This week marks the 23rd anniversary of that event, and to celebrate, astronomers released a breathtaking image of the iconic Horsehead nebula, a vast and dense cloud of gas and dust in Orion.
The nebula, about 1,500 light years away in the constellation of Orion, was imaged in infrared wavelengths against the backdrop of the Milky Way.Dubbed the Horsehead nebula because of its obvious resemblance to a steed or chess piece in profile, has been a favorite target for generations of backyard stargazers.
The object is a popular observing target, and Hubble has taken numerous Horsehead photos over the years -- including in 2001, to celebrate the telescope's 11-year anniversary.
The Horsehead's dramatic pillar is made of sterner stuff than the clouds surrouding the nebula, which have already dissipated. But the pillar will disintegrate as well in another 5 million years or so, astronomers say, and the Horsehead will go the way of the dodo.
In this new portrait, the nebula's normally shadowy facade seen in optical light, now appears in infrared light to be transparent, and lit up against a backdrop of more distant bright nebulae and star clusters scattered in our Milky Way galaxy.
Two new stars are seen in the top ridge of the nebula, and one is emitting "harsh ultraviolet glare" that is slowly evaporating the nebula, NASA noted in a release.
"Gas clouds surrounding the Horsehead already have dissipated, but the tip of the jutting pillar contains a slightly higher density of hydrogen and helium, laced with dust," the agency said.
