Tag Archives: Aliens

Silence Suggests Sim?

In 2010 I explained why I guess I’m not in a sim. In 2011 I explained why sims should be small, and focus on “interesting” folks. In 2001 I explained why it matters if you live in a sim.

Here is Tyler today:

If we are living in a simulation, does that resolve the Fermi paradox? I would think so. The “aliens” would be here, we just would not “see” them as such. … Should we expect to find alien civilizations in a simulation? The priors are not so clear. … For the time being, we are still in a “no aliens” do loop. … The Fermi paradox raises the likelihood that we are living in a simulation.

I don’t buy it. Let’s try two extreme cases. First, assume that the creatures who make your sim copy their own universe in the sim – if it has aliens, then you get aliens; if not, not. Here not seeing aliens says nothing about if you are in a sim.

Now assume the opposite, that whether the creatures running your sim give you aliens has no relation to whether or not they have aliens in their world. They decide whether to give you aliens based on the “story” (= useful sim) value of aliens, regardless of how realistic that seems to them. In this case if the scenario of your world seems to have especially high story value (relative to a real scenario), you should increase your suspicion that you are in a sim. And if your scenario seems to have an especially low story value, you should reduce your suspicion that you are in a sim.

It seems to me that if anything aliens would add to a story value. So not seeing aliens should lower your suspicion you are in a sim. And if you can’t tell if aliens help or hinder a sim story, then not seeing aliens gives no info about if you are in a sim.

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Why Silence Puzzles

Bryan Caplan:

[Recent planet] discoveries seriously undermine the Fermi Paradox. If we’ve only recently confirmed the existence of extrasolar planets, why on earth should we be surprised by the fact that we’ve failed to confirm the existence of extrasolar intelligent life? … Shouldn’t they already be here? Not if space travel (including the value of time) permanently remains extremely costly relative to the value of raw materials. It’s a lot easier to believe that space travel will forever remain a rare luxury for intelligent life than that intelligent life exists on Earth alone. ..

[Some] say, “Whatever intelligent life usually does, surely one species of intelligent life would be the exception that proves the rule.” Facile. When you multiply independent, rare events together, you quickly reach situations with zero examples. … Even if there are seven billion species of intelligent life in the galaxy, there could easily be zero species that entered our solar system during the last century, approached the earth, and stayed long enough for the scientific community to detect and confirm.

When a tree burns, what fraction of its leaves float to another tree still burning enough to ignite it? What fraction of the coconuts on an island float away to a barren island to grow a new tree there? What fraction of the virus copies in someone who is infected fly out in a sneeze to infect a new person? Why should we ever expect such fractions to be large enough to create forest fires, or coconuts on new islands, or viruses that spread to many people?

If we knew that one tree in our dense dry forrest was burned a few days ago, we should be surprised to see untouched trees near where we stand, even if we could not see that burned tree far away. We should also be surprised to see unburned coal near us if we knew a fire had started days ago far away, beyond our sight, in the same rich ventilated coal mine. And if we knew that one drop of spoiled milk was added days ago to a large room temperature vat of milk, we should be surprised to see unspoiled milk in any part of the vat we could see.

We should be surprised to think billions of technologically-advanced intelligent civilizations have existed in our galaxy for billions of years. This is because for a civ only a millennia more advanced than us, it should only take a tiny (i.e., a part in a billion or less) fraction of its resources to send out a self-reproducing seed that could colonize an empty galaxy densely (so that we’d see it everywhere we looked) within a billion years. It doesn’t matter if this venture is expensive and time-consuming relative to the typical hobby budget or time of a human today, or a bacterium on any day. What matters is that civs can be diverse, and contain great internal diversity. And it just takes one spark to start a fire.

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Galaxy Calc Shows Aliens

What makes a planet a good host for life? That is, what does a planet need for life to originate there and then evolve to something at the human level? Astronomers today say a planet at least needs a star that 1) lasts long enough, 2) has enough heavy elements, and 3) is not too often hit by nearby supernovae or gamma ray bursts. Using such criteria, several astronomers (mentioned below) have tried to calculate “galactic habitable zones,” i.e., galactic distributions of good-for-life planets, in both space and time. Such calculations are far more important than I had realized – they can help say how common are aliens! Let me explain.

Imagine that over the entire past and future history of our galaxy, human-level life would be expected to arise spontaneously on about one hundred planets. At least it would if those planets were not disturbed by outsiders. Imagine also that, once life on a planet reaches a human level, it is likely to quickly (e.g., within a million years) expand to permanently colonize the galaxy. And imagine life rarely crosses between galaxies.

In this case we should expect Earth to be one of the first few habitable planets created, since otherwise Earth would likely have already been colonized by outsiders. In fact, we should expect Earth to sit near the one percentile rank in the galactic time distribution of habitable planets – only ~1% of such planets would form earlier. If instead advanced life would arise on about a thousand planets, Earth should sit at the 0.1 percentile rank. And if life would arise on a thousand planets, but only one in ten such life-full planets would rapidly expand to colonize the galaxy, Earth should again sit near the one percentile rank.

Turning this argument around, if we can calculate the actual time distribution of habitable planets in our galaxy, we can then use Earth’s percentile rank in that time distribution to estimate the number of would-produce-human-level-life planets in our galaxy! Or at least the number of such planets times the chance that such a planet quickly expands to colonize the galaxy. If Earth has a low percentile rank, that suggests a good chance that our galaxy will eventually become colonized, even if Earth destroys itself or chooses not to expand. (An extremely low rank might even suggest we’ll encounter other aliens as we expand across the galaxy.) In contrast, if Earth has a middling rank, that suggests a low chance that anyone else would ever colonize the galaxy – it may be all up to us.

At the moment published estimates for Earth’s time percentile rank vary widely. An ’04 Science paper (built on an ’01 Icarus paper) says: Continue reading "Galaxy Calc Shows Aliens" »

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Info Cuts Confidence

An interesting tendency:

By the time Project Blue Book folded in 1969, it had evaluated 12,618 reports of sightings. … Special Report Number 14 [is] a vast statistical analysis of 3,201 UFO cases, with hundreds of graphs, tables, charts, and maps. … According to the report, about 22 percent of sightings were declared “unknown.” That means their origin couldn’t be determined even after all the evidence was in—these were objects that didn’t look like airplanes or balloons or any other discernible vessel. They maneuvered in strange ways, hovering or changing speed and direction suddenly. Sometimes witnesses, many of them Air Force pilots, described seeing actual saucer- or cigar-shaped objects. Unknowns tended to be cases with better information: 35 percent of “excellent” sightings—those with more reliable witnesses and, sometimes, corresponding physical evidence—defied explanation; only 19 percent of poor ones did. And the longer a sighting lasted, Friedman says, the more likely it was to remain unexplained: 36 percent of unknowns were seen for more than five minutes. (more)

Since things with fewer details are seen more in far mode, and since in far mode we are more confident in our theories, we should expect people to be more confident in their classifications of things that have fewer details, and so have a smaller fraction of things left as hard to explain. I’d like to see this tested elsewhere, such as planes seen near or far, or crimes known in little or much detail.

More:

In 1997 a CNN poll found that 80 percent of Americans think the government is hiding information about UFOs, and 64 percent believe that extraterrestrials have contacted humans. In a 2007 Associated Press poll, 14 percent said they’d seen a UFO. … At the end of his lectures, [Friedman] often asks the audience how many of them have seen a flying saucer. … Usually ten percent of the audience have their hands raised. … “But then I ask, ‘How many of you reported what you saw?’” Nearly every hand drops.

Thats a whole lot of skeptics of the usual official UFO story. (I’m not a skeptic.)

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We Live, Unequally

They Live (1988) is a celebrated message movie:

John Nada, a generic drifter who finds his way to Los Angeles as the film begins. … Nada wanders through Los Angeles, gets a job as a construction worker, and is led by a new buddy named Frank to a shantytown. …

Once Nada stumbles upon a package of special sunglasses, the secret is out. When he wears these glasses, he sees subliminal messages everywhere. ”Marry and Reproduce,” says a billboard on which a bikini-clad woman pitches vacations in the tropics. ”Consume,” says a sign advertising a close-out sale. ”This Is Your God,” says a dollar bill, and on the newsstands magazines put forth slogans like ”Honor Apathy” and ”Obey.”

What’s more, the glasses enable Nada to see just who ”they” are: the rich and powerful who, through these lenses, become skeleton-faced ghouls with glittering metallic eyes. (more)

Naturally Nada immediately goes on a murder-all-aliens rampage. Wouldn’t you?

I sure hope not. The movie seems to suggest that one should murder all non-kin elites in any society where elites use psychological tricks to keep non-elites from feeling outraged and going on murderous rampages. (Like pretty much every society ever known.) You might argue that the movie only suggests mass murder for non-kin who are ugly very-distant relations. But then why celebrate this as a “message” movie? Are we supposed to see murdering elites as a metaphor for, say, frowning at them?

The movie tries to transfer xenephobia of space aliens to elites within a city, even when there are no obvious signs that these elites aren’t paying their way, by being more productive. In the movie, aliens bring world peace, let humans continue to live peaceful lives, bring advanced tech, and integrate Earth’s economy with distant planets to achieve gains from trade. None of which, according to this movie, excuses them:

What do these things want?
They’re free-enterprisers.
The earth is just another developing planet. Their third world.
Deplete the planet, move on to another,
They want benign indifference,
We could be pets or food,
But all we really are is livestock.
We need an assault unit.
Someone to hit them hard. (more)

Look, there is a vast space of possible societies, with an incredible number of possible dimensions. Yes, humans are primed to watch for and resist dominance, and to be suspicious of outsiders. And yes maybe more equal societies are better, all else equal. But an overwhelming focus on that one dimension of inequality risks neglect of the other dimensions, which taken together are vastly more important. We should seek social arrangements to help us search this vast space for more productive possibilities, including the possibility of peaceful mutually beneficial trade with outsiders. Even if that increases, horrors, inequality. Or, double horror, subliminal advertising! Really.

Imagine a movie depicting a hero upset by some lazy poor folks on welfare, who then goes on a rampage murdering poor folks. Would this be celebrated as a thoughtful message movie, reminding us all of the importance of hard work? Not a chance.

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Seeking Alien Trash

I was interviewed by Seth Shostak (minutes 15:45 to 23:00 of this show) on possible observational consequences of my game theory model of interstellar colonization. (Previous posts on this here, here, here.)

The bottom line is that even if an alien colonization wave once passed this way, our astronomical theory and observation abilities are probably still just too weak to see the telltale signs of such a wave.

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The SETI Game

When listening for signals from aliens, it isn’t enough to just point an antenna at the sky. One must also choose details like directions, angles, frequencies, bandwidths, pulse widths, and pulse intervals. Apparently most SETI searches assume that for a given signal power density, aliens would pick details to make it as easy as possible for us to detect their signals. So standard SETI searches are optimized for such easily-seen signals. Two excellent papers, published back in July, instead consider what sort of signals would be sent by “beacon” building aliens, who seek to create the maximum possible power density at any given distance away from them.  (One of the authors is SF author Greg Benford.) Such signals are quite different, and most of today’s SETI searches are not very good at seeing them:

Minimizing the cost of producing a desired power density at long range … determines the maximum range of detectability of a transmitted signal. We derive general relations for cost-optimal aperture and power. … Galactic-scale beacons can be built for a few billion dollars with our present technology. Such beacons have narrow “searchlight” beams and short “dwell times” when the beacon would be seen by an alien observer in their sky. … Cost scales only linearly with range R, not as R2. … They will likely transmit at higher microwave frequencies, 10 GHz. The natural corridor to broadcast is along the galactic radius or along the local spiral galactic arm we are in. …

Cost, spectral lines near 1 GHz, and interstellar scintillation favor radiating frequencies substantially above the classic “water hole.” Therefore, the transmission strategy for a distant, cost-conscious beacon would be a rapid scan of the galactic plane with the intent to cover the angular space. Such pulses would be infrequent events for the receiver. Such beacons built by distant, advanced, wealthy societies would have very different characteristics from what SETI researchers seek. … We will need to wait for recurring events that may arrive in intermittent bursts. …

A concept of frugality, economy. … directly contradicts the Altruistic Alien Argument that the beacon builders will be vastly wealthy and make everything easy for us. An omnidirectional beacon, radiating at the entire galactic plane, for example, would have to be enormously powerful and expensive, and so not be parsimonious. … For transmitting time t, receiver detectability scales as t1/2. But at constant power, transmitter cost increases as t, so short pulses are economically smart (cheaper) for the transmitting society. A 1-second pulse sent every 10 minutes to 600 targets would be 1/600 as expensive per target, yet only *1/25 times harder to detect. Interstellar scintillation limits the pulse time to >10-6 s, which is within the range of all existing high-power microwave devices. Such pings would have small information content, which would attract attention to weaker, high-content messages. …

Cost-optimized beacons … can be found by steady searches that watch the galactic plane for times on the scale of years. Of course, SETI literature abounds with consideration of the trade-offs of search strategy (range vs. EIRP vs. pulse vs. continuous (continuous wave, CW) vs. polarization vs. frequency vs. beamwidth vs. integration time vs. modulation types vs. targeted vs. all-sky vs. Milky Way). But, in practice, search dwell times are a few seconds in surveys and 100–200 seconds for targeted searches. Optical searches usually run to minutes. And integration times are long, of order 100 s, so short pulses will be integrated out. …

Behind conventional SETI methods lies the assumption that altruistic beaming societies will send persistent signals. In searches to date, confirmation attempts, when the observer looks back at a target, in practice usually occur days later. Such surveys have little chance of seeing cost-optimized beacons. … Distant, cost-optimized beacons will appear for much less time than as assumed in conventional SETI. Earlier searches have seen pulsed intermittent signals resembling what we (in this paper) think beacons may be like, and may provide useful clues. We should observe the spots in the sky seen in previous work for hints of such activity but over year-long periods. (more)

Of course both the usual assumption that aliens will pay any cost to make a given power density signal easy for us to see, and the new assumption that aliens ignore our costs and merely seek to maximize power density, are both somewhat unsatisfactory. It would be better to model this interaction as a game, where each side has a limited budget and seeks to maximize the probability of at least one successful communication, holding constant the behavior it expects from the other side. Each side would of course also have to integrate over possible locations and budgets for the other side.

I’m very interested in working with (sim, math, or physics) competent folks to more formally model this SETI communication game.

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