We May Be All Alone In the Known Universe, a New Oxford Study Suggests (fortune.com)

A new study by Oxford University's Future of Humanity Institute determined that it's quite likely humans are alone in the observable universe. Fortune reports: The study looked at the Fermi paradox -- the apparent discrepancy between the seeming likelihood of alien life, given the billions of stars similar to our sun, and the scant evidence that such life actually exists. The paradox was named after physicist Enrico Fermi, who famously asked his colleagues at Los Alamos, N.M.. "Where Is Everyone?"

The study authors then examined various hypotheses and equations used to resolve the Fermi paradox. The results weren't pretty: "Our main result is to show that proper treatment of scientific uncertainties dissolves the Fermi paradox by showing that it is not at all unlikely ex ante for us to be alone in the Milky Way, or in the observable universe. Our second result is to show that, taking account of observational bounds on the prevalence of other civilizations, our updated probabilities suggest that there is a substantial probability that we are alone." SpaceX CEO Elon Musk cited the study's conclusions as an "added impetus" for humanity to become a spacefaring civilization capable of extending life beyond Earth. He tweeted: "This is why we must preserve the light of consciousness by becoming a spacefaring civilization & extending life to other planets..."

Comments

Fermi Paradox is useless

[locater16]

The Fermi Paradox is an utterly useless test. It takes variables you have no data on and then says to compute their probability.

Statistical probability, to be of any use in the real world at all, must by definition be based off already measurable data. That we have basically no measurement of any of this data means it is impossible to use the supposed equation of The Fermi Paradox to determine anything at all.

That this "equation" is mentioned with anything like passing respect should be considered a joke. That a paper from Oxford uses it is, one would hope, a joke from a couple drunk frat students hoping to get an easily published paper out to boos their careers.

Re:Fermi Paradox is useless

[Anonymous Coward]

you can use whatever you like. The reality is locater16 is correct. We have almost no data to build any sort of statistical model with. We can't even conclusively say their is no life in our solar system except on earth with any real certainty. At this point we only have a single data point.

Re:Fermi Paradox is useless

[smi.james.th]

I'm going to be pedantic here and point out that there's a difference between the Fermi paradox and the Drake equation, I think you're referring to the latter. Fermi simply asked the question - if the universe is so big and so old, where is everyone else? Frank Drake came up with the equation and the variables to which you're referring, and Carl Sagan popularised it by estimating these probabilities quite optimistically high.

Re:Fermi Paradox is useless

[religionofpeas]

Simple answer to the paradox is that space is just too big. Technology to visit other stars may not be possible, or be sufficiently rare that expansion can go undetected.

Re:Fermi Paradox is useless

[meglon]

Fermi's paradox is telling us something, just not a lot. There is probably no other expansive, technological civilization in the Local Group. That has always looked most likely and it probably always will.

No, it hasn't always looked most likely, and quite frankly it never will.... at least not in the next 1000 years or so. Our data points for life in the observable universe, the local group, or even our galaxy is so infinitesimally small that one would have to be a complete idiot to suggest it says anything other than "we don't have a fucking clue."

Re:Fermi Paradox is useless

[swillden]

The Fermi Paradox is an utterly useless test. It takes variables you have no data on and then says to compute their probability.

You mean the Drake equation, not the Fermi Paradox, and you're wrong about its usefulness, as you'd know if you bothered to read the paper. The authors make a very convincing statistical argument that the Drake equation actually resolves the Fermi Paradox.

Statistical probability, to be of any use in the real world at all, must by definition be based off already measurable data.

True

That we have basically no measurement of any of this data

False. As the paper points out, we can estimate the distribution of many of the astrophysical numbers with relatively low uncertainty -- a few orders of magnitude. And while the others are much more difficult, when we don't know how to estimate a parameter, it is often feasible to bound the parameter and estimate the degree of uncertainty. In this case, the authors construct plausible estimates for the uncertainty of the really difficult parameters. The uncertainties are enormous precisely because we know so little. For example, they estimate that our best estimate of f_l ranges over 200 orders of magnitude. They note that this is a conservative estimate, that the actual uncertainty may be much larger, but that larger uncertainties merely strengthen their result.

The authors assume that the parameter values are uniformly distributed, calculate the resulting PDF of N and conclude that based on our best knowledge (which is very poor -- that's the whole point of the paper, to make sure the paucity of data is properly considered), there is a significant probability that we are alone in the galaxy, and in the observable universe. Their PDF also shows that there is a significant probability that we are not alone. In fact the probabilities of being alone and not being alone are close to equal.

Thus, the paper rigorously demonstrates that the Fermi Paradox is not paradoxical, precisely because we cannot estimate the parameters to Drake's equation. They show that because our knowledge is so poor, universes that are both empty and teeming with intelligent life fall well within the bounds of a careful, rational, and mathematical analysis based on our best knowledge.

In short, they rigorously demonstrated that your intuition about Drake's equation is correct, that our knowledge of the parameters is so weak that the resulting equation does not allow us to predict anything.

However, they also note that the amount of effort we've put into SETI provides us with actual data we can use to revise our estimates of the Drake Equation parameters, albeit only a little bit. They apply Bayes Theorem under a few different models to update their uncertainty estimates, and use the updated parameters to recalculate the probability that we're alone. This is a process that we can continue over time, updating the parameter PDFs based on observations (of various kind, not just SETI null results), gradually narrowing the uncertainty.

That a paper from Oxford uses it is, one would hope, a joke from a couple drunk frat students hoping to get an easily published paper out to boos their careers.

You should read the paper. It's actually quite carefully reasoned and interesting.

Let's ask the oracle!

[SciCom Luke]

"Are we alone in the universe?" she asked.
"Yes," said the Oracle.
"So there's no other life out there?"
"There is. They're alone too."

Re:Let's ask the oracle!

[SciCom Luke]

In all fairness, I shamelessly stole it from James Miller: https://pics.me.me/yes-oracle-...

It's a Calculation problem

[hcs_$reboot]

As long as we don't have the right estimation of the probability that life exists on a planet, we cannot really assess if life exists or no. Now given the gigantic (known) number of galaxies containing a gigantic number of stars, even if that life probability is low, that would be quite a stretch to conclude life exists only on Earth.

Re:It's a Calculation problem

[Anonymous Coward]

We know Jesus lives in Heaven and Superman (used to) live on Krypton. So that's 3 planets already in the numerator. But don't try and bullshit me about global warming. NASA needs to cut that shit out.

Re:It's a Calculation problem

[m.alessandrini]

I don't know, it's true that there are billions of billions of stars and planets, but thinking of the billions of billions ways how random atoms and molecules can combine, to obtain something that vaguely resembles life, i.e. starting replicating and self-organizing and all the rest, I think it's not so absurd to think that it could have happened only a very few times in all the universe.

Re:It's a Calculation problem

[mentil]

random atoms bumping together made life

It's not atoms bumping together. But when two amino acids love each other VERY much...

oblig xkcd

[religionofpeas]

https://xkcd.com/384/

Re:With morons like Trump "running things"

[Immerman]

>The universe is still young by cosmological scales. Why do they assume that extraterrestrial life has to be zipping around the universe building Dyson spheres and shit? How do they know that there isn't life elsewhere that is less advanced than us, as advanced as us or more advanced but not starfaring?

Because our sun is pretty young by the standards of similarly metal-rich stars, and life appears to have started on this planet pretty much as soon as liquid water was able to exist on the surface, suggesting that the odds of life forming are very high. Unless we assume there was something very special about the inert rocks here (and it's generally considered poor science to assume we're in an unusual part of the universe), that in turn suggests that a similar process probably occurred around many other similarly metal-rich stars a billion of years before our planet existed. Even assuming life started on one of the other planets and migrated here via early-system impacts doesn't extend the timeline much (and if life migrated here from another star then it boosts the odds that the same thing happened to other stars as well)

And, given a billion-year head start, even one expansive space-faring species has had enough time to colonize the entire galaxy several times over by now. The fact that we see no evidence of that suggests that either we don't know how to look, or that in all that time not one species has arisen that is at all inclined to leave its home planet. Because once a species is firmly established in space, and thus has all the technology necessary for (slow) interstellar travel, and the proven inclination to expand beyond their world into artificial environments, it seems almost inevitable that some group will eventually head for another star - either for the uncontested riches waiting there, or to get away from a stellar civilization they find unpleasant, or even just out of curiosity.

Re:Don't give up

[Immerman]

In fairness, if we have the technology to effectively colonize Mars, then deflecting an "planet-killer" asteroid should be fairly trivial. And if we're able to travel between stars at even a few percentage of light speed, then it's probably easy enough to just keep moving the Earth further from the sun to maintain a pleasant environment - some size large ion drives on the moon, firing for several million years, should tow the Earth along just fine.

Of course, once you've done that it's not such a stretch to put some size-large lights on the moon as well, to illuminate the Earth in lieu of the sun, and head into interstellar space. With the aid of some mildly efficient mass-energy conversion the moon should provide plenty of power for the journey. The real question is, do all the terraformed planets head to the same star, or do we scatter in all directions?

Re:Don't give up

[Areyoukiddingme]

If an Asteroid decides to come this way then we can't do much about it.

If an asteroid decides to come this way, we're not alone in the universe.

Never anthropomorphize asteroids. They hate that.