This article lists a number of significant events in science that have occurred in the first quarter of 2020.

Events January 1 January Researchers demonstrate an artificial intelligence (AI) system, based on a Google DeepMind algorithm, that is capable of surpassing human experts in breast cancer detection. Astrophysicist Ronald Mallett proposes a theoretical way of building a time machine, albeit with limitations, based on ring lasers and special and general relativity equations. 3 January Astronomers report evidence that suggests that the planet Venus is currently volcanically active, and the residue from such activity may be a potential source of nutrients for possible microorganisms in the Venusian atmosphere, according to researchers. 3–5 January – Chinese virologist Zhang Yongzhen sequences the Severe acute respiratory syndrome coronavirus 2 genome. 6 January The American College of Physicians issues clinical guidelines for exogenous testosterone treatment in adult men with age-related low levels of testosterone. The guidelines are supported by the American Academy of Family Physicians. NASA reports the discovery of TOI 700 d, the first Earth-sized exoplanet in the habitable zone discovered by the Transiting Exoplanet Survey Satellite (TESS). The exoplanet orbits the star TOI 700 101.4 light-years away in the Dorado constellation. Astronomers report that a repeating Fast Radio Burst (FRB) (namely, FRB 180916), the second such FRB precisely located, originated from a medium-sized spiral galaxy 500 million light-years away. The Chinese paddlefish is found to be extinct after extensive surveys failed to find any living specimens, pending official IUCN confirmation. A rare circumbinary planet, called TOI 1338 b, is discovered by Wolf Cukier, a 17-year-old intern at NASA's Goddard Space Flight Center.

7 January Astronomers describe the "Radcliffe Wave", a large ribbon of gas extending 9,000 light years in length and flowing 500 light years above and below the galactic plane, with approximately three million solar masses. The National Science Foundation (NSF) renames the Large Synoptic Survey Telescope (LSST) to the Vera C. Rubin Observatory (VRO) in honor of astronomer Vera Rubin who is notable for her pioneering work with galaxy rotation rates which provided evidence for the existence of dark matter. 8 January The American Cancer Society reports a 2.2% drop in the cancer death rate between 2016 and 2017, the largest single-year decline in mortality for this disease ever recorded in the United States. Scientists publish evidence from Siberian caves suggesting that summer sea ice in the Arctic Ocean plays an essential role in stabilising permafrost and its large store of carbon. 10 January – Scientists report the discovery of the oldest known occurrence of an animal digestive tract, found in fossils, unearthed near Pahrump, Nevada, of Cloudinidae, an extinct wormlike organism that lived during the late Ediacaran period about 550 million years ago. 11 January – After a three-year trial that included testing, commissioning, calibrations and operations authorities declare that China's FAST telescope – the world's largest filled-aperture radio telescope – is starting formal operations after it passed its national acceptance test.

13 January A study finds that ocean temperatures were at a record high in 2019 and underwent the largest single-year increase of the decade. Astronomers report that the oldest material on Earth found so far are Murchison meteorite particles that have been determined to be 7 billion years old, billions of years older than the 4.54 billion years age of the Earth itself. 15 January Astronomers report, for the first time, the origin of phosphorus, an essential element of life as we know it. Phosphorus was found to be initially formed in star-forming regions, and carried by comets, in the form of phosphorus monoxide, throughout outer space, including the early Earth. Scientists report that "Candidatus Prometheoarchaeum syntrophicum", a type of Promethearchaeati archaea microorganism, may be a possible link between simple prokaryotic and complex eukaryotic microorganisms about two billion years ago. Paleontologists report the discovery of Wulong bohaiensis, Chinese for "dancing dragon," a very small feathered dinosaur that lived 120 million years ago, and that may help better explain the link between non-avian dinosaurs and avian dinosaurs (birds).

16 January Scientists report that the extinction of the non-avian dinosaurs about 66 million years ago was mostly a result of a meteorite impact (the Chicxulub impactor) and not a result of volcanism. In a study published on 29 June other researchers also conclude that the asteroid impact was the main driver of this extinction. The giant squid genome is sequenced for the first time. Quantum physicists report the first direct splitting of one photon into three using spontaneous parametric down-conversion and which may have applications in quantum technology.

17 January – For the first time, scientists report a video of atoms bonding and separating. 20 January Astronomers, using X-ray reverberation echo mapping techniques, report the mass and spin, for the first time, of a supermassive black hole, particularly the black hole in the middle of the IRAS 13224-3809 galaxy located about 1 billion light-years from Earth. COVID-19 pandemic: Chinese authorities first publicly confirm that there is human-to-human transmission of severe acute respiratory syndrome coronavirus 2. 21 January Scientists report that the oldest recognised asteroid impact occurred in Western Australia more than 2.2 billion years ago and that it might have ended the ice age at that time. A study finds record high emissions of the potent greenhouse gas, HFC-23. Researchers present evidence that the platypus is at risk of extinction, due to a combination of water resource development, land clearing, climate change and increasingly severe periods of drought. Researchers develop a single molecule that can absorb sunlight from the entire visible spectrum for the production of the fuel hydrogen, harnessing more than 50% more solar energy than current solar cells can. A study by researchers finds that man-made ozone-depleting substances (ODS) caused the largest share of Arctic warming, one-third of global warming and roughly half of Arctic warming and sea ice loss from 1955 to 2005.

22 January – China releases a large amount of data and high-resolution images from the lander and rover of the Chang'e 4 mission which has been studying the far side of the Moon since 3 January 2019. 23 January Researchers announce the first replication of a vocal tract and voice simulation of an Egyptian mummy (the priest Nesyamun). Marine biologists announce new findings that provide evidence that genus Hemiscyllium – also known as "walking sharks" as they can walk on land – was the newest genus of sharks in terms of historical findings on biological evolution.Marine Biologists Solve Mystery of How 'Walking' Sharks Split, 23 January 2020 by Natali Anderson, An international team of marine biologists has found that members of the genus Hemiscyllium are the 'youngest' — as in, the most recently evolved – sharks to ever walk (or swim) our planet. 24 January – For the first time, scientists discover mitochondria existing in human blood that are not part of larger cells.Scientists Find Cell-Free Mitochondria in Human Blood. 24 January 2020 by Enrico de Lazaro. Mitochondria are considered as the power-generating units of the cell due to their key role in energy metabolism and intercellular communication. However, cell-derived mitochondrial components could be found in the extracellular space, as fragments or encapsulated in vesicles. Now, a team of researchers has demonstrated that human blood contains whole functional mitochondria in normal physiological state.Unexpected new component discovered circulating in bloodstream, New Atlas 27 January A new species of dinosaur is discovered, Allosaurus jimmadseni, from genus Allosaurus.New Species of Carnivorous Dinosaur Unveiled: Allosaurus jimmadseni 27 January 2020 by Enrico de Lazaro. A new species of carnivorous theropod dinosaur has been identified from the fossilized remains discovered in the 1990s in northeastern Utah and Wyoming, the United States. Scientists demonstrate a "Trojan horse" designer-nanoparticle that makes blood cells eat away – from the inside out – portions of atherosclerotic plaque that cause heart attacks and are the current most common cause of death globally. 28 January – A new study finds that many of Earth's biodiverse ecosystems are in danger of collapse. The study mapped over 100 high-risk ecosystems and habitats in specific locations, and notes the highly detrimental patterns in each one that result from climate change and local human activities.New study says Earth's most biodiverse ecosystems facing collapse. A new study mapped more than 100 locations where extreme weather events have affected forests and coral reefs. By Joseph Guzman, thehill.com, Jan 28, 2020. Climate change, heatwaves and humans are 'sparking a collapse in reefs and forests', by Rob Waugh, 27 January 2020, Yahoo News. 31 January – Scientists and journalists report overviews of the novel coronavirus SARS-CoV-2 outbreak, later classified as a pandemic, including on the infectability, mortality rate, incubation time, worldwide ability to contain the outbreak, and estimated time for a vaccine (along with a comparison with other similar outbreaks).

February

3 February – Astronomers report in a preprint, later published in a journal in June, that, for the first time, repeating pulses from a source of fast radio bursts seem to have a regular periodicity, particularly FRB 180916, about 500 million light years from Earth, which have been found to have a -day pulse cycle. 4 February – The drugs remdesivir and chloroquine are shown to effectively inhibit SARS-CoV-2 in vitro. 5 February Scientists of the International Muon Ionization Cooling Experiment announce that they have found a way to squeeze the muons of a muon beam into a smaller volume. The muons are cooled into a denser cloud by being directed through specially designed energy-absorbing materials while the beam is tightly focused by powerful superconducting magnetic lenses and can then be accelerated by a normal particle accelerator in a precise direction. This technique may allow the construction of a muon collider. Cooling the muons beams is crucial to achieve a high collision rate. In a study researchers assess that Extant-Native Trophic (ENT), a trophic rewilding approach which restores lost species to ecosystems, can help mitigate climate change. This form of rewilding would restore large-bodied herbivore and carnivore guilds which could reduce methane emissions and according to the study could be an "important complementary strategy to natural climate solutions to ensure other nature-based benefits to biodiversity conservation and society are also delivered". Scientists develop a CRISPR-Cas12a-based gene editing system that can probe and control several genes at once and can implement logic gating to e.g. detect cancer cells and execute therapeutic immunomodulatory responses. Scientists report that 70 million years ago Earth rotated 372 times a year, with a day lasting a half an hour less than today after studying the growth rings of fossilized mollusk shells from the late Cretaceous. The slowdown is due to the tidal effects the Moon has on Earth's rotation. 6 February