Eastern Standard Time (EST) is a time zone that covers the eastern part of North America, including cities such as New York, Washington D.C., Atlanta, and Toronto. The time zone is 5 hours ahead of Coordinated Universal Time (UTC-5). When Daylight Saving Time is in effect, the time zone becomes Eastern Daylight Time (EDT), which is 4 hours ahead of Coordinated Universal Time (UTC-4).

Here is a list of some of the most commonly used time zones:

- UTC (Coordinated Universal Time)
- GMT (Greenwich Mean Time)
- EST (Eastern Standard Time)
- CST (Central Standard Time)
- MST (Mountain Standard Time)
- PST (Pacific Standard Time)
- IST (Indian Standard Time)
- BST (British Summer Time)
- SGT (Singapore Time)
- JST (Japan Standard Time)
- AEDT (Australian Eastern Daylight Time)
- CET (Central European Time)
- EET (Eastern European Time)
- ART (Argentine Time)
- CAT (Central African Time)

This is by no means a comprehensive list, as there are many time zones in use around the world.

https://www.youtube.com/watch?v=X1DkiuaFCuA

Greenwich Mean Time (GMT) is a time standard that is often used as a reference time, as it represents the mean solar time at the Royal Observatory in Greenwich, London. It was once used as the basis for the world's time zones, but has since been largely replaced by Coordinated Universal Time (UTC). GMT is still sometimes used to refer to UTC, especially in the United Kingdom and its territories, where it is considered equivalent to UTC. However, it is important to note that GMT is not a time zone, as it does not observe daylight saving time or other seasonal adjustments.

- The official GMT website: https://greenwichmeantime.com/
- Information on GMT and its history from the Royal Observatory in Greenwich: https://www.rmg.co.uk/discover/astronomy/time/what-greenwich-mean-time
- A time zone converter for GMT and other time zones: https://www.timeanddate.com/worldclock/converter.html
- The Wikipedia page for Greenwich Mean Time: https://en.wikipedia.org/wiki/Greenwich_Mean_Time

https://www.youtube.com/watch?v=X1DkiuaFCuA

Eastern Daylight Time (EDT) is a time zone that covers the eastern part of North America, including cities such as New York City, Washington D.C., Toronto, and Miami. During the summer months, Daylight Saving Time is in effect, and the time is shifted ahead by one hour, resulting in Eastern Daylight Time. The rest of the year, Eastern Standard Time is observed. The time zone is 4 hours behind Coordinated Universal Time (UTC-4).

https://www.timeanddate.com/time/zones/edt

https://www.worldtimebuddy.com/edt-to-gmt-converter

https://www.youtube.com/watch?v=KCoTeBni5As

(EST) Eastern Standard Time