Incredible facts
Have you ever wondered how big the Universe is?
8. However, this is nothing compared to the Sun.
Photo of the Earth from space
9. And this view of our planet from the moon.
10. This is us from the surface of Mars.
11. And this view of the Earth behind the rings of Saturn.
12. And this is the famous photograph" Pale blue dot", where the Earth is photographed from Neptune, from a distance of almost 6 billion kilometers.
13. Here is the size Earth compared to the Sun, which doesn’t even fit completely into the photo.
Biggest star
14. And this Sun from the surface of Mars.
15. As the famous astronomer Carl Sagan once said, in space more stars than grains of sand on all the beaches of the Earth.
16. There are many stars that are much larger than our Sun. Just look how tiny the Sun is.
Photo of the Milky Way galaxy
18. But nothing can compare to the size of the galaxy. If you reduce The sun to the size of a leukocyte(white blood cell), and shrink the Milky Way Galaxy using the same scale, the Milky Way would be the size of the United States.
19. This is because the Milky Way is simply huge. That's where the solar system is inside it.
20. But we see only very much a small part of our galaxy.
21. But even our galaxy is tiny compared to others. Here Milky Way compared to galaxy IC 1011, which is located 350 million light years from Earth.
22. Think about it, in this photograph taken by the Hubble telescope, thousands of galaxies, each containing millions of stars, each with their own planets.
23. Here is one of galaxy UDF 423, located 10 billion light years away. When you look at this photograph, you are looking billions of years into the past. Some of these galaxies formed several hundred million years after the Big Bang.
24. But remember that this photo is very, a very small part of the universe. It's just an insignificant part of the night sky.
25. We can quite confidently assume that somewhere there is black holes. Here's the size of the black hole compared to Earth's orbit.
Which are on it. For the most part, we are all chained to the place where we live and work. The size of our world is amazing, but it is absolutely nothing compared to the Universe. As the saying goes - "born too late to explore the world, and too early to explore space". It's even insulting. However, let's get started - just be careful not to get dizzy.
1. This is Earth.
This is the same planet that is currently the only home for humanity. The place where life magically appeared (or maybe not so magically) and in the course of evolution you and I appeared.
2. Our place in the solar system.
The closest large space objects that surround us, of course, are our neighbors in the solar system. Everyone remembers their names from childhood, and during lessons about the world around them they make models. It so happened that even among them we are not the biggest...
3. The distance between our Earth and the Moon.
It doesn't seem that far, right? And if we also take into account modern speeds, then it’s “nothing at all.”
4. In fact, it’s quite far away.
If you try, then very accurately and comfortably - between the planet and the satellite you can easily place the rest of the planets of the solar system.
5. However, let's continue talking about planets.
Before you is North America, as if it were placed on Jupiter. Yes, this small green speck is North America. Can you imagine how huge our Earth would be if we moved it to the scale of Jupiter? People would probably still be discovering new lands)
6. This is Earth compared to Jupiter.
Well, more precisely six Earths - for clarity.
7. Rings of Saturn, sir.
The rings of Saturn would have such a gorgeous appearance, provided they revolved around the Earth. Look at Polynesia - a bit like the Opera icon, right?
8. Let's compare the Earth with the Sun?
It doesn't look that big in the sky...
9. This is the view of the Earth when looking at it from the Moon.
Beautiful, right? So lonely against the backdrop of empty space. Or not empty? Let's continue...
10. And so from Mars
I bet you wouldn't even be able to tell if it was Earth.
11. This is a shot of Earth just beyond the rings of Saturn
12. But beyond Neptune.
A total of 4.5 billion kilometers. How long would it take to search?
13. So, let's go back to the star called the Sun.
A breathtaking sight, isn't it?
14. Here is the Sun from the surface of Mars.
15. And here is its comparison with the Scale of the star VY Canis Majoris.
How do you like it? More than impressive. Can you imagine the energy concentrated there?
16. But this is all bullshit if we compare our native star with the size of the Milky Way galaxy.
To make it more clear, imagine that we have compressed our Sun to the size of a white blood cell. In this case, the size of the Milky Way is quite comparable to the size of Russia, for example. This is the Milky Way.
17. In general, stars are huge
Everything that is placed in this yellow circle is everything that you can see at night from Earth. The rest is inaccessible to the naked eye.
18. But there are other galaxies.
Here is the Milky Way compared to the galaxy IC 1011, which is located 350 million light years from Earth.
Let's go over it again?
So, this Earth is our home.
Let's zoom out to the size of the solar system...
Let's zoom out a little more...
And now to the size of the Milky Way...
Let's continue to reduce...
And further…
Almost ready, don't worry...
Ready! Finish!
This is all that humanity can now observe using modern technology. It’s not even an ant... Judge for yourself, just don’t go crazy...
Such scales are hard to even comprehend. But someone confidently declares that we are alone in the Universe, although they themselves are not really sure whether the Americans were on the Moon or not.
Hang in there guys... hang in there.
Part one ASTRONOMICAL ASPECT OF THE PROBLEM
1. The scale of the Universe and its structure If professional astronomers constantly and tangibly imagined the monstrous magnitude of cosmic distances and time intervals of the evolution of celestial bodies, it is unlikely that they could successfully develop the science to which they devoted their lives. The space-time scales familiar to us since childhood are so insignificant compared to cosmic ones that when it comes to consciousness, it literally takes your breath away. When dealing with any problem in space, an astronomer either solves a certain mathematical problem (this is most often done by specialists in celestial mechanics and theoretical astrophysicists), or improves instruments and observation methods, or builds in his imagination, consciously or unconsciously, some small model the space system under study. In this case, the main importance is a correct understanding of the relative sizes of the system being studied (for example, the ratio of the sizes of parts of a given space system, the ratio of the sizes of this system and others similar or dissimilar to it, etc.) and time intervals (for example, the ratio of the flow rate of a given process to the rate of occurrence of any other). The author of this book dealt quite a lot, for example, with the solar corona and the Galaxy. And they always seemed to him to be irregularly shaped spheroidal bodies of approximately the same size - something around 10 cm... Why 10 cm? This image arose subconsciously, simply because too often, while thinking about one or another issue of solar or galactic physics, the author drew the outlines of the objects of his thoughts in an ordinary notebook (in a box). I drew, trying to adhere to the scale of the phenomena. On one very interesting question, for example, it was possible to draw an interesting analogy between the solar corona and the Galaxy (or rather, the so-called “galactic corona”). Of course, the author of this book knew very well, so to speak, “intellectually,” that the dimensions of the galactic corona are hundreds of billions of times larger than the dimensions of the solar corona. But he calmly forgot about it. And if in a number of cases the large dimensions of the galactic corona acquired some fundamental significance (this also happened), this was taken into account formally and mathematically. And yet, visually, both “crowns” seemed equally small... If the author, in the process of this work, had indulged in philosophical reflections about the enormity of the size of the Galaxy, about the unimaginable rarefaction of the gas that makes up the galactic crown, about the insignificance of our little planet and our own existence and about other equally valid subjects, work on the problems of the solar and galactic coronas would stop automatically. .. May the reader forgive me this “lyrical digression”. I have no doubt that other astronomers had similar thoughts as they worked through their problems. It seems to me that sometimes it is useful to take a closer look at the “kitchen” of scientific work... If we want to discuss exciting questions about the possibility of intelligent life in the Universe on the pages of this book, then, first of all, we will need to get a correct idea of its spatio-temporal scale . Until relatively recently, the globe seemed huge to people. It took Magellan’s brave companions more than three years to make their first trip around the world 465 years ago, at the cost of incredible hardships. A little more than 100 years have passed since the time when the resourceful hero of Jules Verne’s science fiction novel, using the latest technological advances of the time, traveled around the world in 80 days. And only 26 years have passed since those memorable days for all mankind, when the first Soviet cosmonaut Gagarin circled the globe on the legendary Vostok spacecraft in 89 minutes. And people’s thoughts involuntarily turned to the vast expanses of space in which the small planet Earth was lost... Our Earth is one of the planets of the solar system. Compared to other planets, it is located quite close to the Sun, although it is not the closest. The average distance from the Sun to Pluto, the most distant planet in the solar system, is 40 times greater than the average distance from Earth to the Sun. It is currently unknown whether there are planets in the solar system that are even more distant from the Sun than Pluto. One can only say that if such planets exist, they are relatively small. Conventionally, the size of the Solar System can be taken to be 50-100 astronomical units *, or about 10 billion km. By our earthly scale, this is a very large value, approximately 1 million greater than the diameter of the Earth.Rice. 1. Planets of the Solar System
We can more clearly imagine the relative scale of the solar system as follows. Let the Sun be represented by a billiard ball with a diameter of 7 cm. Then the planet closest to the Sun - Mercury - is located on this scale at a distance of 280 cm. The Earth is at a distance of 760 cm, the giant planet Jupiter is at a distance of about 40 m, and the farthest planet - in many respects, Pluto is still mysterious - at a distance of about 300m. The dimensions of the globe on this scale are slightly more than 0.5 mm, the lunar diameter is slightly more than 0.1 mm, and the Moon’s orbit has a diameter of about 3 cm. Even the closest star to us, Proxima Centauri, is so far away from us that compared to it, interplanetary distances within the solar system seem like mere trifles. Readers, of course, know that a unit of length such as a kilometer is never used to measure interstellar distances**). This unit of measurement (as well as the centimeter, inch, etc.) arose from the needs of the practical activities of mankind on Earth. It is completely unsuitable for estimating cosmic distances that are too large compared to a kilometer. In popular literature, and sometimes in scientific literature, the “light year” is used as a unit of measurement to estimate interstellar and intergalactic distances. This is the distance that light, moving at a speed of 300 thousand km/s, travels in a year. It is easy to see that a light year is equal to 9.46 x 10 12 km, or about 10,000 billion km. In the scientific literature, a special unit called the “parsec” is usually used to measure interstellar and intergalactic distances;
1 parsec (pc) is equal to 3.26 light years. A parsec is defined as the distance from which the radius of the Earth's orbit is visible at an angle of 1 second. arcs. This is a very small angle. Suffice it to say that from this angle a one-kopeck coin is visible from a distance of 3 km.
Rice. 2. Globular cluster 47 Tucanae
None of the stars - the closest neighbors of the Solar System - are closer to us than 1 pc. For example, the mentioned Proxima Centauri is located at a distance of about 1.3 pc from us. On the scale in which we depicted the Solar System, this corresponds to 2 thousand km. All this well illustrates the great isolation of our Solar system from surrounding stellar systems; some of these systems may have many similarities with it. But the stars surrounding the Sun and the Sun itself constitute only an insignificant part of the gigantic group of stars and nebulae, which is called the “Galaxy”. We see this cluster of stars on clear moonless nights as a stripe of the Milky Way crossing the sky. The galaxy has a rather complex structure. In the first, roughest approximation, we can assume that the stars and nebulae of which it consists fill a volume shaped like a highly compressed ellipsoid of revolution. Often in popular literature the shape of the Galaxy is compared to a biconvex lens. In reality, everything is much more complicated, and the picture drawn is too rough. In fact, it turns out that different types of stars concentrate in completely different ways towards the center of the Galaxy and towards its “equatorial plane”. For example, gaseous nebulae, as well as very hot massive stars, are strongly concentrated towards the equatorial plane of the Galaxy (in the sky this plane corresponds to a large circle passing through the central parts of the Milky Way). At the same time, they do not show a significant concentration towards the galactic center. On the other hand, some types of stars and star clusters (the so-called “globular clusters”, Fig. 2) show almost no concentration towards the equatorial plane of the Galaxy, but are characterized by a huge concentration towards its center. Between these two extreme types of spatial distribution (which astronomers call "flat" and "spherical") are all the intermediate cases. However, it turns out that the bulk of the stars in the Galaxy are located in a giant disk, the diameter of which is about 100 thousand light years and the thickness is about 1500 light years. This disk contains slightly more than 150 billion stars of various types. Our Sun is one of these stars, located on the periphery of the Galaxy close to its equatorial plane (more precisely, “only” at a distance of about 30 light years - a value quite small compared to the thickness of the stellar disk). The distance from the Sun to the core of the Galaxy (or its center) is about 30 thousand km. light years. Stellar density in the Galaxy is very uneven. It is highest in the region of the galactic core, where, according to the latest data, it reaches 2 thousand stars per cubic parsec, which is almost 20 thousand times more than the average stellar density in the vicinity of the Sun ***. In addition, stars tend to form distinct groups or clusters. A good example of such a cluster is the Pleiades, which is visible in our winter sky (Figure 3). The Galaxy also contains structural details on a much larger scale. Research in recent years has proven that nebulae, as well as hot massive stars, are distributed along the branches of the spiral. The spiral structure is especially clearly visible in other star systems - galaxies (with a small letter, in contrast to our star system - Galaxies). One of these galaxies is shown in Fig. 4. Establishing the spiral structure of the Galaxy in which we ourselves find ourselves has proven extremely difficult.
Rice. 3. Photo of the Pleiades star cluster
Rice. 4. Spiral Galaxy NGC 5364
Stars and nebulae within the Galaxy move in quite complex ways. First of all, they participate in the rotation of the Galaxy around an axis perpendicular to its equatorial plane. This rotation is not the same as that of a solid body: different parts of the Galaxy have different periods of rotation. Thus, the Sun and the stars surrounding it in a huge area several hundred light years in size complete a full revolution in about 200 million years. Since the Sun, together with its family of planets, has apparently existed for about 5 billion years, during its evolution (from birth from a gas nebula to its current state) it has made approximately 25 revolutions around the axis of rotation of the Galaxy. We can say that the age of the Sun is only 25 “galactic years”; let’s face it, it’s a blooming age... The speed of movement of the Sun and its neighboring stars in their almost circular galactic orbits reaches 250 km/s ****. Superimposed on this regular motion around the galactic core are the chaotic, disorderly movements of stars. The speeds of such movements are much lower - about 10-50 km/s, and they are different for objects of different types. The speeds are lowest for hot massive stars (6-8 km/s); for solar-type stars they are about 20 km/s. The lower these velocities, the more “flat” the distribution of a given type of star is. On the scale that we used to visually represent the Solar System, the size of the Galaxy will be 60 million km - a value already quite close to the distance from the Earth to the Sun. From here it is clear that as we penetrate into increasingly more distant regions of the Universe, this scale is no longer suitable, since it loses clarity. Therefore, we will take a different scale. Let us mentally reduce the earth's orbit to the size of the innermost orbit of the hydrogen atom in the classical Bohr model. Let us recall that the radius of this orbit is 0.53x10 -8 cm. Then the nearest star will be at a distance of approximately 0.014 mm, the center of the Galaxy will be at a distance of about 10 cm, and the dimensions of our star system will be about 35 cm. The diameter of the Sun will have microscopic dimensions : 0.0046 A (angstrom unit of length equal to 10 -8 cm).
We have already emphasized that the stars are located at enormous distances from each other, and are thus practically isolated. In particular, this means that stars almost never collide with each other, although the motion of each of them is determined by the gravitational field created by all the stars in the Galaxy. If we consider the Galaxy as a certain region filled with gas, and the role of gas molecules and atoms is played by stars, then we must consider this gas to be extremely rarefied. In the solar vicinity, the average distance between stars is about 10 million times greater than the average diameter of stars. Meanwhile, under normal conditions in ordinary air, the average distance between molecules is only several tens of times greater than the size of the latter. To achieve the same degree of relative rarefaction, the air density would have to be reduced by at least 1018 times! Note, however, that in the central region of the Galaxy, where stellar density is relatively high, collisions between stars will occur from time to time. Here we should expect approximately one collision every million years, while in the “normal” regions of the Galaxy there have been virtually no collisions between stars in the entire history of the evolution of our stellar system, which is at least 10 billion years old (see Chapter 9). ).
We have briefly outlined the scale and most general structure of the star system to which our Sun belongs. At the same time, the methods with the help of which, over the course of many years, several generations of astronomers, step by step, recreated a majestic picture of the structure of the Galaxy, were not considered at all. Other books are devoted to this important problem, to which we refer interested readers (for example, B.A. Vorontsov-Velyaminov “Essays on the Universe”, Yu.N. Efremov “Into the Depths of the Universe”). Our task is to give only the most general picture of the structure and development of individual objects in the Universe. This picture is absolutely necessary for understanding this book.
Rice. 5. Andromeda Nebula with satellites
For several decades now, astronomers have been persistently studying other star systems that are more or less similar to ours. This area of research is called "extragalactic astronomy." She now plays almost the leading role in astronomy. Over the past three decades, extragalactic astronomy has made astonishing advances. Little by little, the grandiose contours of the Metagalaxy began to emerge, of which our stellar system is included as a small particle. We still don’t know everything about the Metagalaxy. The enormous remoteness of objects creates very specific difficulties, which are resolved by using the most powerful means of observation in combination with in-depth theoretical research. Yet the general structure of the Metagalaxy has largely become clear in recent years. We can define a Metagalaxy as a collection of star systems - galaxies moving in the vast spaces of the part of the Universe we observe. The galaxies closest to our star system are the famous Magellanic Clouds, clearly visible in the sky of the southern hemisphere as two large spots of approximately the same surface brightness as the Milky Way. The distance to the Magellanic Clouds is “only” about 200 thousand light years, which is quite comparable to the total extent of our Galaxy. Another galaxy “close” to us is the nebula in the constellation Andromeda. It is visible to the naked eye as a faint speck of light of 5th magnitude *****. In fact, this is a huge star world, in terms of the number of stars and total mass three times greater than our Galaxy, which in turn is a giant among galaxies. The distance to the Andromeda nebula, or, as astronomers call it, M 31 (this means that in the well-known catalog of Messier nebulae it is listed as No. 31), is about 1800 thousand light years, which is about 20 times the size of the Galaxy. The M 31 nebula has a clearly defined spiral structure and in many of its characteristics is very similar to our Galaxy. Next to it are its small ellipsoidal satellites (Fig. 5). In Fig. Figure 6 shows photographs of several galaxies relatively close to us. Noteworthy is the wide variety of their forms. Along with spiral systems (such galaxies are designated by the symbols Sа, Sb and Sс depending on the nature of the development of the spiral structure; if there is a “bridge” passing through the core (Fig. 6a), the letter B is placed after the letter S), there are spheroidal and ellipsoidal ones, devoid of any traces spiral structure, as well as “irregular” galaxies, a good example of which are the Magellanic Clouds. A huge number of galaxies are observed in large telescopes. If there are about 250 galaxies brighter than the visible 12th magnitude, then there are already about 50 thousand brighter than the 16th. The faintest objects that can be photographed at the limit by a reflecting telescope with a mirror diameter of 5 m are 24.5th magnitude. It turns out that among the billions of such faint objects, the majority are galaxies. Many of them are distant from us at distances that light travels over billions of years. This means that the light that caused the blackening of the plate was emitted by such a distant galaxy long before the Archean period of the geological history of the Earth!
Rice. 6a. Cross spiral galaxy
Rice. 6b. Galaxy NGC 4594
Rice. 6s. Galaxies Magellanic Clouds
Sometimes among the galaxies you come across amazing objects, for example, “radio galaxies”. These are star systems that emit huge amounts of energy in the radio range. For some radio galaxies, the flux of radio emission is several times higher than the flux of optical radiation, although in the optical range their luminosity is very high - several times greater than the total luminosity of our Galaxy. Let us recall that the latter consists of the radiation of hundreds of billions of stars, many of which, in turn, radiate much stronger than the Sun. A classic example of such a radio galaxy is the famous object Cygnus A. In the optical range, these are two insignificant specks of light of the 17th magnitude (Fig. 7). In fact, their luminosity is very high, about 10 times greater than that of our Galaxy. This system seems weak because it is located at a huge distance from us - 600 million light years. However, the flux of radio emission from Cygnus A at meter waves is so great that it even exceeds the flux of radio emission from the Sun (during periods when there are no sunspots on the Sun). But the Sun is very close - the distance to it is “only” 8 light minutes; 600 million years - and 8 minutes! But radiation fluxes, as is known, are inversely proportional to the squares of the distances! The spectra of most galaxies resemble the sun; in both cases, individual dark absorption lines are observed against a fairly bright background. This is not unexpected, since the radiation of galaxies is the radiation of the billions of stars that comprise them, more or less similar to the Sun. Careful study of the spectra of galaxies many years ago led to a discovery of fundamental importance. The fact is that by the nature of the shift in the wavelength of any spectral line in relation to the laboratory standard, one can determine the speed of movement of the emitting source along the line of sight. In other words, it is possible to determine at what speed the source is approaching or moving away.
Rice. 7. Radio galaxy Cygnus A
If the light source approaches, the spectral lines shift towards shorter wavelengths; if it moves away, towards longer ones. This phenomenon is called the "Doppler effect". It turned out that galaxies (with the exception of a few closest to us) have spectral lines that are always shifted to the long-wavelength part of the spectrum (“red shift” of the lines), and the greater the distance the galaxy is from us, the greater the magnitude of this shift. This means that all galaxies are moving away from us, and the speed of “expansion” increases as the galaxies move away. It reaches enormous values. For example, the recession speed of the radio galaxy Cygnus A, found from the red shift, is close to 17 thousand km/s. Twenty-five years ago, the record belonged to the very faint (in optical rays of the 20th magnitude) radio galaxy 3S 295. In 1960, its spectrum was obtained. It turned out that the well-known ultraviolet spectral line belonging to ionized oxygen is shifted to the orange region of the spectrum! From here it is easy to find that the speed of removal of this amazing star system is 138 thousand km/s, or almost half the speed of light! Radio galaxy 3S 295 is distant from us at a distance that light travels in 5 billion years. Thus, astronomers studied the light that was emitted when the Sun and planets were formed, and maybe even “a little” earlier... Since then, even more distant objects have been discovered (Chapter 6). We will not touch upon the reasons for the expansion of a system consisting of a huge number of galaxies here. This complex question is the subject of modern cosmology. However, the very fact of the expansion of the Universe is of great importance for analyzing the development of life in it (Chapter 7). Superimposed on the overall expansion of the galaxy system are the erratic velocities of individual galaxies, typically several hundred kilometers per second. This is why the galaxies closest to us do not exhibit a systematic redshift. After all, the speeds of random (so-called “peculiar”) movements for these galaxies are greater than the regular redshift speed. The latter increases as the galaxies move away by approximately 50 km/s, for every million parsecs. Therefore, for galaxies whose distances do not exceed several million parsecs, the random velocities exceed the receding velocity due to the redshift. Among nearby galaxies, there are also those that are approaching us (for example, the Andromeda nebula M 31). Galaxies are not uniformly distributed in metagalactic space, i.e. with constant density. They show a pronounced tendency to form separate groups or clusters. In particular, a group of about 20 galaxies close to us (including our Galaxy) forms the so-called “local system”. In turn, the local system is part of a large cluster of galaxies, the center of which is in that part of the sky on which the Virgo constellation is projected. This cluster has several thousand members and is among the largest. In Fig. Figure 8 shows a photograph of the famous galaxy cluster in the constellation Corona Borealis, numbering hundreds of galaxies. In the space between clusters, the density of galaxies is tens of times less than inside the clusters.
Rice. 8. Cluster of galaxies in the constellation Corona Borealis
Noteworthy is the difference between clusters of stars that form galaxies and clusters of galaxies. In the first case, the distances between cluster members are enormous compared to the sizes of the stars, while the average distances between galaxies in galaxy clusters are only several times larger than the sizes of the galaxies. On the other hand, the number of galaxies in clusters cannot be compared with the number of stars in galaxies. If we consider a collection of galaxies as a kind of gas, where the role of molecules is played by individual galaxies, then we must consider this medium to be extremely viscous.
Table 1
|
Big Bang |
|
|
Formation of galaxies (z~10) |
|
|
Formation of the Solar System |
|
|
Earth Education |
|
|
The emergence of life on Earth |
|
|
Formation of the oldest rocks on Earth |
|
|
The appearance of bacteria and blue-green algae |
|
|
The emergence of photosynthesis |
|
|
The first cells with a nucleus |
|
| Sunday | Monday | Tuesday | Wednesday | Thursday | Friday | Saturday |
| The emergence of an oxygen atmosphere on Earth | Violent volcanic activity on Mars | |||||
| The first worms | Ocean plankton Trilobites | Ordovician The first fish | Silur Plants colonize land | |||
| Devonian The first insects Animals colonize land | The first amphibians and winged insects | Carbon The first trees The first reptiles | Permian The first dinosaurs | Beginning of the Mesozoic | Triassic First mammals | Yura The first birds |
| Chalk First flowers | Tertiary period First primates | First hominids | Quaternary period First People (~22:30) |
- * Astronomical unit - the average distance from the Earth to the Sun, equal to 149,600 thousand km.
- ** Perhaps, only the speeds of stars and planets in astronomy are expressed in units of “kilometers per second”.
- *** In the very center of the galactic core, in a region 1 pc across, there are apparently several million stars.
- **** It is useful to remember a simple rule: a speed of 1 pc in 1 million years is almost equal to a speed of 1 km/s. We leave it to the reader to verify this.
- ***** The flux of radiation from stars is measured by so-called “stellar magnitudes”. By definition, the flux from a star of the (i+1)th magnitude is 2.512 times less than from a star of the ith magnitude. Stars fainter than 6th magnitude are not visible to the naked eye. The brightest stars have a negative magnitude (for example, Sirius has a magnitude of -1.5).
We think we're studying the stars
but it turned out that we were studying the atom.
R. Feynman
What is meant by the Universe? What is the microworld, macroworld and megaworld and what are their scales? How are our capabilities limited when studying the large scale of the megaworld and the smallest scale of the microworld?
Lesson-lecture
The image of the universe. The Universe is understood as the totality of all objects that are in one way or another observed by humans. Of these, only a few are accessible to observation through the senses. This part of the world is called macrocosm. The smallest objects (atoms, elementary particles) make up microcosm. Objects that are gigantic in size and very far away from us are called megaworld.
Salvador Dali. Nuclear cross
Make a guess why S. Dali called his painting “Nuclear Cross”.
The scale of the worlds. The boundaries between these worlds are quite arbitrary. In order to visualize the objects of the macroworld, microworld and megaworld, we will mentally increase or decrease a certain sphere by a large number of times.
Let's start with a sphere with a radius of 10 cm. This is the typical size of an object in the macrocosm. In order to quickly reach the boundaries of the known world, we will have to increase and decrease the sphere many times. Let's take billion as such a large number.
1. By enlarging a sphere with a radius of 10 cm a billion times, we get a sphere with a radius of 100,000 km. What are these sizes? This is approximately a quarter of the distance from the Earth to the Moon. Such distances are quite accessible for human movement; So, astronauts have already visited the Moon. Everything that has dimensions of this order should be attributed to the macrocosm (Fig. 8).
Rice. 8 The scale of the macrocosm
2. Making an increase another billion times, we get a sphere with a radius of 10 14 km. This. of course, astronomical sizes. In astronomy, for the convenience of measuring distances, light units are used, which correspond to the time it takes light to travel a certain distance.
What is a sphere with a radius of 10 light. years? The distance to the nearest star to us is approximately 4 light years. of the year. (The Sun, of course, is also one of the stars, but in this case we are not considering it.) A sphere with a radius of 10 light. years, whose center is on the Sun, contains about a dozen stars. A distance of several light years is no longer accessible to human travel. At speeds achievable by humans (about 30 km/s), it is possible to reach the nearest star in about 40,000 years. Any other powerful engines, for example those operating on the basis of nuclear reactions, do not currently exist even in the project. So for the foreseeable future, humanity is forced to accept the fact that traveling to the stars is impossible.
Of course, the distance is 10 St. years already belongs to the megaworld. Nevertheless, this is the space closest to us. We know quite a lot about the stars closest to us: the distances to them, the temperature of their surface have been measured quite accurately, their composition, size and mass have been determined. Some stars have satellites - planets. This information was obtained by studying the emission spectra of these stars. We can say that a sphere with a radius of 10 light. space has been quite well studied for years.
3. Making another increase by a billion times, we get a sphere with a radius of 10 billion light. years. It is at this distance from us that the most distant objects that we can observe are located. We have thus obtained a sphere in which all the objects of the Universe we observe lie. Note that objects located at such a great distance from us are very bright luminaries; a star comparable to the Sun would not be visible even in the most powerful telescopes.
It is difficult to say what lies outside this sphere. The generally accepted hypothesis says that we cannot observe objects at all that are more than 13 billion light years away from us. years. This fact is due to the fact that our Universe was born 13 billion years ago, so light from more distant objects simply has not yet reached us. So, we have reached the boundaries of the megaworld (Fig. 9).
Rice. 9. The scale of the megaworld
The boundary of the Universe we observe is located at a distance of approximately 10 billion light years. years.
Let us now move deeper into the microworld. By reducing a sphere with a radius of 10 cm a billion times, we obtain a sphere with a radius of 10 -8 cm = 10 -10 m = 0.1 nm. It turns out that this is a characteristic scale for the microcosm. Atoms and the simplest molecules have dimensions of this order. A microcosm of this scale has been studied quite well. We know the laws that describe the interactions of atoms and molecules.
Objects of this size are inaccessible to observation with the naked eye and are not even visible in the most powerful microscopes, since the wavelength of visible light lies in the range of 300-700 nm, i.e., thousands of times greater than the size of the objects. The structure of atoms and molecules is judged from indirect data, in particular from the spectra of atoms and molecules. All pictures depicting atoms and molecules are the fruits of model images. Nevertheless, we can assume that the world of atoms and molecules - a world of about 0.1 nm in size - has already been studied quite well and no fundamentally new laws will appear in this world.
Of course, this world is not yet the limit of knowledge; for example, the size of atomic nuclei is about 10,000 times smaller. By reducing a sphere with a radius of 0.1 nm a billion times, we obtain a sphere with a radius of 10 -17 cm, or 10 -19 m. We have actually reached the limits of knowledge. The fact is that the sizes of the smallest particles of matter - electrons and quarks (they will be discussed in § 29) - are of the order of magnitude 10 -16 cm, i.e. slightly larger than our sphere. What is inside electrons and quarks, or, in other words, whether electrons and quarks are composite particles, is currently unknown. It is possible that the size of 10 -17 cm no longer corresponds to any real structural unit of matter.
The laws that determine the movement and structure of matter on scales of 10 -15 - 10 -16 cm have not yet been fully studied. Modern experimental capabilities do not allow us to penetrate even deeper into the microworld.
What are the reasons why our access to smaller scales is limited? The fact is that the main method of studying the structure of microparticles is to observe collisions between different particles. The laws of nature are such that at short distances particles repel each other. Therefore, the smaller scales scientists study, the more energy must be imparted to colliding particles. This energy is imparted during the acceleration of particles in accelerators, and the greater the energy that needs to be imparted, the larger the size of the accelerators must be. Modern accelerators are several kilometers in size. In order to move even further into the depths of the microworld, accelerators the size of the globe are needed.
So, now you should imagine what scale the microcosm corresponds to (Fig. 10).
Microworld 10. Scale of the microworld
In the microworld, in the macroworld and in the megaworld, the laws of nature manifest themselves in different ways. Objects of the microworld have both the properties of particles and the properties of waves; in the macroworld and megaworld such objects practically do not exist.
- Why can’t we look “beyond the horizon” of the Universe - see objects that are more than 13 billion light years away from us? years?
- What do experimental methods for studying the megaworld and microworld have in common?
- Some microparticles live for 10 -18 s, after which they disintegrate. What is the corresponding light unit of length (the distance that light travels during this time) comparable to?
> Scale of the Universe
Use online interactive scale of the universe: real dimensions of the Universe, comparison of space objects, planets, stars, clusters, galaxies.
We all think of dimensions in general terms, such as another reality, or our perception of the environment around us. However, this is only part of what measurements actually are. And above all, the existing understanding measurements of the scale of the Universe– this is the best described in physics.
Physicists suggest that measurements are simply different facets of perception of the scale of the Universe. For example, the first four dimensions include length, width, height and time. However, according to quantum physics, there are other dimensions that describe the nature of the universe and perhaps all universes. Many scientists believe that there are currently about 10 dimensions.
Interactive scale of the universe
Measuring the scale of the Universe
The first dimension, as mentioned, is length. A good example of a one-dimensional object is a straight line. This line only has a length dimension. The second dimension is width. This dimension includes length; a good example of a two-dimensional object would be an impossibly thin plane. Things in two dimensions can only be viewed in cross section.
The third dimension involves height, and this is the dimension we are most familiar with. Combined with length and width, it is the most clearly visible part of the universe in dimensional terms. The best physical form to describe this dimension is a cube. The third dimension exists when length, width and height intersect.
Now things get a little more complicated because the remaining 7 dimensions are associated with intangible concepts that we cannot directly observe but know exist. The fourth dimension is time. It is the difference between past, present and future. Thus, the best description of the fourth dimension would be chronology.
Other dimensions deal with probabilities. The fifth and sixth dimensions are associated with the future. According to quantum physics, there can be any number of possible futures, but there is only one outcome, and the reason for this is choice. The fifth and sixth dimensions are associated with the bifurcation (change, branching) of each of these probabilities. Basically, if you could control the fifth and sixth dimensions, you could go back in time or visit different futures.
Dimensions 7 to 10 are associated with the Universe and its scale. They are based on the fact that there are several universes, and each has its own sequence of dimensions of reality and possible outcomes. The tenth and final dimension is actually one of all possible outcomes of all universes.
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