A bubbling sound. / A hookah.

hookah, bong (pipe)

Alternative spelling of hubble-bubble

plural of hubbly bubbly

(astronomy, cosmology) A constant defined as 1/H_0, where H_0 is the Hubble constant. 1/H_0 is equal to 4.55×10¹⁷ seconds or 14.4 billion years.

plural of hubble-bubble

plural of hubble bubble

(astrophysics, cosmology) The motion of galaxies due to the expansion of the universe

Alternative form of hubbly bubbly

(cosmology) the spherical region of the observable universe surrounding an observer beyond which objects recede from that observer at a rate greater than the speed of light due to the expansion of the Universe.