Even if it occurs only once in every 100 galaxies, or every 1,000 galaxies, or every 1,000,000 galaxies.... given the number of galaxies in the universe.....
Bad news for alien life
- Thread starter Cypress
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Even if it occurs only once in every 100 galaxies, or every 1,000 galaxies, or every 1,000,000 galaxies.... given the number of galaxies in the universe.....
Dutch Uncle
* Tertia Optio * Defend the Constitution
Agreed "first contact" is highly unlikely in our life times. Even if just capturing communications in the electro-magnetic spectrum.
It's estimated there are between 100B and 400B stars in the Milky Way depending upon the average mass of stars. As the OP points out, since 70% of the stars are low mass M-class red dwarfs, the higher number of stars is more likely.
Agreed. The discussion is life in our galaxy. What are the odds? The same numbers would apply to other galaxies. A discussion you missed is how advanced civilizations may wipe themselves out before acheiving star flight. We are at risk of doing that ourselves. Another is that a supernova within 10 to 25 light years would kill most, if not all, life on a planet. Those stars toward the galactic center are more at risk than stars like ours in the outer arms due to more densely packed stars at the core.
Dutch Uncle
* Tertia Optio * Defend the Constitution
Cypress isn't arguing against life happening, only that it's rare. I agree with him based upon the results.
His question about "what is intelligence?" is valid. This is where he and I part ways a bit; I lean into the Red Queen hypothesis which, among other things, states that in the never-ending competition between predator and prey, human-level intelligence is inevitable. Cypress disagrees on the inevitability. Additionally, I believe a reason why humans are the only consciously sentient animals on the planet is because we either killed them off or nature took care of it for us. The dinosaur-killer asteroid and the Mount Toba supervolcano are examples of natural life-killers.
Mount Toba: Did a Supervolcano Almost Wipe Out the Human Species?
The eruption of the Toba supervolcano, according to theory, plunged the world into an apocalypse, almost wiping out the entire human species.
www.thecollector.com
We fall into the trap of anthropomorizing other life forms, but I agree there is no reason to automatically assume other species will behave a certain way
There is a kernel of truth in that, but there are also rules that are going to place limitations on life.
We understand chemistry very well, and carbon is really the only element that has the electro-chemical properties and flexibility to make complex bonds with other atoms and build long-chain organic polymers necessary for any conceivable kind of life.
Certain stars just aren't going to be suitable candidates or evolution of life on orbiting planets. Actually, probably the large majority of stars.
Older galaxies are not enriched in heavy elements. The oldest galaxies and stars are pretty much just hydrogen and helium. There can't be any life without iron, phosphorus, oxygen, carbon, and the other heavy elements.
A vast range of solar and planetary orbital dynamics are probably going to preclude any kind of life we would recognize.
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NiftyNiblick
1960s Chick Magnet
Perfect inflation stations for dirigibles and blimps, though.
I do think the balance of probability is that somewhere in the universe there is primordial or multi-cellular life, possibly rarely reaching intelligence levels we see in the higher mammals here.Cypress isn't arguing against life happening, only that it's rare. I agree with him based upon the results.
His question about "what is intelligence?" is valid. This is where he and I part ways a bit; I lean into the Red Queen hypothesis which, among other things, states that in the never-ending competition between predator and prey, human-level intelligence is inevitable. Cypress disagrees on the inevitability. Additionally, I believe a reason why humans are the only consciously sentient animals on the planet is because we either killed them off or nature took care of it for us. The dinosaur-killer asteroid and the Mount Toba supervolcano are examples of natural life-killers.
Mount Toba: Did a Supervolcano Almost Wipe Out the Human Species?
The eruption of the Toba supervolcano, according to theory, plunged the world into an apocalypse, almost wiping out the entire human species.
I think the balance of probability is that we will never see any evidence in the next 200 years that there is a footprint of advanced alien intelligence in the interstellar electromagnetic spectrum, or through other remote-sensing techniques we devise.
Nazi Germany learned the hard way that hydrogen is far too reactive to use safely on blimp airships.
NiftyNiblick
1960s Chick Magnet
Oh, the humanity.....Nazi Germany learned the hard way that hydrogen is far too reactive to use safely on blimp airships.
That was a dirigible, by the way.
It had a frame structure.
I've actually ridden on a Goodyear blimp, with my grandfather, back in 1957.
Not very fast, but less uncomfortable than a commercial airliner coach seat.
Cypress isn't arguing against life happening, only that it's rare. I agree with him based upon the results.
His question about "what is intelligence?" is valid. This is where he and I part ways a bit; I lean into the Red Queen hypothesis which, among other things, states that in the never-ending competition between predator and prey, human-level intelligence is inevitable. Cypress disagrees on the inevitability. Additionally, I believe a reason why humans are the only consciously sentient animals on the planet is because we either killed them off or nature took care of it for us. The dinosaur-killer asteroid and the Mount Toba supervolcano are examples of natural life-killers.
Mount Toba: Did a Supervolcano Almost Wipe Out the Human Species?
The eruption of the Toba supervolcano, according to theory, plunged the world into an apocalypse, almost wiping out the entire human species.
I'm not arguing against the notion of rarity.
I'm just saying that given the insanely, incomprehensibly huge numbers we're talking about, even if a fraction of a percentage of planets in the universe supported life and a fraction of a percentage of those planets evolved intelligent life (close to, equal to or above us) we'd still be talking about millions of civilizations similar to ours across the universe. Tens of millions even. Or more.
I'm torn on the question of ability for intergalactic space travel, though. I used to be of the mind that the same physical limitations which keep us in our own yard, would act upon any other living beings and limit them in the same way. But OTOH, physicists talk about things like wormholes that are shortcuts between otherwise incredibly vast expanses of space.
So, maybe we have been and are being visited.
Maybe these other beings don't show themselves because they understand that we are still too primitive to handle the knowledge.
Maybe we're being cultivated and nurtured by some highly advanced gardeners who plant, grow and monitor the progress of new worlds on life hospitable planets, etc, etc.
Who knows.
It's fun to consider the possibilities and talk about, but a waste of time to seriously speculate about for us average, 'non-doctorial physicist' type folk.
Dutch Uncle
* Tertia Optio * Defend the Constitution
On a side note regarding humanity, human behavior and balloons, a month ago I bought some half-inch flashing LED party balloon lights. This winter, when the winds are right and the temps are cold, I plan on launching 5-10 of them to see how many UFO sightings are reported. LOLOh, the humanity.....Nazi Germany learned the hard way that hydrogen is far too reactive to use safely on blimp airships.
That was a dirigible, by the way.
It had a frame structure.
I've actually ridden on a Goodyear blimp, with my grandfather, back in 1957.
Not very fast, but less uncomfortable than a commercial airliner coach seat.
Dutch Uncle
* Tertia Optio * Defend the Constitution
No one is disagreeing with you about "across the Universe". I'm only trying to narrow down the numbers for our galaxy. Given the OP and other factors previously mentioned, there could be fewer than 1000 advanced civilizations in our galaxy.
Even interstellar flight is nearly impossible. Short of your wormhole, I fail to see how anyone could travel the 200M LY to the Andromeda galaxy. There's also the question of "Why?" since there are over 100 billion stars in our own galaxy worth exploring and exploiting.
Intergalactic travel - Wikipedia
There's been a few SF stories about human beings either being cultivated as warriors or quarantined as a violent race off-limits to other advanced civilizations.
UFO enthusiasts are duped by crop circles and flares, so you shouldn't have any problem creating a panicOn a side note regarding humanity, human behavior and balloons, a month ago I bought some half-inch flashing LED party balloon lights. This winter, when the winds are right and the temps are cold, I plan on launching 5-10 of them to see how many UFO sightings are reported. LOL
Dutch Uncle
* Tertia Optio * Defend the Constitution
I considered doing it on Halloween à la Orson Welles's War of the Worlds but figured that'd be too obvious. LOLUFO enthusiasts are duped by crop circles and flares, so you shouldn't have any problem creating a panic
I don't want the balloons crossing airport flight paths and have to consider both temperature for greatest lift and wind direction.
This astrophysicist thinks life on Earth and the rise of homo sapiens was due to a perfect storm of events and it's likely we are the only technological species in the galaxy.
Are We the Only Intelligent Life in the Galaxy?
"With so many exoplanets out there in the galaxy, it seems reasonable to hope that life may be prevalent. On our planet, it took a series of unusual coincidences to give rise to our intelligent civilization, and it’s quite unlikely such serendipity has taken place elsewhere. Science writer and astrophysicist John R. Gribbin examines how everything had to go just right. Perhaps most unlikely of all, he argues, was the development of our technological species—a feat that is probably unique in the Milky Way."
Source: Scientific American, 'Mind Blowing Science, Season 1'
Are We the Only Intelligent Life in the Galaxy?
"With so many exoplanets out there in the galaxy, it seems reasonable to hope that life may be prevalent. On our planet, it took a series of unusual coincidences to give rise to our intelligent civilization, and it’s quite unlikely such serendipity has taken place elsewhere. Science writer and astrophysicist John R. Gribbin examines how everything had to go just right. Perhaps most unlikely of all, he argues, was the development of our technological species—a feat that is probably unique in the Milky Way."
Source: Scientific American, 'Mind Blowing Science, Season 1'
Dutch Uncle
* Tertia Optio * Defend the Constitution
I have over 100B reasons why he could be wrong.
Perfect storms happen, they're just very rare. What we can do is narrow down where such civilizations could exist. I'd rule out core stars due to supernovas. This thread rules out M-class red dwarfs, which are 70% of stars. On the flip side, with 70% of the Milky Way's stars being lower mass stars, the 100B number goes up mathematically. Perhaps doubling or tripling.
So the initial estimates of fl, fi, and fc in the Drake equation are very, very, very, very, very, very low numbers.
That's what always got me about the Drake Equation. It is just a framework of variables without any real estimate of their relative value. I mean we all know that probability is multiplicative so it doesn't add much to say the probability is the product of many terms. It would be cool if there was something other than straight stacking of the probabilities. I appreciate the attempt at thoroughness to the equation, though. It's a nice start.
It's cool that someone is willing to touch the potentially contentious rail of the probability of life-->technical advancement.-->EM signature It is probably going to be the limiting factors in the probabilities.
I am guessing that fl>fi>>fc in any estimation.
The way I read that interpretation is that because they are so unlikely there currently probably is no other technological civilization contemporaneous with us at this time -- but in the ten billion year history of the galaxy there could have been advanced civilizations in the past history of the Milky Way.I have over 100B reasons why he could be wrong.
What we can do is narrow down where such civilizations could exist. I'd rule out core stars due to supernovas. This thread rules out M-class red dwarfs, which are 70% of stars. On the flip side, with 70% of the Milky Way's stars being lower mass stars, the 100B number goes up mathematically. Perhaps doubling or tripling.
Dutch Uncle
* Tertia Optio * Defend the Constitution
Life could have started in several star systems, but never evolved into advanced civilizations due to being wiped out by natural circumstances as previously discussed. Even if they did reach our current level of civilization, they could have been wiped out by any of the space alien equivalent of the Four Horsemen of the Apocalypse: Pestilence, War, Famine and Death.
Still, there should be vestiges of such civilizations be it radio waves, Dyson rings or anything unnatural. The physics of the Universe dictates how everything in it moves. Life is the only variable that doesn't necessarily follow physics.
What are Dyson spheres, and how do we look for them?
Dyson spheres are hypothetical artificial megastructures built around a star to collect all of its radiant energy.
It's definitely cool to think about advanced alien intelligent life, because advanced sentient life did evolve once during Earth's vast geologic history. I guess that makes it seem inevitable.
Wormholes are completely theoretical, and no one has ever seen one. But it's a valid point that there are technologies we can't even imagine.
With all the telescopes pointed at the sky and with six billion smart phones on the planet, I would think by now we would have a vast canon of crystal clear and convincing video and photo evidence of alien spaceships flying around Earth, and not just a small amount of unexplained, grainy, and indeterminate photos/videos.
It's a good point that actual communication with alien civilizations probably can't happen, but there could be fossil evidence of advanced civilization's footprints in the electromagnetic spectrum if they developed the capability of advanced communication and navigation technologies. Signals that we receive thousands of years after they were generated.Life could have started in several star systems, but never evolved into advanced civilizations due to being wiped out by natural circumstances as previously discussed. Even if they did reach our current level of civilization, they could have been wiped out by any of the space alien equivalent of the Four Horsemen of the Apocalypse: Pestilence, War, Famine and Death.
Still, there should be vestiges of such civilizations be it radio waves, Dyson rings or anything unnatural. The physics of the Universe dictates how everything in it moves. Life is the only variable that doesn't necessarily follow physics.
What are Dyson spheres, and how do we look for them?
Dyson spheres are hypothetical artificial megastructures built around a star to collect all of its radiant energy.www.space.com