Does Google index has expiration?

[informatica810]

Hi, I have this in mind and I think you can help me.

Suppose that I have a pagin something like this: www.mysite.com/politics

where I have a list of the current month news.

Great, everytime the bot check this url, index the links that are there.

What happens next month, all that link are not visible anymore by the user unless he search in a search box or google.

Does google keep those links?

The current month google check that those links are there, but next month are not, but they are alive.

So, my question is, Does google keep this links for ever if they are alive but nowhere in the site (the bot not find them anymore but they work)?

Thanks

[IPROdigital]

I believe they will still be indexed but links leading to them will probably be useful if you want to get a decent page rank.

[informatica810]

Sorry, but I dont understand you.