What time is it?
Ha! It depends on the clock.
It’s possible for a clock to be right only once per year—maybe even longer.
Let’s say a clock is just slightly off, by milliseconds.
It could take a full year or more before that clock aligns perfectly with “true” time.
But that makes perfect sense… compared to what?
Technically, a clock is always right—to itself.
So, does the universe have a consistent clock?
Is there some standard ticking something out there
that we can measure everything else against?
We divide time based on a full rotation of the Earth.
One day: sunrise to sunrise.
Minutes and seconds? Just subdivisions of that rotation.
But time is obviously relative.
What’s a day on Jupiter?
A day on Jupiter is still one full rotation… but it’s much faster.
Here’s a breakdown (thanks, planetsforkids.org):
Mercury – 58 days and 15 hours
Venus – 243 Earth days
Earth – 23 hours and 56 minutes
Mars – 24 hours, 39 minutes, 35 seconds
Jupiter – 9.9 Earth hours
Saturn – 10 hours, 39 minutes, 24 seconds
Uranus – 17 hours, 14 minutes, 24 seconds
Neptune – 16 hours, 6 minutes, 36 seconds
So, no planet agrees with our 24-hour “standard.”
Not even us.
Earth’s actual rotation is 23 hours, 56 minutes, and 4 seconds.
Wait a minute… wait a second…
Stop.
I thought a day was a full rotation—
and we built our clocks around that?
Turns out: yes, that was the idea…
but our original guess was cleaner than reality.
So what did we do?
We kept the guess and made reality adjust.
We add days. Leap years.
Poof—an extra day appears every four years.
Where did it come from?
Like some rogue comet—just orbiting into our calendar?
Time, it turns out, is a slippery concept.
Physics itself has to use two separate theories to talk about it.
For the cosmic scale: Einstein’s relativity.
For the microscopic: Quantum mechanics.
And here’s the kicker—
Quantum mechanics tells us that just measuring time can alter it.
What?
It’s like time is a squirmy child.
You try to measure his height—
he wriggles, bends his knees, stretches his neck—
and now you can’t trust the ruler or the number.
Time isn’t just relative.
It’s fickle.
Which brings me back to the classic:
Even a broken clock is right twice a day.
That’s a far better ratio than a slightly slow one.
