Posts Tagged ‘Alien’
“I’m sure the universe is full of intelligent life. It’s just been too intelligent to come here.”*…
The Fermi paradox, named for physicist Enrico Fermi, is the apparent contradiction between the lack of evidence for extraterrestrial civilizations and various high estimates for their probability (e.g., some of the optimistic estimates for the Drake equation). Fermi wondered, “where are they?”
By way of context, Tim Urban in his wonderful Wait But Why?:
As many stars as there are in our galaxy (100 – 400 billion), there are roughly an equal number of galaxies in the observable universe—so for every star in the colossal Milky Way, there’s a whole galaxy out there. All together, that comes out to the typically quoted range of between 1022 and 1024 total stars, which means that for every grain of sand on every beach on Earth, there are 10,000 stars out there.
The science world isn’t in total agreement about what percentage of those stars are “sun-like” (similar in size, temperature, and luminosity)—opinions typically range from 5% to 20%. Going with the most conservative side of that (5%), and the lower end for the number of total stars (1022), gives us 500 quintillion, or 500 billion billion sun-like stars.
There’s also a debate over what percentage of those sun-like stars might be orbited by an Earth-like planet (one with similar temperature conditions that could have liquid water and potentially support life similar to that on Earth). Some say it’s as high as 50%, but let’s go with the more conservative 22% that came out of a recent PNAS study. That suggests that there’s a potentially-habitable Earth-like planet orbiting at least 1% of the total stars in the universe—a total of 100 billion billion Earth-like planets.
So there are 100 Earth-like planets for every grain of sand in the world. Think about that next time you’re on the beach.
Moving forward, we have no choice but to get completely speculative. Let’s imagine that after billions of years in existence, 1% of Earth-like planets develop life (if that’s true, every grain of sand would represent one planet with life on it). And imagine that on 1% of those planets, the life advances to an intelligent level like it did here on Earth. That would mean there were 10 quadrillion, or 10 million billion intelligent civilizations in the observable universe.
Moving back to just our galaxy, and doing the same math on the lowest estimate for stars in the Milky Way (100 billion), we’d estimate that there are 1 billion Earth-like planets and 100,000 intelligent civilizations in our galaxy.1
SETI (Search for Extraterrestrial Intelligence) is an organization dedicated to listening for signals from other intelligent life. If we’re right that there are 100,000 or more intelligent civilizations in our galaxy, and even a fraction of them are sending out radio waves or laser beams or other modes of attempting to contact others, shouldn’t SETI’s satellite dish array pick up all kinds of signals?
But it hasn’t. Not one. Ever…
Perhaps. as we’ve mused here at (R)D before, life is there, but we’re not seeing it because it isn’t a form of life that we recognize: c.f., “Two possibilities exist: Either we are alone in the Universe or we are not. Both are equally terrifying” and “That is a very Earthling question to ask, Mr. Pilgrim.”
But there are some who’ve refused to give up on the search for more traditionally-defined life; indeed, a new study quantifies the “fraction” (to which Urban alludes, above) of civilizations that could (should?) be communicating around our galaxy:
One of the biggest and longest-standing questions in the history of human thought is whether there are other intelligent life forms within our Universe. Obtaining good estimates of the number of possible extraterrestrial civilizations has however been very challenging.
A new study led by the University of Nottingham and published [earlier this month] in The Astrophysical Journal has taken a new approach to this problem. Using the assumption that intelligent life forms on other planets in a similar way as it does on Earth, researchers have obtained an estimate for the number of intelligent communicating civilizations within our own galaxy -the Milky Way. They calculate that there could be over 30 active communicating intelligent civilizations in our home Galaxy…
Details at (the slightly misleadingly-titled): “Research sheds new light on intelligent life existing across the galaxy.”
* Arthur C. Clarke
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As we stay tuned, we might send far-seeing birthday greeting to Fred Hoyle; he was born on this date in 1915. A prominent astronomer, he formulated the theory of stellar nucleosynthesis. But he is rather better remembered for his controversial stances on other scientific matters—in particular his rejection of the “Big Bang” theory (a term he coined, derisively, in one of his immensely-popular series The Nature of the Universe on BBC radio) and his promotion of panspermia as the source of life on Earth.
“That is a very Earthling question to ask, Mr. Pilgrim”*…
What does it mean to be alive? Science, shockingly, still doesn’t have a consensus. For example, is it fair to say that the novel coronavirus now sweeping the world is alive? The short answer is there isn’t one agreed-upon answer — for something so basic, you’d think life would be easier to define.
The first recorded definition of life came from Aristotle in ancient Greece, around 350 BC. He posited that to be alive, something must grow, maintain itself, and reproduce. In contrast, the most well-known modern definition is probably NASA’s, which says living things must be “a self-sustaining chemical system capable of Darwinian evolution.” Take, for example, great apes: given appropriate resources like food and water, the “machinery” of a great ape — its organs and nervous system — regulates itself, keeping the great ape functioning in most conditions. They are also capable of evolution — just look at us. But this isn’t the only accepted definition of life. There are actually over 100 published definitions!
A lot of the debate comes down to the fact that the various fields of science approach the topic quite differently. A geneticist, whose focus is on known organisms and their genomes, will very likely have a different view on what constitutes life than an astrophysicist, who considers a more expansive, universal definition.
But beyond that, most of these definitions of life fall short in another, very subtle way: They are based on the origins of life on our planet. This means our hypotheses for what sentient and conscious aliens look like almost always reflect humankind. You only have to look at a Star Trek episode to see it — humanity likes to make the world in our image, which is partially why in sci-fi and fantasy a lot of the “aliens” look a lot like ourselves. (Okay, and because it’s easier to dress a human up as a humanoid alien)…
Cal Tech scientist (and published poet) Alison Koontz explains why none of the 100 definitions of life we have may be accurate away from “home”: “Our concept of life is too Earth-centric — alien life might look totally different.”
* Slaughterhouse-Five
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As we confront our chauvinism, we might send speculative birthday greetings to Harlan Jay Ellison; he was born on this date in 1934. A member (with Philip K. Dick, Samuel Delany, Thomas Disch, Ursula K. LeGuin, and Roger Zelazny) of the American “new wave” science fiction vanguard, Ellison wrote more than 1,700 short stories, novellas, screenplays, comic book scripts, teleplays, essays, and a wide range of criticism covering literature, film, television, and print media. Some of his best-known work includes the Star Trek episode “The City on the Edge of Forever“, his A Boy and His Dog cycle, and his short stories “I Have No Mouth, and I Must Scream” and “‘Repent, Harlequin!’ Said the Ticktockman“… for which he won many, many awards, including multiple Hugos, Nebulas, and Edgars.
Ellison is also remembered for his outspoken, sometimes combative personality, of which Robert Bloch (the author of Psycho) said “[Ellison is] the only living organism I know whose natural habitat is hot water.”
“Who you gonna call?”*…
Let’s say your house is on fire, or overrun by a gang of psychotic raccoons. You don’t hesitate—you take out your phone, and you call the fire department, or animal control, and then firemen/raccoon-wranglers are promptly dispatched to your home. These are well-established protocols, essential to the maintenance of a mostly not-on-fire, feral-animal-free society.
But what about UFOs? What about extraterrestrial beings? Faced with some six-eyed slime-being rooting through your trash, or a spacecraft idling above your backyard (provided it’s not Elon Musk’s “nuclear alien UFO” again), who exactly would you think to call? And what would whoever you called do, when you called them?…
Find out at: “If You Find Aliens, Who Do You Call?”
[Picture above: source]
* Ray Parker, Jr., theme from Ghostbusters
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As we let our fingers do the walking, we might recall that it was on this date in 1953 that the Air Force declassified and released a file in which Lt. David C. Brigham, the pilot of an F-84 “Thunderjet,” reported that a small, metallic, disc-shaped object made a controlled, sweeping pass at the American jet fighter-bomber over the Sea of Japan. “It closed rapidly and just before it would have flown into his fuselage, it decelerated to his air-speed almost instantaneously, the pilot reported. “In doing so it flipped up its edge at approximately a 90-degree bank. Then it fluttered within 20 feet of his fuselage for perhaps two or three seconds, pulled away and around his starboard (right) wing, appearing to flip once as it hit the slipstream behind his wing tip fuel tank… Then it passed him, crossed in front of him and pulled up abruptly, appearing to accelerate, and shot out of sight in a steep, almost vertical climb. It did so more sharply than a plane could have done. Its maneuvering throughout was always clear and precise.”
F-84 “Thunderjet,” ca. 1952
HAPPY MOZART’S BIRTHDAY!
“To declare that Earth must be the only planet with life in the universe would be inexcusably bigheaded of us”*…
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If any intelligent life in our galaxy intercepts the Voyager spacecraft, if they evolved the sense of vision, and if they can decode the instructions provided, these 116 images are all they will know about our species and our planet, which by then could be long gone…
When Voyager 1 and Voyager 2 launched into space in 1977, their mission was to explore the outer solar system, and over the following decade, they did so admirably.
With an 8-track tape memory system and onboard computers that are thousands of times weaker than the phone in your pocket, the two spacecraft sent back an immense amount of imagery and information about the four gas giants, Jupiter, Saturn, Uranus, and Neptune.
But NASA knew that after the planetary tour was complete, the Voyagers would remain on a trajectory toward interstellar space, having gained enough velocity from Jupiter’s gravity to eventually escape the grasp of the sun. Since they will orbit the Milky Way for the foreseeable future, the Voyagers should carry a message from their maker, NASA scientists decided.
The Voyager team tapped famous astronomer and science popularizer Carl Sagan to compose that message. Sagan’s committee chose a copper phonograph LP as their medium, and over the course of six weeks they produced the “Golden Record”: a collection of sounds and images that will probably outlast all human artifacts on Earth…
More (including an interactive decoding of the symbols on the disc) at “The 116 photos NASA picked to explain our world to aliens.”
And for an update on NASA”s attempts at interstellar communication, check here.
* Neil DeGrasse Tyson, Death By Black Hole
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As we contemplate co-habitation of the universe, we might send out-of-this-world birthday greetings to Alan B. Shepard; he was born on this date in 1923. A naval aviator and test pilot, he was selected in the first class of American astronauts, the “Mercury Seven”; in 1961, he piloted the first American manned mission, “Freedom 7,” becoming the first American (and second man, after Yuri Gagarin) into space. Ten years later, he was part of the Apollo 14 crew, piloting the lunar module for Nasa’s third successful moon landing.
Shepard during the “Freedom 7” flight
“I’ll reshoot a corridor 13 different ways, and you’ll never recognize them”*…
… one of hundreds of stills of dark passages available at the Sci-Fi Corridor Archive.
* Ridley Scott (from whose Alien [1979] the above example is taken)
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As we watch our steps, we might recall that it was on this date in 1958 that Kurt Neumann‘s cinematic tale of technologically-enabled metamorphosis, The Fly, premiered. With a screenplay by James Clavell (his first), it spawned two sequels and a remake (by David Cronenberg). The original has a “95% fresh” rating on Rotten Tomatoes.
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