We Might Be Alone in the Universe

[doubtingthomas]

why would anybody reading this thread care if the sun has been unusually quiet for 9000 years?

Because if the Sun is usually loud and rarely quiet, it would mean that the Sun is not unusual.

[huckelberry]

why would anybody reading this thread care if the sun has been unusually quiet for 9000 years?

Because if the Sun is usually loud and rarely quiet, it would mean that the Sun is not unusual.

Thomas,
There are lots of different kinds of stars. One could see a variety of ways in which the sun would be unusual. You have spoken of the class, variable stars and if the sun is one of those it is so only barely. It is more like non variable stars than like most variable stars. It is relatively ordinary in that one sense. Do you know what kinds of stars can support life and how many of those are there in the galaxy?

[Gadianton]

The evidence is overwhelming that intelligent life is not both very common and also very willing and able to reveal itself to its neighbours.

Yep, joint hypothesis. Another is that there might be other kinds of life or intelligence.

I'll also note that Kipping may be an exoplanetary specialist, but his overall project requires him to weigh in on topics that he isn't the final authority on. The first is the Copernican principle.

He dismisses it by saying if you picked a green ball out of a bucket, and if you didn't then you die, then the fact that you're still alive gives you no special insight into how many other green balls are in the bucket.

Okay sure. It's easy to sell that to me because of the lavish extents the Copernican principle can be put to use. Two great examples that are fantastic for sci-fi, but I can't for the life of me accept them: the simulation argument; the doomsday argument.

1) for alien life (dismissed by Kipping): We are here on earth, we can't have the hubris to think we're so specially positioned in the universe, therefore alien life must be common.

2) simulation argument (a simplified version): If you believe that computers will ever be powerful enough to run simulations (like the matrix), then there must be far more simulated life out there than real life; we can't have the hubris to think we're so specially privileged to be the ones living in base reality, therefore we are living in a simulation.

3) doomsday argument (by Brandon Carter, astrophysicist): We are here right now living on a single planet, we can't have the hubris to think we're so specially privileged to be in a tail event should humanity one day grow into a galactic civilization -- if humanity ever were to rule the galaxy, we'd expect to have been born millions or billions of years from now at the meridian of time and population density -- if we're in the mean, then humanity doesn't have much time left before being destroyed, never making it off this planet.

On the other hand: I have said myself in this thread, and Kipping also says it, that we don't know the distribution of life. Well, I kinda think this is a frequentist observation begging the question against Bayesian reasoning. Bayesian reasoning is all about being in your own skin, walking down the street and observing something, and now you happened to be there encountering it, what can you make from it? Sure, we don't know the distribution, therefore we look through the glass darkly with Bayes.

On the one hand, I don't want to be forced to accept the doomsday argument, on the other, I don't want to throw Bayes out entirely.

Here is a primer to this kind of Bayesian thinking. The author is summarizing Richard Gott, who is also a professor of astrophysics.

[Physics Guy]

Maybe interstellar civilisations expand, but maybe they just don't. It could be, for instance, that life tends to adapt itself so well to its home planet, whatever that may be like, that very few other planets are useful to it. Perhaps it's a lot easier to build giant space arks than to colonise other planets. Perhaps ancient civilisations look like giant trailer parks, with thousands of huge space arks orbiting around their original suns.

If aliens with super technology want to study us, maybe they have easy ways of studying us without showing themselves to us. Perhaps they've seen millions of younger species like us, and just let some A.I. probe survey our system secretly from a distance for a few hundred years, every few hundred thousand years, just to maintain their database. Maybe some young alien academics will do alien dissertations on us, once in a few thousand years.

We probably wouldn't be anything special to them, after all.

[Res Ipsa]

Your point 4 is wildly incorrect due to cherry-picking, as well as a bizarre formation of the question itself.

You simply hate me for sharing the diabetes studies. I am surprised you haven't called me a sexist yet.

What do you base your conclusion of which interpretation is “unlikely” on? Because that’s not what the authors say in the study you are referencing:

Here's what the study says, "The second possible interpretation ... In this case, the measured solar distribution is different only because the Sun did not exhibit its full range of activity over the last 140 years."

Translation: "This raises the question whether the sun has been going through an unusually quiet phase for several millennia."
https://www.sciencedaily.com/releases/2 ... 150211.htm

Solar cosmogenic isotope data indicate that in the last 9000 years the Sun has not been substantially more active than in the last 140 years (8).

Same translation: "This raises the question whether the sun has been going through an unusually quiet phase for several millennia."
https://www.sciencedaily.com/releases/2 ... 150211.htm

If the Sun frequently has quiet periods, then it would mean the Sun is unusual compared to other Sun-like stars.

You are a Professor of Statistics, you know better.

DT, you could not have provided better evidence of my characterization of how you misuse scientific literature.

Once again, you've pulled out of context snippets to reach a conclusion that is contrary to the evidence that is right there in the paper. Here is the entire second possible interpretation:

The second possible interpretation is that the composite sample in Fig. 3 represents the distribution of possible activity values the Sun (and other stars with near solar fundamental parameters and rotational periods) can exhibit. In this case, the measured solar distribution is different only because the Sun did not exhibit its full range of activity over the last 140 years. Solar cosmogenic isotope data indicate that in the last 9000 years the Sun has not been substantially more active than in the last 140 years (8). There are several ways for this constraint to be reconciled with such an interpretation. For example, the Sun could alternate between epochs of low and high activity on timescales longer than 9000 years.

The sample stars were observed for only four years. The sample consisted of 2898 total sun-like stars. The sample was composed of two subsamples: (1) sun-like stars for which Kepler could determine periodic rotation and that had a rotation period comparable to the sun; and (2) sun-like stars for which Kepler was not able to determine a rotational period.

The periodic subsample contained 369 stars. The non periodic subsample contained 2529 stars.

The study measured changes in brightness over the four years as a proxy for magnetic activity. The average variability of the total sample is higher than the sun's variability over the same time period. But the two subsamples were markedly different in variability. The variability of the periodic subsample was significantly higher than that of the non variable subsample. The sun's variability was typical of the nonperiodic subsample. But, even though the non periodic subsample was seven times the size of the periodic subsample, the degree of the variability of the periodic subsample was so much higher that it pulled the average of the total sample above the variability of the sun.

This was puzzling. Why should there be such a marked difference between the two subsamples? Why should the fact that Kepler could detect a rotation period make such a difference? But what's even more puzzling is that, to compare the sun with the comparison sample on an apples to apples basis, they simulated what Kepler would have seen of the sun had it been just another star that Kepler observed and determined that Kepler would not have been able to detect its periodic rotation. Which means, from what Kepler would have detected, the sun would have been in the non periodic subsample even though we know from other sources what the sun's rotation period is. In other words, of the two subsamples, Kepler would have put our sun the subsample for which its behavior was not unusual at all.

Like good scientists, they straight up admitted that they can't explain the results of their study. But they did offer what they believed were the two plausible explanations they believed could explain the data. The first is:

We suggest two interpretations of our result. First, there could be unidentified differences between the periodic stars and non-periodic stars (like the Sun). For example, it has been proposed that the solar dynamo is in transition to a lower activity regime (32,33) due to a change in the differential rotation inside the Sun. According to this interpretation, the periodic stars are in the high-activity regime, while the stars without known periods are either also in transition, or are in the low-activity regime.

This interpretation does not imply in any way that the sun is somehow unique. The stars in the sample are simply at different stages of normal transitions in sun-like stars.

The second is:

The second possible interpretation is that the composite sample in Fig. 3 represents the distribution of possible activity values the Sun (and other stars with near solar fundamental parameters and rotational periods) can exhibit. In this case, the measured solar distribution is different only because the Sun did not exhibit its full range of activity over the last 140 years. Solar cosmogenic isotope data indicate that in the last 9000 years the Sun has not been substantially more active than in the last 140 years (8). There are several ways for this constraint to be reconciled with such an interpretation. For example, the Sun could alternate between epochs of low and high activity on timescales longer than 9000 years.

This interpretation also does not imply in any way that the sun is somehow unique. The paper itself stated that some of the stars in the periodic subgroup did not exhibit more variability than the sun does. The interpretation accepts the observed distribution of behavior as the normal range of behavior of stars of this type. If there is a broad range of behaviors that are typical of sun-like stars and the sun is within that range, it is simply not unique.

What the authors of the paper do not conclude is what you say they are concluding. Ironically, given your past accusations, it is you who is saying you know more about the author's paper than they do. If the authors thought their data indicated that there was anything unusual about the sun, they were certainly capable of saying so in the conclusion of their paper. They clearly didn't.

And if you step back and think for just a couple minutes about the results of the study, it's pretty obvious why they didn't: in terms of variability, the sun was no different than 87% of the total sample. Being just like 87% of a sample does not support a claim that the sun is "unusual." The authors don't reach the conclusion you so badly want them to because their study doesn't support it.

So, you are citing a study for a proposition that authors didn't make in the paper and that is contrary to the data in the paper.

QED

[Res Ipsa]

You're just miffed that I posted a blog entry by a qualified expert but won't watch a video you want me to watch.

That's true, I admit.

Also, you still haven't linked to the source or sources you are relying on for points 1-4.

Here are my sources

Point one: HIP 102152, a Sun-like star is 8.2 billion years old. https://www.space.com/22563-oldest-sun- ... vered.html
Three-quarters of the stars in the galactic habitable zone today are older than the Sun, 1 billion years older, on average
https://www.science.org/doi/10.1126/sci ... 3.5654.27a

Point Two: Kipping video "Is the Sun unusual?" talks about how scientist calculate a star's age.

Point three: The Paper itself

Point four: The Paper and https://www.sciencedaily.com/releases/2 ... 150211.htm

So what is your conclusion from these points?

[Res Ipsa]

Obviously, the Powerball will be won by (A), someone in the 999 cities. Folks from (B), the unique city of duck people, have a difficult time filling out the lottery forms with their feathery duck hands.

Okay, I did some serious research and found some flaws with Res Ipsa's interpretation.

Another flaw with Res Ipsa's interpretation is that some periodic stars are quieter than the Sun, but that's not the case for the vast majority of periodic stars. I could probably find more flaws if I keep doing research.

Res Ipsa really owes me an apology.

So far, you have found no flaws, let alone a fatal flaw. You've simply doubled down on your cherry picking parts of the study and flat out ignoring the parts that contradict the conclusion you want to reach.

[Res Ipsa]

"Nobody is rejecting the possibility of winning a multi-billion dollar PowerBall in many states. However, if winning is possible everywhere, why do I happen to live in a very unusual state where there actually was a winner?”

Answer, fully vetted by multiple Vegas odd-setters:

“Just lucky, I guess.”

I'll try one more time. Imagine 1,000 cities, but only one city is very unique and different from the rest.

What's the most likely outcome?
A) someone wins the Powerball in one of the 999 cities
B) someone wins in that unique city

DT, this so clearly illustrates what I've been calling the fatal flaw in your argument that I'm surprised you could even type it without recognizing the problem. The answer is obviously and unarguably one of the 999. In fact, there is a 999/1000 chance that the winner will be in one of the other cities based on the information supplied. And the reason is that the degree that a city is unique in some way has nothing to do with winning Powerball. Nothing at all.

For yet another Powerball analogy to the argument you are trying to make. It's like you winning the Powerball, cataloging all the ways that you, as a person, are unusual to the point that you conclude you are unique, and then jumping to the conclusion that no one else can ever win the Powerball because no one else is exactly like you.

What you are failing to do over and over and over again is provide any evidence that the characteristics you claim make our solar system "unique" have any effect on the likelihood that life will exist elsewhere. Even the main scientist you are relying on for your argument admits that we don't know know anything about the conditions necessary for life. You can read as many studies and make as many arguments you want that the earth is "unique" and you won't have advanced your argument an inch.

[Res Ipsa]

And you still missed their final sentence:
Our analysis does not allow us to distinguish between these two interpretations.

Sure, and they have interpretations of the interpretations. It's a mess.

The only hard science is this: "Most of the solar-like stars with well-determined rotation periods show higher variability than the Sun and are therefore considerably more active. These stars appear nearly identical to the Sun, except for their higher variability"

That's laughably false. You're simply inventing a silly excuse to dismiss the parts of the study that contradict the conclusion you want to reach.

[Res Ipsa]

People have gone over this article with you repeatedly

Not after I did some research and posted these four points.

your bizarre interpretations and disagreement with the authors is laughably worthless

The four points don't contradict the results.

Here's what the researchers are saying

The researchers therefore also studied more than 2500 Sun-like stars with unknown rotation periods. Their brightness fluctuated much less than that of the other group.

These results allow two interpretations. There could be a still unexplained fundamental difference between stars with known and unknown rotation period. "It is just as conceivable that stars with known and Sun-like rotation periods show us the fundamental fluctuations in activity the Sun is capable of," says Shapiro. This would mean that our star has been unusually feeble over the past 9000 years and that on very large time scales phases with much greater fluctuations are also possible.

https://www.sciencedaily.com/releases/2 ... 150211.htm

You are just mad because of the diabetes studies I shared.

That quote does not support your conclusion that the sun is unusual. Not at all. Neither you nor the authors have any idea whether any of the stars in the study have periods of relative quiet comparable to the sun. They only have four years worth of the the data. And 87% of the stars in the total sample were as relatively quiet as the sun.