Misplaced Pages

21st century

Article snapshot taken from Wikipedia with creative commons attribution-sharealike license. Give it a read and then ask your questions in the chat. We can research this topic together.

A century is a period of 100 years or 10 decades . Centuries are numbered ordinally in English and many other languages. The word century comes from the Latin centum , meaning one hundred . Century is sometimes abbreviated as c.

#34965

91-538: The 21st century is the current century in the Anno Domini or Common Era , in accordance with the Gregorian calendar . It began on 1 January 2001 and will end on 31 December 2100 . It is the first century of the 3rd millennium . The rise of a global economy and Third World consumerism marked the beginning of the century, along with increased private enterprise and deepening concern over terrorism after

182-521: A gravity assist from Jupiter . Its closest approach to Pluto was on 14 July 2015; scientific observations of Pluto began five months prior to closest approach and continued for 16 days after the encounter. The New Horizons mission also performed a flyby of the small planetesimal Arrokoth , in the Kuiper belt , in 2019. This was its first extended mission. Although many comets have been studied from Earth sometimes with centuries-worth of observations, only

273-602: A better appreciation of the Red Planet but also yield further insight into the past, and possible future, of Earth. The exploration of Mars has come at a considerable financial cost with roughly two-thirds of all spacecraft destined for Mars failing before completing their missions, with some failing before they even began. Such a high failure rate can be attributed to the complexity and large number of variables involved in an interplanetary journey, and has led researchers to jokingly speak of The Great Galactic Ghoul which subsists on

364-461: A close flyby of Saturn's moon Titan, resulting in a trajectory incompatible with a Pluto flyby. Voyager 2 never had a plausible trajectory for reaching Pluto. After an intense political battle, a mission to Pluto dubbed New Horizons was granted funding from the United States government in 2003. New Horizons was launched successfully on 19 January 2006. In early 2007 the craft made use of

455-574: A conspicuous anticyclone storm system rivaled in size only by Jupiter's Great Red Spot . Neptune also proved to have the fastest winds of any planet in the Solar System, measured as high as 2,100 km/h. Voyager 2 also examined Neptune's ring and moon system . It discovered 900 complete rings and additional partial ring "arcs" around Neptune. In addition to examining Neptune's three previously known moons, Voyager 2 also discovered five previously unknown moons, one of which, Proteus , proved to be

546-484: A diet of Mars probes. This phenomenon is also informally known as the " Mars Curse ". In contrast to overall high failure rates in the exploration of Mars, India has become the first country to achieve success of its maiden attempt. India's Mars Orbiter Mission (MOM) is one of the least expensive interplanetary missions ever undertaken with an approximate total cost of ₹ 450 Crore ( US$ 73 million ). The first mission to Mars by any Arab country has been taken up by

637-472: A few clouds in the images of the planet. The magnetosphere of Uranus, however, proved to be unique, being profoundly affected by the planet's unusual axial tilt. In contrast to the bland appearance of Uranus itself, striking images were obtained of the Moons of Uranus, including evidence that Miranda had been unusually geologically active. The exploration of Neptune began with the 25 August 1989 Voyager 2 flyby,

728-650: A few comets have been closely visited. In 1985, the International Cometary Explorer conducted the first comet fly-by ( 21P/Giacobini-Zinner ) before joining the Halley Armada studying the famous comet. The Deep Impact probe smashed into 9P/Tempel to learn more about its structure and composition and the Stardust mission returned samples of another comet's tail. The Philae lander successfully landed on Comet Churyumov–Gerasimenko in 2014 as part of

819-518: A large number of Earth observation satellites have been deployed specifically to explore Earth from a space-based perspective. These satellites have significantly contributed to the understanding of a variety of Earth-based phenomena. For instance, the hole in the ozone layer was found by an artificial satellite that was exploring Earth's atmosphere, and satellites have allowed for the discovery of archeological sites or geological formations that were difficult or impossible to otherwise identify. The Moon

910-538: A new biological era for the human species. Anxiety and depression rates have risen in the United States and many other parts of the world. However, suicide rates have fallen in Europe and most of the rest of the world so far this century, declining 29% globally between 2000 and 2018, despite rising 18% in the United States in the same period. The decline in suicide has been most notable among Chinese and Indian women,

1001-599: A planned crewed landing to occur with Artemis III . The rise of the private space industry also began in earnest in the 2010s with the development of private launch vehicles, space capsules and satellite manufacturing. In the 2000s, China initiated a successful crewed spaceflight program while India launched the Chandrayaan programme , while the European Union and Japan have also planned future crewed space missions. The two primary global programs gaining traction in

SECTION 10

#1732851355035

1092-542: A robotic spacecraft on the far side of the Moon , the first to do so. On 23 August 2023, with the Chandrayaan-3 Mission , India became the first country to touch down near the lunar south pole . War and violence have declined considerably compared to the 20th century, continuing the post-World War II trend called Long Peace . However, since the beginning of the 2020s, geopolitical tensions and wars have been rising across

1183-527: A serious concern; UN Chief António Guterres , for instance, has described it as an " existential threat " to humanity. Furthermore, the Holocene extinction event, the sixth most significant extinction event in the Earth's history, continues with the widespread degradation of highly biodiverse habitats as a by-product of human activity. Economically and politically, the United States and Western Europe were dominant at

1274-612: A sort of bubble of particles made in the Galaxy by the Sun's solar wind . The Sun is a major focus of space exploration. Being above the atmosphere in particular and Earth's magnetic field gives access to the solar wind and infrared and ultraviolet radiations that cannot reach Earth's surface. The Sun generates most space weather , which can affect power generation and transmission systems on Earth and interfere with, and even damage, satellites and space probes. Numerous spacecraft dedicated to observing

1365-417: Is believed to have orbited Earth at a height of about 250 km (160 mi). It had two radio transmitters (20 and 40 MHz), which emitted "beeps" that could be heard by radios around the globe. Analysis of the radio signals was used to gather information about the electron density of the ionosphere, while temperature and pressure data was encoded in the duration of radio beeps. The results indicated that

1456-554: The COVID-19 pandemic began to rapidly spread worldwide, causing more than 7 million reported deaths, and around 18.2 to 33.5 million estimated deaths, while at the same time, causing severe global economic disruption , including the largest global recession since the Great Depression in the 1930s. Due to the sudden proliferation of internet-accessible mobile devices , such as smartphones becoming ubiquitous worldwide beginning in

1547-577: The COVID-19 pandemic . 2000s 2010s 2020s Association football is the most popular sport worldwide with the FIFA World Cup being the most viewed football event. Other sports such as rugby, cricket, baseball, basketball, ice hockey, tennis, and golf are popular globally. In cricket , the emergence of the Twenty20 format and the creation of the Indian Premier League led to changes in

1638-467: The Cassini spacecraft, which lasted from 2004 until 2017. Saturn has at least 62 known moons , although the exact number is debatable since Saturn's rings are made up of vast numbers of independently orbiting objects of varying sizes. The largest of the moons is Titan , which holds the distinction of being the only moon in the Solar System with an atmosphere denser and thicker than that of Earth. Titan holds

1729-759: The Federal Republic of Yugoslavia . The Islamic Republic of Afghanistan replaced the Transitional Islamic State of Afghanistan The Federal Democratic Republic of Nepal replaced the Kingdom of Nepal . The National Transitional Council of Libya replaced the Great Socialist People's Libyan Arab Jamahiriya . The State of Libya replaced the National Transitional Council of Libya . The Islamic Emirate of Afghanistan replaced

1820-657: The International Space Station (ISS). With the substantial completion of the ISS following STS-133 in March 2011, plans for space exploration by the U.S. remained in flux. The Constellation program aiming for a return to the Moon by 2020 was judged unrealistic by an expert review panel reporting in 2009. Constellation ultimately was replaced with the Artemis Program , of which the first mission occurred in 2022 , with

1911-474: The Internet . Telecommunications in the early 21st century are much more advanced and universal than they were in the late 20th century. Only a few percent of the world's population were Internet users and cellular phone owners in the late 1990s; while as of 2023, 67% of the world's population is online, and 78% of all people aged 10 and above own a mobile phone. In the 2010s, artificial intelligence , mainly in

SECTION 20

#1732851355035

2002-566: The Islamic Republic of Afghanistan . These territories have declared independence and secured relative autonomy but they have only been recognized by some UN member states: These territories have declared independence and secured relative autonomy but they have been recognized by no one: These territories were annexed from a sovereign country, the action has only been recognized by some UN member states: These territories were ceded to another country: The Digital Revolution continued into

2093-743: The Russian Invasion of Ukraine and the Israel-Hamas war . The United States has remained the sole global superpower , while China is now considered to be an emerging superpower . In 2022, 45% of the world's population lived in "some form of democracy", although only 8% lived in "full democracies". The United Nations estimates that by 2050, two thirds of the world's population will be urbanized . The world economy expanded at high rates from $ 42 trillion in 2000 to $ 101 trillion in 2022, and though many economies rose at greater levels, some gradually contracted. The European Union greatly expanded in

2184-683: The September 11 attacks in 2001. The NATO intervention in Afghanistan and the United States -led coalition intervention in Iraq in the early 2000s, as well as the overthrow of several regimes during the Arab Spring in the early 2010s, led to mixed outcomes in the Arab world , resulting in several civil wars and political instability. The 2020s saw an increase in wars across the world, as seen with conflicts such as

2275-470: The asteroids , the new planets Uranus and Neptune , and many more satellites . The Orbiting Astronomical Observatory 2 was the first space telescope launched 1968, but the launching of Hubble Space Telescope in 1990 set a milestone. As of 1 December 2022, there were 5,284 confirmed exoplanets discovered. The Milky Way is estimated to contain 100–400 billion stars and more than 100 billion planets . There are at least 2 trillion galaxies in

2366-641: The dwarf planets Ceres and Pluto were orbited by Dawn and passed by New Horizons , respectively. This accounts for flybys of each of the eight planets in the Solar System , the Sun , the Moon , and Ceres and Pluto (two of the five recognized dwarf planets ). The first interplanetary surface mission to return at least limited surface data from another planet was the 1970 landing of Venera 7 , which returned data to Earth for 23 minutes from Venus . In 1975, Venera 9

2457-466: The far side of the Moon . India's Chandrayaan-3 in 2023 achieved the world's first landing on the lunar south pole region. Crewed exploration of the Moon began in 1968 with the Apollo 8 mission that successfully orbited the Moon, the first time any extraterrestrial object was orbited by humans. In 1969, the Apollo 11 mission marked the first time humans set foot upon another world. Crewed exploration of

2548-591: The observable universe . HD1 is the most distant known object from Earth, reported as 33.4 billion light-years away. MW 18014 was a German V-2 rocket test launch that took place on 20 June 1944, at the Peenemünde Army Research Center in Peenemünde . It was the first human-made object to reach outer space , attaining an apogee of 176 kilometers, which is well above the Kármán line . It

2639-817: The 2020s are the Chinese-led International Lunar Research Station and the US-led Artemis Program, with its plan to build the Lunar Gateway and the Artemis Base Camp , each having its own set of international partners. The first telescope is said to have been invented in 1608 in the Netherlands by an eyeglass maker named Hans Lippershey , but their first recorded use in astronomy was by Galileo Galilei in 1609. In 1668 Isaac Newton built his own reflecting telescope ,

2730-535: The 21st century, adding 13 member states , but the United Kingdom withdrew . Most EU member states introduced a common currency, the Euro . The North Atlantic Treaty Organization (NATO), also greatly expanded, adding 13 member states . Effects of global warming and rising sea levels exacerbated the ecological crises , with eight islands disappearing between 2007 and 2014. Globally, from January 2020 to May 2023,

2821-730: The 21st century. This is a list of sovereign states that have gained independence in the 21st century and have been recognized by the UN . These nations gained sovereignty through government reform. The Union of the Comoros replaced the Federal Islamic Republic of the Comoros The Transitional Islamic State of Afghanistan replaced the Islamic State of Afghanistan . The State Union of Serbia and Montenegro replaced

21st century - Misplaced Pages Continue

2912-548: The Moon began with the Ranger 4 impactor in 1962. Starting in 1966, the Soviets successfully deployed a number of landers to the Moon which were able to obtain data directly from the Moon's surface; just four months later, Surveyor 1 marked the debut of a successful series of U.S. landers. The Soviet uncrewed missions culminated in the Lunokhod program in the early 1970s, which included

3003-426: The Moon did not continue for long. The Apollo 17 mission in 1972 marked the sixth landing and the most recent human visit. Artemis II is scheduled to complete a crewed flyby of the Moon in 2025, and Artemis III will perform the first lunar landing since Apollo 17 with it scheduled for launch no earlier than 2026. Robotic missions are still pursued vigorously. The exploration of Mars has been an important part of

3094-407: The Moon, entering in a lunar orbit on 3 April 1966. The first crewed landing on another celestial body was performed by Apollo 11 on 20 July 1969, landing on the Moon. There have been a total of six spacecraft with humans landing on the Moon starting from 1969 to the last human landing in 1972. The first interplanetary flyby was the 1961 Venera 1 flyby of Venus , though the 1962 Mariner 2

3185-460: The Moon. Also, probes were sent throughout the known Solar System, and into Solar orbit. Uncrewed spacecraft have been sent into orbit around Saturn, Jupiter, Mars, Venus, and Mercury by the 21st century, and the most distance active spacecraft, Voyager 1 and 2 traveled beyond 100 times the Earth-Sun distance. The instruments were enough though that it is thought they have left the Sun's heliosphere,

3276-423: The Solar System are accomplished at a cost in energy, which is described by the net change in velocity of the spacecraft, or delta-v . Due to the relatively high delta-v to reach Mercury and its proximity to the Sun, it is difficult to explore and orbits around it are rather unstable. Venus was the first target of interplanetary flyby and lander missions and, despite one of the most hostile surface environments in

3367-539: The Solar System, has had more landers sent to it (nearly all from the Soviet Union) than any other planet in the Solar System. The first flyby was the 1961  Venera 1 , though the 1962  Mariner 2  was the first flyby to successfully return data. Mariner 2 has been followed by several other flybys by multiple space agencies often as part of missions using a Venus flyby to provide a gravitational assist en route to other celestial bodies. In 1967, Venera 4 became

3458-690: The Sun, beginning with the Apollo Telescope Mount , have been launched and still others have had solar observation as a secondary objective. Parker Solar Probe , launched in 2018, will approach the Sun to within 1/9th the orbit of Mercury. Mercury remains the least explored of the Terrestrial planets . As of May 2013, the Mariner 10 and MESSENGER missions have been the only missions that have made close observations of Mercury. MESSENGER entered orbit around Mercury in March 2011, to further investigate

3549-528: The United Arab Emirates. Called the Emirates Mars Mission , it was launched on 19 July 2020 and went into orbit around Mars on 9 February 2021. The uncrewed exploratory probe was named "Hope Probe" and was sent to Mars to study its atmosphere in detail. The Russian space mission Fobos-Grunt , which launched on 9 November 2011, experienced a failure leaving it stranded in low Earth orbit . It

3640-543: The asteroid 4 Vesta , two of the three largest asteroids, were visited by NASA's Dawn spacecraft , launched in 2007. Hayabusa was a robotic spacecraft developed by the Japan Aerospace Exploration Agency to return a sample of material from the small near-Earth asteroid 25143 Itokawa to Earth for further analysis. Hayabusa was launched on 9 May 2003 and rendezvoused with Itokawa in mid-September 2005. After arriving at Itokawa, Hayabusa studied

3731-428: The asteroid's shape, spin, topography, color, composition, density, and history. In November 2005, it landed on the asteroid twice to collect samples. The spacecraft returned to Earth on 13 June 2010. The exploration of Jupiter has consisted solely of a number of automated NASA spacecraft visiting the planet since 1973. A large majority of the missions have been "flybys", in which detailed observations are taken without

21st century - Misplaced Pages Continue

3822-794: The astronomical year 0 corresponding to the year 1 BC, the astronomical year -1 corresponding to 2 BC, and so on. Informally, years may be referred to in groups based on the hundreds part of the year. In this system, the years 1900–1999 are referred to as the nineteen hundreds ( 1900s ). Aside from English usage, this system is used in Swedish , Danish , Norwegian , Icelandic , Finnish and Hungarian . The Swedish nittonhundratalet (or 1900-talet ), Danish nittenhundredetallet (or nittenhundredetallet ), Norwegian nittenhundretallet (or 1900-tallet ), Finnish tuhatyhdeksänsataaluku (or 1900-luku ) and Hungarian ezerkilencszázas évek (or 1900-as évek ) refer unambiguously to

3913-431: The beginning of the century; by the 2010s , China became an emerging global superpower and, by some measures, the world's largest economy . In terms of purchasing power parity , India's economy became more significant than Japan 's around 2011. Bitcoin and other cryptocurrencies are decentralized currencies that are not controlled by any central bank. These currencies are increasing in popularity worldwide due to

4004-684: The distinction of being the only object in the Outer Solar System that has been explored with a lander, the Huygens probe deployed by the Cassini spacecraft. The exploration of Uranus has been entirely through the Voyager 2 spacecraft, with no other visits currently planned. Given its axial tilt of 97.77°, with its polar regions exposed to sunlight or darkness for long periods, scientists were not sure what to expect at Uranus. The closest approach to Uranus occurred on 24 January 1986. Voyager 2 studied

4095-644: The early 2010s, more than two thirds of the world's population obtained access to the Internet by 2023. After the success of the Human Genome Project , DNA sequencing services became available and affordable. There were significant improvements in the complexity of artificial intelligence , with American companies, universities, and research labs pioneering advances in the field. Generative AI -based applications such as ChatGPT and DALL-E have accumulated billions of users, and allow users to instantly generate complex texts, images, art, and video, comparable to

4186-741: The early 21st century with mobile phone usage and Global Internet usage growing massively, becoming available to many more people, with more applications and faster speeds. Social networking emerged in the mid-2000s as a popular form of social communication, partly replacing much of the function of email , message boards and instant messaging services. Twitter , Facebook , YouTube , Instagram , Snapchat and WeChat are all major examples of social media which have gained widespread popularity. The use of webcams and front-facing cameras on PCs and related devices, and services such as Skype , Zoom and FaceTime , have made video calling and video conferencing widespread. Their use hugely increased during

4277-482: The early years of previous centuries were commonly pronounced as, for example, "eighteen oh five" (for 1805) and "nineteen oh five" (for 1905). Generally, the early years of the 21st century were pronounced as in "two-thousand (and) five," with a change taking place around 2010, when pronunciations often shifted between the early-years form of "two-thousand and ten" and the traditionally more concise form of "twenty-ten." The Vancouver Olympics , which took place in 2010,

4368-525: The elderly, and middle-aged Russian men. The entire written works of humanity, from the beginning of recorded history to 2003, in all known languages , are estimated to amount to five exabytes of data. Since 2003, with the beginning of social media and " user-generated content ", the same amount of data is created every two days. With the AI boom of the 2020s gaining international prominence, as of 2024, mass-produced AI-generated content comprised over half of

4459-533: The energy required at launch to reach Jupiter, albeit at the cost of a significantly longer flight duration. Jupiter has 95 known moons , many of which have relatively little known information about them. Saturn has been explored only through uncrewed spacecraft launched by NASA, including one mission ( Cassini–Huygens ) planned and executed in cooperation with other space agencies. These missions consist of flybys in 1979 by Pioneer 11 , in 1980 by Voyager 1 , in 1982 by Voyager 2 and an orbital mission by

4550-444: The expanding availability of the internet and are mainly used as a store of value . There is an ongoing impact of technological unemployment due to automation and computerization : the rate at which jobs are disappearing—due to machines replacing them—is expected to escalate. Automation alters the number of jobs and the skills demands of industries. As of 2019, the production output of first world nations ' manufacturing sectors

4641-407: The exploration of space is currently carried out mainly by astronomers with telescopes , its physical exploration is conducted both by uncrewed robotic space probes and human spaceflight . Space exploration, like its classical form astronomy , is one of the main sources for space science . While the observation of objects in space, known as astronomy , predates reliable recorded history , it

SECTION 50

#1732851355035

4732-504: The first human spaceflight ( Yuri Gagarin aboard Vostok 1 ) in 1961, the first spacewalk (by Alexei Leonov ) on 18 March 1965, the first automatic landing on another celestial body in 1966, and the launch of the first space station ( Salyut 1 ) in 1971. After the first 20 years of exploration, focus shifted from one-off flights to renewable hardware, such as the Space Shuttle program , and from competition to cooperation as with

4823-403: The first fully functional telescope of this kind, and a landmark for future developments due to its superior features over the previous Galilean telescope . A string of discoveries in the Solar System (and beyond) followed, then and in the next centuries : the mountains of the Moon , the phases of Venus , the main satellites of Jupiter and Saturn , the rings of Saturn , many comets ,

4914-458: The first of which was Galileo , which flew past two: 951 Gaspra in 1991, followed by 243 Ida in 1993. Both of these lay near enough to Galileo' s planned trajectory to Jupiter that they could be visited at acceptable cost. The first landing on an asteroid was performed by the NEAR Shoemaker probe in 2000, following an orbital survey of the object, 433 Eros . The dwarf planet Ceres and

5005-506: The first probe to enter and directly examine the atmosphere of Venus. In 1970, Venera 7 became the first successful lander to reach the surface of Venus and by 1985 it had been followed by eight additional successful Soviet Venus landers which provided images and other direct surface data. Starting in 1975, with the Soviet orbiter Venera 9 , some ten successful orbiter missions have been sent to Venus, including later missions which were able to map

5096-412: The first uncrewed rovers and also successfully brought lunar soil samples to Earth for study. This marked the first (and to date the only) automated return of extraterrestrial soil samples to Earth. Uncrewed exploration of the Moon continues with various nations periodically deploying lunar orbiters. China's Chang'e 4 in 2019 and Chang'e 6 in 2024 achieved the world's first landing and sample return on

5187-617: The form of deep learning and machine learning , became more prevalent and in the early 2020s, with the rise of generative AI , the AI boom began. As of 2022, 8.6% of the world's population still lacked access to electricity. In 2001, Dennis Tito became the first space tourist , beginning the era of commercial spaceflight . Entrepreneurs Elon Musk and Richard Branson are working towards commercial space exploration, colonization and tourism, while China and India have made substantial strides in their space programs. On 3 January 2019, China landed

5278-464: The general consensus is that there are between 6,000 and 7,000 languages currently spoken. Between 50% and 90% of those will have become extinct by the year 2100. The top 20 languages spoken by more than 50 million speakers each, are spoken by 50% of the world's population. In contrast, many of the other languages are spoken by small communities, most of them with fewer than 10,000 speakers. Some territories and states have gained independence during

5369-459: The last largest moon in the system. Data from Voyager 2 supported the view that Neptune's largest moon, Triton , is a captured Kuiper belt object. The dwarf planet Pluto presents significant challenges for spacecraft because of its great distance from Earth (requiring high velocity for reasonable trip times) and small mass (making capture into orbit difficult at present). Voyager 1 could have visited Pluto, but controllers opted instead for

5460-523: The longest ever Soviet planetary surface mission. Venus and Mars are the two planets outside of Earth on which humans have conducted surface missions with uncrewed robotic spacecraft . Salyut 1 was the first space station of any kind, launched into low Earth orbit by the Soviet Union on 19 April 1971. The International Space Station (ISS) is currently the largest and oldest of the 2 current fully functional space stations, inhabited continuously since

5551-466: The lunar surface, and 400,171 km (248,655 mi) from Earth, marking the record for the farthest humans have ever traveled from Earth in 1970. As of 26 November 2022 Voyager 1 was at a distance of 159 AU (23.8 billion km; 14.8 billion mi) from Earth. It is the most distant human-made object from Earth. Starting in the mid-20th century probes and then human missions were sent into Earth orbit, and then on to

SECTION 60

#1732851355035

5642-404: The nature of standard centuries. One is based on strict construction, while the other is based on popular perception. According to the strict construction, the 1st century AD , which began with AD 1 , ended with AD 100 , and the 2nd century with AD 200 ; in this model, the n -th century starts with a year that follows a year with a multiple of 100 (except the first century as it began after

5733-410: The nature of the sport. American swimmer Michael Phelps won an Olympic record setting 8 Gold medals at the 2008 Summer Olympics . Century A centennial or centenary is a hundredth anniversary, or a celebration of this, typically the remembrance of an event which took place a hundred years earlier. Although a century can mean any arbitrary period of 100 years , there are two viewpoints on

5824-494: The observations made by Mariner 10 in 1975 (Munsell, 2006b). A third mission to Mercury, scheduled to arrive in 2025, BepiColombo is to include two probes . BepiColombo is a joint mission between Japan and the European Space Agency . MESSENGER and BepiColombo are intended to gather complementary data to help scientists understand many of the mysteries discovered by Mariner 10's flybys . Flights to other planets within

5915-426: The planet's unique atmosphere and magnetosphere . Voyager 2 also examined its ring system and the moons of Uranus including all five of the previously known moons, while discovering an additional ten previously unknown moons. Images of Uranus proved to have a uniform appearance, with no evidence of the dramatic storms or atmospheric banding evident on Jupiter and Saturn. Great effort was required to even identify

6006-493: The possible adverse effects of social media in influencing citizen's views, particularly regarding the 2016 United States presidential election . The world population was about 6.1 billion at the start of the 21st century and reached 8 billion by November 2022. It is estimated to reach nearly 8.6 billion by 2030, and 9.8 billion by 2050. According to the United Nations World Urbanization prospects, 60% of

6097-586: The probe landing or entering orbit; such as in Pioneer and Voyager programs. The Galileo and Juno spacecraft are the only spacecraft to have entered the planet's orbit. As Jupiter is believed to have only a relatively small rocky core and no real solid surface, a landing mission is precluded. Reaching Jupiter from Earth requires a delta-v of 9.2 km/s, which is comparable to the 9.7 km/s delta-v needed to reach low Earth orbit. Fortunately, gravity assists through planetary flybys can be used to reduce

6188-536: The reason NASA was created was as a response to Sputnik I. The launch of the first human-made object to orbit Earth , the Soviet Union's Sputnik 1 , on 4 October 1957, and the first Moon landing by the American Apollo 11 mission on 20 July 1969 are often taken as landmarks for this initial period. The Soviet space program achieved many of the first milestones, including the first living being in orbit in 1957,

6279-447: The retirement age has been called for in view of an increase in life expectancy and has been put in place in many jurisdictions. As of 2009, Ethnologue catalogued 6,909 living human languages. The exact number of known living languages will vary from 5,000 to 10,000, generally depending on the precision of one's definition of "language", and in particular, on how one classifies dialects . Estimates vary depending on many factors, but

6370-414: The satellite was not punctured by a meteoroid . Sputnik 1 was launched by an R-7 rocket. It burned up upon re-entry on 3 January 1958. The first successful human spaceflight was Vostok 1 ("East 1"), carrying the 27-year-old Russian cosmonaut , Yuri Gagarin , on 12 April 1961. The spacecraft completed one orbit around the globe, lasting about 1 hour and 48 minutes. Gagarin's flight resonated around

6461-428: The sole visit to the system as of 2024. The possibility of a Neptune Orbiter has been discussed, but no other missions have been given serious thought. Although the extremely uniform appearance of Uranus during Voyager 2 ' s visit in 1986 had led to expectations that Neptune would also have few visible atmospheric phenomena, the spacecraft found that Neptune had obvious banding, visible clouds, auroras , and even

6552-527: The sophistication of human work. Research into outer space greatly accelerated in the 2020s, with the United States mainly dominating space exploration , including the James Webb Space Telescope , Ingenuity helicopter , Lunar Gateway , and Artemis program . There is a lack of general agreement over how to pronounce specific years of the 21st century in English. Academics have pointed out that

6643-436: The space exploration programs of the Soviet Union (later Russia), the United States, Europe, Japan and India. Dozens of robotic spacecraft , including orbiters , landers , and rovers , have been launched toward Mars since the 1960s. These missions were aimed at gathering data about current conditions and answering questions about the history of Mars. The questions raised by the scientific community are expected to not only give

6734-715: The surface of Venus using radar to pierce the obscuring atmosphere. Space exploration has been used as a tool to understand Earth as a celestial object. Orbital missions can provide data for Earth that can be difficult or impossible to obtain from a purely ground-based point of reference. For example, the existence of the Van Allen radiation belts was unknown until their discovery by the United States' first artificial satellite, Explorer 1 . These belts contain radiation trapped by Earth's magnetic fields, which currently renders construction of habitable space stations above 1000 km impractical. Following this early unexpected discovery,

6825-477: The world's human population are projected to live in megacities and megalopolises by 2030, 70% by 2050, and 90% by 2080. Life expectancy has increased as child mortality continues to decline. A baby born in 2019, for example, will, on average (globally), live to 73 years—27 years longer than the global average of someone born in 1950. Ten million Britons (16% of the United Kingdom population) will, on average, live to 100 or older. Climate change remains

6916-449: The world, as seen with the deterioration of US-China relations , Russian Invasion of Ukraine , Tigray War , Sudanese civil war , Israel–Hamas War , etc. Poverty is still widespread globally, but fewer people live in the most extreme forms of poverty. In 1990, 37.9% of the world's population lived in extreme poverty ; by 2022, this had dropped to just 9%. The Facebook–Cambridge Analytica data scandal drew international attention to

7007-423: The world; it was a demonstration of the advanced Soviet space program and it opened an entirely new era in space exploration: human spaceflight . The first artificial object to reach another celestial body was Luna 2 reaching the Moon in 1959. The first soft landing on another celestial body was performed by Luna 9 landing on the Moon on 3 February 1966. Luna 10 became the first artificial satellite of

7098-430: The year 1 BC ) and ends with the next coming year with a multiple of 100 ( 100n ), i.e. the 20th century comprises the years 1901 to 2000 , and the 21st century comprises the years 2001 to 2100 in strict usage. In popular perception and practice, centuries are structured by grouping years based on sharing the 'hundreds' digit(s). In this model, the n -th century starts with the year that ends in "00" and ends with

7189-433: The year 2000. The other, Tiangong space station built by China, is now fully crewed and operational. Voyager 1 became the first human-made object to leave the Solar System into interstellar space on 25 August 2012. The probe passed the heliopause at 121 AU to enter interstellar space . The Apollo 13 flight passed the far side of the Moon at an altitude of 254 kilometers (158 miles; 137 nautical miles) above

7280-408: The year ending in "99"; for example, in popular culture , the years 1900 to 1999 constitute the 20th century, and the years 2000 to 2099 constitute the 21st century. (This is similar to the grouping of "0-to-9 decades" which share the 'tens' digit.) To facilitate calendrical calculations by computer, the astronomical year numbering and ISO 8601 systems both contain a year zero , with

7371-546: The years 1501–1600 or 1500–1599. While the century has been commonly used in the West, other cultures and calendars have utilized differently sized groups of years in a similar manner. The Hindu calendar , in particular, summarizes its years into groups of 60, while the Aztec calendar considers groups of 52. Space exploration Space exploration is the use of astronomy and space technology to explore outer space . While

7462-468: The years 1900–1999. In Swedish, however, a century is in more rare cases referred to as det n-te seklet/århundradet ("the n-th century") rather than n-hundratalet , i.e. the 17th century is (in rare cases) referred to as 17:(d)e/sjuttonde århundradet/seklet rather than 1600-talet and mainly also referring to the years 1601–1700 rather than 1600–1699; according to Svenska Akademiens ordbok , 16:(d)e/sextonde århundradet may refer to either

7553-628: Was a vertical test launch. Although the rocket reached space, it did not reach orbital velocity , and therefore returned to Earth in an impact, becoming the first sub-orbital spaceflight . In 1949, the Bumper-WAC reached an altitude of 393 kilometres (244 mi), becoming the first human-made object to enter space, according to NASA . The first successful orbital launch was of the Soviet uncrewed Sputnik 1 ("Satellite 1") mission on 4 October 1957. The satellite weighed about 83 kg (183 lb), and

7644-745: Was being officially referred to by Vancouver 2010 as "the twenty-ten Olympics". Technologies such as ultrasound , prenatal genetic testing and genetic engineering have advanced significantly. Because of sex-selective abortion , fewer girls have been born in the 21st century (and since the early 1980s) compared to past centuries, mostly because of son preference in East and South Asia. In 2014, only 47 percent of Indian births were of girls. This has led to an increase in bachelors in countries such as China and India. The first genetically modified children were born November 2018 in China to significant controversy, beginning

7735-449: Was doubled when compared to 1984 output; but it is now produced with one-third fewer workers and at significantly reduced operating costs . Half of all jobs with requirements lower than a bachelor's degree are currently in the process of being replaced with partial- or full-automation. The World Economic Forum forecast that 65% of children entering primary school will end up in jobs or careers that currently do not yet exist. A rise in

7826-462: Was driven by a " Space Race " between the Soviet Union and the United States . A driving force of the start of space exploration was during the Cold War. After the ability to create nuclear weapons, the narrative of defense/offense left land and the power to control the air the focus. Both the Soviet Union and the U.S. were racing to prove their superiority in technology through exploring space. In fact,

7917-434: Was the development of large and relatively efficient rockets during the mid-twentieth century that allowed physical space exploration to become a reality. Common rationales for exploring space include advancing scientific research, national prestige, uniting different nations, ensuring the future survival of humanity, and developing military and strategic advantages against other countries. The early era of space exploration

8008-399: Was the first celestial body to be the object of space exploration. It holds the distinctions of being the first remote celestial object to be flown by, orbited, and landed upon by spacecraft, and the only remote celestial object ever to be visited by humans. In 1959, the Soviets obtained the first images of the far side of the Moon , never previously visible to humans. The U.S. exploration of

8099-435: Was the first flyby of Venus to return data (closest approach 34,773 kilometers). Pioneer 6 was the first satellite to orbit the Sun , launched on 16 December 1965. The other planets were first flown by in 1965 for Mars by Mariner 4 , 1973 for Jupiter by Pioneer 10 , 1974 for Mercury by Mariner 10 , 1979 for Saturn by Pioneer 11 , 1986 for Uranus by Voyager 2 , 1989 for Neptune by Voyager 2 . In 2015,

8190-477: Was the first to return images from the surface of another planet, returning images from Venus. In 1971, the Mars 3 mission achieved the first soft landing on Mars returning data for almost 20 seconds. Later, much longer duration surface missions were achieved, including over six years of Mars surface operation by Viking 1 from 1975 to 1982 and over two hours of transmission from the surface of Venus by Venera 13 in 1982,

8281-480: Was to begin exploration of the Phobos and Martian circumterrestrial orbit, and study whether the moons of Mars, or at least Phobos, could be a "trans-shipment point" for spaceships traveling to Mars. Until the advent of space travel , objects in the asteroid belt were merely pinpricks of light in even the largest telescopes, their shapes and terrain remaining a mystery. Several asteroids have now been visited by probes,

#34965