Cypress (03-25-2023)
Cypress (03-25-2023)
In statistics, the higher the number, the more likely a rare event will occur. It doesn't matter if the odds of life are low, the more opportunities, the more likely life will develop.
Our Sun will eventually become a white dwarf. It's too small to nova. After a few billion years, it'll become a red giant and smoke the Earth, but warming the gas giants where life could develop (or move to) their moons. Eventually the Sun will shrink to a white dwarf.
https://www.nasa.gov/image-feature/g...e-a-black-hole
Will the Sun become a black hole? No, it's too small for that!
The Sun would need to be about 20 times more massive to end its life as a black hole. Stars that are born this size or larger can explode into a supernova at the end of their lifetimes before collapsing back into a black hole, an object with a gravitational pull so strong that nothing, not even light, can escape. Some smaller stars are big enough to go supernova, but too small to become black holes — they'll collapse into super-dense structures called neutron stars after exploding as a supernova. But the Sun's not big enough for this fate, either: It has only about one-tenth of the mass needed to eventually become a neutron star.
So what will happen to the Sun? In some 6 billion years it will end up as a white dwarf — a small, dense remnant of a star that glows from leftover heat. The process will start about 5 billion years from now when the Sun begins to run out of fuel.
Like most stars, during the main phase of its lifetime, the Sun creates energy by fusing hydrogen atoms in its core. In about 5 billion years, the Sun will start to run out of hydrogen in its core to fuse, and it will begin to collapse. This will let the Sun start to fuse heavier elements in the core, along with fusing hydrogen in a shell wrapped around the core. When this happens, the Sun's temperature will increase, and the outer layers of the Sun's atmosphere will expand so far out into space that they'll engulf Earth. (This would make Earth uninhabitable for life as we know it — though other factors in planetary evolution might make it uninhabitable before that point.) This is the red giant phase, and it will last about a billion years, before the Sun collapses into a white dwarf.
"Hatred is a failure of imagination" - Graham Greene, "The Power and the Glory"
Cypress (03-25-2023), Saint Guinefort (03-26-2023)
Before our sun becomes a white dwarf it will vaporize our oceans and incinerate our atmosphere. So we aren't going to be looking to white dwarfs as candidates for habitable systems.
NASA's estimate of 300 million systems with rocky planets that potentially could host life is only based on being located in the Goldilocks zone, and even the authors admitted this was a weakness of their paper since there are other criteria that make a planet habitable.
This is my thought experiment on other potentially neccessary criteria for a planet to possibly host life:
Probability liquid water exists - 50% (p50). Our system has two near-Earth sized rocky planets in the Goldilocks zone, only one of which has liquid water. So p50 seems like a reasonable guess.
Probability of a strong magnetic field - 33% (p33). Of three rocky planets in the Goldilocks zone of our system, only one has a strong magnetic field. So p33 seems like a reasonable guess.
Probability of permanent stable orbital mechanics - 50% (p50). In the absence of tangible information, an even chance seems like a reasonable guess.
Probability of large gas giant in outer system to clear out any frequent incoming asteroids of a lethal size - 50% (p50). In the absence of tangible information, an even chance seems like a reasonable guess
Probability abiogenesis will actually take place, even if all conditions are met: if we assume the emergence of cellular life for prebiotic materials is difficult to achieve and something of a fluke, assume probability of 1%. If we assume life readily emerges in the presence of liquid water, assume probability 50%.
High end estimate: 6.25 million planets in Milky Way host life.Water = p50.
Magnetic field = p33
Stable orbital mechanics = p50
Gas giant clearing asteroids = p50.
Abiogenesis, low confidence = p1
Abiogenesis, high confidence = p50
Low end estimate: 125,000 planets in Milky Way host life.
Either way, that is less than 0.00001 percent of star systems in Milky Way that would host life.
And that is without further culling for the probability intelligent life would emerge on a planet that happens to have a biosphere.
Doc Dutch (03-25-2023)
"Hatred is a failure of imagination" - Graham Greene, "The Power and the Glory"
Cypress (03-26-2023)
The JWT found no evidence of an atmosphere at the near Earth-sized rocky planet Trappist-1.
But there are other near Earth-sized rocky exoplanets in the Trappist system which haven't been examined for atmospheres yet.
https://www.space.com/james-webb-spa...st-1-exoplanet
Doc Dutch (03-28-2023)
I can prove YOU wrong. Is there any evidence there is alien life out there? Answer; NO.
Yet, I don't know how anyone, particularly those who refuse to acknowledge the possibility that there is a God, can ridicule the idea there is no alien life out there based on facts.
It's a REALITY thing. There has been ZERO evidence of alien life except for Hollywood's versions of it.
"When government fears the people, there is liberty. When the people fear the government, there is tyranny."
A lie doesn't become the truth, wrong doesn't become right, and evil doesn't become good just because it is accepted by a majority.
Author: Booker T. Washington
That didn't prove me wrong. I never said there was DEFINITELY life in elsewhere in the universe. Just that scientifically, it's a very logical proposition. I personally can't imagine trillions of other suns, and ours is the only one that has a planet w/ life.
Are you referring to me w/ that 2nd line? I never said there isn't the possibility of a God.
And back to the 1st line: You have NO IDEA if there is or isn't evidence of alien life "out there." No idea whatsoever. There could be a HUGE amount of evidence. We just haven't discovered it yet. You know - there is the whole "don't have the technology to travel many light years" issue.
You know there is a form of atheism that basically just fails to believe in God as opposed to "refusing the acknowledge the possibility". I'm that kind of atheist. While I accept that I COULD BE WRONG right now I fail to see sufficient evidence for God. But if more information comes to me that proves to be compelling I will hopefully change my mind.
Sounds like that is what you are in relation to alien life. You simply fail to see any evidence for it, so you assume it likely doesn't exist. If such evidence comes to the fore you'll change your mind. Fair enough.
As the other poster noted, however, no one on here is saying for sure there's alien life. Just that all things considered the likelihood is non-zero. But it's all a guess anyway.
I tend towards being agnostic about alien life or supreme dieties.
But, the universe itself seems primed for life. Carbon and water are almost uniquely adapted to provide the scaffolding for the emergence of life.
We can't categorically discount that this planet has the only life in the galaxy. But the fact that pre-biotic amino acids are ubiquitous in the universe is at least circumstantial evidence that the universe is primed for life.
On the flip side, I don't think there's any direct evidence of a Christian God who became incarnate as Jesus. But I am prepared to accept the possibility there is some higher organizing principle underlying the cosmos and all of reality, the the fine tuning of the cosmos may be circumstantial evidence of it.
Saint Guinefort (03-29-2023)
Primed? The elements are there. The only thing missing is life itself. It's like prepping a garden; pick a nice sunny spot, till the soil, add fertilizer, install a watering system. So what's missing? Seeds of life.
While it's possible, that the seeds could spontaneously generate, the odds of doing so seem a bit long. LOL
FWIW, I do believe, given enough attempts, the seeds could self-generate, but it would take billions of years and trillions of attempts. The current results bear this out.
"Hatred is a failure of imagination" - Graham Greene, "The Power and the Glory"
Cypress (03-30-2023)
"Hatred is a failure of imagination" - Graham Greene, "The Power and the Glory"
Saint Guinefort (03-30-2023)
Agreed, that's what I'm saying. The building blocks for life are there, but the jump from pre-biotic chemistry to cellular life seems neither obvious nor easy.
My guess is that it takes a rare set of perfect storm conditions for self replicating life to emerge from inert chemicals.
I think we should get closer to an answer by establishing whether or not microbial life exists, or did exist, on Mars, Europa, Enceladus, Ganymede. And also if we can detect atmospheres with biosignatures on exoplanets.
Detecting artificial radio signatures in the EM spectrum is a search for a needle in a haystack, and if primitive life is as rare as I think it is, I doubt there are very many technologically advanced civilizations in the galaxy.
Doc Dutch (03-30-2023)
"Hatred is a failure of imagination" - Graham Greene, "The Power and the Glory"
Cypress (03-30-2023)
Doc Dutch (03-30-2023)
Bookmarks