The noösphere is the universe of memes
The noösphere (and the diaresis is important to prevent the word being pronounced “new-sphere,” though apparently some use that pronunciation) is a term used by Pierre Teilhard de Chardin in Cosmogenesis and seems to correspond to the universe of memes, as defined by Richard Dawkins: the transmissible units of cultural knowledge—basically, all the skills you learn by imitation and the knowledge you are taught (and thus can pass along).
The noösphere (or the meme universe) is an emergent phenomenon, just like the biosphere (the universe of living organisms) is emergent from the geosphere (the material world and its processes).
In all three spheres, change is constant. The geosphere changes through a variety of mechanims: tectonic plate movement, volcanic action, weather, solar radiation, and the like. The biosphere is subject to geospherical processes (e.g., natural disasters such as drought, flooding, tsunami, and so on), but the mechanism of change within the biosphere is through evolution.
In the noösphere, the primary drive of change is also evolution, but the evolution of memes rather than lifeforms.
The biosphere exploits the materials of the geosphere, and the noösphere exploits the capabilities of the biosphere—namely, through the human capability of hosting and transmitting memes. Just as humans are not independent of the geosphere, the noösphere is not independent of humans. Nonetheless, it is useful to distinguish lifeforms from non-living matter, and to distinguish memes from the humans that host them.