Category: Science
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Son of Great Filters
Robin Hanson, who invented the term "Great Filter" in the first place, comes back to the topic in his own blog for a look at a couple of neglected aspects of the topic. You can read his whole post here. One of the key issues he raises is whether or not a given planet (for…
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PhilCon 2020 Goes Virtual
This year's PhilCon — the venerable Philadelphia-era science fiction con now in its 84th year — is going to be all-online. On the plus side that means no New Jersey traffic and mall food; on the minus side it means no spontaneous conversations in the hotel lobby, no room parties, and no basic human contact.…
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Ancient Alien Astronauts
When does speculative science cross the invisible line and become pseudoscience? That's a topic I grapple with when writing science fiction, and one which crops up whenever scientists air some of their wilder theories. For example, Dr. James Benford recently published a paper on searching for alien "technosignatures" on Near-Earth Objects in our own Solar…
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Twenty Years!
Today marks a significant anniversary. Twenty years ago, on October 31, 2000, the first crew launched to the International Space Station. Station crews are called "Expeditions," so Expedition 1 began on that date. We're currently on Expedition 64, with three in the pipeline and many more planned. The Expeditions overlap, so that the new crew…
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Great Filters, Part 9: Odds and Ends
Well, I think I've come to the end of my series on the Great Filters and the Fermi Paradox. There are a few bits which didn't quite fit into any of the earlier posts. So here they are, in more or less random order. Have We Looked? First, there's the issue of what Michael Hart…
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Great Filters, Part 8: Space Filters
Wow, I've been doing this for two months and am not done yet. Now I know how Proust must have felt. Assuming Proust was writing blog posts about the Fermi Paradox, of course. So far I've looked at all the Great Filters which lie in our past — barriers to the evolution of life, barriers…
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Great Filters, Part 7: Disaster Filters!
We've brought ourselves up to the present day in the evolution of the Earth, life, and human civilization. My estimates for the various filters we've passed through indicate that there ought to be around fifty other civilizations in the Milky Way. The principle of mediocrity suggests that a good half of those fifty should be…
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Great Filters, Part 6: Civilization Filters
In my previous posts on the topic of Great Filters, I've looked at all the hard science limits on life and intelligence on other worlds. Those limits left us with a ballpark figure of 5,000 intelligent species in the Milky Way. Now we're shifting to the "softer" sciences, with a focus on history and archaeology.…
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Great Filters, Part 5: Intelligence Filters
I finished up last week's post on Great Filters by looking at the Galaxy according to the numbers I've cooked up. It produced the surprising figure of lifebearing planets every 50 light-years or so. In cosmic terms that's right next door. It means that in the near future we have a pretty decent chance of…
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Great Filters, Part 4: Life Filters
Having considered how uncommon Earthlike worlds are, now we're going to look at potential Great Filters in the history of life itself. The first is more of a meta-filter, and affects some of the possible stellar and planetary filters already discussed. It's simply this: what is the range of potential forms of life in the…
The Cambias Digression 