Naked Science's top scientific breakthroughs of 2024: from the end of the universe to the reasons behind Ragnarok.

Dark Energy Is No Longer a Constant, and It Has Changed the Fate of the Universe

While the highlight of observational astronomy in 2024 is the new data from the James Webb Space Telescope, unfortunately, we cannot include it in the breakthroughs of 2024. Yes, it has revolutionized our understanding of the early Universe, but the issue is that Naked Science already noted in 2023 that such a revolution "led by James Webb" has begun and will result in a paradigm shift in cosmology (we even named a candidate for a new cosmology compatible with the observations of the space telescope).

However, 2024 also witnessed astronomical observations that pushed physics and cosmology forward significantly. The scientific collaboration Dark Energy Spectroscopic Instrument (named after the instrument itself) analyzed the redshift of a million galaxies at varying distances from us. Their findings indicated that the acceleration of the Universe's expansion, discovered a quarter-century ago, varies. In other words, yes, the expansion is still accelerating, but this acceleration was higher 13 billion years ago. What does this imply?

At the end of the 20th century, astronomers observed that type Ia supernovae from the early Universe had luminosities lower than expected. Physically, this is unlikely: this type of supernova explodes upon reaching the same mass, thus the energy of the explosion is the same. Hence, such objects are termed "standard candles of cosmology."

This led to a single scientific conclusion: the Universe is not expanding at a uniform rate, but is gradually accelerating. But what could cause it to expand with acceleration? The simplest and most natural explanation for most scientists seemed to be the cosmological constant—a kind of repulsive vacuum pressure.

Now, the observations from DESI in 2024 effectively rule out this hypothesis with a probability of 3.5 sigma. A definitive closure will occur when the data reaches 5 sigma, but even 3.5 is substantial enough to make the outcome somewhat predictable today.

What are the practical implications of the gradual decrease in the acceleration of the Universe's expansion? If dark energy were a constant, the Universe would expand infinitely. The result would be a heat death of the Universe. Thus, DESI allows for a very important conclusion: infinite expansion may not occur. The expansion of the Universe in volume could theoretically slow down or even reverse, preventing its heat death from ever happening.

Of course, the question arises: if the Universe is not pushed by vacuum pressure, then what? Naked Science stated in the 2023 conclusions that the most plausible answer to this question is: dark energy does not exist. The accelerated expansion of the Universe after the Big Bang is caused by entirely different factors than we previously assumed.

Details can be found in our extensive article, or in the book by Russian physicist Nikolai Gorky, published in 2023, which has already undergone its first reprint in 2024.

Biologists Have Found an Absolutely New Form of Pathogens—Including Inside Humans

When biologists study some extremely small forms of life, they are driven not only by abstract curiosity. We study bacteria to learn how to protect ourselves from plagues, tuberculosis, and leprosy. Protists of the Plasmodium genus cause malaria, which has killed 50 billion people out of the 110 billion that have lived throughout human history. The need to study viruses is also self-evident, considering that the excess coronavirus mortality in Russia in 2024 is clearly over 70 thousand people.

In 2024, biologists unexpectedly discovered something microscopic with a genetic code inside, but what exactly it is remains poorly understood. We are talking about strange viroid-like structures consisting of circular RNA. A viroid is also a closed ring of RNA (single-stranded, not double), containing less than five hundred nucleotides. They differ from viruses not only in that viruses have at least two thousand nucleotides, but also in that viruses have their own protein coat, which simplifies their spread from one organism to another (for example, through the air).

It seems that obelisks differ from viroids in that they can code for at least two proteins (likely more). They have about a thousand nucleotide bases, which is clearly more than viroids but significantly less than the most compact virus. Additionally, their circular RNA is covered by a pillar-like outer structure, which is why the discoverers named the newly found class of pathogens "obelisks."

It is clear that obelisks should not reproduce without some host cells: their genetic code is too simple, and there are no apparent mechanisms for independent, non-parasitic reproduction within them.

It raises a very complex question: can this be considered life? Many biologists do not regard viruses and viroids as living because they are obligate parasites. In other words, they either parasitize other organisms or cannot reproduce themselves. Other biologists traditionally argue: if an ascarid does not parasitize another organism, it also cannot reproduce itself; does this mean that the ascarid is not a living organism?

Such disputes have a philosophical tinge, so we will refrain from engaging in them. However, it should be noted that obelisks have already been found in 50 percent of human saliva samples across various continents. They are also present in 7% of human stool samples. What they do inside us remains unknown. Can they cause diseases like viruses in us or viroids in plants? Or, conversely, do they parasitize the bacteria living in our bodies and help maintain their population at a safe level for us?

To find answers to these questions, time is needed. For now, we have discovered a group of pathogens whose origins are unclear—whether they came from viruses, viroids, or something entirely unknown—and which live inside us, yet it is unknown what they do there.

At first glance, this discovery is alarming. On second thought, it invokes an involuntary pride in science. Just think, such large and unexpected discoveries in such a well-studied area as the human body are possible, as a fundamentally unknown class of pathogens is being uncovered there.

A Vaccine Has Shed Light on the Most Widespread Cause of Dementia on Earth

There are over 55 million documented cases of acquired dementia caused by Alzheimer's disease on the planet (many undiagnosed cases are believed to exist). Meanwhile, the number of those suffering from it is growing at an alarming rate. The increase in life expectancy—in medically developed countries and in China, it exceeds 80 years—means that a growing share of the population will become its victims in the future. By mid-century, their number is expected to exceed one hundred million, and by the end of the century, if the trend continues, it may surpass a billion.

The danger of this disease is hard to underestimate: at the end of the road, besides the dementia it causes, the patient faces death. What is particularly unpleasant is that while this disease used to mainly affect people over 65 years old, it is now rapidly "youthing." About 10 percent of all patients are aged between 30 and 65 years.

The most challenging aspect of the issue has long been the scientific misunderstanding of the cause of the disease. Since it is neurodegenerative, it has been primarily studied by brain specialists. However, all their proposed explanations were more descriptive: they did not know what specifically causes the disease.

In 2024, a small revolution occurred in medicine. Scientists discovered that the probability of the disease is significantly reduced through vaccination against the Varicella zoster virus. Moreover, the new vaccine, which provides better protection against this virus than older ones, results in a lower likelihood of developing Alzheimer's compared to those who received the old Varicella zoster vaccine.

From this, scientists conclude that various viral diseases affecting brain cells could be the cause of Alzheimer's disease. That Varicella zoster can do this has been discussed in medical literature for decades, but until the new study, it was more of a theory than verified data.

The Varicella zoster virus causes two widespread diseases that are essentially the same: "childhood" chickenpox and "shingles", which is not a rash at all. The reason is that the chickenpox virus does not disappear from the infected person's body; it merely "sleeps" in their neurons. As a person ages, their immunity weakens, and the virus awakens—becoming more frequent the older one gets.

It appears that the very "shingles" is just one form of its activity, and another could be Alzheimer's disease itself.

Of course, this does not mean that only Varicella zoster affects human brain cells. It is well known that influenza and coronavirus do the same. Moreover, there are already scientific studies showing that people who regularly get vaccinated are significantly less