You can't actually "see" DNA itself because it is smaller than the wavelength of light. Those groves are 50nm and the wavelength of blue light is about 480nm.
You essentially stick some special molecules on the DNA that absorb light in one frequency and then they emit light in another frequency. So you blast the molecules with light of one frequency and then use a dichroic mirror to filter that light out and you only see the emissions and thus you see where the DNA is, but you don't "see" the DNA itself.
Like STM itself what we mean when we "see" something at those length scales is interesting. Scanning Tunnelling Microscopy is like a blind man reading braille - not really "seeing" anything but getting enough info to describe the picture.
source: I used to work in the same lab as Dan. Hi Dan!
What does this mean to the value of what we are "seeing"?
The example used before - that it is equivalent to a deaf man seeing a music visualisation - is apt. It is some sort of model, but not particularly close. It might still be useful, of course.
Not "seeing a music visualisation" (was it edited maybe?), reading braille. STM involves sticking a probe microscopically close to the thing-being-scanned, and reading how the surface's atoms deflect it. Which is very close to "literally feeling" the surface, as all "touch" is just electrons repelling each other at a distance - this is just at a slightly larger distance. https://en.wikipedia.org/wiki/Scanning_tunneling_microscope
Maybe a more human-scale-friendly analogy would be "finding the hot burner by moving your hand near it". In STM, each atom is a hot burner. You can pretty accurately figure out the arrangement of burners on your stove without needing to see or touch it.
Molecular biologists aren't stupid. They fluorescent tagged the pieces that get incorporated into the DNA and not into anything else. There will have been positive and negative controls to gain confidence that the tagging worked as expected.
You might want to lose the snarky attitude as it's not a good look when you're really ignorant about the techniques you're sneering at. You seem curious. Just learn without the snark.
EDIT> This is the kind of thing you learn in 1st and 2nd year university biology courses. Especially cell bio / molecular bio lab technique courses.
Its not even really false color, its just a look up table applied to the data, which is some equi-tunneling current or height map, don't know exactly how this is done, bit out of my field.
Perhaps this is a water filter advert:
"Using activated carbon filtration devices (like Brita filters) can help reduce TCE in drinking water"
But really, how could they possibly narrow it down to that? How can they ignore all the metals that we are injected and sprayed with as possible alternative causes?
But its not showing things directly, is it? Its interpreting a frequency and converting that to an image. Is it really that different to a music visualiser?
Directly as in: you do it yourself, without going through a bunch of intermediaries who will dazzle you with their pretty pictures, you yourself are the one observing the results.
Of course a STM does not work with visible light so it's pretty damn obvious that any measurements will use some other mechanism, and will have to have their measurements converted into an image that we can see. But that does not mean we are not observing. As opposed to reading about someone else's observations.
I take it you also believe that quasars have not been observed and ditto for the dark side of the moon?
There are an incredible number of recurrent top-down connections in your vision processing areas. You do not really see what's there in any meaningful way. What you see is heavily conditioned on what other modules of your brain "expect" to see.
Consider foveated vision. The idea that you can actually see what is going on on your desk all at the same time is an illusion.
Of course your eye is a sensor. As are all your senses. The difference is that the input it receives is unmediated by external sensors and software. Visualising atoms or DNA is fine, but it is an inferior source of information. By a long way.
Imagine you were born deaf and couldn't hear music. But that someone showed you a music visualiser.
Do you think if you were watching the output of that visualiser you would now know the music in some meaningful way?
Would it be possible for you to try at least to contribute to the discussion? This out of hand dismissal seems to be a bit of an issue for you, maybe try harder?
How is it inferior? We can't see in for e.g. the IR spectrum. But we can turn an IR image into a false-colour image that our eye and brain can make great use of. Using your eyes to directly see in IR will inherently be inferior to processing the results from a sensor into a form that we can see.
You seem really hung up on some pedantry about "see" and "seeing". Why? This may seem like some kind of strong criticism to you, but it just seems as though you are unaware of these technologies and haven't really thought through what constitutes a measurement or observation.
I don't understand the downvotes. That's an honest fundamental question.
It's not "showing things directly" because it can't. The limit of what you can see with light is proportional to the wavelength of the light (this is called the diffraction limit). For visible light and lens-based optics that's around 1/2 micron.
The distance between the atoms in that graphite is ~3 angstroms, that about 2000 times smaller than the diffraction limit for visible light.
You CAN get atomic resolution with a transmission electron microscope. Instead of light it uses electrons and has a far finer diffraction limit that visible light. Instead of lenses it uses electrostatic deflection.
Because the comment is factually wrong. Because it tries to argue something in bad faith.
> That's an honest fundamental question.
But it wasn't a question, it was a statement, and a faulty one at that.
Best case interpretation would require substituting 'current' for 'frequency' and even then it would be inaccurate because the current is a proxy for the Z-distance to the tip which is then used to convert to a 3D map, which in turn can be visualized.
It is fairly obvious that this is an indirect process so clear the word 'directly' wasn't about 'seeing atoms' but all about the fact that you can make the observations yourself.
Whether you are measuring a current or looking through an eyepiece both are observations. And looking at the resulting image is also an observation.
As opposed to reading about STMs and looking at pretty pictures online or in books.
It's a shallow comment masquerading as an insightful one, the worst way to derail any conversation.
The GP's "statement" contained three relevant sentences, two ending with question-marks. I learned from both your answer and its parent, furthering conversation, for me at least.
Read the rest of their comments and see if you still feel that way. As well as the novelty account made for the express purpose of further derailing the conversation.
So ... how about some self-reflection in your bubble of self-righteousness?
And actually answer to the answer of jacquesm?
"But it wasn't a question, it was a statement, and a faulty one at that
Best case interpretation would require substituting 'current' for 'frequency' and even then it would be inaccurate because the current is a proxy for the Z-distance to the tip which is then used to convert to a 3D map, which in turn can be visualized.
"
So it seems you were just wrong in your statement and therefore downvoted.
In general, I would agree that the downvoting habit here is sometimes over the line. Like I would not have downvoted your original question, even though it did contained a false statement. But how you react to an answer actually explaining the reasoning - does not speak for you in this case.
"A dance of “glorious and strange beauty” took place in a wintry garden in the south of England on January 6, 1614."
So specific!! And that's just the first line!
Is it just me, or are they just telling stories about the 16th century? Historians themselves will say history is an interpretative act. 'History' is for us in the present - it only lightly relates to what may or may not have occurred in the past, even if it presented as a fait accompli. I don't think it is possible to get this detail about what went on back then.
I see this sort of article as 'myth making'. Its not to do with reality - no sources are provided for us to check. Its just presented as a ready narrative, and we are meant to accept it.
So, what if that is the myth what are meant to take from it? I think we are meant 'edu-tained'. We can laugh at the fools back then who were literally blowing smoke up each others arses, in reclined splendour. We can enjoy a cannabis narrative - this talks to how we legalise it nowadays. These sorts of myths support the idea of how we are progressed, superior, etc.
Author here - was it really glorious and strange and beautiful? All subjective judgements, so who can truly say. But I can tell you that those judgements are at least drawn from an actual primary source, published in 1614: the stage directions for the performance itself. The link: https://www.google.com/books/edition/The_Maske_of_Flowers/qC...
Incidentally, that source is linked in the article more than once, along with others.
Correct. There were two recorded performances, one in December, 1613, the second in January, 1614. I went ahead and described the second because it's better documented. I got the exact date from a journal article by a garden historian. [0] These are the kind of things that footnotes are helpful for - if I were writing this up as an academic paper, I'd get into the weeds with these details, but unfortunately it just doesn't work when you're writing it as a straight-ahead narrative without footnotes. That's especially true because it was basically just an introductory anecdote, not the focus of the piece.
I agree though, digging deep into historical sources, I think, should make us all uncomfortable. As you said, historians should never claim to have direct access to historical truth. It's all mediated and all potentially corrupted by the bias of observers/recorders. That's just a fact of doing history, and it's why we're not humanists, not scientists. It's also why I find it so endlessly interesting.
This is why I said that history is an interpretative act. I don't have an issue with the making the best of a past that is hard (impossible?) to discern. And that while our subject matter might be the past, we ourselves are in the present and express our understanding from our own biases and understandings - we talk ourselves into the past, in a way.
What I object to is the indisputable tone - this happened, these are the reasons, etc. It gives the reader the impression of knowledge, but this is an illusion, possibly a dangerous one. It conveys none of the reasoning, jumps and ambiguity that, I think, are the main part of these sorts of investigation.
Personally I would rather have the ambiguity, referring to source material, and try to develop a theory given the evidence - evidence-driven theories. I don't mind if there is no overarching narrative to explain it all. But it seems to me that professional historians feel empowered to present exactly that sort of a narrative, sometimes whether or not it is really supported by the evidence.
Totally agree. When reading history, you can and should substitute an invisible "According to the limited sources I consulted, and modulo their biases/mistakes/oversights, it seems to me the best interpretation of the given data that..." before every statement. Virtually no professional historian is going to claim to be 100% certain of any interpretation they make. It's often the case that more you dig into sources, the less certain you get. (Which is why almost every academic history paper's argument boils down to "this [person/event/era] turns out to be more complicated than we thought").
I also really like Fernand Braudel on events as a kind of epiphenomena of history, the misleading surface disturbances underneath the actual, barely-discernible patterns.
which seems a fair synopsis for me, of Hayden White's position in Metahistory. I thought this quote was interesting:
"In this climate, White (1966) believes that the duty of the researchers in present time is to transform the historical studies so as to liberate the present from the burden of history and to make the historical studies fit in the aims of the community. Seen in this light, history is not seen as a fixed ultimate entity that cannot be touched and that the historians have to accept it as it is. However, the historians should refuse to study the past as an end or ultimate being but contribute to offer some solutions for the problems of the present, which the professional historiography is unable to achieve."
I liked the general analysis that it seems White provides, but I don't like the moral relativism that is implied in the quote above. Why is it a historian's job to provide solutions for the present? What special values do they have? I don't like post-modern, moral relativism - where 'my truth' is the same as 'the truth'.
My position is that our knowledge of history is imperfect, that we cannot know the past. But a single past really did occur. Rather than express the evidence and express their reasoning for what that means, when historians apply narratives over the evidence they are covering an mystifying the past. This is to say I am receiving negative knowledge - I am receiving an informed but biased view that I will find it hard to unpick. And that is all history afaik! So little primary evidence, so many books and articles!
Perhaps similar to the OP, I'm accustomed to more explicit citations, so throughout the article it's really unclear to me what source applies to which quote. Is that standard practice in your domain?
I much prefer footnotes myself, where you can see directly what is being cited. Unfortunately there's a wide range of practices for online writing, but the norm I've found is usually just hyperlinks to digitized sources.
The Appendix, the online history journal I helped create back in the day, tried to experiment with a more detailed way of doing in-line citations, via small icons that you can click to see images, citations of primary source texts, even music or films on occasion. You can see it in action here:
What helps, I find, is to think of governments as administrations. The civil service does implements whatever it has been told. Politicians are voted in - this is a slight of hand to distract the public. (I think of politics as a soap opera for the middle classes.) All the while the real governors operate through global undemocratic organisations, such as the UN and the WHO.
The UN and the WHO are not covert control operations but simply troughs where the friends of the rich can feed.
The real governors operate from their country clubs and banquettes. No proper kingmaker would be so obvious as to grab headlines or make public announcements. Where is the personal enrichment in that?
A simple rule of thumb: if you know who they are, they're not the people in control.
I enjoyed this article. Perhaps because I agree! There are many quotes I could pull, but I liked this:
"true education is the opposite of what many think it is. For many, becoming educated means knowing things and feeling assured that there are no important questions left in the fields you have studied and that you have now become more capable and powerful than those without an education."
I would even push a little bit further... Where the author says:
"Aside from math/formal systems, the only way we truly know anything is by honest conversations between people of drastically different experiences and worldviews."
Well, what is maths? 1 + 1 = 2, right? While that is fine conceptually, what is the real world application? What things are 'ones' that can be counted as if they were the same? Is there anything that is the same as another thing? I don't think so. Which is to say, that maths is a model too - a useful one - but it does not describe an underlying reality, only the fabricated one we create for ourselves!
For me, this touches on everything that is wrong with the setup we find we have. How we lose our privacy and are beholden to our corporations and governments.
* We are separated from our data. It should be ours, and we should be able to allow for corporates to access it if we choose to and we are able to understand the usage.
* The options we are given here are to be able to move our data from one corporate entity to another. Hardly the solution individual ownership of one's data and privacy.
* We are looking to government legislation to make this right for us, but governments like having access to all the data that the corporations share with them. Governments are in the business of managing populations at scale - the more information they have, the better modelling, nudging, manipulations of the population they can do. Basically corporate and governmental interests align.
* Not to forget that corporations lobby governmental entities for the legislation they want. Even if the legislation states one thing, there are ALWAYS backdoors that are understood.
I'm sorry to say that the attack on privacy is a coordinated one with governments AND corporations. If you hope that this time the government will write better legislation or that corporates will do the right thing, you are mistaken. They only care about being perceived to do the right thing - so public relations.
If you are aware of all that, and have a solution, I would be interested to hear. I think any solution would involve individuals acting very defensively about their data. Any solution that begs government or corporations for better action this time is doomed.
Your product has a feature that curtails 'addiction' for the benefit of the user - ie to improve knowledge via spaced repetitions. A knowledgeable customer will recommend you and come back for more. Great!
Social media requires time from those users - they want to know you, crack you open psychologically, so they can then be better at selling you stuff (and, incidentally, pass all that info on to 3 letter agencies for their population modelling etc). That is a different model. They want you to be deeply engaged for a long time. The longer the better.
But, the reality we need to accept and work from is that with vested corporate interests aligning so well with intrusive governmental and military interests, nothing is going to change.
Don't hold your breath for privacy protection legislation.
Seriously though, how do we know that is DNA? It just looks like wiggly worms.
And the DNA pic is black and white, but the picture of graphite is in colour. How is it in colour? Is it 'enhanced' with photoshop or something?