Twenty years ago, the Hubble Space Telescope revealed a giant crab in the sky. Now, just before its 29th birthday (Hubble was launched into space April 24, 1990), the telescope again trains its lenses on the Southern Crab Nebula to provide the world with a stunning reminder that, a) the cosmos is mysterious and beautiful, and, b) launching giant cameras into space is a really neat idea.

Every year, Hubble spends a small portion of its time snapping a gorgeous anniversary picture like this one, according to a statement from the European Space Agency (ESA), the agency that manages the telescope in cooperation with NASA. The decision to image the Southern Crab Nebula for this year's birthday photo recalls the first encounter between the photographer and its subject in 1998, when Hubble imaged the complete hourglass structure of the nebula for the first time. [Spaced Out! 101 Astronomy Images That Will Blow Your Mind]

The Southern Crab Nebula sits in the constellation Centaurus, about 7,000 light-years away from Earth. What look like the legs and pincers of a cosmic crab are actually twin bubbles of gas and dust burped out by a pair of stars at the nebula's center. This celestial Odd Couple is composed of one red giant — a huge, dying star in the process of molting its outer shell of matter — and one white dwarf — the tiny, dead husk of hot crystal that remains once a red giant has loosed its last burst of gas.

According to the ESA, this binary duo coexists in a relationship where the dying red giant continuously feeds gas and dust into the white dwarf via its gravitational pull. After piling up for thousands of years, all that space schmutz may spark an eruption on the white dwarf's sizzling surface, sending matter scattering through space in giant bubbles. Astronomers think this has happened twice in the relatively recent past, giving rise to the twin splatters of glowing matter visible in Hubble's images of the nebula.

A similar celestial explosion could even happen again under Hubble's watch, turning this giant space crab into — what? A Three-Leafed Clover Nebula? A Sprig of Holly Nebula? Call us crabby but, somehow, those nicknames just don't have the same ring to them.

Originally published on Live Science.