UTC、GMT、CST

UTC( World standard time )

Coordinated universal time , Also known as world standard time or world coordinated time , abbreviation UTC（ From English “Coordinated Universal Time”／ French “Temps

Universel Coordonné” And come ）, Is the main world time standard , It's based on the atomic time and second length , Try to be as close to Greenwich mean time as possible .

GMT( Greenwich mean time )

Greenwich mean time （ Also known as Greenwich mean time or Greenwich mean time , Greenwich mean time ; English ：Greenwich Mean

Time,GMT） It is the standard time of the Royal Greenwich Observatory in the suburb of London , Because the prime meridian is defined as the meridians passing through it .

In theory , Midday GMT is when the sun crosses the Greenwich meridian （ At the highest point over Greenwich ） Time for . Because the earth's velocity in its elliptical orbit is not even , This moment may be different from the actual solar time , The maximum error is 16 minute .

Because the earth's daily rotation is somewhat irregular , And it's slowing down , Therefore, Greenwich mean time is no longer used as standard time . Now standard time , It is coordinated universal time that is annunciated by the atomic clock （UTC）.

CST( Beijing time. )

Beijing time. ,China Standard Time, China standard time . In time zone division , It belongs to Dongba district , Earlier than coordinated universal time 8 Hours , Write it down as UTC+8.

But this CST The crux of this abbreviation is that it can represent four different times at the same time ： Central Standard Time (USA) UT-6:00

Central Standard Time (Australia) UT+9:30 China Standard Time UT+8:00

Cuba Standard Time UT-4:00

Java Date Use UTC Time , Such as Tue Jan 05 14:28:41 CST 2016 Express China Standard Time UT+8:00 .