The Hubble constant. Expansion of the universe. The Hubble Act

If someone thinks that the word "run up" has a purely athletic, in extreme cases, "anti-suppressive" character, it is mistaken. There are much more interesting interpretations. For example, the cosmological law of Hubble testifies that the galaxies are dispersing!

Three types of nebulae

Imagine: in a black, huge airless space, star systems quietly and slowly move away from each other: "Farewell! Goodbye! Goodbye!". Perhaps, we will leave aside "lyrical digressions" and turn to scientific information. In 1929, the most influential astronomer of the 20th century, the American scientist Edwin Powell Hubble (1889-1953) came to the conclusion that the Universe is steadily expanding.

The man who devoted his entire life to the solution of the structure of the cosmos was born in Marshfield , Missouri. He was interested in astronomy since the early nails, although in the end he became a certified lawyer. After graduating from Cambridge University, Edwin worked in Chicago, at the York Observatory. In the First World War (1914-1918) fought. The front-line years only pushed the revelation in time. Today the whole learned world knows what the Hubble constant is.

On the way to discovery

Returning from the front, the scientist turned his gaze to the high mountain observatory Mount Wilson (California). He was taken to work there. In love with astronomy, the young man spent a lot of time looking at the lenses of huge telescopes measuring 60 and 100 inches. For that time - the largest, almost fantastic! Over the devices, the inventors worked almost a decade, achieving the maximum possible increase and clarity of the image.

Recall, the visible boundary of the universe is called the Metagalaxy. It comes to the state at the time of the Big Bang (cosmological singularity). Current provisions say that the values of physical constants are uniform (we mean the speed of light, elementary charge, etc.). It is believed that the Metagalaxy holds 80 billion galaxies (an amazing figure sounds like this: 10 sextillions and 1 septillion stars). Form, mass and size - for the universe are completely different than accepted on Earth, concepts.

Mysterious Cepheids

To justify the theory explaining the expansion of the universe, it took long, in-depth studies, complex comparisons and calculations. In the early twenties of the 20th century, yesterday's soldier was finally able to classify nebulae observed separately from the Milky Way. According to his discovery, they are spiral, elliptical and irregular (three kinds).

In the nearest stellar system, but not the nearest Andromeda spiral nebula, Edwin saw the cepheids (a class of pulsating stars). Hubble's law has become closer than ever to its final formation. The astronomer calculated the distance to these beacons and the size of the largest galaxy of the Local Group. According to his conclusions, Andromeda contains approximately one trillion stars (2.5-5 times the size of the Milky Way).

Constant

Some scientists, explaining the nature of cepheids, compare them with inflatable rubber balls. They then increase, then decrease, then approach, then move away. The radial velocity thus fluctuates. At compression, the temperature of the "travelers" increases (although the surface decreases). Pulsating stars are an unusual pendulum, which, sooner or later, will stop.

Like other nebulae, Andromeda is characterized by the scientist as an island universe space, reminiscent of our galaxy. In 1929, Edwin discovered: the radial velocities of galaxies and their distances are interrelated, linearly dependent. The coefficient, expressed in km / s per megaparsec (MPS), was determined. This is the so-called Hubble constant. The universe is expanding - a constant is changing. But at a specific moment in all points of the system of the universe it is the same. In 2016, 66.93 ± 0.62 (km / s) / Mpc.

Representations about the system of the universe, continuing evolution, expanding, then received an observational basis. The process was actively studied by an astronomer until the very beginning of the Second World War. In 1942 he headed the Department of External Ballistics at the Aberdeen Test Site (USA). Is this the dream of an associate, perhaps the most mysterious science in the world? No, he wanted to "decipher" the laws of the hidden corners of distant galaxies! As for political views, the astronomer openly condemned the leader of the Third Reich Adolf Hitler. At the end of his life, Hubble was known as a powerful opponent of the use of weapons of mass destruction. But let us return to the nebulae.

The Great Edwin

Many astronomical constants are corrected with time, new discoveries appear. But all of them do not go in comparison with the Law of the Universe expansion. The famous astronomer of the twentieth century, Hubble (since Copernicus was no equal!) Put in a row with the founder of experimental physics Galileo Galilei and the author of the innovative conclusion about the existence of stellar systems, William Herschel.

Even before the law of Hubble was discovered, its author became a member of the National Academy of Sciences of the United States of America, later academies in different countries, has many awards. Many have probably heard about the fact that over a decade ago, put into orbit and successfully operates the Hubble Space Telescope. This name carries a crater on the moon, one of the small planets that rotate between the orbits of Mars and Jupiter (an asteroid).

It will not be entirely fair to say that the astronomer only dreamed of perpetuating his name, but there is indirect evidence that Edwin liked to attract attention. There are photos, where he positively poses next to the movie stars. A little later we will talk about his attempts to "fix" the achievement at the laureate level, and thus also enter into the history of cosmology.

Henrietta Leavitt's Method

The famous British astrophysicist Stephen Hawking in his book "A Brief History of Time" wrote that "the discovery that the universe is expanding has become the greatest intellectual revolution of the 20th century". Hubble was lucky enough to be in the right place at the right time. The Mount Wilson Observatory was the center of the observational work underlying the new astrophysics (later called cosmology). The most powerful Hooker telescope on Earth then only came into operation.

But the Hubble constant was unlikely to be discovered only on the basis of luck. We needed patience, perseverance, and the ability to defeat scientific rivals. So the American astronomer Harlow Shapley proposed his model of the Galaxy. He was already known as a scientist who determined the dimensions of the Milky Way. He widely applied the technique of determining distances by Cepheids, using a technique compiled in 1908 by Henrietta Swan Leavitt. It set the distance to the object, relying on the standard variations of light from bright stars (cepheid variables).

Not dust and gas, but other galaxies

Harlow Shapley believed that the width of the galaxy is 300,000 light years (about ten times the permissible value). However, Shapley, like most astronomers of the time, was sure: the Milky Way is the whole Universe. Despite the assumption first made by William Herschel in the 18th century, he shared the widespread belief that all the nebulae for relatively nearby objects are just stains of dust and gas in the sky.

How many bitter, cold nights Hubble spent sitting by the powerful Hooker telescope before he could prove that Shapley was wrong. In October 1923 Edwin noticed in M31 the nebula (constellation of Andromeda) a "flashed" object and suggested that it does not belong to the Milky Way. After careful study of the photographic plates on which the same area was previously imaged by other astronomers, including Shapley, Edwin realized that it was a cepheid.

Discovered the Cosmos

Hubble used the Shapley method to measure the distance to a variable star. It turned out that it is estimated in millions of light years from the Earth, which is far beyond the Milky Way. The galaxy itself contains millions of stars. The famous universe expanded dramatically on the same day and, in a sense, the Cosmos itself was discovered!

The New York Times wrote: "Discovered spiral nebulae are stellar systems, Dr. Hubbel (as in the original) confirms the view that they are similar to" island universes "similar to our own." The discovery was of great importance for the astronomical world, but Hubble's greatest moment was yet to come.

No static

As we said, the victory to Copernicus No. 2 came in 1929, when he classified all known nebulae and measured their velocities from the spectra of the emitted light. His startling discovery that all galaxies are retreating from us at speeds that increase in proportion to their distance from the Milky Way shocked the world. Hubble's law abolished the traditional view of the static universe and showed that it itself is full of dynamics. Einstein himself bowed his head in front of such stunning observation.

The author of the theory of relativity corrected his own equations, which justified the expansion of the universe. Now Hubble showed that Einstein was right. The Hubble time is the reciprocal of the Hubble constant (t _H = 1 / H). This is the characteristic time of expansion of the universe at the moment.

Exploded and scattered

If the constant in 2016 is 66.93 ± 0.62 (km / s) / Mpc, the expansion is currently characterized by the following figures: (4.61 ± 0.05) · 10 ¹⁷ s or (14.610 ± 0.016) · 10 ⁹ years. And again a little humor. Optimists say: it's good that galaxies "run up". If we imagine that they are coming together, sooner or later the Big Bang would come. But it was with him that the birth of the universe began.

The galaxies "jerked" (started moving) in different directions simultaneously. If the rate of removal were not proportional to the distance - the theory of the explosion is meaningless. Another derivative of the constant is the Hubble distance, the product of time and the speed of light: D _H = ct _H = c / H. At the current moment - (1,382 ± 0,015) · 10 ²⁶ m or (14,610 ± 0,016) · 10 ⁹ light years.

And again about the inflatable ball. There is an opinion that even astronomers do not always correctly interpret the expansion of the universe. Some experts believe that it swells, like a rubber ball, not knowing any physical limitations. In this case, the galaxies themselves not only move away from us, but also chaotic "fuss" inside the fixed clusters. Others claim that the distant galaxies "swim away" with the shrapnel of the Big Bang, but they do it in a sedate manner.

Could have become a Nobel laureate

Hubble tried to get the Nobel Prize. In the late 1940s, he even hired an advertising agent (he would now be called a PR manager) to promote the case. But the effort was in vain: there was no category for astronomers. Edwin died in 1953, in the course of scientific research. For several nights he observed extragalactic objects.

His last ambitious dream has remained unfulfilled. But a scientist would surely be glad that a space telescope was named in his honor. And the generations of brothers on the mind continue to explore the vast and wonderful space. It still hides many mysteries. How many discoveries lie ahead! And the Hubble constant derivatives, for sure, will help one of the young scientists to become "Copernicus No. 3".

Contesting Aristotle

What will be proved or disproved, as when the theory of infinity, eternity and immutability of space around the Earth, which Aristotle himself supported, flew to pieces? He attributed symmetry and perfection to the universe. The cosmological principle confirmed: everything flows, everything changes.

There is an opinion that in billions of years the heavens will be empty and dark. The expansion will "take" the galaxy beyond the cosmic horizon, from where the light can not reach us. Will the Hubble constant for an empty universe be actual? What will become of cosmology with science? Will it disappear? All these are assumptions.

Redshift

Meanwhile, the Hubble telescope took a picture, which shows that until the universal emptiness is far away for us. In a professional environment in the course of the opinion that the value of the discovery of Edwin Hubble, but not his law. However, it was he who was almost immediately recognized in the scientific circles of that time. Observations of the "red shift" not only won the right to exist, it is also relevant in the XXI century.

And today, determining the distance to the galaxies, they rely on the superse of the scientist. Optimists say that even if our galaxy remains the only one, we will not have to "miss". There will be billions of dwarf stars and planets. So, next to us there will still be "parallel worlds", which will need to be investigated.