It seems that exoplanets and relic radiation is a necessary business and the choice of candidates is obvious. But we dug deeper into the issue and found out that in fact the choice of the Nobel Committee on Physics was rather strange.
The Nobel Committee awarded the Physics Prize to James Peebles - for contributions to cosmology, Michel Mayor and Didier Keloz - for the discovery of the alleged "first exoplanet" (we will show below that this is not the case). Let's try to take a closer look at the awards.
Did Peebles Determine the Basis of Cosmology
From the wording of the Nobel Committee this year, it is difficult to understand why the first part of the prize went to James Peebles. The press release explains the choice simply: for "theoretical discoveries in the field of cosmology." But which ones? Release on details: "Its theoretical framework, developed by him since the mid-1960s, is the basis of our modern ideas about cosmology."
It didn't become clearer. Our modern ideas about cosmology are based on the Big Bang, after which the universe expanded under the influence of such key factors as dark matter (slows expansion) and dark energy (accelerates expansion). Peebles was not involved in the discovery of any of these phenomena.
When the release of the Nobel Committee is mysterious, it is worth looking at the accompanying document, where the contribution of the Nobel Prize is described with technical details. There is such a document this year, but it also does not clarify the situation very much. It says: in 1965, Penzias and Wilson discovered relic radiation during observations, the discovery was "unexpected". It was only through contacts with theorists, including Peebles and his scientific advisor Dicke, that astronomers were able to understand what they were observing at all.
Background radiation: the first confirmation of the Big Bang
To understand the significance of the discovery of the CMB, one should remember how it was predicted in general. This was done by Georgy Gamov, a Soviet defector physicist. In 1948, he hypothesized that the universe at the time of the Big Bang was not only dense, but also very hot. So hot that at first the entire space was filled with plasma - a medium where there are no neutral atoms - only ionized gas. It absorbs photons, so at the very beginning no radiation in the Universe could propagate in principle. Some time later - we now know that it was 380 thousand years after the Big Bang - the temperature dropped enough to produce many neutral hydrogen atoms, and the plasma content in space dropped dramatically. However, the gas was still quite hot by modern standards, so it continued to emit. It is this very first radiation that is called "relict".
The importance of Gamow's idea of relic radiation is enormous. Before him, the idea of the Big Bang was speculative, irrefutable, but also unprovable due to the absence of such physical consequences of the explosion that could be observed in our time.
The expansion of the Universe was already known, but a variety of scenarios could lead to it: both the "cold" Universe, and even the Universe of the "stable state". The matter was complicated by the fact that the concept of the origin of the Universe at some point in the past contradicted the long history of physical concepts of its eternity and immutability. Many physicists of the first half of the twentieth century complained that the idea of "the emergence of the universe" was introducing religious ideas into science.
These theses were especially poignant because one of the founders of the Big Bang concept, Georges Lemaitre, was a Catholic priest who did not hide the fact that he believed in the creation of the universe by God.Many physicists like Arthur Eddington said bluntly that the idea of "the beginning of time" (the Big Bang) was "unbearable" for them. All this meant that the concept of the Big Bang itself could not win: it contradicted the views typical of most physicists of that time.
A strong impulse was needed to break such a preconceived notion that had no scientific roots, but, as is often the case, an extremely tenacious irrational attitude towards the Big Bang hypothesis.
The discovery of cosmic microwave background radiation was the most powerful and accessible of all proofs of the concept of a hot Big Bang - the cornerstone of the modern understanding of the origin and evolution of the universe. If Peebles had discovered it, or at least played a large role in its discovery, then, undoubtedly, the press release of the Nobel Committee would be correct: "Its theoretical structure, developed by him since the mid-1960s, is the basis of our modern ideas about cosmology." It remains only to check whether this is so.
"And then they just forgot about them": why scientists can only see what they understand
CMB, like many things in physics, is not something that can be discovered before you understand what it is. The observer is powerless here: without the help of a theoretician, he can observe the background radiation of the Universe as much as he wants, but still cannot understand what exactly he sees.
In 1941 in the West and in 1955 in the USSR, background radiation was recorded, which we now know as relic radiation. But neither there nor there no one understood what it was, and these observations had no consequences and could not have. There are so many little-explained observational effects in astronomy then and now that you can't remember everything. Without a normal theory, such observations are often dead weight.
In 1941, there was no theory of the hot expansion of the Universe after the Big Bang (Georgy Gamov invented it only seven years later), and in 1956 it was, but people from the Soviet Pulkovo Observatory, where another observation of the relic radiation was made at that time, nothing about it did not know - due to a moderate acquaintance with the corresponding newest ideas in physics. Therefore, as a modern scientist describes the Pulkovo “discovery” of relic radiation, “none of the astrophysicists and cosmologists paid attention to this significant fact, since they did not know anything about the existence of relic radiation and did not attach due importance to the results of these measurements, and then they simply forgot about them".
In science (and not only in science!), One should not leave the available facts without due attention and understanding.
Here is another modern review about the Soviet 'discovery' of relic radiation: “This whole story once again reminds of the well-known, but not always observed commandment: in science (and not only in science!), The available facts should not be left without due attention and understanding, no matter how insignificant they may seem at first glance. For their timely understanding, the outlook of the researcher is also important …"
Who opened the eyes of the observers: Gamow, Peebles and all-all-all
But Peebles was neither the first, nor the second, nor the third to predict relic radiation. The first such person was Georgy Gamow in 1948, he also predicted (without giving any calculations) that the temperature of this radiation is about three Kelvin. Speaking about radiation, which will later be called relict, Gamow noted that it could arise only at a certain moment in the history of the Universe, when the matter in it cooled down enough for the plasma to become neutral atoms that do not absorb photons as actively as plasma. Obviously, for this, the Universe had to cool down to the level when the hydrogen plasma becomes neutral hydrogen - up to a few thousand degrees. It is clear that since then the Universe has expanded greatly, that is, the temperature of that very first radiation has already dropped dramatically - it was he who defined it at three Kelvin.
Gamow was not the only predictor of the CMB. At that time, physicists rarely read all the papers published on their topic.Therefore, its publication in 1948 went unnoticed. And by the beginning of the 60s, the ideas of Gamow and his co-authors were deeply forgotten: they were discovered in the second round by both Yakov Zeldovich in the USSR and Robert Dicke in the USA. And not only them.
In 1964, astrophysicists Doroshkevich and Novikov in the USSR tried to estimate the possibility of detecting relic radiation according to Gamow's concept. They found that the Bell Laboratory Horn antenna, where the Americans Penzias and Wilson made their discovery in 1965, could have been the best detector for relic radiation. Let's think for a second: Soviet astrophysicists from across the ocean saw an instrument for searching for relic radiation, but did not know that hundreds of kilometers from them - in Pulkovo near Leningrad - there were quite suitable antennas. Naturally, they knew absolutely nothing about the fact that the relic radiation had already been detected there. As the reader already guesses, no one noticed the work of Novikov and Doroshkevich either.
So, as we can see, Peebles was far from in the first row of those who, based on the model of the hot Universe, expected the discovery of the CMB. Moreover, Peebles' paper in 1965 estimated the temperature of this radiation at seven Kelvin. This is worse than Gamow's in 1948, and worse than the estimates from the 50s (five Kelvin). It follows that Peebles was neither the very first nor the most accurate of the theorists to predict CMB.
He, like the rest of Dikke's group, really helped Penzias and Wilson. Like many observers, these two were far from new physical theories. Therefore, when they discovered some strange radiation coming from all directions, they could act in two ways: simply score, “and then just forget,” like scientists from the Pulkovo Observatory in 1956, or still try to broaden their horizons on the topic … They chose the second path: they were not too lazy to call their respected university (Princeton), where Dicke's group worked, and ask: comrade theorists, we are observing something strange here, you have no idea what it could be?
From this it is clear: Penzias and Wilson received the Nobel Prize for the cause in 1978. Persistence and will to expand one's own horizons - this is what distinguishes an ordinary scientist from someone who has a chance for a Nobel Prize.
But that can't explain the 2019 Peebles Prize. The prize can be given for perseverance and curiosity, but it cannot be awarded only for the fact that he was in the right place in the team of the right supervisor.
An explanatory document of the Nobel Committee notes that in 1965 Peebles made another, "key contribution", suggesting that the background radiation had an impact on the formation of galaxies. This influence is really important: the "lumpy" distribution of matter, which made possible the formation of stars, and galaxies, and life, including you and me, without the relict radiation would be completely different, much less homogeneous. There is another point: later Peebles was able to show that before the first stars a noticeable amount of elements heavier than helium in the Universe could not have been formed. Peebles was also an active supporter of the idea of cold dark matter, but here he is more a distributor than an author: the term "dark matter" was introduced by Henri Poincaré in 1906, and Kelvin was the first to indicate it in 1884.
Are Peebles' accomplishments outlined above really "the foundation of our modern ideas about cosmology"? In practice, both of these results are just a consequence of the hot Big Bang model and the idea of relic radiation. It is not for nothing that the press release of the Nobel Committee on Peebles mentions none of these works: they are too little suited for the role of what the Nobel Prize is awarded for.
The Nobel Prize is rarely given for the totality of works, but I think this is just such a case.
Academician Valery Rubakov
The most probable assumption about why it was he who received the prize was put forward by Academician Valery Rubakov: “The Nobel Prize is rarely given for the totality of works, but it seems to me that this is just such a case”.
In general, there is nothing wrong with this: a person has worked all his life for the good of science and, in aggregate, has done a lot. However, let us note that it is somewhat strange to give "by aggregate" in the presence of living physicists who deserve it without aggregates. The same Rubakov mentions that Peebles' work on relic radiation is similar to the results obtained by Rashid Sunyaev a little earlier. In addition, Sunyaev has a number of other extremely impressive achievements on his account. It is with the help of the Sunyaev-Zeldovich effect discovered by him that the diameter of galaxy clusters is measured, this is a "measuring ruler" when constructing a distance scale in the Universe. He is also behind the prediction of accretion disks around black holes - the most important element by which these objects devour matter. It is known that it is thanks to black holes and the effects of their accretion disks that galaxies, in one of which we also live, were generally able to form in their current form. As we can see, the words from the 2019 Nobel press release are much more suitable for the discoveries made by Sunyaev: "… the basis of our modern ideas about cosmology."
Why was Peebles given the prize, while Sunyaev - we are almost sure of this - not only was not given, but also not given? Academician Rubakov answers this question simply: "The fact that Peebles received the prize today, and not, say, Sunyaev, is a decision of the committee, I take him calmly."
We would also advise you to take it calmly. Modern science is American-centric, and, among other things, this means that discoveries that attract the attention of American scientists are much more likely to be noticed in it than discoveries equal to them that did not attract the attention of researchers from the United States. This is life, and other countries can only come to terms with it.
The discovery of exoplanets: who actually did it first and why the award went to others
The second half of the Nobel Prize in Physics went to Michel Mayor and Didier Kelosa. These Swiss scientists discovered the planet 51 Pegasi b in 1995. Although the planet orbits the yellow dwarf 51 Pegasus (about 50 light-years from Earth), it is extremely far from those familiar to us in the solar system. This is "hot Jupiter" - a class of planets orbiting close to their star and, as a rule, throwing all other planets out of their planetary system.
The Nobel press release confidently states that these two scientists in October 1995 "announced the first discovery of a planet outside our solar system." Allegedly, this began a revolution in astronomy, as a result of which thousands of exoplanets have been discovered today. Unfortunately, this is actually not true.
Perhaps a brown dwarf and maybe even a giant planet.
The first undoubtedly discovered exoplanet was HD 114762 b - 126 light years from the Sun. It revolves around its star in an orbit similar to that of Mercury in our system. Already in 1989 - 30 years ago! - at the time of its discovery, the mass of this object was designated as approximately 11 Jupiter masses. Bodies whose mass is defined as above 13 Jupiter's masses are called brown dwarfs (a kind of failed stars). However, everything below this level is considered to be planets, so HD 114762 b is a planet. Let's open an article in Nature from 1989, in which the authors, led by David Lathmemo, write: "Perhaps a brown dwarf and maybe even a giant planet." To date, the estimate of the object's mass has not changed, so the decision of the Nobel Committee, frankly speaking, does not fully correspond to the one stated in the press release.
In the explanatory document, the Nobel Committee - 2019 does not mention this planet at all, although its discovery was made by the same radial velocity method as 51 Pegasi b. This does not mean that its authors do not know about the discovery: in the seventh link of the document, when listing the early attempts to detect planets, Latham's work is indicated.However, that's all: the Nobel Committee decided, even in footnotes, not to try to explain why the 1989 discovery, confirmed in 1991, cannot be considered the first exoplanet, but the 1995 discovery can. Perhaps this is due to the assumption that the mass of HD 114762 b is determined inaccurately and in fact it is, in fact, a brown dwarf. But if it is precisely this doubt, then the committee should have dwelt on this in more detail, which it did not do.
Let us emphasize: when the committee does not experience difficulties in substantiating its decisions, it writes about why this or that exoplanet was not counted by it "first". For example, about the planets of the PSR1257 + 12 system, two of which were open by 1992, the accompanying committee document sets out the situation honestly.
Indeed, the committee notes, these exoplanets were discovered years earlier than 51 Pegasi b. But the method by which this was done is not the method of radial velocities. The planets Poltergeist and Phobetor of this system were discovered because they blocked the radio signal of their star - a neutron star. Today, such planets are considered rare (in fact, neutron stars are not particularly frequent against the background of ordinary ones). That is, the detection method used by the discoverers of the Poltergeist cannot be massive. In general, it is believed that the nature of the planets around neutron stars is different, and, although life is also possible there, special attention is not paid to such bodies.
The choice of Major and Keloz as Nobel laureates - and not Latham's group - is somehow justified. Undoubtedly, Latham's discovery was ahead of its time; immediately after it, the boom in the discovery of new exoplanets was impossible for technical reasons. The work of Major and Keloz appeared when the technique was already ready, and immediately after their discovery, dozens of others followed.
Nevertheless, it would be much more honest if the Nobel Committee explicitly indicated that the prize was awarded to the current laureates with the proviso that they had predecessors - people who actually discovered the exoplanet first. Well, or at least presented an award for the discovery of the "first exoplanet around a yellow dwarf" - and "not the first exoplanet" in general.