will an RSS feed bring my subsite posts into my main site?

Hey. I’m trying to accomplish something and learn how it fits into the context of an ‘RSS’ feed.

So, I have a publication-site; which features the posts of Authors in my multisite.

The publishing platform is the main site (http://www.intothemythica.com)

And i’m wanting to show posts with featured images and a link on an aggregate page; from say, example; (mysubsite.intothemythica.com)

This is an aspect of WordPress i’m just coming to understand; I see it implemented everywhere is seems; posts in newsfeeds, this that and the other thing.

How can I accomplish this on my site?