In the mid-IR range, the entire planet Earth and all objects on it, even ice, shine.
In the middle and far infrared, bolometers are used to indicate changes.
In the mid-IR range, the entire planet Earth and all objects on it, even ice, shine. Due to this, the Earth is not overheated by solar heat. But not all infrared radiation passes through the atmosphere. There are only a few windows of transparency, the rest of the radiation is absorbed by carbon dioxide, water vapor, methane, ozone and other greenhouse gases that prevent the Earth from cooling rapidly.
Due to the absorption in the atmosphere and thermal radiation of objects, telescopes for the middle and far infrared are carried out into space and cooled to the temperature of liquid nitrogen or even helium.
The infrared range is one of the most interesting for astronomers. Space dust shines in it, which is important for the formation of stars and the evolution of galaxies. Infrared radiation is better than visible radiation passes through clouds of cosmic dust and allows you to see objects inaccessible to observation in other parts of the spectrum.
Hubble can see more galaxies than stars in infrared
A fragment of one of the so-called Hubble Deep Fields. In 1995, a space telescope accumulated light coming from one area of the sky for 10 days. This made it possible to see extremely faint galaxies, the distance to which is up to 13 billion light years (less than one billion years from the Big Bang). Visible light from such distant objects experiences a significant redshift and becomes infrared.
The observations were carried out in an area far from the plane of the galaxy, where relatively few stars are visible. Therefore, most of the registered objects are galaxies at different stages of evolution.
Sombrero Galaxy in the infrared
A giant spiral galaxy, also referred to as M104, is located in the cluster of galaxies in the constellation Virgo and is visible to us almost edge-on. It has a huge central bulge (a globular thickening in the center of the galaxy) and contains about 800 billion stars – 2-3 times more than the Milky Way.
At the center of the galaxy is a supermassive black hole with a mass of about a billion times the mass of the Sun. This is determined by the velocities of the stars near the center of the galaxy. In the infrared range, a ring of gas and dust is clearly visible in the galaxy, in which stars are actively being born.
Nebulae and dust clouds near the center of the Galaxy in the infrared range
Spitzer Infrared Space Telescope
The main mirror, 85 cm in diameter, is made of beryllium and is cooled to a temperature of 5.5 K to reduce the mirror’s own infrared radiation.
The telescope was launched in August 2003 under the program of the four great NASA observatories, including:
gamma observatory “Compton” (1991–2000, 20 keV-30 GeV), see the Sky in gamma rays with an energy of 100 MeV,X-ray observatory “Chandra” (1999, 100 eV-10 keV),space telescope “Hubble” (1990, 100-2100 nm),infrared telescope “Spitzer” (2003, 3-180 microns).
The Spitzer telescope is expected to have a service life of about 5 years. The telescope got its name in honor of the astrophysicist Lyman Spitzer (1914–97), who in 1946, long before the launch of the first satellite, published an article “Benefits for astronomy of an extraterrestrial observatory”, and 30 years later convinced NASA and the American Congress to start developing a space telescope ” Hubble “.
Near-infrared sky 1-4 μm and mid-infrared 25 μm (COBE / DIRBE)
In the near infrared, the Galaxy is seen even more clearly than in the visible.
But in the mid-IR range, the Galaxy is barely visible. Observations are greatly hampered by dust in the solar system. It is located along the plane of the ecliptic, which is inclined how to write a conclusion for a synthesis essay to the plane of the Galaxy at an angle of about 50 degrees.
Both surveys were obtained by the DIRBE (Diffuse Infrared Background Experiment) instrument aboard the COBE satellite (Cosmic Background Explorer). This experiment, begun in 1989, produced complete maps of the infrared brightness of the sky in the 1.25 to 240 µm range.
The device is based on an electron-optical converter (EOC), which makes it possible to significantly (from 100 to 50 thousand times) amplify weak visible or infrared light.
The lens creates an image on the photocathode, from which, as in the case of a photomultiplier, electrons are knocked out. Then they are accelerated by a high voltage (10–20 kV), focused by electronic optics (an electromagnetic field of a specially selected configuration) and fall on a fluorescent screen similar to a television. On it, the image is examined through the eyepieces.
The overclocking of photoelectrons makes it possible in low-light conditions to use literally every quantum of light to obtain an image, but in complete darkness, illumination is required. In order not to betray the presence of an observer, they use a near-infrared projector (760-3000 nm).
There are also devices that capture the own thermal radiation of objects in the mid-IR range (8-14 microns). Such devices are called thermal imagers, they allow you to notice a person, an animal or a heated engine due to their thermal contrast with the surrounding background.
All the energy consumed by an electric heater is ultimately converted to heat. A significant part of the heat is carried away by the air, which comes into contact with the hot surface, expands and rises, so that it is mainly the ceiling that heats up.
To avoid this, the heaters are equipped with fans that direct warm air, for example, to the feet of a person and help to mix the air in the room. But there is another way of transferring heat to surrounding objects: infrared radiation from the heater. The hotter the surface and the larger its area, the stronger it is.
To increase the area, the radiators are made flat. However, in this case, the surface temperature cannot be high. Other models of heaters use a spiral that heats up to several hundred degrees (red heat) and a concave metal reflector that creates a directed stream of infrared radiation.
Next: Radio emission and microwaves
1,8 km / h
37 km / h
100 meter short distance speed record: Asafa Powell, Jamaica, 2004
47 km / h
Inline skates: Ippolito Sanfratello, Italy, 2006
53 km / h
Skates: Joji Kato, Japan, 2005
72 km / h
73 km / h
Bicycle (regular): Curtis Harnett, Canada, 1995
100 km / h
130 km / h
Velomobile: Varna Diablo II, USA-Bulgaria, 2002
388 km / h
Fastest production car: Koenigsegg CCR, Sweden, 2005
Wheel drive car
738 km / h
Fastest Wheel Drive Vehicle: Turbinator, USA, 2001
Land vehicle on wheels
1228 km / h
Fastest land vehicle on wheels: Thrust SSC, USA, 1997
What do a tree, a seashore, a cloud, or blood vessels in our hand have in common? There is one property of structure inherent in all the listed items: they are self-similar. From the branch, as well as from the trunk of the tree, there are smaller branches, from them – even smaller ones, etc., that is, the branch is like the whole tree. The circulatory system is arranged in a similar way: arterioles depart from the arteries, and from them – the smallest capillaries through which oxygen enters the organs and tissues. Let’s look at satellite images of the sea coast: we will see bays and peninsulas; let’s take a look at it, but from a bird’s eye view: we will see bays and capes; Now let’s imagine that we are standing on the beach and looking at our feet: there are always pebbles that protrude further into the water than the rest. That is, the coastline, when zoomed in, remains similar to itself. The American (though raised in France) mathematician Benoit Mandelbrot called this property of objects fractality, and such objects themselves – fractals (from the Latin fractus – broken).
One interesting story is connected with the coastline, or rather, with an attempt to measure its length, which formed the basis of Mandelbrot’s scientific article, and is also described in his book “The Fractal Geometry of Nature”. This is an experiment led by Lewis Fry Richardson, a highly talented and eccentric mathematician, physicist and meteorologist. One of the directions of his research was an attempt to find a mathematical description of the causes and likelihood of an armed conflict between the two countries. Among the parameters that he took into account was the length of the common border of the two warring countries. When he collected data for numerical experiments, he found that in different sources the data on the common border between Spain and Portugal are very different. This prompted him to the next discovery: the length of the borders of the country depends on the ruler with which we measure them. The smaller the scale, the longer the border is. This is due to the fact that at higher magnification it becomes possible to take into account more and more coastal bends, which were previously ignored due to the roughness of the measurements. And if with each increase in the scale, the previously unaccounted for bends of the lines will open, then it turns out that the length of the boundaries is infinite! True, in reality this does not happen – the accuracy of our measurements has a finite limit. This paradox is called the Richardson effect.
Nowadays, the theory of fractals is widely used in various fields of human activity. In addition to fractal painting, fractals are used in information theory to compress graphic data (here the property of self-similarity of fractals is mainly used – after all, to remember a small fragment of a drawing and transformations with which you can get the rest of the parts, much less memory is required than to store the entire file). By adding random perturbations to the formulas defining the fractal, one can obtain stochastic fractals that very plausibly convey some real objects – relief elements, the surface of water bodies, some plants, which is successfully used in physics, geography and computer graphics to achieve greater similarity of simulated objects with real. In radio electronics, in the last decade, they began to produce antennas with a fractal shape. Taking up little space, they provide quite high-quality signal reception. And economists use fractals to describe the curves of currency rate fluctuations (this property was discovered by Mandelbrot more than 30 years ago).
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What capabilities and abilities of a person are decisive for his leadership on the planet?
Movement on the ground
M. S. Gelfand,Doctor of Biological Sciences, Candidate of Physical and Mathematical Sciences,Institute for Information Transmission Problems RAS”Chemistry and Life” No. 9, 2009
Everyone knows that bioinformatics is somehow related to computers, DNA and proteins and that it is the cutting edge of science. Not everyone can boast of more detailed information, even among biologists. Mikhail Sergeevich Gelfand told Chemistry and Life about some of the problems that modern bioinformatics solves (interview was recorded by Elena Kleshchenko).
Information in biology
In recent decades, many new scientific disciplines have appeared with fashionable names: bioinformatics, genomics, proteomics, systems biology, and others. But in fact, bioinformatics, like, say, proteomics, is not a science, but several convenient technologies and a set of specific problems that are solved with their help. We can say that every person who determines the concentration of proteins by mass spectrometry or studies protein-protein interactions, works in the field of proteomics. But it is possible that over time this division will become less important: the technology used will be less significant than the way to think, to pose questions. And in this sense, bioinformatics, as the most ancient of these sciences – it is as much as 25 years old – plays the role of a cementing principle, because no matter how the data is obtained, they still end up in the computer. It cannot be otherwise: the size of the bacterial genome is millions of nucleotides, the size of the higher animal is hundreds of millions or billions. Transcriptomics, which studies the activity of genes, receives data on the concentrations of tens of thousands of messenger RNAs, proteomics – on hundreds of thousands of peptides and protein-protein interactions. You cannot work with so much information manually. We still remember how we printed the nucleotide sequences on paper, then cut out the printed lines, substituted them under each other and made alignment in such a handicraft way – looking for similar areas. This was possible when it was about tens to hundreds of nucleotides or amino acids, but with the current volume of data, special tools are needed. A set of such tools is provided by bioinformatics – in practical terms, it is an applied science serving the interests of biologists.
Since my own work is mainly related to the analysis of genomic data, the following discussion focuses mainly on genomics. Even before the last generation of sequencers, data volumes began to outpace Moore’s Law: the nucleotide sequences of genomes accumulated faster than the power of computers grew. It would not be a big exaggeration to say that in recent years biology has begun to turn into a science “rich in data.” Relatively speaking, in “classical” molecular biology, one biological fact was established in one experiment: the amino acid sequence of a protein, its function, how the corresponding gene is regulated. And now such facts are obtained industrially. Molecular biology is moving along the path that astrophysics and high energy physics have already followed. When there is a constantly working radio telescope or accelerator, the problem of data extraction is solved, and the problems of data storage and processing come to the fore.
The same thing happens with biology, and very quickly, and it is not always easy to readjust. However, those who succeed are the beneficiaries. At our seminar, a biologist told how he and his colleagues studied a certain protein using traditional methods of experimental biology. This is a difficult task: knowing that a certain function is performed in the cell, find the protein that is responsible for it. They found this protein, began to study it and were convinced that there must be another protein with similar properties, since the presence of the first does not explain all the observed facts. It was even more difficult to look for a second protein against the background of the first, but they coped with that. And then the human genome was published – and, having access to its sequence, they found a dozen more such proteins …
It does not at all follow from this example that practical molecular biology has exhausted itself. Rather, she learned to use new tools: to interpret not only the strips in the gel after electrophoresis, the concentration of mRNA and proteins, or, say, the growth rate of bacteria, but also the colossal arrays of data stored in the computer.