I agree, but what we’re admitting really is that we don’t particularly care if the claim is true or not, so we’d be polite. Well that’s how I would reason that anyway.
Again I’d agree, but this is because I know that science rigorously polices claims, and peer reviewed journals can harm their reputation if they have to later retract. So my rationale is that one source strictly and painstakingly evidences their claims, the others believe what makes them happy, and are impervious to facts. An important difference (one of) between (for example) science and religion, is that science polices it’s ideas, and all facts must remain tentative in the light of new evidence, even well established facts (scientific theories), whereas religions and the religious make claims for “absolute or immutable truth”. The scientific position is the definition of an open mind, and the religious position of a closed mind.
And of course I don’t have to personally understand the evidence from science, as the reliability of the method is manifest in its results, as of course are religious claims, since no one has yet demonstrated that faith in subjective religious beliefs, has helped us understand reality in any objective way. Faith doesn’t design and build planes, or skyscrapers, there is no objective evidence it can cure or even heal diseases, and it produces no new technologies. This does not seem to be a coincidence.
We’re still waiting to reach the point where gravitational wave detectors can reliably distinguish between primordial gravitational waves, and gravitational waves of more recent origin. Once that stage is reached, the test can begin, but we’re not there yet.
I ask because its my current understanding that what’s needed is not just greater sensitivity but also a change of scale.
Earthbound detectors having a smaller baseline results in them being more sensitive to ‘high pitched’ small-scale events like stellar black hole mergers. Whereas a space-based detector like LISA would have massively a longer baseline and so be more sensitive to ‘lower pitched’ large-scale sources, like the mergers of SMBH’s.
The way I think of it is that a microphone designed to pick up birdsong won’t do very well picking up whale song, which is many octaves lower.
So, do we happen to know whether primordial gravitational waves will be high pitched or will they be low pitched because they have been stretched by the expansion of the universe, shifting them down the tonal spectrum?
Shorter wavelengths translates to high pitch. But you need to measure both short and long wavelengths. This is a basic necessity if one is to construct a rigorous power spectrum.
The prediction is that there will be a deficit in long wavelengths, and an augmentation in short wavelengths, but unless you can measure both across a suitably wide range of values, testing this prediction will be difficult.
If I have read the literature correctly, I don’t think gravitational waves are subject to cosmological redshifting, but I’ll have to double check on this sometime. But even if they are, the power spectrum should still emerge from the data. But if cosmological redshifting does affect gravitational waves, this will complicate the task of compiling the power spectrum. It will increase the range of wavelengths that need to be surveyed in depth.
That’s another complicating factor that will have to be addressed - whether or not cosmological redshifting affects gravitational waves.
And, very quickly, I found a scientific paper that answers the question, namely this one, and yes, it appears that cosmological redshifting does affect gravitational waves. Which complicates the picture.
I’m grateful to you for exhorting me to check that feature, as it is one I hadn’t previously considered.
Ok, its a popular level science book, but in it Kinney proposes that as well as B-mode oscillations there’s another ‘smoking gun’ indicator of inflation that’s already been detected. Something called superhorizon perturbations. Which is, quite frankly, a bit beyond me. Anyway, he writes…
The cleanest signal for superhorizon perturbations is the statistical corrlelation between the polarization and the fluctuations of the temperature of the CMB, called the cross-correlation of the temperature and polarization. Figure 6.1 shows the cross-correlation as measured by the Planck satellite.
What we can clearly see in the Planck data is a negative correlation between the temperature and the polarization on scales larger than a degree on the sky, which is an unambiguous signal of superhorizon density perturbation modes.
The figure Kinney refers to in the book is the 14th slide in this presentation.
TE : Planck Data Releases 2 (February 2015)
As I said, this is beyond me. But I’m curious about it. If what Kinney claims is a ‘smoking gun’ for inflation, why hasn’t this made news all around the world? The BICEP2 claim for B-modes did that.
The BICEP2 findings were later refuted, because it was demonstrated that the signal could be produced by cosmic dust. More on this in this paper.
There are plans to try and declutter any B-mode signal from the signal produced by dust, but even so, a quantity known as the tensor to scalar ratio (r) needs to be fairly high, and at the moment, the value of r is around 0.06. I suspect it’ll take a serious curve ball to revise that figure upwards, as the tendency of increased sensitivity experiments has been to reduce it.
Here Druso betrays his ignorance of how science functions. The only branch of the sciences that uses proofs is mathematics. The empirical sciences (physics, chemistry, biology, etc.) do not use proofs. They accumulate evidence.
Proofs are final, absolute and unchangeable. But the empirical sciences are always open to change as new data and new evidence comes to hand. That is why theories and hypotheses in the empirical sciences can be refuted by the advent of new data.
Whereas, in mathematics proofs stand for all time. They cannot be refuted or overturned by anything. 2 + 2 will always and has always equalled 4, everywhere. No amount of recalculation or new evidence can ever overturn this absolute proof.
So Druso is quite wrong. Nobody demands that everything must be empirically proven. Because nothing empirical can be proven. Ever.
