One verse

Srimad Bhagavatam 3.11.3

3.11.3

एवं कालोऽप्यनुमित: सौक्ष्म्ये स्थौल्ये च सत्तम । संस्थानभुक्त्या भगवानव्यक्तो व्यक्तभुग्विभु: ॥ ३ ॥

evam kalo ’py anumitah sauksmye sthaulye ca sattama samsthana-bhuktya bhagavan avyakto vyakta-bhug vibhuh

evam
thus
kalah
time
api
also
anumitah
measured
sauksmye
in the subtle
sthaulye
in the gross forms
ca
also
sattama
O best
samsthana
combinations of the atoms
bhuktya
by the motion
bhagavan
the Supreme Personality of Godhead
avyaktah
unmanifested
vyakta-bhuk
controlling all physical movement
vibhuh
the great potential.

One can estimate time by measuring the movement of the atomic combination of bodies. Time is the potency of the almighty Personality of Godhead, Hari, who controls all physical movement although He is not visible in the physical world.