A Continuest Riddle

A line, a dot, a mark, continuest it goes. Never stopping, yet bold. Can be etched in many similar symbols it resembles. Whilst over many years, its still used today. What am I?

written word

Nope.

music

Nope again.

A circle?

Nu uh, I'll give a hint. "What am- (?)"

An exclamation point, maybe, punctuation?

Nope. Look again. But closer.

...By that. I mean look up to the first said riddle. :b

I?

Your very close...

What does it resemble though?

A 1?

The letter I

Yes. A one. Think of the times of roman numerals.

Anyhow! Another Riddle that leads off from the first one!

I'm read from the skies from the moon and sun. Light bringing shadow. Marked by the lingering shadows from the suns arays. Yet consumed by the nights moon. They keep passing by knowing the environment changes around us. But one thing is certain, everything ages. What made it so?

Hint: What ages things.

Time

Clouds.

Water.

Nope.

Light.

Nope again.

I feel like this is going to be wrong; could it be a sun dial?

Its close... Very close.

day?

Nope.

A clock

Deterioration of cells

Science stuff.

Clocks is the define line you should lead down on. But science is the one that cradled the idea.