Ma turns something

every four seconds

This something

is unknown to us (at least to me) and doesn't need to be identified. It can be anything that can be turned.

We only know that it is numbered from 1 at 00:00:04 to 21600 at midnight

That's why

- every day, at 1:12 she turns 18 (72 = 18 × 4 seconds)
- every day, at 2:16 she turns 34 (136 = 34 × 4 seconds)

[Edit] Maybe Ma is

a lighthouse?

Ma turns something

every four seconds

This something

is unknown to us (at least to me) and it can be anything that can be turned, even herself.

We only know that it is numbered from 1 at 00:00:04 to 21600 at midnight

That's why

- every day, at 1:12 she turns 18 (72 = 18 × 4 seconds)
- every day, at 2:16 she turns 34 (136 = 34 × 4 seconds)

[Edit] Maybe Ma is

a lighthouse?

[Edit #2] Following the publication of hint 2, Ma might be

a rotating celestial object with a 4-second spin period, like a neutron star (for example, pulsar J1814-1744's spin period is exactly 4s).

How is it related to hint 2? ma is the abbreviation of milli-arcsecond which is a unit used in astronomy.

Ma turns something

every four seconds

This something

is unknown to us (at least to me) and doesn't need to be identified. It can be anything that can be turned.

We only know that it is numbered from 1 at 00:00:04 to 21600 at midnight

That's why

- every day, at 1:12 she turns 18 (72 = 18 × 4 seconds)
- every day, at 2:16 she turns 34 (136 = 34 × 4 seconds)

Ma turns something

every four seconds

This something

is unknown to us (at least to me) and doesn't need to be identified. It can be anything that can be turned.

We only know that it is numbered from 1 at 00:00:04 to 21600 at midnight

That's why

- every day, at 1:12 she turns 18 (72 = 18 × 4 seconds)
- every day, at 2:16 she turns 34 (136 = 34 × 4 seconds)

[Edit] Maybe Ma is

a lighthouse?