Glossary term: Time

Description: Time is the process of continuous and indefinite progression of events from the past through the present to the future, and it is an irreversible process. Perhaps the term time is the most difficult to define, as time is something we feel, measure or guess, and it varies according to the point of view from which we look so that we can talk about psychological time, physical time, or imaginary time. Time can be considered as the fourth dimension of reality, and it is used to describe events in three-dimensional space. It is not something we can see, touch or taste, but we can measure its passage. Will time expire? The answer to this question is unknown. If the Universe expands forever, then time will continue. If a new Big Bang occurs, our timeline will end and a new one will begin.

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Term and definition status: This term and its definition is still awaiting approval

The OAE Multilingual Glossary is a project of the IAU Office of Astronomy for Education (OAE) in collaboration with the IAU Office of Astronomy Outreach (OAO). The terms and definitions were chosen, written and reviewed by a collective effort from the OAE, the OAE Centers and Nodes, the OAE National Astronomy Education Coordinators (NAECs) and other volunteers. You can find a full list of credits here. All glossary terms and their definitions are released under a Creative Commons CC BY-4.0 license and should be credited to "IAU OAE".