Conversion from 2 Seconds to Milliseconds

Information about the Second (s)

The second is the base unit of time in the International System of Units. Its symbol is s. It is defined by fixing the frequency of the caesium-133 hyperfine transition at exactly 9,192,631,770 cycles per second, so a second is the duration of that many oscillations.

The name records a division that no longer exists in practice. Medieval astronomers divided the hour into sixty minutae primae, first small parts, and each of those into sixty minutae secundae, second small parts. English kept the first as minute and the second as second, leaving the ordinal in the name of a unit almost nobody thinks of as ordinal.

For most of history the second was defined from the rotation of the Earth, as one 86,400th of a mean solar day. That definition failed once clocks became better than the planet: the Earth's rotation is irregular, slowing over centuries from tidal friction and wobbling on shorter timescales. The atomic definition adopted in 1967 severed the link, which is why leap seconds are occasionally inserted to keep civil time aligned with the sun.

Every other time unit is now built on it, and the second underpins most of the rest of the SI as well. The metre is defined through the speed of light in metres per second, the kilogram through the Planck constant which carries a second in its units, and the ampere through the elementary charge per second. Caesium fountain clocks realise the unit to a few parts in ten to the sixteenth, and optical clocks now do better still.

Because atomic clocks keep better time than the planet does, the two have to be reconciled. The Earth's rotation is slowing irregularly, so a day is now a millisecond or two longer than 86,400 atomic seconds, and the difference accumulates. Since 1972 the answer has been the leap second: an extra second inserted at the end of a June or December, announced months in advance, which has happened twenty-seven times. Computer systems handle the repeated timestamp badly enough that outages have been traced to it, and in 2022 the world's metrology bodies voted to abandon the practice by 2035, letting civil time drift from solar time instead.

One second equals 1000 milliseconds, one sixtieth of a minute, or about 0.000277778 hours.

Information about the Millisecond (ms)

The millisecond is a unit of time equal to one thousandth of a second. Its symbol is ms. It is the shortest interval that people encounter by name in everyday life, largely because computing and networking made it a household measurement.

Human perception sets the scale that makes it interesting. The eye fuses separate images into motion somewhere around forty milliseconds apart, which is why cinema at twenty-four frames a second works. Audio is far less forgiving: a delay of more than about ten milliseconds between a musician's action and the sound they hear is enough to disrupt playing, and stereo direction is judged from arrival-time differences between the ears of well under one millisecond.

Network latency is quoted in milliseconds and is the number that determines whether a connection feels responsive. Light travels about three hundred kilometres in a millisecond in fibre, so intercontinental round trips have an irreducible floor: London to New York cannot go below roughly sixty milliseconds no matter how much is spent on equipment. Competitive online gaming, financial trading and video calling are all shaped by that limit.

Reaction time is measured in the same unit. A trained sprinter responds to a starting gun in around 150 milliseconds, and athletics rules treat anything below 100 milliseconds as a false start on the grounds that no human can react faster. Simple visual reaction times in a laboratory typically fall between 200 and 250 milliseconds.

Computing uses milliseconds as the natural unit for anything involving storage or human interaction. A mechanical hard disk seeks in several milliseconds while a solid-state drive answers in a fraction of one, a difference of two orders of magnitude that explains most of the change in how computers feel over the last two decades. Timestamps in most programming environments count milliseconds since the start of 1970.

Photography borrows it for shutter speeds, where a thousandth of a second is a common setting for freezing motion, and physiology uses it for the duration of a nerve impulse, which lasts one to two milliseconds.

One millisecond equals 0.001 seconds, 1000 microseconds, or one 3,600,000th of an hour.