumped in. “We’ve been working on a program that can identify planetary systems, look at the makeup and activity of the star, the planetary configurations, and much more. It’s not quite done, but it’s very close. We have now taken Don’s laundry list of stellar and planetary requirements for a habitable planet and created a search algorithm. It won’t be very fast, but it should work.”
Thomas asked, “Why won’t it be fast?”
“Because it effectively has to render the universe as it goes so that the program can look at it.”
“Oh.”
“While it’s running, we won’t be able to render anything. Also, it will slow universe processing…dramatically.”
Thomas frowned.
“So, we don’t know how long it will take to find targets. But we can’t scan the whole universe because of the rendering requirements, so we will focus on a short list of target galaxies.”
“Which we’ve already identified manually, by the way,” Don added. “We were able to pick target galaxies visually and mark target regions for scanning.”
“Even so,” Stephen continued as he ran his hands across his rapidly thinning hair, “we will be limited. Don’t expect a giant list of target planets. If we find even one in a reasonable period of time, I’ll be ecstatic.”
The whole group, bar Catherine, nodded. Everyone stood up, ready to get back to work.
Stephen added, “Oh, also—if we
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