According to the standard big bang model of cosmology, time began together with the universe in a singularity approximately 14 billion years ago.
For 13.8 billion years, the universe has been expanding, cooling and evolving. Textbooks often say that the start of this expansion — the Big Bang — was the start of time.
The measurement of time began with the invention of sundials in ancient Egypt some time prior to 1500 B.C. However, the time the Egyptians measured was not the same as the time today's clocks measure. For the Egyptians, and indeed for a further three millennia, the basic unit of time was the period of daylight.
Ours happens to be one of the babies that worked out, and kept growing and growing and is still doing so after 13.7 billion years. So, within our universe, time had a beginning. In a real sense, the only time that exists is classical time.
The span of recorded history is roughly 5,000 years, beginning with the Sumerian cuneiform script. Ancient history covers all continents inhabited by humans in the period 3000 BC – AD 500.
A monk called Dionysius Exiguus (early sixth century A.D.) invented the dating system most widely used in the Western world. For Dionysius, the birth of Christ represented Year One. He believed that this occurred 753 years after the foundation of Rome.
The first year of the world was between 4 and 4.5 billion years ago. The earth, as a planet, formed sometime during the Hadean Eon.
ACCORDING TO archaeological evidence, the Babylonians and Egyptians began to measure time at least 5,000 years ago, introducing calendars to organize and coordinate communal activities and public events, to schedule the shipment of goods and, in particular, to regulate cycles of planting and harvesting.
The initial singularity is a singularity predicted by some models of the Big Bang theory to have existed before the Big Bang and thought to have contained all the energy and spacetime of the Universe.
The universe will get smaller and smaller, galaxies will collide with each other, and all the matter in the universe will be scrunched up together. When the universe will once again be squeezed into an infinitely small space, time will end.
Sundials. The earliest known timekeeping devices appeared in Egypt and Mesopotamia, around 3500 BCE. Sundials consisted of a tall vertical or diagonal-standing object used to measure the time, called a gnomon.
The ancient Egyptians are seen as the originators of the 24-hour day. The New Kingdom, which lasted from 1550 to 1070 bce, saw the introduction of a time system using 24 stars, 12 of which were used to mark the passage of the night.
Time is one of the most basic examples of something that is socially constructed.
"When you see things in the really distant Universe, because of the expansion of the Universe, it takes longer for things to happen," she says. The effect is known as cosmological time dilation and it's far more powerful than the tiny time changes seen near Earth.
In the beginning, there was an infinitely dense, tiny ball of matter. Then, it all went bang, giving rise to the atoms, molecules, stars and galaxies we see today. Or at least, that's what we've been told by physicists for the past several decades.
The Earth's motion became the standard of time when humans found out that the Earth rotates. The display on a clock shows time, so the time keeps track of our daily activities. Clocks convert the motion into time because the clock's display corresponds to Earth's rotational motion.
Putting all this together, between 9,800 and 9,700 years ago is an accurate date of creation for Adam and Eve. During this time, the Upper Paleolithic/Lower Mesolithic, humans created before Adam and Eve were yet hunter-gatherers.
It is impossible to destroy and create matter. Thus, everything that has existed still exists, and everything that will exist already exists, just not in the state(s) it did or is going to. And even if time is infinite you would not be born again.
Earth formed around 4.54 billion years ago, approximately one-third the age of the universe, by accretion from the solar nebula. Volcanic outgassing probably created the primordial atmosphere and then the ocean, but the early atmosphere contained almost no oxygen.
The Earth is loosely divided into 24 regions (time zones) separated by longitude. Not counting local variations, each line of longitude is divided by fifteen degrees; as a general rule and depending upon which way one travels, time moves forward or backward one hour for every fifteen degrees of longitude.
Sir Sandford Fleming was Canada's foremost railway construction engineer, as well as an inventor and scientist. He developed the system of standard time, still in use today (courtesy NAC/C-14128). Canada's Sir Sandford Fleming played a crucial role in developing a global system for setting time.
Who decided on these time divisions? THE DIVISION of the hour into 60 minutes and of the minute into 60 seconds comes from the Babylonians who used a sexagesimal (counting in 60s) system for mathematics and astronomy. They derived their number system from the Sumerians who were using it as early as 3500 BC.
Historians have never included a year zero. This means that between, for example, 1 January 500 BC and 1 January AD 500, there are 999 years: 500 years BC, and 499 years AD preceding 500. In common usage anno Domini 1 is preceded by the year 1 BC, without an intervening year zero.
The earliest record of Homo is the 2.8 million-year-old specimen LD 350-1 from Ethiopia, and the earliest named species is Homo habilis which evolved by 2.3 million years ago.
Ibn al-Haytham (Book of Optics), Avicenna, Averroes, and Abu Rayhan al-Biruni all flourished around the year 1000.