It's been around for millions of years, but it's no more than a month old. What is it?

Who makes it, has no need of it.
Who buys it, has no use for it.
Who uses it can neither see nor feel it.

"I never was, am always to be,
No one ever saw me, nor ever will
And yet I am the confidence of all
To live and breathe on this terrestrial ball."