In 1997, UCLA astronomers using NASA's Hubble Space identified what may be the most luminous star known. Truly, a celestial mammoth and 25,000 light years away, the star releases up to 10 million times the power of the Sun and is big enough to fill the diameter of Earth's orbit.

Unfortunately, this amazing star is not visible to the unaided eye. It is located in the direction of the constellation Sagittarius, hidden behind the great dust clouds along the Milky Way.

Astronomer Don Figer suggested that this star also created a surrounding cloud of glowing gas, which has been dubbed the Pistol Nebula. As such, this powerhouse star is called the Pistol Star.

The Pistol Star unleashes as much energy in six seconds as our Sun does in a year.

Look to the south-southwest sky after darkness has fallen to find Sagittarius, often depicted in allegorical star atlases as a centaur but who long ago was not a centaur at all but simply standing Archer (looking with some apprehension toward the Scorpion immediately to his west).

About two-fifths of the way up from the star Al Nasl northwest to Theta Ophiuchi lies the direction of the center of our Milky Way system, appearing as a veritable cloud of stars. This is also the same region of the sky where the Pistol Star is located, but it is hidden from our view by a cloak of interstellar dust.

Interestingly, on average, there are less than half a dozen specks of this microscopic matter in each cubic mile of space, yet this total is still sufficient enough to present a solid and impenetrable curtain between us and this most luminous of all stars.

Even the most powerful telescopes cannot see this star in visible wavelengths.

However, about 10 percent of the infrared light leaving the star does manage to reach Earth, putting it within reach of infrared telescopes, which have seen rapid technological advances in recent years -- spurred by projects such as Hubble’s Near-Infrared Camera and Multi-Object Spectrometer (NICMOS).

The Pistol Star might be only 1 million to 3 million years old, astronomers say, and it will live for only another similar amount of time before exploding in a supernova.