We Might Be Alone in the Universe

[Physics Guy]

Another speculation is the optimistic one: that our fears of advanced aliens coming to steal our planet are like fears in a primitive tribe today that First World humans will eat them. Over the past hundred years or so we’ve gotten better at not taking advantage of people just because we can, and as centuries pass we may get better still. Anyway we’re not that short of food. Nobody is going to try to contact an uncontacted tribe just to eat them. We’ll order pizza.

Maybe the kind of wondrous technology that would enable an alien species to take our planet will also mean that they’ll have no interest in taking it.

[Res Ipsa]

Stumbled upon a Scientific American article from a couple of years ago that shows the huge range of opinion on the question of whether there is other intelligent life in the universe and, if so, how frequent it is.https://www.scientificamerican.com/arti ... r-answers/ The answers seem to range from "probably no other intelligent life" to "36 currently existing civilizations capable of communicating with us through electronic signals. I think it's pretty clear we haven't even come to a consensus on how best to think about how to answer the questions.

[doubtingthomas]

There are so many things about intelligent alien life that we don't know, and which could all be decisively important, that it would take a weird fluke for all of our ignorant guesses to be right about them. Trying to build a strong conclusion of any kind, in our current state of knowledge, is trying to build a heavy structure out of uncooked spaghetti. None of the components is strong enough to bear the weight it will need to bear.

We don't know many things about intelligent life, all we know is that advanced civilizations are advanced.

” it would only take a single malevolent race willing to break its self-imposed silence to explain the “Great Silence.”"
https://adsabs.harvard.edu/full/1983QJRAS..24..283B

[doubtingthomas]

So? Did the authors of the paper take into account the stars ages? If so, how did they do it?

By focusing on stars with near-solar fundamental parameters and rotation periods

Wrong. They used a common technique used to estimate the age of stars. It's right there in the methods section. But you have to be curious about what you don't know to recognize and understand it. Here's a general article for general audiences that discusses the technique the authors used to account for age in both the known period and unknown period subsamples. sun's.https://www.sciencenews.org/article/sta ... life-cycle: it's use of what are called "Hertzsprung-Russell diagrams." And here is the part of the methods section of the paper that describes the use of HRDs to constrain both subsamples:

We further restrict the samples using astrometric data from the Gaia spacecraft (22). Using the sample stars’ apparent magnitudes, distance measurements (23), and interstellar extinctions from Gaia data release 2 (Gaia DR2 (24)), we construct a Hertzsprung-Russell diagram (HRD) by computing the absolute Gaia G-band magnitudes MG (Fig. 1). The absolute magnitudes of our samples are restricted by selecting stars from the HRD with near-solar ages between 4– 5 Gyrs (Sun: 4.57 Gyr) and metallicities in the range -0.8 dex to 0.3 dex. This is realized by fitting isochrones (i.e. evolutionary tracks of constant age (13)) to the HRD, and then selecting periodic and non-periodic stars between a lower isochrone of 4 Gyr and metallicity of [F e/H ] = −0.8, and an upper isochrone of 5Gyr and metallicity of [Fe/H] = 0.3 (Fig. 1A-B).

This shows another of your many claims about this study to be complete B.S.

Anyways, the second study doesn't take into account one important thing: The average age of non-periodic stars. If most non-periodic stars are older than the Sun, then the data makes a lot of sense.

viewtopic.php?p=2818421#p2818421

The authors used HRDs to narrow both the period and non-periodic subsamples to "between 4-5 Gyrs (Sun: 4.57Gyr).

by the way, your claim that the paper describes two studies is complete BS you made up as a pathetic justification for ignoring the non-periodic subsample. I've read hundreds of academic papers. I put myself through university in part by proofreading academic papers for a Microbiology journal. Some papers do cover more than one study. It's easy to identify those because the authors tell you that they are reporting on more than one study. They also have to have separate methods sections for each study.

This paper says nothing about two studies -- not a word. It contains a single methods section that includes both subsamples that is easily discernible by reading the damn text. By claiming two studies when there is only one as an excuse for ignoring the part of the study you don't like, you're torturing the paper to try and make the authors say what you want them to say instead of trying, in a non-result oriented way, to understand what the authors are actually saying. In terms of my claims of how you misuse scientific research papers, that's game, set and match.

"Astronomers have long known that stars experience a process known as ‘magnetic braking’: a steady stream of charged particles, known as the solar wind, escapes from the star over time, carrying away small amounts of the star’s angular momentum. This slow drain causes stars like our Sun to gradually slow down their rotation over billions of years."
https://ras.ac.uk/news-and-press/resear ... isis-stars

So? The paper itself said it used the HRD method to constrain both samples to solar-like ages.

But none of that changes the fact that the stars in the two groups were identical except for whether Kepler identified the period of rotation.

The researchers didn't take into account the age of the non-periodic stars. It's like doing a clinical trial without knowing the ages of the participants.

Flat ass wrong. See above. You spent a ton of time and effort trying to torture a meaning out of the paper that just isn't there instead of recognizing what you don't know and approaching it with curiosity to make sure you understood what you were reading.

1) Stars generally have a kind of magnetic menopause in middle age. When their gradually slowing rotation rate slips below a critical value, in relation to their size and temperature and composition, something changes in the complex magneto-hydrodynamics of stellar convection, and the result is a steadier stellar magnetic field. The sun may be in this magnetic menopause, or have gone through it already, while more of the stars of which the rotation rate could be measured have not yet reached this point.

Right, but the researchers did focus on sun-like stars (periodic) about the same age as the Sun.

Wrong. The paper doesn't focus on the periodic stars. It focuses on both subgroups. What you are doing here is committing the base rate fallacy in a way that is inexcusable, given the discussion in this thread that occurred yesterday. "Periodic" and "Nonperiodic" aren't intrinsic properties of the stars in the sample. They are simply labels based on whether Kepler could detect the rotation period. The paper doesn't claim that the stars in the nonperiodic subsample don't rotate or don't rotate at a specific rate. Kepler simply couldn't identify the rate. It's an instrumentation issue, not a distinction between an intrinsic property of the stars.

2) Perhaps all stars that are roughly like the sun have occasional quiet periods that last ten thousand years or more, when they happen. Our sun happens to be in such a lull now.

Yes, thank you. So, what are the odds that our Sun happens to be unusually quiet right now?

You won the lottery today. What are the odds you won the lottery?

Nobody knows what the usual behavior of sun-like stars is over their lifetime. 9000 years is a blink in the lifetime of our sun.

they wanted to compare the sun with the sample on an apples to apples basis -- as viewed by Kepler.

Did the researchers assign the Sun as "non-periodic" when comparing it with periodic stars? Why would they do that? And why would the researchers call their paper "The Sun is less active than other solar-like stars" if the Sun is just a non-periodic star as viewed by Kepler?

Stop torturing the paper and read it with an eye toward understanding it. The researchers didn't "assign" the sun. They ran a test to see if Kepler would be able to detect the sun.

To compare the Sun with the stars observed by Kepler, we simulated how it would have appeared in the Kepler data by adding noise to the TSI time series (Fig. S7). The variability range was then computed for 10,000 randomly selected 4-year segments from ∼140 years of reconstructed TSI data (13).

Why would they do that? Because they're not dumbasses who insist on committing the base rate fallacy out of sheer stubbornness. Never once have you stopped and asked a fundamental question even though PG explicitly raised it: Given the existence of a sun-like star (including its "quietness,") how likely is it that Kepler would be able to determine its rotational period? Kepler was unable to determine the rotation period for 87% of the stars in the total sample. Did you ever stop and ask why? Did you lift a finger to trying and find out?

No, you didn't. In fact, you didn't even bother to read the discussion in this very thread from yesterday, which answered this very question. If Kepler had looked at the sun, there is only a 3% chance that Kepler would have been able to detect its rotation period. viewtopic.php?p=2818491#p2818491 Apparently you had time yesterday to start a thread about a guy talking about masturbation, but couldn't be bothered to read this thread.

The very low ability of Kepler to detect sun-like stars in quiet periods is the nail (more like a thousand screws) in the coffin of the conclusions you've been trying to draw from the paper. Both determining the period of a stars rotation and determining whether a star is "noisy" depend on exactly the same thing: variations in the brightness of the star. The only difference is the time scale. So, by selecting to consider only the "periodic" stars, you've also selected for "noisy" stars. In other words, if you start with the entire sample examined in the study, when you remove the stars for which Kepler could calculate a rotational period, you've automatically removed the stars least likely to be like the sun.

That's why you can't claim the the solar system is a cosmic oddity using that study as evidence. The paper doesn't claim that. The paper shows the exact opposite of what you are trying to make it say.

Part of the context of a scientific paper includes what came after a given paper was published. There's no magic to finding the additional information I found. I simply recognized that I didn't understand why Kepler couldn't identify rotation periods for such a large percentage of otherwise sunlike stars. I was curious. And that led me to a more recent paper that answered the question. That's how you understand a scientific paper. You have to know what you don't know and spend the time to figure out what you don't know. If you double, triple, and quadruple down based on your interpretation of a snippet from a study, you're much more likely to make a stupendous blunder like making absolutely false claims about how the study was done or reaching conclusion that contradicts what the study says.

As for titles, I dunno. Go as the authors.

That's more than enough wading through nonsense for today. Now I see you've produced new snippets from a new study. Tell me, after how many times you've been absolutely wrong and made absolutely false claims about the Reinhold paper, what incentive do I have to spend the time and effort necessary to see whether you've, yet again, misused a study.

Maybe later. That's plenty for today.

[doubtingthomas]

Added this to the post above.

"The fraction of stars from Fig. 18 as quiet as the Sun (≤ 12.5 ppm) is 23%, which contrasts with expectations"
https://arxiv.org/abs/1107.5207

[doubtingthomas]

However, the interpretation that our Sun is currently in an unusually quiet period, is unlikely. Does Res Ipsa have any evidence that our Sun has been unusually quiet for 9,000 years.

What do you base your conclusion of which interpretation is “unlikely” on?

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

your bizarre interpretations

PhysicsGuy just said, "2) Perhaps all stars that are roughly like the sun have occasional quiet periods that last ten thousand years or more, when they happen. Our sun happens to be in such a lull now."

And "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

And you still hate me very much just because of the diabetes studies I shared.

[Marcus]

What do you base your conclusion of which interpretation is “unlikely” on?

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

your bizarre interpretations

PhysicsGuy just said, "2) Perhaps all stars that are roughly like the sun have occasional quiet periods that last ten thousand years or more, when they happen. Our sun happens to be in such a lull now."

And "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

And you still hate me very much just because of the diabetes studies I shared.

Lol. Your post just now completely supports my analysis. Stop trying to manufacture drama and stop cherry-picking from articles.

[doubtingthomas]

If you linked me to a transcript of one of Dr. Kipping's videos, I'd be happy to review it.

Here's a transcript.

aging stars is notoriously difficult but recently Timo Reinhold and colleagues found a way around this. Remember that since the spin of stars slows down with age, they decided to take a group of stars with similar masses and sizes to the Sun just like Gilliland but further constrain the sample to only those stars with similar rotation periods to the Sun 25 days. In their new paper published just recently in science, they yet again find that the Sun is quieter than average ... they showed that the sun's typical activity places it in the lowest third of quiet sun-like stars[see Figure 3]......there is an emerging picture that the Sun, at least we see it today, appears to be unusually quiet compared to stars of similar type and using indirect evidence that behavior of the Sun in the last century and a half, doesn't seem to be any different than that of the preceding 9 thousand years, we really do seem to have a quiet home star.

"Is the Sun Unusual?"
https://youtu.be/TAQKJ41eDTs?t=1097

Background

David received his B.A. and M.Sc. in Natural Sciences at Cambridge University, UK followed by a Ph.D. from University College London, UK. Before joining Columbia University, David spent time at Harvard as a postdoc through the Sagan and Menzel fellowships.

Research Topics
Extrasolar planets, moons & rings; stellar rotation, granulation & limb darkening; astrostatistics

That guy has published 232 peer-reviewed articles (see Google scholar) and he is under 40 years old.

The paper doesn't claim that the stars in the nonperiodic subsample don't rotate or don't rotate at a specific rate. Kepler simply couldn't identify the rate.

I agree. I never said they don't rotate.

Wrong. The paper doesn't focus on the periodic stars. It focuses on both subgroups.

I never said the researchers didn't study both subgroups.

Apparently you had time yesterday to start a thread about a guy talking about masturbation, but couldn't be bothered to read this thread..

I didn't finish watching that video.

The paper doesn't claim that. The paper shows the exact opposite of what you are trying to make it say.

Perhaps Professor Kipping is just a dishonest troll who spreads misinformation to his viewers. The authors of the paper are dishonest trolls too for creating a misleading title.

I'll have to get back to you on this.

Nobody knows what the usual behavior of sun-like stars is over their lifetime. 9000 years is a blink in the lifetime of our sun.

That's true, we don't know for sure, and I agree 9,000 years is a blink of an eye.

[Res Ipsa]

Now you're back to throwing tantrums. I clearly made mistake by giving you another chance to demonstrate that you know how to read, understand, and draw conclusions from a scientific paper. If you're going pout by defaming the scientists, that's your problem.

I'm done. Don't waste your time arguing with me further.

[Physics Guy]

If the Sun is only slightly unusual, such as in belonging to a 1/3 minority of stars or so, then it makes no sense to even mention this issue in a discussion of the abundance of intelligent life. There are decisively important factors in that question about which we are uncertain by factors of trillions. A mere 1/3 versus 2/3 issue probably won't deserve attention, in this context, until the galactic conference of 24523.

And if it is only right now that the Sun is unusual at all, because it happens now to be in a 100,000-year episode that all stars go through now and then, or because it happens now to have hit a stage in life that all stars eventually hit, then the Sun is not unusual at all on the billion-year time scale over which life can emerge. So this kind of temporary unusualness isn't important at all for the abundance of intelligent life in the universe.

And even if the Sun were an extremely unusual kind of star—like the rare, weird class of Wolf-Rayet stars that have blown off their non-fusing envelopes to leave the fusion core naked—there would not actually be any valid inference to be drawn from that fact about how rare intelligent life must be. Any impression to the contrary is a subtle logical fallacy involving the distinction between probabilities for any one particular intelligent species and probabilities for some intelligent species out of many.

It is still possible, in spite of all that, that intelligent life is extremely rare and that this is partly because it requires a rare combination of circumstances that our planet happens to have, as very few planets do. We can speculate about ways in which this might be true. We don't currently have any particular reason to believe it, however. The life-is-rare hypothesis is one possible explanation for why we have yet to see any signs of alien life. Deciding that one hypothesis about a complex issue is likely to be true, just because it would fit a small amount of evidence, is not good scientific practice, however. We can think of several other explanations that would also fit our available evidence, and even if we couldn't think of any other theories in particular, we should be expecting, from our great ignorance on this subject, that there may be many other explanations that we just don't yet imagine.

It's good scientific practice to avoid premature confidence in any conclusion by looking for loopholes in arguments, kicking the tires on evidence, and considering unpopular alternative theories. It's probably a good scientific contribution, to a fascinating subject which is on the fringes of sciences because of lack of good evidence, to propose that we might possibly be as good as alone in the universe. It might even be fair enough to argue that the possibility of our being alone is much less unlikely than one might think. It's not good science, though, to present that as a conclusion which is supported as probable by current evidence.