I'm not saying it's aliens, but...

[bilby]

http://www.independent.co.uk/news/science/aliens-proof-evidence-facts-stars-scientists-extraterrestrial-life-et-intelligence-a7377716.html




Only slightly less sensational than the popular press accounts is the paper itself, by Borra and Trottier (arXiv:1610.03031v1 [astro-ph.SR])

A Fourier transform analysis of 2.5 million spectra in the Sloan Digital Sky Survey was carried out to detect periodic spectral modulations. Signals having the same period were found in only 234 stars overwhelmingly in the F2 to K1 spectral range. The signals cannot be caused by instrumental or data analysis effects because they are present in only a very small fraction of stars within a narrow spectral range and because signal to noise ratio considerations predict that the signal should mostly be detected in the brightest objects, while this is not the case. We consider several possibilities, such as rotational transitions in molecules, rapid pulsations, Fourier transform of spectral lines and signals generated by Extraterrestrial Intelligence (ETI). They cannot be generated by molecules or rapid pulsations. It is highly unlikely that they come from the Fourier transform of spectral lines because too many strong lines located at nearly periodic frequencies are needed. Finally we consider the possibility, predicted in a previous published paper, that the signals are caused by light pulses generated by Extraterrestrial Intelligence to makes us aware of their existence. We find that the detected signals have exactly the shape of an ETI signal predicted in the previous publication and are therefore in agreement with this hypothesis. The fact that they are only found in a very small fraction of stars within a narrow spectral range centered near the spectral type of the sun is also in agreement with the ETI hypothesis. However, at this stage, this hypothesis needs to be confirmed with further work. Although unlikely, there is also a possibility that the signals are due to highly peculiar chemical compositions in a small fraction of galactic halo stars.

Interesting stuff. Of course, lots of natural phenomena were first thought to be caused by aliens - pulsars, for example. Perhaps some G type stars just do this naturally. As the paper says:

In principle, rapid pulsations in small regions of the atmospheres of the stars could generate the signals (Borra 2010). However, the periods in Figure 2 show that the period of the pulsation would have to be of the order of 1.65x10^-12 seconds, which appears unrealistically small for stars.

The biggest question for me is, assuming that these signals are generated by aliens, why are they doing it? Perhaps I have just been reading too much Liu Cixin, but I would have thought that any civilizations in the wider universe might be better off keeping their existence to themselves.

 

[DBT]

Marvellous, if true. Still interesting if not.

 

[barbos]

Damn, I have a possible mundane explanation.

 

[barbos]

The biggest question for me is, assuming that these signals are generated by aliens, why are they doing it? Perhaps I have just been reading too much Liu Cixin, but I would have thought that any civilizations in the wider universe might be better off keeping their existence to themselves.

Could be interstellar TV broadcasts or narrowcasts actually.

 

[barbos]

OK, I scanned the paper more slowly and found out that, their signal for individual stars is actually consistent with noise. To get a decent S/N ratio they combine all their signals. They can do that because signal just happened to be in the same place for all these stars at 1.65e-12sec.
What are the chances of all these ~70 alien civilisaztions choosing the same frequency for sending their signals to Earth? One cane say they all are somehow connected I will say yes, it's possible but what is more possible is instrumental error. So the only thing they currently have is their words that this signal correlates with star spectral type. This can be explained away too. But I would rather do the measurements with different telescope/spectrograph first.

 

[Tom Sawyer]

Damn, I have a possible mundane explanation.

Don't derail the thread. It's frigging aliens and you're happy about how it's aliens. Get with the program.

 

[skepticalbip]

Damn, I have a possible mundane explanation.

But since the goal is apparently to have the public interested in the work, which headline would be more likely to succeed?

“Strange messages coming from the stars are ‘probably’ from aliens, scientists say”

or

“Scientists have detected stellar spectrum that they can not yet explain”

 

[barbos]

It's almost as if people were willingly looking for some instrumental flukes and then suppressing their own healthy skepticism in order to have publication which everybody will talk about and then certain russian billionaire who is interested in aliens will give them more money....... Wait, this is exactly like that!

 

[DBT]

It's almost as if people were willingly looking for some instrumental flukes and then suppress their own healthy skepticism in order to have publication which everybody will talk about ...... Wait, this is exactly like that!

If it is purely a case of instrumental flukes, would it not show up on most, if not all stars of that class?

 

[barbos]

It's almost as if people were willingly looking for some instrumental flukes and then suppress their own healthy skepticism in order to have publication which everybody will talk about ...... Wait, this is exactly like that!

If it is purely a case of instrumental flukes, would it not show up on most stars of that class?

Not necessarily. It's a fluke which is below noise level, which means it normally masked by that noise. So if they repeat the measurement they will get same number of 70 stars but they will be different ones.

 

[bigfield]

The biggest question for me is, assuming that these signals are generated by aliens, why are they doing it? Perhaps I have just been reading too much Liu Cixin, but I would have thought that any civilizations in the wider universe might be better off keeping their existence to themselves.

Perhaps it's a civilisation with 70 of these:

And instead of sneaking through the forest, this hunter has a convoy of 4WD trucks with spotlights, machine-guns and loud country music.

 

[DBT]

If it is purely a case of instrumental flukes, would it not show up on most stars of that class?

Not necessarily. It's a fluke which is below noise level, which means it normally masked by that noise. So if they repeat the measurement they will get same number of 70 stars but they will be different ones.

Possibly. I'm strongly inclined toward a natural explanation...but I imagine that they would have considered your explanation and tested for it?

 

[barbos]

Not necessarily. It's a fluke which is below noise level, which means it normally masked by that noise. So if they repeat the measurement they will get same number of 70 stars but they will be different ones.

Possibly. I'm strongly inclined toward a natural explanation...

Natural explanation would be pretty extraordinary discovery. They say rotational degrees of freedom can produce such effect, I don't really see how, rotational degrees give E=n^2 (n the is an integer) hardly a spike in a Fourie transformation. And it would have to be pretty slow rotation too, which means heavy molecules, DNA remnants of self-destructed alien civilization?

but I imagine that they would have considered your explanation and tested for it?

Do they read this forum?
Instrumental errors could be anything but I will bet small amount of money on dumb mistake in data processing. Some data list typo and you have older (and buggy) version of calibration used on some of the data. It could happen to anybody even to people who actually understand all the nuts and bolts of the experiment and these people are not I think. and it does not have to be their mistake, these experiments are large collaborations with summer students from Korea who can certainly screw things up for you.

 

[DBT]

Do they read this forum?

I don't know, I assume that they have sufficient brain power to consider all possibilities, including whatever FRDB members may come up with. But, maybe not. Who knows.

Instrumental errors could be anything but I will bet small amount of money on dumb mistake in data processing. Some data list typo and you have older (and buggy) version of calibration used on some of the data. It could happen to anybody even to people who actually understand all the nuts and bolts of the experiment and these people are not I think.

It's possible, but extremely embarrassing for them if that's what it turns out to be.

 

[barbos]

I don't know, I assume that they have sufficient brain power to consider all possibilities, including whatever FRDB members may come up with. But, maybe not. Who knows.

Don't assume they are smarter than randomly selected FRDB member. There are a lot of dumb people in science.

Instrumental errors could be anything but I will bet small amount of money on dumb mistake in data processing. Some data list typo and you have older (and buggy) version of calibration used on some of the data. It could happen to anybody even to people who actually understand all the nuts and bolts of the experiment and these people are not I think.

It's possible, but extremely embarrassing for them if that's what it turns out to be.

If you are easily embarrassed then research is not for you.

 

[skepticalbip]

Don't assume they are smarter than randomly selected FRDB member. There are a lot of dumb people in science.

Instrumental errors could be anything but I will bet small amount of money on dumb mistake in data processing. Some data list typo and you have older (and buggy) version of calibration used on some of the data. It could happen to anybody even to people who actually understand all the nuts and bolts of the experiment and these people are not I think.

It's possible, but extremely embarrassing for them if that's what it turns out to be.

If you are easily embarrassed then research is not for you.

Indeed.

Maybe you remember that Italian research group a couple years ago that declared to the press that they had detected neutrinos that travel faster than the speed of light.

It turned out that there was a loose connector on some of their instrumentation. The superluiminal property of those neutrinos vanished after the connector was tightened.

 

[barbos]

Don't assume they are smarter than randomly selected FRDB member. There are a lot of dumb people in science.

Instrumental errors could be anything but I will bet small amount of money on dumb mistake in data processing. Some data list typo and you have older (and buggy) version of calibration used on some of the data. It could happen to anybody even to people who actually understand all the nuts and bolts of the experiment and these people are not I think.

It's possible, but extremely embarrassing for them if that's what it turns out to be.

If you are easily embarrassed then research is not for you.

Indeed.

Maybe you remember that Italian research group a couple years ago that declared to the press that they had detected neutrinos that travel faster than the speed of light.

It turned out that there was a loose connector on some of their instrumentation. The superluiminal property of those neutrinos vanished after the connector was tightened.

I remember that. Speaking of embarrassing, that thing was less "embarrassing" than people (theorists) who started publishing theories which involve superluiminal neutrinos, that's what I call embarrassing. This happens every time when obviously bullshit result gets publicity (EM drive, cold fusion, etc), It pisses me off.

 

[DBT]

Even if embarrassment is not a personal issue. A big public announcement that subsequently proves to be a knucklehead error is embarrassment to their careers and reputations.

 

[barbos]

Even if embarrassment is not a personal issue. A big public announcement that subsequently proves to be a knucklehead error is embarrassment to their careers and reputations.

You would think that, but in reality it is not. If you do it right it actually helps your reputation and career. People will know your name and that you actually try something. Cold fusion guys were idiots because they actually believed their own crap for way too long, that's what damaged their reputation more than anything else. Fuck-ups is a daily occurrence in that business, if you don't fuck-up you don't exist.

 

[DBT]

Everyone fucks up. I guess that professional reputation depends on the nature and scale of the fuck up.