The Hubble volume

The Hubble volume is the sphere of space visible to the Hubble telescope—i.e. everything that’s not receding from us at a rate greater than the speed of light due to the expansion of the universe. The Hubble volume is an unfathomably large 1031 cubic light years.
That’s 846,800,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000 cubic kilometers.