Top 10 Science Stories of 2019

As every year, here we review the main scientific advances that that last twelve months of science have brought us.

1. The first photo of a black hole

Culminating ten years of meticulous and complex work in which hundreds of researchers have participated, in 2019 we finally witnessed a historic and long-awaited achievement: the first real image of a black hole.

The first results from the Event Horizon Telescope, a network of terrestrial telescopes that turned our planet into a giant eye to offer us what has undoubtedly been the scientific image of the year, were finally published on 10 April. The 347 participating researchers, handling immense volumes of data, had to develop new algorithms to obtain the first low resolution photo of the super-massive black hole in the centre of the giant galaxy M87, a colossus of 6.5 billion solar masses located 55 million light years away. The EHT team, which has earned this year’s Breakthrough Award, continues to work and expand its network in order to increase the quality of its images.

2. Climate change is now a climate emergency

Although alarms about climate change have been sounding for decades and the scientific reality of the issue has managed to permeate public opinion for years, never has the spotlight been so focused on this problem of our era as it was in 2019. In September, the United Nations climate summit in New York was accompanied by an report from the Intergovernmental Panel on Climate Change (IPCC) on the state of the oceans and the cryosphere that once again showed us the unsustainable state of our planet. On November 28, the European Parliament approved the declaration of a climate emergency, while in Nature a group of scientists warned that we could already be at a point of no return in the deterioration of the climate.

In spite of all this, the COP25 in Madrid was preceded by the news that 2019 has broken a new record for greenhouse gas emissions, and that the current commitments by countries will not achieve the objectives of limiting the increase in temperature set in 2015 by the Paris Agreement. Although the forecasts are far from rosy, the warning voice is today stronger than ever, and much of this is due to the person who has already become the greatest environmental influencer of our time, the young Swedish activist Greta Thunberg.

3. The Artemis programme, a big step for women

This year we have commemorated the half-century since man first set foot on the Moon, with the Apollo 11 mission and the famous small step for (a) man, but a giant leap for mankind, by astronaut Neil Armstrong. This year of celebrations was the ideal one to make the announcement of the return to the Moon in the next decade.

In May, NASA published the details of its new program Artemis, which aims to bring humans back to our satellite in 2024. But in this case, with an welcomed novelty: Artemis, appropriately named after the sister of Apollo, goddess of the Moon in Greek mythology, will take the first woman to the lunar surface. The first one hundred percent female space walk on the International Space Station, conducted on October 18 by astronauts Christina Koch and Jessica Meir, was another sign that equality is finally reaching space as well.

4. Arrokoth, the most distant object visited by a probe

2019 arrived along with a new record in space exploration. On January 1, while humanity was still celebrating the new year, NASA’s New Horizons probe flew past the most distant celestial body ever visited by a human-built device. This trans-Neptunian object, located 6.6 billion kilometres away and offering the curious appearance of a space snowman, changed its provisional name from 2014 MU69 to Ultima Thule, in reference to the name that Greek and Roman sources gave to their world’s northernmost frontier. In May, the results were published in the journal Science. However, the name chosen sparked some controversy because of its connotations, since this was what the mythology of Nazi occultism called the cradle of the presumed Aryan race. In November, and at the suggestion of NASA, the debate was settled by renaming the object Arrokoth, a term from the language of the Powhatan natives of North America meaning “sky.”

5. A new human species?

In recent decades, that old illustration of human evolution represented as a row of increasingly sophisticated hominins, leading up to us, has been pulverized by evidence of what has proved to be a much more complex drawing, so much so that scientists cannot even agree on the number of human species we know of today. The latest of them appeared on the pages of Nature in April, when an international team of researchers described the discovery of Homo luzonensis, a human that lived on the island of Luzon (Philippines) at least 50,000 years ago and that exhibits a mixture of modern and primitive features.

The finding has been controversial: some paleoanthropologists questioned whether the unearthed remains, which do not include any skull fragments, are sufficient to justify the minting of a new human species, suggesting that the fossils found could correspond to a local adaptation of another type of Homo already known. In any case, the story serves to illustrate how far we still are from obtaining a clear and complete picture of the intricate odyssey of human evolution.

6. The second visitor from the stars

In 2017 we learned of ‘Oumuamua, the first object discovered in the Solar System that turned out to be a visitor of interstellar origin in our cosmic neighbourhood. This year we have encountered the second body from outside the Solar System of which we are aware. Unlike ‘Oumuamua, 2I/Borisov is clearly a comet, and its observations have once again served to make us realise the insignificance of our blue planet; the entire length of the comet, including the coma and tail, is 14 times the size of the Earth.

The discovery, made on August 30, had a rare peculiarity in this era of scientific teamwork, as it was the work of Crimean telescope maker and amateur astronomer Gennadiy Borisov thanks to a telescope he built by himself. On December 8, 2I/Borisov reached its closest proximity to the Sun, twice the distance of our planet, while its nearest approach to the Earth will occur on December 28, some 290 million kilometres away.

7. Quantum supremacy is now here, or almost here

One of the triumphs of technology in this year is also one the main scientific advances.

Although the concept of the technological singularity has become quite popular, the moment when Artificial Intelligence will escape human control and emancipate itself from us, 2019 was when many of us first heard about another technological milestone called quantum supremacy, the moment when quantum computing will solve problems unattainable by classical computers. The term splashed across the headlines last October 23, when Google researchers announced in Nature the achievement of this breakthrough.

According to the authors, its quantum processor completed in 200 seconds a task that would take 10,000 years for the IBM Summit, currently the world’s most powerful supercomputer. While researchers from the latter company have countered that their machine could run the process in considerably less time, only 2.5 days, and other experts have pointed out that there is still a long way to go, the advance has been compared in importance to the pioneering flight of the Wright brothers.

8. One more milestone towards genomic editing

It has just been one year since Chinese scientist He Jiankui reaped the general condemnation of the scientific community and the public when he announced the birth of the first two babies with edited genomes, which the researcher had modified to make the two girls resistant to the AIDS virus. One year later, neither He’s research has been formally published, nor has the scientist’s whereabouts and future been clarified. This December, MIT Technology Review has had access to He’s work, revealing that the DNA editing carried out on Lulu and Nana failed to reproduce the natural mutation he was trying to mimic, and that he may have introduced other potentially dangerous changes to the girls’ genomes. The problem lies in the limitations of the CRISPR system, the genome-editing tool on which so much hope has been placed in the fight against many diseases, but which has yet to be perfected. Fortunately, this path is already being followed: in October, researcher David Liu, one of the creators of CRISPR, published a new variant called Prime Editing, more powerful and precise than the original one, which according to the scientist could correct 89% of the more than 75,000 genetic alterations that cause diseases.

9. Water on a planet in a habitable zone

The discovery of exoplanets is today one of the scientific areas that most often attract the interest of the media and the general public. And while more than 4,000 extrasolar planets have now been confirmed, including an enormous diversity of different sizes and conditions, much remains to be discovered; in fact, the long-awaited Earth twin, a planet similar to ours that would be the best candidate to harbour perhaps intelligent alien life, has yet to be found. In 2019 a new milestone has been surpassed when water was detected for the first time on an exoplanet in the habitable zone of its star. Two independent teams found the signature of this molecule so essential for life in the atmosphere of K2-18b, a planet discovered in 2015 by the Kepler space telescope and that orbits a red dwarf star 111 light years from us. Although various experts have questioned whether K2-18b really possesses conditions compatible with life, the finding has provided a glimpse of what in the near future will be a simpler task thanks to the new telescopes currently under construction.

10. The fastest spacecraft in history, closer than ever to the Sun

In spite of the familiarity of its presence in the sky, and the fact that nothing casts light into the darkness like it does, in reality the Sun has many secrets of that are still enveloped in darkness. This year has seen published the first results from Parker Solar Probe, the most ambitious mission ever launched to deepen our knowledge of solar processes. The data, published in Nature in December, has surprised scientists. Among the findings, it has been demonstrated that the Sun vaporises the space dust in its vicinity, creating around it a zone free of these particles. Another discovery is that the magnetic lines of the star do not always radiate outwards as was believed, but sometimes bend inwards and point directly back at the Sun in rapid whip-like movements, dubbed “switchbacks.” These are two of the surprises revealed by a probe that has already beaten the record for the closest proximity to the Sun and the highest velocity ever reached by a human-built device, two milestones that the probe itself will continue to break in the coming years.

Javier Yanes

@yanes68