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We consider five dimensional deSitter spacetimes with a deficit angle due tothe presence of a closed 2-brane and identify one dimension as an extradimension. From the four dimensional viewpoint we can see that the spacetimehas a structure similar to a Kaluza-Klein bubble of nothing, that is, fourdimensional spacetime ends at the 2-brane. Since a spatial section of the fulldeSitter spacetime has the topology of a sphere, the boundary surface surroundsthe remaining four dimensional spacetime, and can be considered as thecelestial sphere. After the spacetime is created from nothing via an instantonwhich we describe, some four dimensional observers in it see the celestialsphere falling down, and will be in contact with a 2-brane attached on it.Comment: 5pages, 4figures, to be published in GR

Kaluza-Klein bubble like structure and celestial sphere in the inflationary universe