When reading the popular media about scientific discoveries, sometimes I come across claims that a certain scientific visualization is actually a photograph. For example: ” First ever photograph inside of a hydrogen-atom“.
A photograph is an image made from photons of light reflecting off an object and striking a photosensitive surface such as a film or a digital sensor. Because light carries information relating to shape, texture, and color, photographs are representations (images of the object) that retain some semblance of the original.
We live in a world that is no longer dominated by photography, one in which data visualizations are used to “see” scientific phenomena and data in different ways.
These visualizations are made at different scales, from geological to quanta. These visualizations were created using techniques that show the differences between photography and scientific visualization – as well as the possibility of combining the two.
- Australia as seen from 700km above Earth
Twelve months over the Gulf of Carpentaria. Grayson Cooke Author provided (no re-use).
Grayson Cooke, a multimedia artist, works with data collected by satellites in a low-Earth orbit. These satellites are equipped with sensors that capture electromagnetic radiation, including ultraviolet, visible, and infrared wavelengths.
This image is a composite of several frames taken over a year over the Gulf of Carpentaria. It combines both infrared wavelengths and visible ones.
This image is a part photo, as it was created using visible light. It is part of data visualization, but it also uses invisible infrared light, which has been given a visible color.
- Rat retina with fluorescing pigment
The other side of the molecular divide: digital micrograph 2013 Andrea Rasell Author provided (no re-use)
Confocal Microscopy uses fluorescent dyes – commercially produced antibodies with fluorescent molecules attached – to bind specifically to the cell and tissue protein in biological specimens. When excited by the lasers of the microscope, fluorescent molecules are visible and can be viewed using either a camera or photodetector.
In this example, the layering of tissue is revealed by using antibodies that contain colored molecules. This image is of fluorescent molecules and not of tissue.
- Graphene viewed through an atomic force microscopy.
Video stills from Movement I: Nanomorphology 2018 Andrea Rasell. Author provided.
The image above is a microscopic view of graphene. This substance has multiple layers of carbon lattices that are stacked together like paper. The idea was captured with an atomic-force microscope.
Microscopical imaging has traditionally been a process of direct optical image capture. The microscope magnifies the details of an object by amplifying the light waves that reflect off it.
This process is not applicable to phenomena occurring at the nanoscale. (A nanometre equals one billionth of a meter). The visible light waves are too big to hit objects smaller than 400 nanometres, so a microscope cannot reflect them.
The atomic force microscopy uses a different method of detection – a probe that looks like a stylus used on a recorder. It is used to “feel” and scan a sample.
The resolution of a micrograph is determined by the sharpness of the tip of the probe, which is typically only a few nanometres in width. This allows the visualization of smaller phenomena than what can be detected by light.
To create micrographs, the spatial data produced by the instrument — depth, width, and height — is translated through a variety of instrumental and computation processes. This process converts tactile data into visual information.
- X-rays reflected by a protein.
Andrew Martin, Author, provided.
Simulations of X-ray scattering are commonly used to determine the shape of molecules. This example is a simulation of an X-ray pattern for a protein called GroEL, which has a diameter of about 60,000 atoms (ten nanometres).
A beam of X-rays directed at a sample of protein creates this type of visualization. The X-rays scatter and change direction depending on the interaction with the protein atoms. The atoms can be dense or sparse in different areas.
The patterns created by X-rays can be reverse-engineered and measured to determine the structure of the proteins that caused them. Crystallographers can recover the three-dimensional protein structure using computational analysis.
- Theoretical Images of Molecules
Fluorobenzene calculated image (2011) Ula Alexandr Author provided (no re-use)
This is an image calculated of a molecule of fluorobenzene at 25degC.
Calculated images can be used to measure the changes in a molecule as it rotates and interacts with light. The images are created using data obtained from experiments. The information is then modified to match the pattern of the experiment.
This is a probability chart of the likelihood that the molecule will absorb or emit light. The artificial colorisation is then assigned according to how likely it is. The molecule’s rotation in space, its atomic vibration, and its shape all affect the artificial colorisation.
The two-dimensional image is created by stacking horizontal images. The dots of any of these series are like an energy ladder that corresponds to the amount of rotation the molecule began with.
These series will be short if the molecules are not rotating very much. However, molecules that are rotating faster and are warmer will produce a series with more dots.
