Showing posts with label cosmic background radiation. Show all posts
Showing posts with label cosmic background radiation. Show all posts

Thursday, March 23, 2023

Can we see the beginning of the universe?

As I often point out in these posts, the mainstream media, and sometimes high-profile popular magazines as well, may not be quite accurate when they announce science news. With headlines, especially, they tend to make major mistakes, because they try to make them as appealing as possible, which means that they also suffer from the greatest distortions.

Let us look at a recent news. This is the headline:

Scientists figured out how to see the beginning of time

Wednesday, December 9, 2020

Striking Errors in Scientific Research

Venus. Image taken
by Mariner 10

Errors are not rare in scientific research. Since man is doing science (i.e. since man is man), errors have been made. Science often progresses by trial and error, which means that something is tried, found to be wrong, and then something else is tried. From that point of view, making mistakes and verifying that they are errors is one of the typical procedures of the scientific method, so no one should be criticized for using it.

The problem is, in late times the way to publish the results of an observation or an experiment has changed. Up to now, a well-founded article was written, criticized by a number of scientists in the field, and published in a magazine, which disseminated the finding. This is still being done today, but mass media are often used, before or after the article is published, to spread the "discovery" much more quickly and to many more people. If we take into account that the knowledge about science in mass media is usually ridiculously small, the news is often accompanied by misleading headlines (and sometimes misleading texts), as I have denounced in previous posts in this blog.

Since the dissemination of scientific discoveries is done in this way, the general public frequently finds out about the supposed "discovery", but not about its refutation, because this has not the same appeal and the media don't usually publish it. For this reason, the supposed "discoveries" can be engraved in the people's mind, and it's very difficult to eradicate them.

Let's look at a few examples of striking mistakes made in scientific research:

         The discovery of polywater: in the late 1960s, some Soviet chemists claimed to have discovered a new form of polymerized liquid water, which would arise spontaneously when normal water passes through very narrow capillaries. At that time, the media did not spread it much. For example, the Spanish major newspaper La Vanguardia just published an article on October 21, 1969, saying this:

The surprise has now come from water, as it seems that there exists a polywater. That such a simple liquid, so familiar to us, which has been studied a lot, can still give us surprises, will seem strange to some.

Another piece of news, published on March 26, 1972, is a review of a lecture given by Luis Miravitlles, where he was already suspicious about the existence of polywater:

Despite the many results obtained to date... it is still impossible to decide whether polywater is a true polymer or an artifact produced by conditions in the preparation.

The second alternative turned out to be true. Experiments carried out around the world showed that the properties of polywater were a consequence of the presence of impurities in ordinary water. But La Vanguardia did not publish another article on the subject, so the final refutation did not receive the same diffusion as the original news.

         The discovery of cold fusion: 20 years after polywater, this new "discovery" received much more attention by the media. In the archive of La Vanguardia, for instance, there are dozens of news items related to this, the first of which was published on April 13, 1989. This was due to the fact that, for the first time in the history of science, a "scientific discovery" was disseminated through a press conference before being published in a scientific magazine. And since, from the beginning, most physicists considered the "discovery" impossible, the media echoed them, so just a year later it was considered a failure by almost everyone.

Thalidomide molecule.
A scientific mistake
with awful consequences

Let's look at a few recent cases, which not so long ago made big headlines and then faded away:

         A bacterium uses arsenic rather than phosphorous in its DNA: Announced with fanfare by NASA in December 2010, this "discovery" was removed from the scientific heritage less than two years later.

         Neutrinos faster than light. The news came out in 2011, but it was soon refuted by the discoverers themselves, who found a loose cable that had broken synchronism between the starting point and the arrival point of the neutrinos.

   Gravitational waves in the cosmic background radiation. Announced in 2014, the "discovery" of those waves was supposed to confirm the inflationary theory of the early universe. (Some media incorrectly spoke of a confirmation of the existence of the multiverse). In less than a month it was found that the effect detected had been produced by the dust of our own galaxy. It is still unobserved in the background radiation.

         Presence of phosphane in the atmosphere of Venus, news of 2020, which could be considered as an indication of the possible existence of microscopic life. Subsequent analyzes have not confirmed the presence of phosphane.

The same post in Spanish

Thematic Thread about Science in General: Previous Next

Manuel Alfonseca

Thursday, February 27, 2020

4 clarifications about the history of the universe

James Peebles
Certain statements by James Peebles, recent Nobel Prize in physics, have aroused controversy, although what he said is not something new, as theoretical physicists have long been saying precisely the same thing.
The Big Bang theory was proposed in 1931 by Georges Lemaître, by extending to the past the Hubble-Lemaître law. In 1948, Ralph Alpher and Robert Herman predicted that, if the Big Bang theory is correct, there must be a cosmic background radiation with a temperature close to 5 Kelvin. In 1965 Arno Penzias and Robert Wilson discovered the existence of such cosmic radiation, whose temperature proved to be 2.72548 Kelvin. The temperature is exactly the same in all directions, except for two effects that cause small differences, but never affecting more than the third decimal place.

Thursday, November 28, 2019

The problem with the Hubble constant

Cosmic Microwave Background Radiation
NASA-WMAP

The Hubble constant, which measures the speed of expansion of space in the universe, has very curious properties. For instance, although we call it constant, it turns out that it is not a constant, as it varies over time. That is why its current value is represented by the symbol H0, but since its value was different at other times, it can be represented by other symbols, such as HCMBR, which refers to its value at the time when the cosmic microwave background radiation originated, about 13.7 billion years ago.

Thursday, October 31, 2019

Media manipulation: the Nobel Prizes and religion

James Peebles
The 2019 Nobel Prize in Physics has been assigned to cosmology and divided among three scientists: James Peebles, a Canadian, who receives half the prize for his theoretical work; and Michel Mayor and Didier Queloz, who have shared the other half for having discovered the first planet outside the solar system that revolves around a star in the main sequence.
The theory of the Big Bang was proposed in 1931 by George Lemaître, as a consequence of the extension to the past of the Hubble-Lemaître law. In 1948, Ralph Alpher and Robert Herman predicted that, if the Big Bang theory is correct, there must be a cosmic background radiation with a temperature close to 5 Kelvin. In 1965 Arno Penzias and Robert Wilson discovered the existence of such cosmic radiation, whose temperature turned out to be close to 3 Kelvin. That same year, Robert Dicke, James Peebles and other collaborators reasoned that the radiation discovered by Penzias and Wilson is precisely the signature of the Big Bang predicted by Alpher and Herman. During the 70s, Peebles was one of the leading theoretical cosmologists who studied the field of the formation of the great cosmic structures (galaxies and groups of galaxies). For these works he has now been awarded the Nobel Prize.

Thursday, June 14, 2018

Mistakes in popular science in the media: Stephen Hawking didn’t discover everything

Stephen Hawking
Stephen Hawking has been in the last decades a scientific icon for the media. His painful personal situation turned him into a celebrity who inevitably attracts attention. Therefore, the media have a tendency to exaggerate his scientific work, attributing to him achievements that weren’t his, which he would be the first to repudiate, if he were still among us.
For example, on the occasion of his death, the following headlines appeared in several media:
         ElTiempoHoy: Creador de la teoría del Big Bang y los agujeros negros: fallece Stephen Hawking a los 76 años. (Creator of Big Bang’s theory and black hole theory: Stephen Hawking dies at 76).

Thursday, May 3, 2018

The standard cosmological model

Map of the Cosmic Background Radiation
In 1927, the Belgian priest and astronomer Georges Lemaître discovered Hubble’s law.
Yeah that’s right. Hubble did not discover the law until 1929. What happened was that Lemaître published it in French in a low-impact journal (Annales de la Société Scientifique de Bruxelles), while Hubble published it two years later in English in the Proceedings of The National Academy of Sciences, received much more publicity and his name got associated with the discovery.
Combined with Einstein’s cosmological equation, Lemaître-Hubble’s law implies that the universe is expanding. In an article published in 1931 in Nature, Lemaître drew the consequence by proposing the Big Bang theory, so called in derision by its opponent Fred Hoyle in 1950. The name caught on.
In 1948, Ralph Alpher, George Gamow and Robert Herman made two surprising predictions, based on the Big Bang theory: the average composition of the mass of the cosmos (three quarters hydrogen and one quarter helium), and the existence of the cosmic background radiation. Both were confirmed during the sixties. From that point, the Big Bang theory became the standard cosmological theory.

Thursday, October 26, 2017

Some clarifications on the cosmic background radiation

In 1948, Ralph Alpher and Robert Herman (both in George Gamow’s team) came to the conclusion that if the universe had come out of a Big Bang and had expanded since that point in time, there should exist a cosmic background radiation in the frequency of microwaves (or what means the same, at a temperature of about 5K, 5 degrees above absolute zero). Alpher and Gamow had published that same year another prediction about the average composition of the cosmos, starting from the Big Bang theory.
In 1964, Arno Penzias and Robert Wilson were working with a newly built very powerful radio telescope and detected a background noise that could not be eliminated. First they thought that it would be of terrestrial origin, but once all the possible sources of noise had been taken into account, the effect persisted. Then they came to the conclusion that such noise could not come from the solar system or from our galaxy (for in that case it would be more intense in one direction than in another), and that its origin had to be cosmic. The temperature of that radiation (that is, its frequency, considering the Wien equation) turned out to be about 3K. Robert Burke of MIT suggested to Penzias that such noise could be the cosmic background radiation predicted by Alpher and Herman. This was in fact confirmed. For their discovery, Penzias and Wilson received the Nobel Prize in 1978.
Along with the argument based on the average composition of the universe, the cosmic background radiation gave the accolade to the Big Bang theory, which became the standard cosmological theory (although see an earlier article on this blog).

Thursday, November 17, 2016

Alternatives to the Big Bang

The Big Bang theory has a problem, which can be explained by the following set of questions:
  • The farthest we can see is the cosmic microwave background radiation, which originated about 380,000 years after the Big Bang. We cannot see directly what happened before, because it is hidden behind that radiation.
  • It is true that we cannot see, but we can deduce what happened in those first 380,000 years by applying the standard physical theory, i.e. general relativity. It is also possible to check those deductions, for they offer predictions, such as the average composition of the cosmos, which fit well with the experimental data.
  • The problem is, general relativity does not take us to time zero, the Big Bang itself. This theory can be applied only from 5×10-44 seconds after the Big Bang (the Planck time), as quantum effects were predominant before that time, and we do not have a physical theory that unifies quantum mechanics with general relativity.

Thursday, February 12, 2015

A photograph from the abyss of time

The cosmic background radiation as detected by the Planck satellite telescope
When the space telescopes sent by NASA and the European Space Agency (COBE, WMAP, Planck) send us data on the cosmic background radiation, the corresponding images usually appear on the first page of high-diffusion newspapers, accompanied by headlines that are not always correct. Let's look at a few, published in Spanish newspapers: