The mass of galaxies can be determined through various methods. One way is by studying the motion of stars and other celestial bodies within the galaxy. By analyzing their velocities and trajectories, scientists can calculate the gravitational forces at play and infer the mass of the galaxy.
Another method involves observing the effects of gravitational lensing. When light from distant objects passes near a massive galaxy, it can be bent and distorted due to the gravitational pull. By studying these distortions, astronomers can estimate the mass of the intervening galaxy.
Additionally, the study of galaxy clusters can provide insights into the mass of galaxies. By measuring the motions and distribution of galaxies within a cluster, scientists can estimate the total mass of the cluster and infer the individual masses of the galaxies within it.
In some cases, the presence of supermassive black holes at the centers of galaxies can also give clues about the galaxy’s mass. The gravitational effects of these black holes can be observed through the motion of nearby stars and gas, providing information about the mass of the black hole and, by extension, the mass of the galaxy.
The red shift observed in the spectra of all galaxies is indicative of the increasing rate of expansion of the Universe as galaxies move away from each other, as described by Hubble’s law.
Solving the Issue
Determining Galaxy Mass
There exist two methods for determining the mass of a galaxy.
The first approach involves initially measuring the luminosity of the galaxy and then measuring the luminosity of a single star. Dividing the first value by the second provides the number of stars in the galaxy. By multiplying the number of stars by the mass of a single star, the mass of the galaxy can be calculated.
One way to determine the mass of a galaxy is by using Kepler’s laws. By knowing the mass of a star, the radius of its orbit, and its velocity, we can calculate the mass of the entire galaxy. However, observations have shown that the velocities of stars do not match up with the calculated mass, which includes the masses of stars, gas nebulae, and clusters that make up the galaxy.
The motion of stars suggests that the actual mass of the galaxy is much greater than what is calculated.
This discrepancy between observed mass and calculated mass is referred to as “dark matter.”
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The arrangement of celestial bodies in our universe is fascinating. The solar system, with the Sun as its main luminary, and all the stars visible to us without any instruments, belong to a group of bodies that are under the influence of a central gravitational force. This group is known as the Milky Way.
Within this vast expanse, there are massive collections of stars, gas, and dust clouds known as galaxies.
There are different types of galaxies based on their structure:
Among these galaxies, there are what we call active galaxies, which include radio galaxies and quasars.
According to current scientific knowledge, it is believed that the nuclei of galaxies contain massive black holes.
Galaxies also come together to form clusters, where gravitational forces bind them together and they share a common central core.
The red shift observed in the spectra of all galaxies is evidence of the increasing rate of expansion of the Universe as galaxies move away from each other, as described by Hubble’s law.
Solution to the problem
Determining the mass of a galaxy
There are two methods for determining the mass of a galaxy.
The first method involves measuring the luminosity of the galaxy and then measuring the luminosity of a star. By dividing the luminosity of the galaxy by the luminosity of the star, we can determine the number of stars in the galaxy. Multiplying this number by the mass of one star allows us to calculate the mass of the galaxy.
The second approach involves utilizing Kepler’s laws. By determining the mass of a particular star, along with its orbital radius and velocity, we can derive the mass of an entire galaxy. However, empirical data indicates that the velocities of stars are not adequately explained by the cumulative mass of stars, gas nebulae, and clusters within the galaxy.
Based on the motion patterns of stars, it is apparent that the actual mass of the galaxy is significantly higher than what is calculated.
This discrepancy in observed mass is commonly referred to as “dark matter,” as it remains elusive and difficult to directly observe.
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Physical Education and Fundamentals of Safety
When considering the amount of matter in the universe, astronomers are faced with the challenge of finding creative solutions. It is not possible to measure the mass of a single galaxy on an industrial scale. Even if such a possibility existed, Isaac Newton believed that the effects of Earth’s gravity would need to be taken into account. However, there is a classical method for determining the amount of matter in objects such as planetary satellites, planets, and stars. This involves measuring their gravitational interaction with other objects. Early calculations combined Newton’s law of universal gravitation with Johannes Kepler’s laws of planetary motion. These calculations focus on the relationship between the orbital velocity of a planet and the distance to the other object.
During the 1970s, Vera Rubin, an astronomer, and her colleague Kent Ford made an observation of the Andromeda galaxy, which is the closest large galaxy to us. Their findings contradicted the previous assumption. They discovered that the stars located at the outer edges of the galaxy were moving at almost the same speed as those in the center. This was surprising because based on their speed, the outer stars should have caused the galaxy to break apart. Rubin concluded that there must be invisible matter, known as dark matter, that is distributed around the edges of the galaxy. This dark matter is responsible for the unusual movement of the stars. However, the presence of this invisible matter has made it challenging to accurately measure the mass of galaxies.
Now scientists working in the field of astronomy are striving to improve their methods in order to find a solution to the enigma of dark matter that is known to exist within galaxies. During a presentation at the American Astronomical Society conference last spring, Ekta Patel, a graduate student from the University of Arizona, introduced a groundbreaking technique that has the potential to greatly enhance the accuracy of mass calculations. The primary objective of Patel’s team was to address the challenges associated with estimating the mass of dark matter, while also aiming to achieve the remarkable feat of determining the mass of our own galaxy, the Milky Way. Unlike other galaxies, such as the Andromeda galaxy, which can be observed in great detail using powerful telescopes, we face significant limitations in our ability to measure the mass of our own galaxy due to our position on one of its spiral arms. Patel aptly describes this predicament by comparing it to taking the U.S. Census without the Internet and without leaving your own city, or attempting to examine a mole on your back without the aid of a mirror. In essence, we simply do not have a comprehensive view of our own galaxy.
Instead of categorizing the stars in the Milky Way based on their distances, which is a difficult task to accomplish by observing beyond the galactic center, Peitel and his colleagues are examining the rotational momentum of the satellite galaxies of the Milky Way. These galaxies are influenced by our gravitational force and there are approximately 50 of them that are currently known. Peitel refers to them as “tracer objects” because their motion follows the mass distribution within their parent galaxy. However, their movement across the sky is incredibly slow. Peitel states, “These movements are so minuscule that it’s comparable to measuring the growth of a person’s hair from as far away as the moon.” The ability to make such measurements is only possible today thanks to space telescopes, as ground-based measuring instruments lack the necessary resolution for this type of work. Additionally, space telescopes remain in orbit for a sufficient amount of time to observe the measurable distance traveled by these tracer objects.
The Hubble Space Telescope, which is currently the leading observatory for gathering such information, is providing significant advantages to researchers like Peitel. The Space Telescopy Institute in Baltimore, Maryland, is responsible for operating Hubble, and its dedicated team meticulously tracks even the tiniest movements of satellite galaxies in the celestial sphere.
Initially, the Pateel team conducted a study on the trajectories of nine tracer objects in order to determine the mass of the Milky Way. However, the scientists are now looking to enhance their calculations by incorporating data from observations made by the European telescope “Gaia”. This telescope has been operational for slightly over four years and has recently released its second dataset. This provides enough information to begin analyzing the movements, allowing Pateel to expand their study to include approximately 30 Milky Way tracers. Pateel predicts that by the end of the Gaia mission, which spans another four or five years and includes several additional datasets, the collected data will rival the accuracy of the Hubble telescope. Furthermore, the James Webb Space Telescope, which is set to launch in the early 2020s, will also play a significant role in these observations.
Peitel and his colleagues will employ cosmological simulations to study the development of galaxies similar to the Milky Way and their accompanying galaxies. These simulations offer statistical insights into the evolutionary trajectory of the observed galaxies. By utilizing this innovative approach, Peitel and his team have refined previous estimations of the Milky Way’s mass, reducing the range from 700 billion to two trillion solar masses to a more precise value of 0.96 trillion solar masses.
Due to the previous wide range of mass values, it was not feasible to provide precise answers using mass calculations. What is the amount of dark matter present in the Milky Way? How did this galaxy develop, and how did its current shape come into being? “The lack of understanding of mass hindered us from establishing further connections among various physical inquiries regarding the evolution of galaxies similar to our own Milky Way,” Peitel explains. The key point is that each problem has its own set of solutions. She also acknowledges that there is a certain degree of uncertainty in her conclusion. As a result, scientists will continue to refine the mass value through the observation of tracer objects.
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– So, what is the weight of this galaxy?
We have no clue. We don’t even know the number of planets the closest stars have or what they are like. It’s similar to the medieval times.
Response to “Cool Girl”.
Every morning on my way to work, I pass by a public garden that has these fancy rubber paths designed for joggers. There are traffic lights at this square, which usually causes a small traffic jam for about 10-15 minutes. Since I have the rightmost lane on my route, I get a perfect view and enough time to observe.
For the past three years, I’ve noticed a man there who appears to be around 50-55 years old.
Initially, he would walk along these paths with the help of a walker. He moved slowly and quietly, but he did it every day.
After some time, he started walking confidently with the assistance of the walker.
Then, he transitioned from using a walker to using two canes. At first, his pace was slow, but gradually he gained more confidence.
Eventually, he only needed one cane to walk along the same path.
Now, he walks on his own without any assistance. In the beginning, he would cautiously extend his arms as if trying to balance himself. But now, he confidently moves forward, dragging his feet.
Each passing week, he became increasingly vigilant. And his stride began to resemble that of a typical person.
Without fail, every day, regardless of the weather, rain or shine, I would spot him in the morning at that very square.
About a year ago, I witnessed him running. Yes, it was slow, as if he was gradually decelerating and carefully maintaining his balance, clearly struggling.
But he’s running, for goodness sake. I still remember when he used to shuffle around with his walker. And now he’s running. I just wanted to step out and offer my congratulations.
His running is becoming more steady now. Slowly, but he doesn’t need to be fast, I don’t believe.
I’m unsure of what happened to him – perhaps a stroke, injury, or surgery. But I deeply admire his perseverance and discipline.
Over two years. Every single day, at least on weekdays. From relying on a walker to now running!
Hey, if you happen to come across this message (which is highly unlikely, but you never know) – I just wanted to let you know that I’m a huge admirer of yours!
-Losing 100 pounds within a year
Disclaimer: Firstly, it is important to maintain a healthy weight and avoid becoming overweight. Secondly, the following method may not be suitable for everyone.
Background: My weight gain journey started when I was 22 years old. At that time, I weighed around 100 kg with a height of 183 cm. Over the years, I gradually gained 5-10 kg each year. Why did this happen? It was due to my improper and unhealthy eating habits, sedentary lifestyle, self-neglect, and long-lasting depression. All these factors combined resulted in me reaching a weight of 240 kg by the age of 34.
After successfully overcoming this debilitating depression and restoring my mental well-being, I was confronted with a shocking realization about my physical health. Determined to make a change, I wasted no time in seeking professional help. My journey led me to an endocrinologist who has been guiding and supporting me throughout this process.
During my initial consultation, I underwent a thorough examination, including weighing myself and undergoing various tests. The results revealed that as of August 10, 2022, my weight was recorded at 236.7 kg. Armed with this information, I eagerly listened to the endocrinologist’s recommendations for improving my overall health and well-being.
The endocrinologist advised me to establish a consistent sleep schedule, emphasizing the importance of quality rest. Additionally, I was strongly encouraged to completely eliminate alcohol and fast food from my diet. Instead, I was advised to focus on counting calories and consuming a more balanced and nutritious diet. Furthermore, incorporating regular physical activity into my daily routine was suggested as a means to enhance my overall mobility.
And the weight disappeared! In the first month, I managed to shed over 12 kg. My blood sugar levels were elevated, hovering around 8, but fortunately, I was not diagnosed with diabetes. Over time, my sugar levels began to decline, and now they are around 4 when I get tested.
During that time, it was incredibly challenging for me to move around due to the intense pain in my back. As a solution, I made the decision to invest in a treadmill specifically designed for walking, even though it came with a hefty price tag similar to that of a Boeing wing. I started off slowly, aiming to walk 2-3 thousand steps per day. Gradually, I started to improve and increased the number of steps each day, resulting in a significant reduction in back pain. After a month, I began working out with an online trainer, and I also purchased dumbbells to perform simple muscle-strengthening exercises.
When it came to my nutrition, I found a simple resolution – I started ordering pre-made meals that were tailored to provide 1600-1800 kcal per day. This took the guesswork out of meal planning.
Initially, I considered undergoing bariatric surgery, but after consulting with an endocrinologist, I abandoned that idea. In my case, surgery would be futile since I do not have any underlying issues that contribute to my weight, such as excessive eating or cravings (and what cravings could there be when my fridge only contains my daily ration and a bottle of vinegar?). Surprisingly, I rarely experienced hunger (which is a common occurrence among larger individuals), but I still eat according to a schedule, regardless of whether I feel hungry or not.
Additionally, I have been working with a psychotherapist to address and resolve the internal struggles in my mind (not only those related to weight), ultimately making my life more manageable. The therapy has been incredibly beneficial!
How can I manage everything? It’s quite simple – I embrace this lifestyle. I’ve never been overly concerned about food, so I don’t stress about eating right or controlling my calorie intake. I thoroughly enjoy my new routine, genuinely relishing my workouts at the gym. Boxing is a particular favorite of mine, even though I occasionally feel fatigued, but that’s to be expected. Life is truly wonderful for me at the moment, and I couldn’t be happier.
I want to express my gratitude to all those who have been supporting me throughout this journey (and they will all read this post as I will provide them with a link), as it would have been much more challenging without all of you! A special thanks to the “Lose Weight with Peekaboo” chatroom for their unwavering support and additional motivation (they will share the link in the comments).
I’m ready to answer any questions, so feel free to ask away. I’ll probably do my next post in the autumn or around the New Year.
In early September, a photo was taken with a weight of approximately 225 pounds.
Despite the immense distances that separate even the closest galaxies from us, astronomers have gained a great deal of confidence in their ability to determine the masses of these systems, which consist of billions of stars. The masses of galaxies are now known to be closely related to their luminosities. Therefore, by measuring the luminosity of a galaxy, we can make an estimate of its mass. This same method allows us to calculate not only the masses of individual stellar systems, but also of groups of galaxies.
Up until now, astronomers have treated the determination of galaxy cluster masses as a purely technical process, until they stumbled upon an intriguing discovery.
The fact is that there exists another method for estimating the masses of galaxies.
The movements of stars, just like the orbiting of planets around the Sun, comply with both the law of gravity and Kepler’s laws, but their nature is quite distinctive. The galaxy, as a system of celestial bodies, is fundamentally dissimilar to the solar system, where 99 percent of the mass is concentrated in its core, namely, the Sun. Nevertheless, even in the solar system, the movement of an individual planet is noticeably affected not only by the Sun, but also by all the other planets. In galaxies, while there are central concentrations of matter, known as nuclei, they only contain a relatively small portion of the total mass of these stellar systems. Therefore, the motion of each star within the galaxy is heavily influenced not only by the gravitational pull of the central nucleus, but also by the entire mass of its constituent objects: stars and scattered matter.
By measuring the velocities of stars at various distances from the galactic center, it becomes possible to estimate the mass of the galaxy. The same technique can be used to determine the mass of a group of galaxies. Instead of measuring the velocities of individual stars, the velocities of entire galaxies within the group are measured.
This method of determining the mass of celestial objects is known as “virial” mass. One might expect that different methods of measuring the mass of the same objects would yield similar results. However, it has been found that the mass of a galaxy cluster determined by its luminosity does not match up with the mass determined through dynamical considerations.
If these masses were to differ by around 5-10 percent, it would be acceptable. This discrepancy could then be attributed to small errors in determining the physical characteristics of the objects under study, calculation errors, and so on. However, in reality, the virial masses of clusters exceed the luminosity-based masses by a factor of two, ten, and sometimes even a hundred!
Back in 1933, American astronomer Zwicky was the first to discover and formulate this mysterious paradox as a significant scientific problem. Since then, methods for determining the luminosity of celestial objects and measuring their motion have greatly improved. However, the paradox of mass mismatch has not only failed to go away but may have even worsened.
The paradox has become a pressing issue, and simply ignoring it is not a viable solution. This is mainly due to the fact that the only path towards progress lies in conquering this obstacle.
Exploring the Universe’s History
Let’s make another attempt to comprehend the meaning of Zwicky’s paradox. When we assess the mass of a cluster of galaxies based on their luminosity, we are essentially referring to the mass of observable entities, visible matter. However, if the virial mass calculated using dynamical considerations is greater, it suggests the presence of concealed, imperceptible masses within the cluster. Although we cannot directly observe them, these masses possess a certain gravitational force and thus contribute to the overall dynamics of the cluster, influencing the motion of the constituent galaxies. What might these unseen, concealed masses be and what could be their underlying physical nature?
If we consider the Zwicky paradox, it becomes a significant issue not only for individual groups and clusters of galaxies, but also for the entire metagalaxy including all surrounding stellar systems.
Furthermore, it is not just the dynamics that are affected. The existence of hidden masses also influences the geometry of the universe. According to the general theory of relativity, the curvature of the universe is determined by the average density of matter. If this density exceeds a certain value, the universe becomes closed and finite. The fate of our universe, whether it will continue to expand indefinitely or eventually contract, also depends on the value of the hidden mass.
Therefore, it appears that when we calculate the average density by examining the luminosity of celestial bodies, the result is significantly lower than the critical value. However, if we take into account dynamic factors, the average density may either match the critical value or even surpass it….
According to the theory, the proportion of helium among all chemical elements should be between 22 and 28 percent. However, observations reveal that it is 25 percent, which indicates a close agreement between theory and observation. This suggests that the theory can be trusted. One practical application of this theory is that it allows us to calculate the amount of deuterium in the early stages of expansion by examining its observed quantity in the modern Universe. The content of deuterium is directly linked to the average density of matter. Therefore, we have another method at our disposal for determining the average density, which involves studying the chemical composition of the Universe.
On the other hand, as we already know, the average density derived from dynamical considerations is approximately equal to the critical density. This presents another discrepancy. Are these hidden masses behaving a bit too boldly?
However, it is essential not to underestimate the significance of the dynamical aspects. Disregarding them would require a significant overhaul of the fundamental principles of contemporary physics. Would these principles, which have dutifully guided us for a century, truly fail us? Before discarding them entirely, it would be wise to double-check the calculations of the mean density of matter in the Universe. It is possible that the assumptions underlying these calculations contain inaccuracies or fail to accurately reflect the true state of affairs in our world.
The theories surrounding the concept of a hot expanding Universe, which involve calculating the amount of deuterium during the early stages of expansion, are highly credible and supported by observational evidence. However, further investigation is needed to understand the connection between the deuterium content and the overall density of matter. Surprisingly, this relationship is influenced by the distribution of matter throughout space.
At this critical juncture, the perplexing issue of mass mismatch transforms into a valuable tool for gaining knowledge and understanding.
The theory of expansion is founded on the assumption that throughout all phases of evolution, the Universe was uniform, meaning that matter was evenly distributed in space. However, this assumption is based solely on the fact that the current Universe, as observed, appears to be quite uniform on a large scale. Nevertheless, it cannot be conclusively deduced from the present-day homogeneity of the Universe that it has always been this way. In fact, according to cosmologist A. L. Zelmanov, the non-uniformity and even anisotropy (i.e., the variation of properties in different directions) of the early stages of the expanding Universe could potentially be equalized in the future.
Put simply, in this scenario there is a strong consensus with the measurement of the typical density determined through dynamic analysis.
This is a highly significant finding that the examination of the enigmatic mass paradox brings us to in comprehending the chronicles of the Cosmos. However, in order for this assertion to be adequately credible, it must be consistently validated through autonomous means.
Not gas or dust.
Let us return to the Zwicky paradox concerning galaxy clusters. What other factors could account for the difference between the observed and virial masses? It is reasonable to question the accuracy of mass estimation relying on dynamical considerations. The determination of a galaxy’s affiliation with the studied cluster may be prone to errors. A galaxy that appears to be part of the cluster in photographs may actually have no connection to it and is simply coincidentally projected onto its background…
Introducing a certain level of uncertainty in the calculations of the virial mass is a circumstance that cannot be overlooked. However, it is possible to make an approximate estimation of the extent of this uncertainty. Surprisingly, it can lead to an error in the mass value by a factor of 2-3. On the other hand, as mentioned earlier, the discrepancy between the virial and observed masses is as high as a hundredfold. This serves as yet another argument in support of the existence of invisible masses situated between galaxies.
Astronomer J. Einasto, who works at the observatory in Tartu, has come up with an intriguing concept. He suggests that what we perceive as galaxies is actually just a small fraction of the entire stellar system. Beyond these visible parts, there exists a vast amount of matter. Even at distances up to 10 times the apparent size of galaxies, there is still a significant density of matter in the intergalactic space. According to Einasto, the visible portions of galaxies only represent the central regions of these stellar systems. They are surrounded by peculiar coronae, which have a total mass much greater than that of the observed region.
If this hypothesis is proven true, it could potentially resolve the Zwicky paradox for small groups of galaxies. However, for densely populated clusters of stellar systems, the mass divergence remains immense and the paradox persists.
In one of his works, astrophysicist I. D. Novikov demonstrated that neither dust nor gas are capable of fulfilling this role. The detection of a significant amount of dust would be relatively easy. As for the gas, it could exist in the form of either neutral hydrogen (H) or ionized hydrogen (H2) in interstellar space.
Radio emissions can be used to detect neutral hydrogen. Such measurements have already been conducted and they reveal that the mass of neutral hydrogen in galaxy clusters is several times smaller than the mass of even the visible matter composed of stars.
The existence of ionized hydrogen (H2) remains undetectable through radio emission, but it is expected to emit X-rays. However, the examination of X-ray cosmic radiation has failed to reveal sufficient quantities of ionized hydrogen within galaxy clusters. For instance, a galaxy cluster in the constellation Veronica’s Hair has been found to contain a total mass of hot hydrogen ranging from 2.5 to 10 to the power of 14 solar masses. Although significant, this amount is still ten times less than the gas required to resolve the Zwicky paradox. To put it into perspective, this quantity of gas could create a thousand galaxies similar to our own.
Here’s another idea – a more unique one. Perhaps in the vast expanse of intergalactic space, there exists a plethora of “dark voids” that have formed due to the gravitational collapse of massive stars? These celestial objects are known to be invisible, yet they possess powerful gravitational fields.
However, this hypothesis implies that in the past, galaxies were surrounded by an abundance of massive stars. Consequently, galaxies that are located far enough away from us (and whose light we are currently witnessing from their distant past) would have these objects within their midst. However, this is not the case…
Therefore, it is reasonable to assume that galaxies are instead surrounded by dim, non-radiant dwarf stars with masses tens or hundreds of times smaller than that of the Sun. These stars could potentially be formed on the outer edges of galaxies as a result of the compression of diffuse matter caused by shock waves.
However, the possibility of resolving the enigma of concealed masses remains purely speculative, as there is no concrete evidence substantiating the existence of dim, non-luminous dwarf stars surrounding galaxies.
Or perhaps they are mere figments of imagination?
Irrespective of the intricate paradoxes and inconsistencies that scientists come across in their investigations, their primary aim is to conquer these challenges using the tools at their disposal, relying on established theoretical concepts and refraining from adopting any radically new ideas until the opportune moment arises. Determining when this moment arrives, however, is a rather arduous task…..
One intriguing option is to challenge the validity of the general theory of relativity and the law of gravitation. If the gravitational force does not decrease in proportion to the square of the distance, but rather at a slower rate, then the mass paradox is automatically resolved. However, there is currently no justification for such a radical revision of the fundamental principles of modern physics.
Another possibility, which was first suggested by Academician V. A. Ambartsumian in 1953, is based on the general concept developed by astronomers regarding nonstationary phenomena in the Universe and the formation of cosmic objects through the decay of superdense bodies. What if the velocities of galaxies within clusters are not random, but instead directed away from a central point, indicating that clusters are unstable and rapidly expanding?
However, this represents a different set of dynamics and equations… The virial mass calculated from these equations is almost identical to the mass determined by luminosity. Additionally, there are no concealed masses! Furthermore, the average density of matter in the Universe is still several times lower than the critical density, and the Universe itself continues to expand without restraint.
Could Zwicky’s paradox be considered indirect evidence supporting this perspective? After all, if all other possibilities are exhausted, this is the only remaining option….
Considering the overall size and mass of the Universe, the process by which black holes increase in number and size may be exceptionally slow.
The age of the universe is estimated to be around 15 billion years, although the exact figure is still uncertain. Black holes, being extremely difficult to detect, may very well be a small fraction of the universe’s mass. It is possible that there are many undetected black holes that contribute to the “missing” mass required for a closed universe. In this scenario, black holes could account for anywhere between 50 to 90 percent of the total mass.
Even as the universe continues to evolve over the next half a trillion years, black holes might still only represent a small portion of the overall mass.
However, as the universe eventually begins to contract, the presence of black holes could become even more significant and potentially catastrophic.
The black holes that appeared during the period of expansion were most likely restricted to the cores of galaxies. However, as galactic clusters move closer together and the Universe becomes more abundant in energy radiation, it is certain that black holes will start to form in greater quantities and expand at a faster rate.
During the final stages, when galactic clusters begin to merge, black holes will also merge, ultimately resulting in a compression into a massive universal black hole, resembling a cosmic egg.
Nevertheless, the mass of the Universe confined within the boundaries of a cosmic egg would essentially be an enormous black hole.
Yet, if nothing can already emerge from a cosmic black hole, how can a cosmic egg, formed through the compression of the universe, explode and give rise to a new universe?
What is the region of the universe filled with matter?
How can the cosmic egg that existed 15 billion years ago undergo a massive explosion to give rise to the universe we currently occupy?
In order to comprehend this phenomenon, it is crucial to acknowledge that black holes do not possess equal densities. Initially, the greater the mass of an object, the more intense its surface gravity (assuming it is a regular star) and the higher its escape velocity – the second cosmic velocity. Consequently, the object requires less compression to raise the escape velocity to a value equivalent to the speed of light, resulting in a larger Schwarzschild radius at which the compression ceases.
As previously mentioned, the Sun has a Schwarzschild radius of 3 kilometers.
If a star with a mass three times greater than that of the Sun were to contract to its Schwarzschild radius, this radius would measure 9 kilometers.
Simply put, the larger a black hole’s mass, the lower its density.
If we were to compress the entire Milky Way Galaxy, which is about 150 billion times the mass of the Sun, into a black hole, its Schwarzschild radius would measure 450 billion kilometers, equivalent to approximately 1/20th of a light year.
This black hole would have an average density of around 1/1000th of the density of the air we breathe. It may appear like a complete vacuum to us, but it would still retain its black hole properties, with nothing able to escape its grasp.
In the hypothetical scenario where there is enough mass in the universe to cause it to become closed, and if all that mass were compressed into a black hole, the resulting Schwarzschild radius would stretch over approximately 300 billion light years!
Such a black hole would surpass the volume of the entire known Universe and possess a density significantly lower than the currently accepted density of the Universe.
Let’s imagine a scenario where every galaxy has lost a significant portion of its matter to a black hole. As a result, the universe we have now consists of a vast number of black holes, possibly exceeding a hundred billion, with each black hole having a diameter of about 1/500 to 1 light-year, depending on its mass. These black holes are so powerful that nothing can escape from them.
However, as we approach the final stages of compression, all these individual black holes come together and merge into a single black hole. This new supermassive black hole now possesses the entire mass of the universe and has a Schwarzschild radius of 300 billion light-years!
Within this radius, nothing can escape its gravitational pull, but it is conceivable that there might be expansions occurring within this confined space. It is possible that the sudden rush outward, emanating from this radius, could be the event that triggers the explosive birth of the universe, known as the Big Bang.
If we accept the implications of these statements, it appears that we must conclude that the Universe cannot be infinite and boundless, and it cannot expand endlessly into the future.
The initial point of expansion must have been a black hole with a suitable Schwarzschild radius, giving birth to the cosmic egg.
In the event that the Universe were to expand infinitely, certain regions would surpass the Schwarzschild radius, which appears to be implausible. Hence, the Universe must be enclosed, and the rotation must take place prior to reaching the Schwarzschild radius (which is why I previously mentioned my conviction in the closed nature of the Universe, contrary to the prevailing belief that it is not closed).
Quasars
Out of the three catastrophic events of the first category, which would have devastating consequences for life across the entire Universe – the expansion leading to heat death, the contraction resulting in a cosmic egg, and the contraction into individual black holes – the third event is distinct from the first two in several crucial ways.
Both the expansion of the universe towards heat death and the contraction towards a cosmic egg would have a similar impact on the entire universe.
In both scenarios, assuming that human life would endure for another trillion years from our current time, there is no reason to believe that our position in the universe would grant us an exceptionally long or short lifespan. Our section of the universe would not be significantly affected sooner or later than any other region of the universe.
When it comes to the third disaster involving individual black holes, the situation is quite distinct.
Here, we are faced with a sequence of localized disasters. A black hole can emerge in one place but not another, resulting in an uninhabitable environment in one location while life remains unaffected elsewhere. Ultimately, everything will inevitably merge into a black hole, but the black holes that form in the present may render it impossible to reside nearby, even though life elsewhere may continue without any concerns for countless years. Therefore, we must question the current existence of black holes.
And if they do exist, we must determine their probable locations and the likelihood of any of them posing a threat to us with a catastrophe before (potentially long before) the final catastrophe.
It goes without saying that the formation of a black hole is most likely to happen in areas where a significant amount of mass has already accumulated.
The greater the mass of a star, the more suitable it becomes for becoming a black hole. A cluster of stars, where multiple stars are closely packed together, is an even more ideal candidate.
The largest clusters, densely populated with stars, are found in the cores of galaxies, particularly in giant galaxies like our own, or even larger ones.
Within these clusters, several million to several billion stars are concentrated in a very small space, making it the most likely location for a catastrophic black hole event to occur.
Just twenty years ago, astronomers were completely unaware that galactic centers are where the most intense phenomena take place.
In the centers of these establishments, the stars are in close proximity to one another, however, even in the centers of vast galaxies, the stars are separated by approximately one-tenth of a light-year. In essence, they have ample space to maneuver without significantly impeding each other.
If our Sun were situated in such a vicinity, we would behold over 2.5 billion stars with the naked eye, and roughly a million of them would possess a brightness equivalent to or even surpassing that of first magnitude. Nevertheless, each star would only be perceptible as a radiant speck.
The light and warmth emitted by these stars could amount to a quarter of that radiated by the Sun. Consequently, this additional illumination and heat might render the Earth unsuitable for habitation. However, it could be habitable if it were positioned at a greater distance from the Sun, such as the location of Mars.
The excessive utilization of antibiotics results in the eradication of the most thriving microorganisms.
The individuals of civilization were connected to the earth through their possessions.
It was not possible to discover chemicals that could control insects.
Cultures.
The more scientists discovered about the energy on earth, the source of millions of.
In the 1920s, the renowned Soviet physicist A. A. Friedman determined that according to the equations of the general theory of relativity, the universe cannot remain unchanged, it must be undergoing evolution.
It is possible that our world is either contracting or expanding. From the perspective of an observer (regardless of their location, as the world is uniform and everything happens the same way in every point), all objects that are far away are moving away from the observer (or approaching them) at a greater speed the farther they are. Additionally, the average density of matter in the Universe is changing.
The expansion of the Universe is evident in observations through the shift of absorption lines in the spectra of distant galaxies towards the red side of the spectrum. This phenomenon is known as redshift.
Redshift provides a straightforward explanation for the photometric paradox. As an observer moves towards more and more distant objects, the brightness of a star decreases because the energy of a quantum decreases due to redshift.
As the speed of removal gets closer to the speed of light, the star becomes undetectable.
The crucial density of the universe
In Friedman’s theory, there is a parameter known as the critical density, which can be defined in terms of the Hubble constant:
Where H represents the Hubble constant, and G is the gravitational constant.
Space-time
Space and time properties at large scales (tens and hundreds of megaparsecs) depend on the average density of matter in the Universe (ρ̅).
If this density is lower than a critical value (ρ̅k), the universe extends infinitely in both time and space.
Its geometric characteristics are described by Lobachevsky geometry, which posits that an infinite number of lines parallel to a given point can be drawn through that point.
When ρ̅=ρk, the universe is described by the familiar Euclidean geometry (only one line parallel to a given line can be drawn through a point). In these cases, the universe is infinite.
At ρ̅>ρk, the universe has a finite volume and contains a finite mass of matter.
When it comes to this scenario, the concept of a boundary-less world becomes unfathomable. Our experience is limited to a three-dimensional world, making it impossible to imagine anything beyond that. However, according to the general theory of relativity, the world is actually four-dimensional, consisting of three spatial dimensions and time.
An analogy that closely resembles a closed and finite world, which we are familiar with, is the surface of a ball. Similar to the ball’s surface, our world is also finite and lacks any boundaries.
Currently, the true average density of the Universe remains somewhat uncertain. Based on current calculations, the average density is believed to fall within the range of 5 – 10-27 to 3 – 10-28 kg/cm3.
However, these calculations are derived from observations of known forms of matter and are significantly lower than the critical density. Generally, it is widely agreed upon that the average density is nearly equivalent to the critical density.
The future outcome of the Universe is determined by its average density (ρ̅). If ρ̅ exceeds ρk, the pace of expansion will gradually decrease, leading to a reversal of the expansion and a return to the Universe’s original state.
However, if ρ is less than or equal to ρk, the expansion will continue indefinitely. Source: http://wikiwhat.ru
Origin of the Universe
According to the general theory of relativity, the Hubble constant can be understood as the reciprocal of the time interval since the beginning of the Universe:
When we trace back in time, we discover that approximately 15-20 billion years ago, the Universe existed with no size and an infinitely dense state.
Which area of the universe is occupied by substance?
This condition is known as singularity, which exists in all versions of the Friedman model. It is evident that the theory’s range of applicability ends here, and it is essential to surpass this model. Quantum effects become decisive at sufficiently short times (as GR is solely a classical theory).
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Information on the following subjects can be found on this page:
Friedman’s concept of presenting the structure of the universe
R determining the average density of the universe
The critical density of matter within the universe
What is the typical density of matter in the universe
Understanding the Friedman model
The masses of celestial objects
To comprehend the scale of mass in the universe, we must analyze the various objects within it and assess their individual masses. These objects consist of stellar bodies like stars and galaxies.
A metagalaxy represents the observable portion of the Universe. However, there are different methods of observing it, including naked eye observation, binoculars, and a 6-meter telescope.
As a result, many galaxies are not observable to us, but we have the ability to calculate their position, density, and mass.
Is there a limit to the mass of the universe?
By making an approximation of the size and average density of matter in the Metagalaxy, we can make an estimate of the total mass of matter contained within the volume bounded by the cosmological horizon – the mass of the Metagalaxy. This gives us a value on the order of 1053kg.
With knowledge of the distances to several thousand galaxies, we are able to construct a spatial model.
In this constructed model, the spatial structure of galaxy distribution becomes evident. It is revealed that galaxies form cells resembling honeycombs. Galaxies line the walls of these cells, while voids exist within.
Galaxies can be found in the sky in both a uniform and non-uniform manner. When observing a small area of a few square degrees, the distribution of galaxies may appear surprisingly even. It is important to note that on a larger scale, beyond the size of individual cells, the distribution of matter remains perfectly uniform. This means that if we were to take two giant cubes with sides measuring 100 million light-years and calculate the amount of matter contained within each cube, the result would be the same regardless of their placement within the Metagalaxy.
To determine the average density of matter in the Universe, we divide the total mass by the volume of the cube. This yields a value of p= 3 x 10-27 – 10-26 kg/m3.
Clusters of galaxies tend to have an almost spherical shape and can contain hundreds or even thousands of individual galaxies.
The constellation Virgo contains the nearest major galaxy cluster to us, which is made up of 3000 galaxies. Galaxy clusters typically range in size from 1 to 3 Mpc.
Galaxy clusters can also take on a more amorphous shape, resembling clouds of galaxies. There are also smaller collections of galaxies known as groups of galaxies. One example is the Local Group, which consists of two large spiral galaxies: our own Milky Way and the Andromeda Nebula. The Local Group also includes a number of smaller galaxies. Additionally, each spiral galaxy in the Local Group has several satellite galaxies.
The Andromeda Nebula boasts a collection of five sizable satellites as well as five smaller ones. The most prominent satellites in our galaxy, however, are the Large and Small Magellanic Clouds. Furthermore, the Andromeda Nebula is accompanied by a multitude of dwarf galaxies, with at least 14 known entities. All in all, the Merna Group of galaxies contains a total of 38 galaxies. Situated 3 Mpc away in the constellation of the Hound Dogs, there exists another assemblage of 34 galaxies.
Currently, there are numerous groups of galaxies that have been discovered, with several dozen such groups in total. These groups typically span a range of sizes, from 0.1 to 1 Mpc.
Galaxies, these immense clusters of stars, come in a variety of shapes and sizes. The radiance of galaxies can be attributed to the brilliance of stars, the countless billions of stars that comprise them. Additionally, galaxies contain a mixture of gaseous elements, primarily hydrogen and helium, as well as minuscule particles of dust. Typically, the quantity of gas and dust within galaxies is relatively small, comprising only a small percentage of the overall mass of the stars.
Consequently, the collective mass of stars, gas, and dust accounts for a mere fraction of the total mass of galaxies, representing a mere 1/10. The remaining 9/10 of a galaxy’s matter exists in a concealed, imperceptible form. This enigmatic “hidden mass” is housed within the expansive halos, or shells, of galaxies, taking the shape of faintly glowing gas, as well as numerous extinct or never-ignited stars (known as brown dwarfs) and dark planets.
There are techniques available to determine the masses of galaxies. Utilizing these methods, it has been determined that the majority of galaxies have masses ranging from 10^9 to 10^12 times the mass of the Sun.
Our Galaxy, including its hidden mass, appears to approach the upper end of this mass range. The size of galaxies, specifically their visible component, typically spans from 1 to 100 kiloparsecs.
Most galaxies exhibit a spiral morphology, including the Andromeda Nebula, the Triangle Nebula, and our own Galaxy (although, unlike other galaxies, we have never observed our own Galaxy from an external perspective). Approximately a quarter of all known galaxies possess a round or elliptical shape. The third category of galaxies consists of irregular galaxies that display an asymmetric shape. These galaxies are referred to as irregular galaxies. Many galaxies have a luminous and compact nucleus located in their central region.
Scientists have recently made a groundbreaking discovery of celestial objects that bear a striking resemblance to active galactic nuclei. These remarkable objects, known as quasars, possess a star-like appearance and are considered to be the most distant entities ever observed in the vast expanse of the Universe. Some quasars exist at such immense distances that ordinary galaxies are rendered undetectable in comparison. The farthest documented quasar to date is a staggering 14 billion light-years away.
It is now understood that quasars are the highly active nuclei of galaxies located in remote regions of space. Currently, over 4,000 quasars have been identified and studied. The masses of these extraordinary objects are estimated to be a mind-boggling 106 times greater than that of our own sun.
Within the realm of star clusters, there exist two distinct types: globular and diffuse clusters.
Our Galaxy contains approximately 500 globular clusters and around 20,000 scattered clusters. Globular clusters are the oldest formations in the Galaxy, acting as remnants from the early stages. These clusters typically have an age of 15 billion years. Globular clusters are massive objects with a regular spherical shape, housing hundreds of thousands or even millions of stars.
Their masses vary greatly, ranging from 103 to 107M °. The size of globular clusters is approximately 100 pc. Scattered star clusters can be observed in any part of the sky, although they are most abundant near the Milky Way. These clusters contain tens, hundreds, or even thousands of stars. Among the scattered clusters, there is a mixture of relatively old clusters with ages of several billion years and very young ones.
An illustration of a relatively youthful cluster is the Pleiades: it is estimated to be around 60 million years old. The human eye can perceive 6-7 stars.
In actuality, there are numerous hundred stars within this cluster. Currently, it is firmly established that the second variation occurs in nature. Stars are not born individually, but in groups from massive gas-dust clouds.
A star serves as the fundamental structural component of the megaworld. The larger-scale structures mentioned earlier consist of stars. The visible radiation emitted by star clusters, galaxies, and their clusters is the cumulative radiation from stars.
Stars are natural reactors, where matter undergoes chemical evolution and is processed at the nuclear level. Astronomers have identified various types of stars, and a single star can transition between different phases depending on its mass and age. There are two main categories of stars: ordinary stars, also known as “normal stars,” and compact stars. The latter group includes white dwarfs, neutron stars, and black holes, which are the final products of stellar evolution.
The size of normal stars can range from that of the Sun or slightly smaller to the immense size of supergiant stars, spanning from 108 m to 1011 m. Compact stars, on the other hand, can vary in size from a few kilometers for black holes and neutron stars to a few thousand kilometers for white dwarfs.
The masses of stars have a relatively narrow range, ranging from 0.01 to 60 M °. Typically, planetary systems form alongside stars.
When we talk about a planetary system, we typically refer to our solar system. However, there is substantial evidence suggesting the existence of other planetary systems. In some cases, we can estimate the masses of the planets within these systems. There are also known objects that indicate the formation of planetary systems, such as protostars with protoplanetary disks. Currently, our Solar System is the only definitively known planetary system.
The measurement of its magnitude can be described as the diameter of Pluto’s orbit: 40 a.u., or 1013 meters. Celestial bodies such as planets, comets, asteroids, and dwarf planets are commonly referred to as cosmic objects. The upper limit is defined by the size of gas giants (Jupiter, Saturn, Uranus, Neptune) with their rings, while the lower limit is determined by the size of dwarf planets and comet nuclei (approximately -10 km).
The techniques used to calculate the masses of celestial objects are based on the principles of gravity and its derivatives. The most frequently utilized method is a generalized version of Kepler’s third law, as formulated by Newton.
The distances between the bodies in the pairs are so vast that the sizes of the bodies themselves appear minuscule in comparison (even the Sun’s radius is 1000 times smaller than the distance between the Sun and Jupiter), allowing them to be treated as mere points of matter.
In certain instances, the trajectory of the bodies does not conform to the model of two material points.
For instance, the Mir space station circles around the Earth at a height of 330 km, which is merely 1/20th of the Earth’s radius. However, even in this scenario, the space station perceives the Earth’s gravitational force as if the entire mass of the Earth were concentrated at its center, 6700 km away from the station. In the case of the space station, it becomes apparent that both the station itself, the astronaut inside it, and even the astronaut’s pencil (all objects with different masses) move independently along the same orbit, whose characteristics are solely determined by the Earth’s mass.
This autonomy gives rise to the phenomenon of weightlessness. For all Earth satellites, the ratio a3/T2- remains constant. The period T of the Mir space station’s orbit around the Earth is 84 minutes.
The period of the satellite increases as it moves farther away from the Earth. When the satellite is positioned at an altitude of 36000 km from the Earth’s surface, its orbit period matches the Earth’s rotation period.
This type of orbit is known as geostationary. From the perspective of the rotating Earth, the satellite appears to remain stationary above the same point on the Earth.
There is a technique for determining the mass of the central object: by determining the size of the satellite’s orbit and its orbital period around the central object, we can calculate the desired mass. This method can be used to determine the mass of the Sun based on the motion of Jupiter.
The masses of planets with natural satellites (determined by the motion of these satellites) have also been discovered using the same technique: Mars, Jupiter, Saturn, Uranus, and Neptune. Mercury and Venus do not have any natural satellites. Their masses were accurately measured only after the introduction of artificial satellites near them. This method can also be applied to determine the masses of large cosmic structures such as globular clusters and galaxies. Similar to a space station in Earth’s orbit, a star located at the outer edge of a cluster perceives the total mass of the cluster as if it were concentrated at the center of the cluster.
If we can determine the size of the star’s orbit and how long it takes to orbit the center of the cluster, we can use formula (2.10) to calculate the mass of the entire cluster. It is not difficult to find the size of the orbit if we know the distance to the cluster.
The mass of a star is a crucial characteristic that determines its luminosity, structure, lifespan, and overall evolution.
When it comes to a double star, we can determine the masses of the two stars in the pair. Unlike a planet orbiting the Sun, the stars in a double star system have similar masses. Therefore, we can’t assume that a star with less mass orbits a star with greater mass. In reality, both stars orbit elliptically around the system’s common center of mass (also known as the center of gravity).
One notable characteristic is that celestial bodies revolve in such a manner that their centers (A and B) and the center of mass (point C) consistently align on a linear path.
Another noteworthy aspect is the lever rule, which is well-established in the realm of physics education: the ratio of the lengths of AC and BC (lever arms) is inversely proportional to the masses of the stars. М1 and М 2.. In this scenario, we must rely on Kepler’s third law. The stars orbit around the system’s center of mass. When the orbital plane is suitably aligned, one star approaches us while the other star simultaneously moves away from us.
Consequently, in accordance with the Doppler principle, the spectral lines of the first star undergo a violet shift, while those of the second star experience a red shift.
After a period of time, the situation completely changes. Instead of one line in the spectrum, there are now multiple lines that are converging and diverging. The star with a lower mass has a faster orbit and greater velocity, resulting in a larger Doppler shift. On the other hand, a higher-mass star will have a smaller Doppler shift. The ratio of Doppler shifts in the spectra of these two stars is directly proportional to the ratio of their radial velocities and inversely proportional to the ratio of their masses.
The total displacement is directly proportional to the combined mass of the stars. The most “successful” scenario (in terms of determining the mass) for a spectral-double system is when the orbital plane aligns perfectly with the line of sight. The ideal situation is when eclipses occur, with one star overshadowing the other.
This phenomenon is evident through periodic fluctuations in the brightness of the binary star. Astronomers possess the ability to derive various significant characteristics of the stars that comprise the system: their masses, sizes, and average density. The theory of eclipses, which enables this determination, is both straightforward and extensively developed.
Consequently, the determination of stellar masses can be broken down into three sequential steps. Initially, the masses of stars within binary star systems are established. Next, the mass-luminosity diagram is constructed based on the known masses and luminosities of these stars. Finally, in the third step, the mass of any star with a known luminosity can be determined using this diagram.
