The end time, end times, or end of days is a time period described in the eschatological writings in the three Abrahamic religions (Judaism, Christianity, and Islam) and in doomsday scenarios in Hinduism, Buddhism and various other non-Abrahamic religions.

In Christianity, the End Times are often depicted as a time of tribulation that precedes the Second Coming of the Christian "savior" or a "hoped-for deliverer", Jesus, the Christian Messiah, who will usher in the fullness of the Kingdom of God and bring an end to suffering and evil and all things wrong with the current world which is tainted by Original Sin.

In Islam, Yawm al-Qiyāmah "the Day of Resurrection" or Yawm ad-Din "the Day of Judgement", Allah's final assessment of humanity, is preceded by the end of the world.

In Judaism the term "End of Days" is a reference to the Messianic era and the Jewish belief in the coming of Mashiach and the Olam Haba, that will usher in peace and unity for all mankind, in the service of one God.

Various other religions also have eschatological beliefs associated with turning and redemption.

Since the advent of modern science in the 18th century, the discovery of deep time, and the age of the Earth, the concept of an "End of Days" has been replaced in contemporary discourse with questions about the ultimate fate of the universe. Most scientists believe that the "end time" will finally occur hundreds of billions of years from now with the heat death of the universe.

Islam[link]

There are various signs (as many as up to 100) given in the Sunnah and Quran for the coming of Judgment Day. These signs can be divided into two parts, minor and major. The major signs include

1. And you will see people entering religion of God in crowds. (Qur'an Surat an-Nasr, 1-2)
2. the coming of the one-eyed Dajjal (Evil Antichrist), Imam Mahdi and then Prophet Jesus (who will combine forces of good, against evil), (Qur'an 43:61)
3. the blowing of Trumpet and the minor signs will precede them.
4. the Earth will experience an earthquake that will cause mountains to crash down. The Earth's inner body will break out, and the Earth will be stretched out.99:1, 69:13-14, 70:8, 84:3-4, 20:105-107, 99:1-6.
5. Earthquakes from the East, the West, and one in the Arabian Peninsula
6. Gog (yahjuj) & Magog (mahjuj) will be released and will destroy the crops, animals, water and kill everything.
7. Smoke will spread and cause non-believers to fall ill whereas the believers will catch a mere cold. Later, Allah will send a cool wind, taking life (gently) from all of the believers, leaving only the Kufaars (unbelievers) to see the last day till the Day Of Judgment will arrive.

Islamic eschatology is concerned with the Qiyamah (end of the world; Last Judgment) and the final judgment of humanity. Eschatology relates to one of the six articles of faith (aqidah) of Islam. Like the other Abrahamic religions, Islam teaches the bodily resurrection of the dead, the fulfillment of a divine plan for creation, and the immortality of the human soul; the righteous are rewarded with the pleasures of Jannah (Heaven), while the unrighteous are punished in Jahannam (Hell). A significant fraction of the Quran deals with these beliefs, with many hadith elaborating on the themes and details. Islamic apocalyptic literature describing the Armageddon is often known as fitna (a test) and malahim (or ghayba in the shi'ite tradition).

Christianity[link]

Some Christians in the first century believed that Jesus would return during their lifetime, because Jesus had said to his followers to be alert or be ready at all times. From this belief came the first evidence of the doctrine of imminence.^{[citation needed]} When the converts of Paul in Thessalonica were persecuted by the Roman Empire, they believed the end was upon them.^[1]

Tribulation in the New Testament:

The prophetic theme of the New Testament also mirrors the Old Testament, namely, Tribulation. In the New Testament, Jesus refers to this as the "Great Tribulation", "Affliction", and "days of vengeance."

Matthew 24:15-22 (King James Version): "When ye therefore shall see the abomination of desolation, spoken of by Daniel the prophet, stand in the holy place, (whoso readeth, let him understand). Then let them which be in Judaea flee into the mountains. Let him which is on the housetop not come down to take any thing out of his house. Neither let him which is in the field return back to take his clothes. And woe unto them that are with child, and to them that give suck in those days! But pray ye that your flight be not in the winter, neither on the sabbath day. For then shall be great tribulation, such as was not since the beginning of the world to this time, no, nor ever shall be. And except those days should be shortened, there should no flesh be saved: but for the elect's sake those days shall be shortened.

Mark 13:14-20 (King James Version): "But when ye shall see the abomination of desolation, spoken of by Daniel the prophet, standing where it ought not, (let him that readeth understand,) then let them that be in Judaea flee to the mountains: And let him that is on the housetop not go down into the house, neither enter therein, to take any thing out of his house: And let him that is in the field not turn back again for to take up his garment. But woe to them that are with child, and to them that give suck in those days! And pray ye that your flight be not in the winter. For in those days shall be affliction, such as was not from the beginning of the creation which God created unto this time, neither shall be. And except that the Lord had shortened those days, no flesh should be saved: but for the elect's sake, whom he hath chosen, he hath shortened the days.

Luke 21:20-33 (King James Version): "And when ye shall see Jerusalem compassed with armies, then know that the desolation thereof is nigh. Then let them which are in Judaea flee to the mountains; and let them which are in the midst of it depart out; and let not them that are in the countries enter thereinto. For these be the days of vengeance, that all things which are written may be fulfilled. But woe unto them that are with child, and to them that give suck, in those days! for there shall be great distress in the land, and wrath upon this people. And they shall fall by the edge of the sword, and shall be led away captive into all nations: and Jerusalem shall be trodden down of the Gentiles, until the times of the Gentiles be fulfilled. And there shall be signs in the sun, and in the moon, and in the stars; and upon the earth distress of nations, with perplexity; the sea and the waves roaring; Men's hearts failing them for fear, and for looking after those things which are coming on the earth: for the powers of heaven shall be shaken. And then shall they see the Son of man coming in a cloud with power and great glory. And when these things begin to come to pass, then look up, and lift up your heads; for your redemption draweth nigh. And he spake to them a parable; Behold the fig tree, and all the trees; When they now shoot forth, ye see and know of your own selves that summer is now nigh at hand. So likewise ye, when ye see these things come to pass, know ye that the kingdom of God is nigh at hand. Verily I say unto you, This generation shall not pass away, till all be fulfilled. Heaven and earth shall pass away: but my words shall not pass away."

Catholicism[link]

Catholicism mainly adheres to the Amillennial school of thought, promoted by Augustine of Hippo in his work "The City of God". Augustine claims a non-literal fulfillment of prophecy. Catholics may also refer to Matthew's Gospel, Chapter 24, Verse 36, in which Christ is quoted as saying:

"But of that day and hour no one knows, neither the angels of heaven, nor the Son, but the Father alone." (NAB translation)

While some who believe in the literal interpretation of the Bible insist that the prediction of dates or times is futile, some other writers believe that Jesus foretold of signs which would indicate that the "end of days" was near. Some of these signs include earthquakes, natural disasters, civil problems, "wars and rumors of wars," and other catastrophes. Of the precise time, however, it will come like a "thief in the night" (1 Thess. 5:2).

According to the Catechism of the Catholic Church, the Catholic beliefs concerning the End Times are addressed in the Profession of Faith.^[2]

Protestantism[link]

The Antichrist, by Lucas Cranach the Elder (1521) Here the Antichrist is shown wearing the triple crown of the Roman papacy.

Millennialists concentrate on the issue of whether the true believers will see the tribulation or be removed from it by what is referred to as a Pre-Tribulation Rapture. Amillennialists believe that the end times encompass the time from Christ's ascension to the Last day, and maintain that the mention of the "thousand years" in the Book of Revelation is meant to be taken metaphorically (i.e., not literally, or 'spiritually'), a view which continues to cause divisions within evangelical Christianity.

End-times beliefs in Protestant Christianity vary widely. Christians premillennialists who believe that the End Times are occurring now, are usually specific about timelines that climax in the end of the world. For some, Israel, the European Union, or the United Nations are seen as major players whose roles are foretold in scriptures. Among dispensational premillennialists writers, there are those who believe that Christians will be supernaturally summoned to Heaven by Jesus in an event called the Rapture, which occurs before the biblical "Great Tribulation" prophesied in Matthew 24-25; Mark 13 and Luke 21. The Great Tribulation is also mentioned in the last book of the Bible — the book of Revelation.

'End times' may also refer simply to the passing of a particular age or long period in the relationship between man and God. Adherents to this view sometimes cite St. Paul's second letter to Timothy, and draw analogies to the late 20th/early 21st centuries.

Post-Exilic Hebrew books of prophecy such as the Book of Daniel and Book of Ezekiel are given new interpretations in this Christian tradition, while apocalyptic forecasts appear in the Judeo-Christian Sibylline Oracles and in the whole field of apocalyptic literature, which includes the Book of Revelation ascribed to John, the apocryphal Apocalypse of Peter, and the Second Book Of Esdras.

Most fundamentalist Christians anticipate that the biblical prophecy will be fulfilled literally. They see current world and regional wars, earthquakes, hurricanes and famines as the beginning of the birth pains which Jesus described in Matthew 24:7-8 and Mark 13:8. They believe that mankind started in the garden of Eden, and point to Megiddo as the place that the current world system will finish, with the Advent of Messiah coming to rule for 1,000 years.

Contemporary use of the term End Times has evolved from use around a group of literal beliefs in Christian millennialism. These beliefs typically include the ideas that the Biblical apocalypse is imminent and that various signs in current events are omens of a climax to world history known as the battle of Armageddon. These beliefs have been widely held in one form, by the Adventist movement (Millerites), by Jehovah's Witnesses, and in another form by dispensational premillennialists. In 1918 a group of eight well known preachers produced a London Manifesto warning of an imminent second coming of Christ shortly after the 1917 liberation of Jerusalem by the British.

Religious movements which expect that the second coming of Christ, will be a cataclysmic event, generally called adventism, have arisen throughout the Christian era; but they became particularly common during and after the Protestant Reformation. Shakers, Emanuel Swedenborg (who considered the second coming to be symbolic, and to have occurred in 1757), and others developed entire religious systems around a central concern for the second coming of Christ, disclosed by new prophecy or special gifts of revelation. The Millerites are diverse religious groups which similarly rely upon a special gift of interpretation for fixing the date of Christ's return.

The chief difference between the 19th century Millerite and Adventist movements and contemporary prophecy belief is that William Miller and his followers fixed the time for the Second Coming by calendar calculations based on interpretations of the Biblical apocalypses; they originally set a date for the Second Coming in 1844. These sorts of computations also appear in some contemporary prophecy beliefs, but few contemporary End Times prophets use them to fix a date; their timetables will be triggered by future wars and moral catastrophes, and accordingly believe that God's judgment against the conflict-ridden and corrupt world is close at hand.

Seventh-day Adventists believe that Biblical prophecy foretells an end time scenario in which the United States works in conjunction with the Catholic Church to mandate worship on a day other than seventh-day Sabbath (Saturday) as prescribed in the Ten Commandments (Exodus 20:8-11), thereby bringing about a situation where one must choose for or against the Bible as the revealed will of God.^[3] Short paperback books like National Sunday Law promise that, just in the day of the Roman emperor Constantine, Sunday religious worship will be enforced on pain of death: this is anathema to those who believe they must worship on Saturday. Seventh-day Adventists interpret the "two horned beast" that "came out of the wilderness" and "spoke meekly" to mean the United States because it passed the Declaration of Independence and the Constitution, was established in a thinly settled part of the world compared to Roman and Byzantine Europe, and because it declared support for democracy, rule of law, and at least the rights of all white men, rich or poor. Books such as The Pearl of Great Price do much to remind the reader that Christians of conscience have struggled to translate and read the Bible according to their own conscience. When caught, these Christians have not compromised their beliefs nor engaged in violence. The Seventh-day Adventists would be the first in line to oppose the right-wing incorporation of religious agenda into politics, not only because Seventh-day Adventists and other Christians (such as Jehovah's Witnesses) have been arrested and tried for offenses such as draft evasion, but because the politicization of any religious agenda may lead to an official religion and not only first criminalize the losers, but if there is a power shift, also come to criminalize the ex-winners, too.

Preterism[link]

Another view of the 'end times' known as preterism differentiates between the concept of 'time of the end' and 'end of time', and promotes a different understanding of these prophecies, in that they took place in the 1st century, more specifically in year AD 70, when the Jewish Temple was destroyed, and animal sacrifices were stopped. In this view, the 'time of the end' concept is referring to the end of the covenant between God and Israel, rather than the end of time, or the end of planet Earth. Unlike all the other Christian theological systems, preterism holds an exclusive and unique view on the nature and timing of the 'End Times', in that preterists teach the 'end times' to be in the 1st century AD.

Preterists believe that prophecies such as the Second Coming, the defiling of the Temple, the destruction of Jerusalem, the Antichrist, the Great Tribulation, the advent of The Day of the Lord and the Final Judgment were fulfilled at or about the year AD 70 when the Roman general (and future Emperor) Titus sacked Jerusalem and destroyed the Jewish Temple, putting a permanent stop to the daily animal sacrifices.

Proponents of full preterism do not believe in the bodily resurrection of the dead and place this event as well as the Second Coming in AD 70, whereas proponents of partial preterism do believe in a bodily resurrection of the dead at a future Second Coming. Full preterists contend that those who consider themselves to be partial preterists are actually just futurists since they believe the Second Coming, Resurrection, Rapture and Judgment are still in the future.

Many preterists believe the 1st-century living Christians were literally raptured off the earth to be with Christ. At that time, their bodies were changed to be like Christ's. Preterists also believe the term 'Last Days' or 'Time of the End' refers not to the last days of planet Earth, or last days of mankind, but to the last days of the Old Covenant, the Mosaic Covenant which God had exclusively with Israel until year AD 70.

According to preterism, many 'time passages' in the New Testament indicate with apparent certainty that the Second Coming of Christ, and the 'End Times' predicted in the Bible were to take place within the lifetimes of Christ's disciples: Matt. 10:23, Matt. 16:28, Matt. 24:34, Matt. 26:64, Rom. 13:11-12, 1 Cor. 7:29-31, 1 Cor. 10:11, Phil. 4:5, James 5:8-9, 1 Pet. 4:7, 1 Jn. 2:18.

Dispensationalist prophecies[link]

The reestablishment of Israel in 1948 provided a major impetus to the dispensationalist belief system. Israel's history of wars after 1948 with its Arab neighbors provided further research as was seen in at least one book by John F. Walvoord.^[4] After the Six Day War in 1967, and the Yom Kippur War in 1973, it seemed plausible to many Fundamentalist Christians in the 1970s that Middle East turmoil may well be leading up to the fulfillment of various Bible prophecies and to the Battle of Armageddon.

Members of the dispensationalist movement such as Hal Lindsey, J. Dwight Pentecost, John Walvoord, all of whom have Dallas Theological Seminary backgrounds, and some other writers, claimed further that the European Economic Community founded on the Treaty of Rome was a revived Roman Empire, and would become the kingdom of the coming Antichrist and the Beast. The Roman Empire also figured into the New Testament writers' vision of the future. The fact that in the early 1970s, there were (erroneously thought to be) seven nations in the European Economic Community was held to be significant; this aligned the Community with a seven-headed beast mentioned in Revelation. This specific prophecy has required revision, but the idea of a revived Roman Empire remains.

The separate destinies of the Church and Israel, a belief which is inherent in dispensationalism is a particular concern to some Jews and to some evangelical Christians. Evangelicals who reject dispensationalism, such as those who hold to a Post Tribulation Rapture, (or more accurately a Post Tribulation Resurrection-Rapture), see both the Church and Israel entering the crucible of the End Time together.

Dispensationalism, in contrast to the Millerite Adventist movement, had its beginning in the 19th century, when John Nelson Darby, founder of the Plymouth Brethren religious denomination, incorporated into his system of Biblical interpretation a system of organizing Biblical time into a number of discrete dispensations, each of which marks a separate covenant with God. Darby's beliefs were widely publicized in Cyrus I. Scofield's Scofield Reference Bible, an annotated Bible that became popular in the United States of America.

Since the majority of the Biblical prophets were writing at a time when [Israel] was mostly Jewish, and the Temple in Jerusalem was still functioning, they wrote as if those institutions would still be in operation during the prophesied events. According to preterism this was the very fulfillment of the prophecies. However, according to Futurists their destruction in AD 70 put the prophetic timetable, if there is one, on hold. Many such believers therefore anticipated the return of Jews to Israel and the reconstruction of the Temple before the Second Coming could occur. (See Christian Zionism)

Post-tribulation pre-millennialists[link]

A view of the Second Coming of Christ as held by post-tribulational pre-millennialists is unique, though not widely held in the Protestant Church because of its connotations, in particular that the Church of Christ will have to undergo great persecution.

Specific prophetic movements[link]

• In 1843, William Miller made the first of several predictions that the world would end in only a few months. As his predictions did not come true (referred to as the Great Disappointment), followers of Miller went on to found separate churches, the most successful of which is the Seventh-day Adventist Church.

Restorationism (Christian primitivism)[link]

End times theology is also significant to restorationist Christian religions, which consider themselves distinct from both Catholicism and Protestantism.

Jehovah's Witnesses[link]

Jehovah's Witnesses have their own unique eschatology, involving very specific doctrines on the End Times, which is explained in detail in their literature. For example, Witnesses teach that the Greek word parousia, often translated as 'coming', means 'presence' and that the term "last days" refers to the concluding time period of this system of things. They also have a long history of failed end-time predictions.^[5][6]

Witnesses currently teach that the last days began in 1914 with the events surrounding the outbreak of World War I.^[7] In the future, God is expected to cleanse the earth of all wickedness and Satan will be bound for 1,000 years. During this time period, people will be resurrected to life on earth and given a chance to learn about God (Jehovah) and to live under the rule of Jesus Christ. Christ will rule over the earth from heaven with 144,000 co-rulers, restoring earth to its original paradise-like state. They teach that Biblical prophecy shows there will be no more death, sickness and that people will live in peace and harmony as God's originally purposed for mankind. Jehovah's Witnesses' unique beliefs postulate the order of events relating to the End Times and subsequent restoration of earth:

1. King Nebuchadnezzar's dream at Daniel chapter 4 refers to the kingdom of God, to be given to Jesus Christ, after "seven times". Until then, the kingdom of God, represented by Jerusalem, was trampled on by "the nations", represented in the book of Daniel by wild beasts. After successive kingdoms, beginning with Nebuchadnezzar, and then Medo-Persia, Greece, Rome, and the Anglo-American world powers, God would reassert the authority of his kingdom by 'crushing' those kingdoms. (Luke 21:24, Ezekiel 21:26,27, Luke 1:32,33 )
2. The "seven times" began after Zedekiah, the last king in the typical kingdom of God, was removed from the throne in Jerusalem by Nebuchadnezzar. 607 BC (rather than the secularly accepted 587 BC) is selected based on their beliefs that the Jews returned from captivity by fall of 537 BC (They believe that returning of the Jews took a short period of time which ended by the fall of 537 BC, though the release from exile was formally decreed by King Cyrus at 538 BC or 537 BC according to secular historians.^[8][9])

and that the Jews were exiled in Babylon for exactly 70 years. The "seven times", based on a comparison with the 42 months (3½ years or 1,260 days) at Revelation 11:2,3 and 12:6,14, are construed to mean 2,520 days. A year is counted for each of the 2,520 days to arrive at 2,520 years, which are counted from October 607 BC to arrive at October 1914.( Daniel 4: 10-16, Numbers 14:34, Ezekiel 4:6)

1. In October 1914, at the end of "seven times" Christ was installed as king in heaven and Satan and his angels were hurled down to the earth, marking the beginning of the end times or "last days".(Daniel 7:13,14, Revelation 12:7-12)
2. Fulfillment of prophecies in Matthew 24, Mark 13, Luke 21 about the "conclusion of the system of things" has occurred since 1914 to provide a composite "sign" that Jesus' invisible presence in heaven has begun.
3. Jehovah's worshippers will be gathered and restored. They do not engage in wars. They will walk in the name of 'Jehovah'. (Isaiah 2:2-4, Micah:4:5 )
4. The goodnews about God's kingdom will be preached to all nations.(Mathew:24:14)
5. There will be a worldwide "cry of 'peace and security'" before the "great tribulation" begins.(1 Thessalonians 5:3)
6. All religions, represented by the Babylon the Great, except Jehovah's Witnesses, will be destroyed by the United Nations.(Revelation 17:16-18)
7. Satan will attack God's people. (Ezekiel: 38: 10-12,16,18)
8. Political rulers and other wicked people will be destroyed by God at Armageddon.(Revelation:16:14-16)
9. Jesus will bind Satan in an abyss. (Revelation 20:1-3)
10. Jesus will reign for 1000 years from heaven, during which righteous people delivered through Armageddon will work together with the help of Jesus and 144,000 to make the earth a paradise, like the original Garden of Eden. In addition, the dead will gradually be resurrected and given the chance to learn righteousness without Satanic influence. Mankind will be restored to perfection.(Revelation 20:5,6, 5:10, 21:3-5, John:5:28,29)
11. At the end of the 1000 years, Satan will be let loose for a short time as a final test to "mislead the nations", after which he will be destroyed along with his followers. (Revelation 20:7-10)
12. Our planet earth will not be literally destroyed, except the wicked. (Psalms 104:5, 78:69, 37:9-11, Mathew:5:5)
13. With only perfect mankind remaining, Jesus will handover the kingdom to the Almighty God 'Jehovah'. (1 Corinthians:15:24-28)
14. Those righteous people, who survive the final test at the end of the thousand year rule, will live forever on a paradise earth.(Psalms:37:29, 72:7,8)
15. All who live on earth will worship the only true God, "Jehovah". (Isaiah:11:9)
16. Thus God's original purpose for mankind on earth, will be fulfilled. (Genesis:1:28)

Witnesses remain neutral in political affairs and teach that believers on earth will be spectators only in the above-mentioned scenario, not participating in any type of warfare.^[10][11]

They generally do not use the expression 'end of the world', with its connotations of the destruction of humanity or the planet, but prefer to use the expression 'conclusion of a system of things', thus maintaining the distinction between the original-language words kosmos (world) and aion (age), or system of things.

The Church of Jesus Christ of Latter-day Saints[link]

Like many Christian adherents, members of The Church of Jesus Christ of Latter-day Saints (LDS church), believe that there will be a Second Coming of Jesus Christ to the earth sometime in the future and that humanity is living in the last days. However, they do not speculate as to the time, day or year of the second coming, but watch for Biblical indications, or "Signs of the Times" that the event is approaching. Current church leaders do not make any predictions of the actual date of the Second Coming.

The LDS Church believes that, when Christ comes again, he will come in power and great glory,^[12] and that all the world will know of His coming, both those who believe in him, and those who do not, and all the world will know that He has come again.^[13][14] They also believe that this is the same person who ascended into heaven^[15] and that he will still have the marks of the nails in his hands and feet.^[16]

Judaism[link]

In Judaism, End Times are usually called The End of Days (aḥarit ha-yamim, אחרית הימים), a phrase that appears several times in the Tanakh. The idea of a messianic age has a prominent place in Jewish thought. It is an event with a pre-determined date (which is unknown), but can come earlier through religious observance and good deeds.

The term may refer to a number of interwoven themes:

• Jewish messianism
• The ingathering of the exiles
• The land of Israel will turn from a desert into a garden, flourishing with fruits
• Rebuilding of the Temple
• Animal sacrifice or Korban^[17][18][19]
• The World to Come (Olam Haba) is an ambiguous term that may refer to the afterlife, the messianic world, or the life of the resurrected.

End of Days recorded in the Tanakh:

Tumultuous events will overturn the old world order, as is recorded in the following passages from the Old Testament (Tanakh):

Deuteronomy 4:29-39 (King James Version): But if from thence thou shalt seek the LORD thy God, thou shalt find him, if thou seek him with all thy heart and with all thy soul. When thou art in tribulation, and all these things are come upon thee, even in the latter days, if thou turn to the LORD thy God, and shalt be obedient unto his voice; (For the LORD thy God is a merciful God;) he will not forsake thee, neither destroy thee, nor forget the covenant of thy fathers which he sware unto them. For ask now of the days that are past, which were before thee, since the day that God created man upon the earth, and ask from the one side of heaven unto the other, whether there hath been any such thing as this great thing is, or hath been heard like it? Did ever people hear the voice of God speaking out of the midst of the fire, as the seas turn black and feel like mud, and all will know the wrath and atonement of their sins? Or hath God assayed to go and take him a nation from the midst of another nation, by temptations, by signs, and by wonders, and by war, and by a mighty hand, and by a stretched out arm, and by great terrors, according to all that the LORD your God did for you in Egypt before your eyes? Unto thee it was shewed, that thou mightest know that the LORD he is God; there is none else beside him. Out of heaven he made thee to hear his voice, that he might instruct thee: and upon earth he shewed thee his great fire; and thou heardest his words out of the midst of the fire. And because he loved thy fathers, therefore he chose their seed after them, and brought thee out in his sight with his mighty power out of Egypt; to drive out nations from before thee greater and mightier than thou art, to bring thee in, to give thee their land for an inheritance, as it is this day. Know therefore this day, and consider it in thine heart, that the LORD he is God in heaven above, and upon the earth beneath: there is none else.

Isaiah 2:1-5 (King James Version): The word that Isaiah the son of Amoz saw concerning Judah and Jerusalem. And it shall come to pass in the last days, that the mountain of the LORD's house shall be established in the top of the mountains, and shall be exalted above the hills; and all nations shall flow unto it. And many people shall go and say, Come ye, and let us go up to the mountain of the LORD, to the house of the God of Jacob; and he will teach us of his ways, and we will walk in his paths: for out of Zion shall go forth the law, and the word of the LORD from Jerusalem. And he shall judge among the nations, and shall rebuke many people: and they shall beat their swords into plowshares, and their spears into pruning hooks: nation shall not lift up sword against nation, neither shall they learn war any more.

Micah 4:1-5 (King James Version): But in the last days it shall come to pass, that the mountain of the house of the LORD shall be established in the top of the mountains, and it shall be exalted above the hills; and people shall flow unto it. And many nations shall come, and say, Come, and let us go up to the mountain of the LORD, and to the house of the God of Jacob; and he will teach us of his ways, and we will walk in his paths: for the law shall go forth of Zion, and the word of the LORD from Jerusalem. And he shall judge among many people, and rebuke strong nations afar off; and they shall beat their swords into plowshares, and their spears into pruning hooks: nation shall not lift up a sword against nation, neither shall they learn war any more. But they shall sit every man under his vine and under his fig tree; and none shall make them afraid: for the mouth of the LORD of hosts hath spoken it. For all people will walk every one in the name of his god, and we will walk in the name of the LORD our God for ever and ever.

These events create a new order in which God is universally recognized as the ruler over His creation, which includes everyone and everything.

Description of the Messianic Era

According to Jewish tradition, the Messianic Era will be one of global peace and harmony, an era free of strife and hardship, and one conducive to the furtherment of the knowledge of the Creator. The theme of the Messiah ushering in an era of global peace is encapsulated in one of the most famous scriptural passages from the book of Isaiah:

"They shall beat their swords into plowshares and their spears into pruning hooks; nation will not lift sword against nation and they will no longer study warfare (Isaiah 2:4)."

In his Mishneh Torah, Maimonides describes the Messianic Era:

"And at that time there will be no hunger or war, no jealousy or rivalry. For the good will be plentiful, and all delicacies available as dust.

The entire occupation of the world will be only to know God... the people Israel will be of great wisdom; they will perceive the esoteric truths and comprehend their Creator's wisdom as is the capacity of man. As it is written (Isaiah 11:9): "For the earth shall be filled with the knowledge of God, as the waters cover the sea." "^[20]

Advent of the Messianic Era

According to the Talmud,^[21] the Midrash,^[22] and the medieval Kabbalistic work, the Zohar,^[23] the Messiah must arrive before the year 6000 from the time of creation. (According to Orthodox Jewish belief, the Hebrew calendar dates to the time of creation. The year 2010 corresponds to the year 5770 from creation, or before the year 2240).

The Midrash comments:

"Six eons for going in and coming out, for war and peace. The seventh eon is entirely Shabbat and rest for life everlasting^[22] ".

There is a kabbalistic tradition^[24] that maintains that each of the 7 days of the week, which are based upon the seven days of creation, correspond to the seven millennia of creation. The tradition teaches that the seventh day of the week, the Sabbath day of rest, corresponds to the seventh millennium, the age of universal 'rest' - the Messianic Era. The seventh millennium perforce begins with the year 6000, and is the latest time the Messiah can come. Supporting and elaborating on this theme are numerous early and late Jewish scholars, including the Ramban,^[25] Isaac Abrabanel,^[26] Abraham Ibn Ezra,^[27] Rabbeinu Bachya,^[28] the Vilna Gaon,^[29] the Lubavitcher Rebbe,^[30] the Ramchal,^[31] Aryeh Kaplan^[32] and Rebbetzin Esther Jungreis.^[33]

Hinduism[link]

In Hinduism, time is cyclic, consisting of cycles or "Kalpa", repeating infinitely. The "End Time" as we understand from other religions does not exists as such. However, Kalpa (and its sub cycles) has its own start and end. One Kalpa lasts 8.64 billion years, illustrates the pattern of decline in the state of nature and civilization between periods of timelessness when Brahma (Matter,mass) regenerates the world of existence/reality. Brahma has a lifespan of 311 Trillion, 40 Billion Years, then the universe will contract to a singularity and again will be evolved from the singularity. As Hindus do not consider humans as special or noble creations of god, unlike some other religions, the wrong doings or such things committed by humans shall have no effects on the end of time, as the end of time as per Hinduism is purely a property of matter. There are four yugs, or ages, in this process from complete purity to complete impurity. The final is Kali Yuga, or the Dark Age, where civilization becomes spiritually degraded, human lives are shortened by violence and disease, and there is a general state of decay in nature. This is the worst period before complete destruction which is then followed by a Golden Age.^{[34][citation needed]}

Hindu traditional prophecies, as described in the Puranas and several other texts, say that the world shall fall into chaos and degradation. There will then be a rapid influx of perversity, greed and conflict, and this state has been described as:

"Yada Yada Hi Dharmasya Glanir Bhavati Bharata, Abhyuthanam Adharmasya Tadatmanam Srijami Aham". Bhagavad Gita (Chapter IV-7)

"Whenever there is decay of righteousness O! Bharatha And a rise of unrighteousness then I manifest Myself!"

Thus whenever there is intolerable evil and chaos in the world, there is an appearance of an Avatar. In the current yuga, known as the Kali (the most evil) yuga, "The Lord shall manifest Himself as the Kalki Avatar… He will establish righteousness upon the earth and the minds of the people will become as pure as crystal."

In Hinduism, there is no eternal damnation of souls or end times. After this evil Kali yuga ends, the next yuga or epoch would be Satya yuga where everyone will be righteous, followed by Treta yuga,Dwapara yuga and then another Kali Yuga. Thus time is cyclical and the epochs keep repeating infinitely. However, the extent of tolerable evil and degradation in each epoch is different and therefore the threshold that is necessary for the manifestation of God's incarnation is different for each yuga. The current yuga is the most evil and so the threshold for the appearance of the Avatar is so high that the world needs to degrade to the maximum levels.

Buddhism[link]

Gautama Buddha was a spiritual teacher from India and the founder of Buddhism. The exact dates of his birth and death are uncertain, but a number of 20th-century historians have dated his lifetime from circa 563 BC to 483 BC. Some more recent scholars, however, have suggested dates of 410 to 400 BC for his death.^[35] This alternative chronology has not been accepted by other historians.^[36][37]

The Buddha predicted that his teachings Dharma (Buddhism) would disappear after 5,000 years,^[38] when no one practices the actual teachings any more. It would last so long as someone practiced. According to the Sutta Pitaka, the "ten wholesome courses of conduct" will disappear and people will follow the ten unwholesome concepts of theft, violence, murder, lying, false speech, sexual misconduct, abusive and idle talk, covetousness and ill will, wanton greed, and uncontrolled lust resulting in poverty and the breakdown of law and cooperation or regard for the dharma.^{[citation needed]}

As part of Buddhist eschatology, it is believed that the age leading up to the coming of the next Buddha Maitreya will be characterized by impiety, physical weakness, sexual depravity, and general social disarray.

Commentators like Buddhaghosa predicted a step-by-step disappearance of the Buddha's teachings. During the first stage, arahants would no longer appear in the world. Later, the content of the Buddha's true teachings would vanish, and only their appearance or outward form would be preserved. Finally, even the form of the Dharma would be lost. During the final stage, the memory of the Buddha himself would be forgotten, and the last of his relics would be gathered together in Bodh Gaya and cremated. Some time following this devolution a new Buddha named Maitreya will arise to rediscover and reveal the timeless teachings of dharma and rediscover the path to Nirvana. Maitreya is said to currently reside in the Tushita world, before his final rebirth in the human world.

The decline of Buddha's teaching in the human world, and its eventual re-establishment by Maitreya, are in keeping with the general shape of Buddhist cosmology. Like Hindus, Buddhists generally believe in cycles of destruction and creation, of which the current epoch represents only the latest step. The historical Buddha Shakyamuni is only the latest in a series of Buddhas that stretches back into the past.

Zoroastrianism[link]

Zoroastrian eschatology is the oldest eschatology found in recorded history.^[39][40][41] By the year 500 BC, a fully developed concept of the end of the world was established in Zoroastrianism.

According to Zoroastrian philosophy, redacted in the Zand-i Vohuman Yasht, "at the end of thy tenth hundredth winter...the sun is more unseen and more spotted; the year, month, and day are shorter; and the earth is more barren; and the crop will not yield the seed; and men ... become more deceitful and more given to vile practices. They have no gratitude." "Honorable wealth will all proceed to those of perverted faith...and a dark cloud makes the whole sky night...and it will rain more noxious creatures than winter."

At the end of this spiritual battle between the righteous and wicked, a final judgment of all souls will occur. Sinners whose bad deeds are more than their good deeds will be punished for 3 days, but will eventually be forgiven. The world will reach perfection as all evil traits such as poverty, old age, disease, thirst, hunger, and death will disappear from the earth. Zoroastrian concepts parallel greatly with those of Jewish, Christian, and Islamic eschatological beliefs. Zoroaster also preached that bliss will be everywhere, and not just in a remote kingdom of paradise.

Benjamin Beit-Hallahmi states the Brahma Kumaris' prediction of the imminent 'End of the World', or Destruction as it is called, is generally hidden from non-members.^[42] Before destruction everyone on earth must come to know their God and purify themselves. Much of the Earth's land mass is also predicted to become submerged beneath the oceans of the world and the government of India will hand over power to them.^[43]

Greek religion[link]

Greek mythology is derived primarily from Greek literature and representations on visual media dating from the Geometric period (c. 900-800 BC) onward.^[44]

Ancient Greek mythology claimed that Zeus, as he had previously overthrown his father, Cronus, would in turn also be overthrown by a son. This story can be seen as the equivalent to the end of the world, or the end of an age. Prometheus revealed to him that this son would be born from Zeus and Thetis, if they copulated. In order to prevent this from happening, Zeus married Thetis to Peleus, a mortal hero. This union produced Achilles, the protagonist of the Iliad and one of the greatest heroes of Greek myth.

Norse religion[link]

In Norse mythology, Ragnarök (Old Norse "Final destiny of the gods" - c.f. Ragn-: power, -a-: via, -rök: rest of volition) refers to a series of major events, including a great battle foretold to ultimately result in the death of a number of major figures (including the gods Odin, Thor, Freyr, Heimdall, and the jötunn Loki), the occurrence of various natural disasters, and the subsequent submersion of the world in water. Afterwards, the world resurfaces anew and fertile, the surviving gods meet, and the world is repopulated by two human survivors. Ragnarök is an important event in the Norse canon, and has been the subject of an amount of scholarly discourse and theory.

Fulfillment[link]

While most religious traditions remain waiting for end time events, some believe that the events have been fulfilled. Several established religions believe that their founder represents the coming of the Promised One of previous scriptures, and that the spread of their teachings will ultimately bring about the desired society of unity and justice.

Bahá'í Faith[link]

The founder of the Bahá'í Faith, Bahá'u'lláh claimed that he was the return of Christ as well as prophetic expectations of other religions. The inception of the Bahá'í Faith coincides with Millerite prophesy pointing to the year 1844. With respect to particular expectations of the end times, it has been argued that the Battle of Armageddon has already passed^[45] and that mass martyrdoms anticipated during the End Times had already passed within the historical context of the Bahá'í Faith.^[46] Bahá'ís expect their faith to be eventually embraced by the masses of the world, ushering in a golden age of society.

Ahmadiyya[link]

In Ahmadiyya, the present age has been a witness to the wrath of God with the occurrence of the World Wars and the frequency of natural disasters.^[47] In Ahmadiyya, (consider separate from Islam) Ghulam Ahmad (d. 1908) is seen as the promised Messiah whose teachings will establish spiritual reform and ultimately establish an age of peace upon earth. This age continues for around a thousand years as per Judeo-Christian prophecies; and is characterised by the assembling of mankind under one faith as per Ahmadiyya belief .^[48]

Rastafari movement[link]

Rastafarians have a unique interpretation of the end times, based on the Old Testament and the Book of Revelation. They believe Ethiopian Emperor Haile Selassie is God incarnate, the King of kings and Lord of lords mentioned in Revelation 5:5. While on the one hand Selassie's crowning was seen as the second coming, and events such as the Second Italo-Ethiopian War were seen as fulfillments of biblical and specifically Revelation prophecy there is also expectation that Selassie will call a day of judgment, when he will bring home the lost children of Israel (the black peoples taken out of Africa during the slave trade) to live with him in peace, love and harmony in the Mount Zion in Africa.

See also[link]

• Apocalypticism
• Abomination of Desolation
• BKWSU Brahma Kumaris World Spiritual University
• Christian Eschatology
• End of the world (disambiguation)
• Endtime Ministries
• Katechon
• Mysticism
• Number of the Beast
• Prophecy of Seventy Weeks
• Revelation
• Summary of Christian eschatological differences
• The Two Witnesses
• Ultimate fate of the Universe
• Unfulfilled religious prophecies
• Whore of Babylon
• Year 6000

References[link]

External links[link]

• Library of Date Setters of The End of the World: "Over 200 predictions and counting."
• The Ending World- Current event Dealing with the End of the World from a Christian perspective.
• Religious Tolerance- A list of different groups claiming to predict the end of the world prior to 2000.

Look up end in Wiktionary, the free dictionary.

End or Ending may refer to:

• End (philosophy)
• In mathematics:
  • End (category theory)
  • End (topology)
• End (American football)
• End, a division of play in the sports of curling and target archery
• End key on a modern computer keyboard
• End Records, a record label
• "End", a song by The Cure from Wish
• "End", a Song from Silent Night Fever by Dimension Zero
• End, in weaving, a single thread of the warp

END may refer to:

• European Nuclear Disarmament
• Endoglin, a glycoprotein
• Equivalent narcotic depth, a concept used in underwater diving

Ending may refer to:

• Ending (linguistics)
• Alternate ending
• End of a part of a baseball game
• False ending
• Happy ending
• Multiple endings
• Twist ending
• Endings (film)

See also[link]

• All pages beginning with "End"
• All pages with titles containing "End"
• The End (disambiguation)
• End of the world (disambiguation)
• Front end (disambiguation)
• Boundary (disambiguation)
• Telos (philosophy), a goal or final state
• Conclude (disambiguation)
• Terminate (disambiguation)

This disambiguation page lists articles associated with the same title. If an internal link led you here, you may wish to change the link to point directly to the intended article.

The flow of sand in an hourglass can be used to keep track of elapsed time. It also concretely represents the present as being between the past and the future.

Time
Major Concepts
Past ♦ Present ♦ Future Eternity Arguments for eternity
Broad Studies
Chronology History (Paleontology) Futurology
Philosophy
Presentism ♦ Eternalism, Fatalism Philosophy of Space and Time
Religion
Creation End Times Day of Judgement Immortality Afterlife ♦ Reincarnation Kalachakra
Time measurement and Standards
Metric Time ♦ Hexadecimal time
Related
Spacetime, Motion ♦ Space Event ♦ Continuum Time Travel ♦ (Grandfather Paradox)
v t e

Time is the indefinite continued progress of existence and events that occur in apparently irreversible succession from the past through the present to the future.^[1] Time is a component quantity of many measurements used to sequence events, to compare the durations of events and the intervals between them, and to quantify rates of change of quantities in material reality or in the conscious experience.^[2][3][4] The temporal position of events with respect to the transitory present is continually changing; events happen, then are located further and further in the past. Time has been a major subject of religion, philosophy, and science, but defining it in a manner applicable to all fields of study without circularity has consistently eluded scholars.^[5] A simple definition states that "time is what clocks measure".^[2][5]

Time is one of the seven fundamental physical quantities in the International System of Units. Time is used to define other quantities — such as velocity — so defining time in terms of such quantities would result in circularity of definition.^[6] An operational definition of time, wherein one says that observing a certain number of repetitions of one or another standard cyclical event (such as the passage of a free-swinging pendulum) constitutes one standard unit such as the second, is highly useful in the conduct of both advanced experiments and everyday affairs of life. The operational definition leaves aside the question whether there is something called time, apart from the counting activity just mentioned, that flows and that can be measured. Investigations of a single continuum called spacetime bring questions about space into questions about time, questions that have their roots in the works of early students of natural philosophy.

Two contrasting viewpoints on time divide many prominent philosophers. One view is that time is part of the fundamental structure of the universe, a dimension in which events occur in sequence. Sir Isaac Newton subscribed to this realist view, and hence it is sometimes referred to as Newtonian time.^[7][8] Time travel, in this view, becomes a possibility as other "times" persist like frames of a film strip, spread out across the time line. The opposing view is that time does not refer to any kind of "container" that events and objects "move through", nor to any entity that "flows", but that it is instead part of a fundamental intellectual structure (together with space and number) within which humans sequence and compare events (such as, change of conditions within an ever-present, allowing an endless 'succession' of changes). This second view, in the tradition of Gottfried Leibniz^[9] and Immanuel Kant,^[10][11] holds that time is neither an event nor a thing, and thus is not itself measurable nor can it be travelled.

Temporal measurement has occupied scientists and technologists, and was a prime motivation in navigation and astronomy. Periodic events and periodic motion have long served as standards for units of time. Examples include the apparent motion of the sun across the sky, the phases of the moon, the swing of a pendulum, and the beat of a heart. Currently, the international unit of time, the second, is defined in terms of radiation emitted by caesium atoms (see below). Time is also of significant social importance, having economic value ("time is money") as well as personal value, due to an awareness of the limited time in each day and in human life spans.

Ray Cummings, an early writer of science fiction, wrote in 1922, "Time... is what keeps everything from happening at once",^[12] a sentence repeated by scientists such as C. J. Overbeck,^[13] and John Archibald Wheeler.^[14][15]

Temporal measurement[link]

Temporal measurement, or chronometry, takes two distinct period forms: the calendar, a mathematical abstraction for calculating extensive periods of time,^[16] and the clock, a physical mechanism that counts the ongoing passage of time. In day-to-day life, the clock is consulted for periods less than a day, the calendar, for periods longer than a day. Increasingly, personal electronic devices display both calendars and clocks simultaneously. The number (as on a clock dial or calendar) that marks the occurrence of a specified event as to hour or date is obtained by counting from a fiducial epoch — a central reference point.

History of the calendar[link]

Artifacts from the Palaeolithic suggest that the moon was used to reckon time as early as 6,000 years ago.^[17] Lunar calendars were among the first to appear, either 12 or 13 lunar months (either 354 or 384 days). Without intercalation to add days or months to some years, seasons quickly drift in a calendar based solely on twelve lunar months. Lunisolar calendars have a thirteenth month added to some years to make up for the difference between a full year (now known to be about 365.24 days) and a year of just twelve lunar months. The numbers twelve and thirteen came to feature prominently in many cultures, at least partly due to this relationship of months to years.

The reforms of Julius Caesar in 45 BC put the Roman world on a solar calendar. This Julian calendar was faulty in that its intercalation still allowed the astronomical solstices and equinoxes to advance against it by about 11 minutes per year. Pope Gregory XIII introduced a correction in 1582; the Gregorian calendar was only slowly adopted by different nations over a period of centuries, but is today by far the one in most common use around the world.

History of time measurement devices[link]

Horizontal sundial in Taganrog.

A large variety of devices have been invented to measure time. The study of these devices is called horology.

An Egyptian device dating to c.1500 BC, similar in shape to a bent T-square, measured the passage of time from the shadow cast by its crossbar on a nonlinear rule. The T was oriented eastward in the mornings. At noon, the device was turned around so that it could cast its shadow in the evening direction.^[18]

A sundial uses a gnomon to cast a shadow on a set of markings which were calibrated to the hour. The position of the shadow marked the hour in local time.

The most precise timekeeping devices of the ancient world were the water clock or clepsydra, one of which was found in the tomb of Egyptian pharaoh Amenhotep I (1525–1504 BC). They could be used to measure the hours even at night, but required manual upkeep to replenish the flow of water. The Greeks and Chaldeans regularly maintained timekeeping records as an essential part of their astronomical observations. Arab inventors and engineers in particular made improvements on the use of water clocks up to the Middle Ages.^[19] In the 11th century, Chinese inventors and engineers invented the first mechanical clocks to be driven by an escapement mechanism.

A contemporary quartz watch

The hourglass uses the flow of sand to measure the flow of time. They were used in navigation. Ferdinand Magellan used 18 glasses on each ship for his circumnavigation of the globe (1522).^[20] Incense sticks and candles were, and are, commonly used to measure time in temples and churches across the globe. Waterclocks, and later, mechanical clocks, were used to mark the events of the abbeys and monasteries of the Middle Ages. Richard of Wallingford (1292–1336), abbot of St. Alban's abbey, famously built a mechanical clock as an astronomical orrery about 1330.^[21][22] Great advances in accurate time-keeping were made by Galileo Galilei and especially Christiaan Huygens with the invention of pendulum driven clocks.

The English word clock probably comes from the Middle Dutch word "klocke" which is in turn derived from the mediaeval Latin word "clocca", which is ultimately derived from Celtic, and is cognate with French, Latin, and German words that mean bell. The passage of the hours at sea were marked by bells, and denoted the time (see ship's bells). The hours were marked by bells in the abbeys as well as at sea.

Chip-scale atomic clocks, such as this one unveiled in 2004, are expected to greatly improve GPS location.^[23]

Clocks can range from watches, to more exotic varieties such as the Clock of the Long Now. They can be driven by a variety of means, including gravity, springs, and various forms of electrical power, and regulated by a variety of means such as a pendulum.

A chronometer is a portable timekeeper that meets certain precision standards. Initially, the term was used to refer to the marine chronometer, a timepiece used to determine longitude by means of celestial navigation, a precision firstly achieved by John Harrison. More recently, the term has also been applied to the chronometer watch, a wristwatch that meets precision standards set by the Swiss agency COSC.

The 555 timer IC is an integrated circuit (chip) used in a variety of timer, pulse generation and oscillator applications.

The most accurate timekeeping devices are atomic clocks, which are accurate to seconds in many millions of years,^[24] and are used to calibrate other clocks and timekeeping instruments. Atomic clocks use the spin property of atoms as their basis, and since 1967, the International System of Measurements bases its unit of time, the second, on the properties of caesium atoms. SI defines the second as 9,192,631,770 cycles of that radiation which corresponds to the transition between two electron spin energy levels of the ground state of the ¹³³Cs atom.

Today, the Global Positioning System in coordination with the Network Time Protocol can be used to synchronize timekeeping systems across the globe.

In medieval philosophical writings, the atom was a unit of time referred to as the smallest possible division of time. The earliest known occurrence in English is in Byrhtferth's Enchiridion (a science text) of 1010–1012,^[25] where it was defined as 1/564 of a momentum (1½ minutes),^[26] and thus equal to 15/94 of a second. It was used in the computus, the process of calculating the date of Easter.

As of May 2010^[update], the smallest time interval uncertainty in direct measurements is on the order of 12 attoseconds (1.2 × 10⁻¹⁷ seconds), about 3.7 × 10²⁶ Planck times.^[27]

Definitions and standards[link]

The SI base unit for time is the SI second. From the second, larger units such as the minute, hour and day are defined, though they are "non-SI" units because they do not use the decimal system, and also because of the occasional need for a leap second. They are, however, officially accepted for use with the International System. There are no fixed ratios between seconds and months or years as months and years have significant variations in length.^[30]

The official SI definition of the second is as follows:^[30][31]

The second is the duration of 9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium 133 atom.

At its 1997 meeting, the CIPM affirmed that this definition refers to a caesium atom in its ground state at a temperature of 0 K.^[30] Previous to 1967, the second was defined as:

the fraction 1/31,556,925.9747 of the tropical year for 1900 January 0 at 12 hours ephemeris time.

The current definition of the second, coupled with the current definition of the metre, is based on the special theory of relativity, which affirms our space-time to be a Minkowski space.

World time[link]

Time-keeping is so critical to the functioning of modern societies that it is coordinated at an international level. The basis for scientific time is a continuous count of seconds based on atomic clocks around the world, known as the International Atomic Time (TAI). Other scientific time standards include Terrestrial Time and Barycentric Dynamical Time.

Coordinated Universal Time (UTC) is the basis for modern civil time. Since January 1, 1972, it has been defined to follow TAI with an exact offset of an integer number of seconds, changing only when a leap second is added to keep clock time synchronized with the rotation of the Earth. In TAI and UTC systems, the duration of a second is constant, as it is defined by the unchanging transition period of the caesium atom.

Greenwich Mean Time (GMT) is an older standard, adopted starting with British railways in 1847. Using telescopes instead of atomic clocks, GMT was calibrated to the mean solar time at the Royal Observatory, Greenwich in the UK. Universal Time (UT) is the modern term for the international telescope-based system, adopted to replace "Greenwich Mean Time" in 1928 by the International Astronomical Union. Observations at the Greenwich Observatory itself ceased in 1954, though the location is still used as the basis for the coordinate system. Because the rotational period of Earth is not perfectly constant, the duration of a second would vary if calibrated to a telescope-based standard like GMT or UT—in which a second was defined as a fraction of a day or year. The terms "GMT" and "Greenwich Mean Time" are sometimes used informally to refer to UT or UTC.

The Global Positioning System also broadcasts a very precise time signal worldwide, along with instructions for converting GPS time to UTC.

Earth is split up into a number of time zones. Most time zones are exactly one hour apart, and by convention compute their local time as an offset from UTC or GMT. In many locations these offsets vary twice yearly due to daylight saving time transitions.

Time conversions[link]

These conversions are accurate at the millisecond level for time systems involving earth rotation (UT1 & TT). Conversions between atomic time systems (TAI, GPS, and UTC) are accurate at the microsecond level.