At this point I think it can be argued that the most extraordinary claim would be that Earth is the only place with life of some sort. Obviously we have no proof of life elsewhere but it would be strange indeed if we were alone.
That there must be hundreds of thousands of earth-like planets at an absolute minimum in this galaxy alone seems like a foregone conclusion, if not millions of them. The idea that life might only have developed on earth is more a Biblical dogma than a scientific hypothesis. A more reasonable hypothesis is that the vastness of relativistic space-time ensures that it’s astronomically improbable that such intelligent life forms will ever encounter each other. Though I imagine there are probably some interesting planetary systems richer in life than ours, where multiple planets in the same stellar system are inhabited by independently developed life forms.
We have no data as to the likelihood of life arising on another planet - for all we know, life is so ridiculously improbable that it might not occur on average in the lifespan of a single universe. As to this planet, all we know is that it is not unreasonably large and that if there were water on it then that water could be liquid. We know nothing else about, say, its atmosphere, its general composition, whether it has a magnetic field, whether it is tidally locked, whether it has a satellite large enough to help keep its axis of rotation reasonably stable, whether it manages to go long periods free of catastrophic asteroid bombardment… and at 1400 light-years distance, our chance of finding meaningful answers to these questions is not very much greater than our chance of ever going there in person.
I really hate how every even remotely similar planet is described as “Earth 2”.
No, it’s hotter and 5 times more massive than Earth. It would have less than twice normal Earth gravity, I believe, but that would still be very problematic for Humanity, along with the brutal temperatures that wouldn’t be friendly toward our preferred plant life.
That being said, we’re getting closer. This one has definitely had a long time in a habitable zone to cook something up.
Something like the Terrestrial Planet Finder will probably be the next step in helping to answer such questions (if NASA will ever bother to fund the thing).
Solid data, no. But we do know that physics and chemistry seems to be the same in the entire observable universe, and that organic compounds are found throughout the solar system. The anthropic principle leaves open the possibility that you suggest, but it seems far more likely that life is simply a natural consequence of chemical processes in suitable environments over long periods of time. If not, there is not even the vaguest hypothesis for why we are so special.
Life (of a chemical nature) is either so vastly improbable–the odds for spontaneous abiogenesis beyond astronomical–that it only occurred once in the universe, or such a natural, emergent consequence of any complex collection of chemicals that has a tendency to regulate the flow of energy that it probably spontaneously emerges all over the damned place. We don’t have enough empirical data about the emergence and distribution of life to arrive at anything more than speculative conclusions, but the fact that we are made of ordinary chemicals which are found on planets and moons, in interplanetary space, and even in the interstellar medium argues toward the potential of frequent occurrance. However, we shouldn’t assume that “terrestrial” (e.g. Earthlike) planets are a necessary or even most favorable condition for life to emerge. We tend to think Earth is pretty keen because it has a nice balance of light and dark, liquid water, good weather (at certain latitudes), the appropriate mixture of oxygen, nitrogen, carbon dioxide, and trace gases to let both us and plantlife breathe (at least, this geologic period), just enough ultraviolet light, and so forth, but for other forms of life this may well be a completely hostile environment.
However, we cannot even speculate with any authority at this point about the likelihood or distribution of complex, much less intelligent life. And it is unlikely that we’ll reach any firmer conclusions on this with remote observation at interstellar distances even if we find strong evidence for the existance of life.
Stranger
Amino acids have been found in space.
Obviously not proof of life, but it shows that the necessary molecules seem to be common, at least in our solar system. It seems like we’d have to explain why this wouldn’t be so in other systems and why life wouldn’t evolve when the right molecules and conditions are present. Granted, complex life, let alone intelligent technological life, is another thing altogether.
The interest in “earth-like” conditions isn’t entirely naive, though. It’s premised on the fact that organic chemistry requires those conditions, and that the unique role of carbon in being able to form the complex molecules necessary for life pretty much dictates organic chemistry as the basis for it. It’s been speculated that silicon is a potential alternative basis for life-generating molecular chemistry which could exist under entirely different conditions, but that’s just pure speculation.
Well, it is more predicated on the notion that liquid water is the necessary solvent for biochemistry, and water will only be found on ‘terrestrial’ worlds with a surface temperature that varies (mostly) above the freezing point of water and well below 100 degrees Celsius. But both of those are assumptions that are not necessarily valid; among astrobiologists there is a strong consensus that Europa and Ganymede (and perhaps even cold Titan) are the most likely bodies in the solar system to contain actively functioning life. (The consensus on Mars is split, with some claiming that life may have existed once but will only be found in fossil form, while others insisting that extremophiles could live in Mars’ current arid and thin atmosphere, somewhere under the surface where the strong UV can’t touch them. Nobody believes that Mars is likely to harbor complex, multicellular life.)
I think life, if it is not uncommon, will be found in the most unexpected places and environments that we wouldn’t have believed it could exist. It may or may not be more prevalent in terrestrial-type worlds, but to look for a planet with characteristics very like ours is using excessively restrictive search parameters. What is more important is to look for key qualities; a high rate of energy throughput or flow, moderate climate variability, an accumulation of complex chemical compounds, and relatively stable orbital parameters. Insisting on liquid surface water or blue skies are just too narrow a set of criterion.
Stranger
What would this discovery change? It’s not like we didn’t expect to find planets similar to Earth.
“Event X has been observed once, we don’t know why it happened, we don’t know how it happened, but I’m sure it’s a pretty common event?” That’s supposed to be a scientific approach? :dubious: I call that a completely unsupported gut feeling.
What makes you think it has to be either very likely or incredibly unlikely? Why couldn’t it be moderatly common or very unlikely?
Why would we need to explain why life wouldn’t appear? How could we do that? We don’t know what the process is. We don’t know how you get from organic molecules to primitive life forms. If it could be established how exactly life appeared, we could guesstimate the likelihood of it appearing again when such or such conditions are met. But lacking this knowledge, it’s impossible to state whether this process is incredibly unlikely or probably extremely common.
It seems to me that it’s people who are convinced there’s intelligent life somewhere out there who are acting on faith. We don’t have the knowledge that would allow us to make even an educated guess:
-We don’t know how life appeared hence how likely such an event is.
-We don’t know what conditions are required for life to be sustainable. For instance some believe that it wouldn’t on Earth lacking a huge satellite that stabilize our orbit. And the existence of the moon required a pretty peculiar cosmic event. If this is true, then the number of planets that are fit candidates for life would be drastically reduced.
-We don’t know how likely it is that life will evolve into complex form. It took the longest time for muticellular life forms to appear. I don’t think there’s any clear theory about why it appeared then and not earlier or never at all. Given that, it might be that this is extremely unlikely, even when simple life forms are thriving on the planet.
-Intelligent life at least seems pretty uncommon. As far as we know it only happened once on Earth despite the huge numbers of complex species that populated our planet for hundreds of millions of years. So what is this likelihood? How could we tell? We don’t have any data.
Any news what the Planet is like?
Whats the surface gravity? Average temperature?Atmosphere?
Have to disagree with this one — strongly.
Homo sapiens are not the first intelligent species on Earth.
Even if you limit “intelligence” (a pretty slippery term) strictly to human intelligence, it’s not like that intelligence suddenly sprang into being with homo sapiens. Other “homo” species were also intelligent. Difficult to say when that slippery term “intelligence” evolved, but multiple species have had it.
And I’m not one to limit the word “intelligence” strictly to humans. Self-awareness, tool use, tool making, problem solving all exist in other species. As Darwin said, "The difference in mind between man and the higher animals, great as it is, certainly is one of degree and not of kind.”
Mass appears to be between 3 and 7 Earths (5 +/- 2), radius ~ 1.6 Earths with a gravity of ~1.8 Earths.
Wikipedia’s Kepler-452b article has a nice summary. Along with a neat new thing (to me at least ) called an Earth Similarity Index. I’m curious how the various data gets weighted to arrive at a score.
This page has the most information I’ve found on it so far.
I’m curious about its sun. Have been ever since the news said the planet is a billion years older than Earth. I’m curious because a billion years from now, that’s when the Earth (by some estimates) will no longer be able to support complex life due to the sun’s getting hotter.
I found where its sun is hotter than our, yet Kepler-452b’s got the pretty much the same orbital distance from its sun as we do from ours.
So is it a dying planet? Like what we will be in a billion years…a planet in the process of getting cooked by its sun?
This one particular discovery doesn’t change anything. I never said that.
That’s the frustrating part. This planet is over 1000 LY away. Everything we know about physics says that we’ll never go there, and nothing from there will ever come here. Sure, people can speculate about wormholes and faster-than-light travel, but that stuff is so far beyond theoretical that, if you’re honest about it, they’re just gluing some flashing LEDs onto a magic wand and pretending it’s science.
If you restrict yourself to humanoids, I’m not sure what your disagreement is. Australaupithecus appeared about 5 millions years ago, which means extremely recently. Compared to the lenght of time during which there was life and as far as we know no intelligent life, it hints at intelligence not appearing very frequently even when life is thriving.
If you include, say, wolves, crows and octopuses in “intelligent life”, well, maybe you have a point, but I’m not convinced that’s what people had in mind when refering to intelligent life in this thread.
That is a good question that deserves a much longer explanation than I could post here, but it boils down to what I all the Law of No Small Quantities: that is, in the universe there are unique conditions or phenomena which may be counted in occurrence as zero, one, or essentially infinite. That is, such phenomena are either physically impossible (invisible flying pink elephants), totally unique (the Big Bang), or occur in the aggregate at a rate, in cosmological terms, that is beyond our ability to count or conceive (stars, galaxies, atoms, electrons, Marvel movies). The in-between values–that a unique condition could happen only a handful of times over billions of years–is actually the most unlikely of probability distributions, requiring the probability density function to be almost, but not quite, absolutely flat with just a sharp bump at the mean. Such distributions simply do not occur in nature, and the reason for this is clear when you think about it; even the most unlikely–in probability terms, least dense–event even accumulates incidences over a long enough period of time and area to become very probable. If a phenomena such as abiogenesis (the conception of life from ‘non-living material’) is a naturally occurring confluence of conditions or events, even if those events are seriously unlikely–even if they may come together once every billion billion billion chemical reactions on one thousandth of a percent of planets around only G-type stars–the sheer number of potential reactions over a long enough period of time (millions of eons) not only allows for it to occur but makes it practically inevitable in every plausible environment in which it could occur.
The other choice is the PDF equivalent of a Dirac delta function; only a uniquely specific confluence of events and conditions could result in life, hence why we have thus far observed it only once. However, this posture can only be adopted under the presumption that we are somehow specially privileged and uniquely star-bellied sneetches in a universe otherwise devoid of them, which is the same argument made from time immemorial for the presence of an unseen supernatural agency which endowed us with that special privilege, usually in exchange for undying devotion, or at least so say the priests collecting the tithes. (We may question their objectivity just as we would look in askance to a car salesman who insists that his particular Ford Pinto is immune from gas tank rupture because of the special potting compound he painted on the rear bumper.)
Although it is true we have a cohort of exactly one data set, i.e. that all life on Earth appears to have an origin with a common ancestor, we may observe that this life has been extremely proliferate, expanding and adapting to every marine and terrestrial niche, expanding geometrically to the limits of resource and competition in the harshest of environments. Even today, we are surprised to find life in an environments that we have previously assumed could not support such, and further and further back in Earth’s history than we thought the planet could support life. Life on Earth has gone from surviving in a scalding hot reducing environment barely more amenable than the modern day Venus to the toxic highly oxygenated atmosphere that killed nearly every form of anaerobic life on the planet. We may therefore reasonably conclude that when life gets a toehold in any kind of environment that provides nutrients and a flow of energy that can be mediated by chemical reactions it adapts and grows to a high degree of robustness, and hence with even a small probability of occurrence over a sufficiently long interval of time, it is almost inevitable for life to arise in any plausible environment. I would personally give even odds of finding non-terrestrial life on at least one of the Jovian or Saturnian moons that has subterranean water or liquid regardless of the lack of suitable habitability for Earth life, and that the occurrence of life elsewhere in the universe is common rather than infrequent in any zone that has a certain threshold of energy flow (less than harshly ionizing high energy gammas, greater than the inky depths of trans-Neptunian space). However, life that has evolved elsewhere may not look or behave anything we would consider life, and we need to relax our expectations sufficiently to look for any kind of self-organizing and reproducing energy flow mediating patterns in any active environment.
As for intelligent life, I think it is true that we can only speculate very informally about its occurrence and what it would look like, other than that it is manifestly unlikely to occur in the form of bumpy headed humanoids swinging bladed weapons and quoting Shakespeare “in the original” alien form. Although the same arguments as above apply (that if it occurs once, it is probably that it occurs many times) and has certainly lead humanity to occupy every terrestrial environment by the use of tools and technology, human-level cognitive intelligence has not been established as an effective survival strategy over the long term (more than a few million years) and may be mostly a novelty in terms of ultimate evolutionary success. Intelligent alien species may arise frequently but fail against competition pressure with itself or other species, or may be subsumed by the equivalent of plague and disease. And even if intelligence life does occur in frequency elsewhere in the Universe, the large spacing in both time and distance combined with the rapid, cognition augmented adaptive capability may make it hugely improbably that two species at anything like intellectual parity will contact one another and exchange ideas. Even the notion of intellectual parity may itself be hugely improbable; another intelligent species may have evolved so differently that there is just no commonality–in thought, language, philosophy, or even fundamental technology such as mathematics–sufficient to allow for an interchange of ideas any more than you can teach a cephalopod to play gin rummy.
Stranger