It is well known that today's world is dominated by science and technology. Since the birth of laser, optics and photonics have penetrated into all aspects of people's life. This article reviews the 2020 major progress in the field of optics and photonics and draws up an inventory of ten optical research directions, in which the related research may likely have enormous impact on human existence and way of life in the future.

This paper reviews the hot astronomical events in 2020 from two aspects: Aastronomical equipment and scientific research. In 2020 Mars was at the favourable opposition, traveling to Mars came to a new climax. Many countries succeeded in sampling soil in space. The FAST took the relay baton from the Arecibo telescope, contributing to uncovering the mechanism of rapid radio bursts. LIGO/Virgo collaboration grew and grew. Neowise flitted across the northern sky. The life signals found in the atmosphere of Venus caused widespread controversy. One possible driven mechanism of the fast radio burst was observed. eROSITA and Gaia drew precise pictures of the Milky Way.

This paper summarizes the research hotspots of near space science and technology in 2020. China, Japan and FranceUS joint team made some progress in near space experimental exploration and scientific understanding. Near space low dynamic aircraft and its application technology also made remarkable achievements. Softbank's "sunglider" and South Korea's eav-3 injected new vitality into the development of solar powered UAVs. Google's project Loon created a new record of controllable staying area, flight duration and commercial application customers. The HAPS alliance established by more than 10 tycoons in the aviation and telecommunication fields helped to promote the healthy development of near space long endurance platform. In terms of near space high dynamic aircraft and its application technology, the commercial travel of suborbital vehicle was delayed again, and Russia basically formed hypersonic strike capability with land, sea and air-based diversified launches and long, medium and short-range multiple models.

The global deep space exploration endeavor was pushed forward steadily in 2020. In this article we review the outstanding engineering success and scientific output in the year, analyze the results of Chang'E 5 sampling return mission and Chang'E 3/4 missions in the Chinese Lunar Exploration Program, compare the main scientific goals and payloads of the three Mars missions by US, China and United Arab Emirates, and summarize the scientific findings about the sun and solar system given by the 35 deep space missions operating in orbit. We also review the scenario of future deep space exploration especially affected by the COVID-19 pandemic. We conclude the article with the prospect of future launches in 2021.

In 2020, atmospheric science underwent deep cross integrations with environmental protection and medical sciences. A series of research results were achieved. This paper introduces the research focuses such as climate change, COVID-19 pandemic, air pollution, large-scale wildfires and climate prediction, and reviews their interdisciplinary results.

In 2020, a series of new progress were made in the field of seismic hazard analysis and research and new results were achieved in many research directions. This paper selects five research directions as representatives: global seismic hazard research, marine seismic hazard assessment, deterministic-probabilistic seismic hazard assessment methods, hazard assessment of induced earthquake, and new technologies for seismic hazard assessment in the next-generation zoning map, so as to review the hot researches seismic hazard assessment in 2020.

Earth data science is combination of earth science and data science, and is a frontier cross field of earth science research and a paradigm shift of data-driven scientific discovery. This paper reviews the progress of big earth data research in 2020 from the aspects of earth data science program, scientific data governance, and earth science data sharing. It focuses on the Deep-Time Digital Earth Science Program, Big Earth Data Science Engineering Project and achievements in global data aggregation, authentication, repository, policies, standards, and identification, as well as practices of the earth science data centers, databases, data models, data integration, and data publishing. The paper also points out that it is still an urgent need to pay full attention to the rules of scientific data governance, promote the development of earth science big data programme, strengthen the establishment of earth science data ecology, and improve all aspects of cooperation in the field of earth science data.

Marine meterology is important to global climate and meteorological disaster. We summarize the development in weather processes and mechanisms which influenced the climate of East Asia in 2020, including the Meiyu front, monsoon, tropical cyclone, air-sea fluxes, and storm surge. We also discuss the future hotspots in marine meterology.

Ocean is the most realistic space to solve conflicts among population, resources and environment. The development and utilization of marine resources and space are inseparable from various types of deep-sea equipment. In 2020 significant progress was made in the research and development of deep-sea equipment at home and abroad. Focusing on the research and development of manned/unmanned underwater vehicles, this paper introduces the international and domestic research hotspots and highlights in 2020, analyzes the international status of China's marine technology, and provides some suggestions on future development directions of China's deep-sea submersible field.

This article briefly summarizes the hotspots and advances of cell mechanics research in 2020. The effects of cell membrane surface tension, cell adhesion, cell elastic modulus, and relative stiffness of cell to nanoparticles on biological behaviors of cells and its potential applications are discussed.

Since SARS-CoV-2 was discovered in December 2019, the coronavirus has caused a serious pandernic of severe respiratory infectious disease, which subsequently spread globally. The scientific community reacted immediately to perform comprehensive and exhaustive studies on SARS-CoV-2 and the diseases it caused. Benefited from the knowledge accumulated in previous studies of SARS-CoV and MERS-CoV, the research work of SARS-CoV-2 got extensive achievements in 2020, especially in molecular pathology. Mastering the knowledge has built a solid foundation for the drug and vaccine development against SARS-CoV-2. In this review, the research history of coronaviruses is briefly reviewed, followed by a summary of molecular pathological studies on SARS-CoV-2 in 2020, as well as the progress of drug and vaccine development against SARS-CoV-2.

As a new subject emerging with the green revolution, agroecology focuses on the total relationships between agricultural organisms and both their organic and inorganic environments, which is playing a key role in global sustainable development. From molecular to landscape scale, this paper reviews the achievements in non-point source pollution, highefficient use of agricultural resource, establishment of agro-ecosystem, agricultural landscape and its ecosystem service, and impact of global climate change on agriculture. A game-changing innovation of sustainable food production system and food chain management for human health are becoming the research hotspots in the future agroecology.

In 2020 the development of eco-materials led to significant progresses in environmental governance, clean energy and clean production. In this paper, some selected hot topics about recent breakthroughs of eco-materials are reviewed, including plastic degradation, catalytic purification of mobile/industrial exhaust gas, CO₂ conversion, solar cell, lithium battery, energy conservation, and additive manufacturing. In the end, the developing tendency of eco-materials is indicated.

In 2020 because of the impact of the COVID-19 pandemic, the study of biologcal metamaterials was a focused topic in the field of metamaterials. By reviewing the application of metamaterials in the biological field and the latest research progress, the future development of biological metamaterials and their related applications are analyzed in this paper.

As a new concept originated in early 21st century, metamaterials have since attracted extensive attention of both scientific research and industry. Different from traditional materials, the properties of the metamaterials are created by artificial structures instead of intrinsic compositions of the materials, thus they exhibit many extrondinary properties beyond nature. Optical materials is one of the most important parts in this field, playing a significant role in information technology. In 2020, there were a lot of excellent research works in the optical metamaterials field. Here, we give a comprehensive review based on the works in nonlinear optical metamaterials, artificial intelligence metamaterials, and optical metasurface.

In 2020, terahertz science and technology made a series of breakthroughs in the fields of radiation source, detector, 5G/6G communication, medical, agriculture, security inspection, military, etc. These achievements are playing a positive role in promoting engineering application and industrialization of terahertz. In this paper, key hotspots of terahertz science and technology, including 6G communication, terahertz medical erahertz military application, are summarized and their development trends are prospected.

3D printing is an additive manufacturing technology that rapidly turns computer-aided designs into complex 3D objects on demand. As an attractive research field and emerging industrial technology, 3D printing research made great progress in mechanism, method and functionalization in 2020. This article reviews the research hotspots and representative results of 3D printing from the aspects of printing method improvement, new ink development, solidification nucleation mechanism, new structure preparation, as well as new applications.

Extended reality (XR) technology showed some new development trends in 2000. This article summarizes the research hotspots and development trends of XR in the past year from four aspects: terminal side, software side, content side and application side. Corresponding suggestions and countermeasures are put forward through analyzing the main problems in the development process of China's XR industry, which would provide reference for relevant personnel.

The year 2020 witnessed new opportunities and challenges for the development and application of unmanned aerial vehicles (UAVs). More profound thoughts were invoked on the developments of UAV industry with some new features. This paper tries to summarize and analyze some hot topics and new developments of UAV in 2020 from the aspects of new regulations, key technologies, practical applications and so on. Under the promotion of innovation and relevant policies, the UAV industry will reach a new point and have new vitality. Swarm autonomy, intelligent action and actual combat are still the important directions of UAV developments in the future.

In 2020, a series of valuable research results were achieved in clean energy technology. Electrochemical conversion of small molecules, such as CO₂, accelerated the realization of ‘carbon neutrality’. The conversion efficiency of solar cells exceeded 29.15% in 2020. The alkaline membrane fuel cells' power density exceeded 2.58 W cm^-2, making the low-cost fuel cell closer to commercialization. Biomass energies are also prospected in this article.

As China is advancing the cause of garbage classification, many problems have emerged in the process of kitchen waste classification, collection, treatment and disposal. This article introduces the current implementation of China's garbage classification policy as well as the generation and treatment of kitchen waste. Several research advances made in 2020 on kitchen waste treatment technologies are reviewed, such as anaerobic digestion, composting, bio-drying, scavenger breeding and physical pretreatment. At the same time, the article also compiles the research hotspots and engineering cases related to food waste treatment to attempt to provide guidance for further technology development and application in waste treatment.