A star is, essentially, an ongoing, ceaseless nuclear explosion fueled by the interstellar gas that was originally brought together by gravity. The energy released by the nuclear activity at the center of a star pushes outward and prevents the weight of the overlying gas from collapsing toward the middle. So long as there is sufficient material to fuel the internal nuclear reaction, a star will shine and maintain its diameter. However, with every star there comes a point when the central nuclear fires become exhausted and, thus, loose their ability to stop the outer layers from crushing inward. The ultimate fate of a star is dependant upon its mass when this compression commences. If a star is more that three times as massive as our Sun, then the weight of the matter rushing inward can never be stopped. It will squeeze upon itself in a never-ending process of shrinking until it becomes a singularity- a thing with unbelievable mass but no volume, an object weighing something like a planet per teaspoonful! Its gravitational force is so significant, that anything which ventures beyond a spherical gravitational boundary that surrounds it, known as the event horizon, is forever trapped and inexorably pulled in- including light! In short, the star becomes a black hole.
The first stars that arose following the beginning of the Universe were enormous objects hundreds or thousands of times more massive than our Sun. They burned their nuclear material at a tremendous rate and only shined for a few hundred million years before they collapsed into super-massive black holes. They attracted material that surrounded them and thus became the seeds of the first proto-galaxies. Over time, these initial galaxies merged and as they did, their central black holes also combined and grew. This process of galactic accretion is still occurring today.
Studies of Milky Way's central region have shown that the super-massive black hole, located there, is surrounded by orbiting stars, gas and dust that are keeping their distance so that the amount of material falling onto its event horizon is very small. It is believed this situation is similar in most other galaxies that surround ours, however, in some the central black hole is far from dormant!
Located about 60 million light years from Earth, towards the direction of the constellation named Cetus, is an enormous galaxy, much larger than our own, that is surrounded by a even larger cloud of obscuring dust. This galaxy does not have a common name but was designated by Charles Messier, the French comet hunter, as M-77. Although it was mistaken as a nearby nebula when it was discovered in 1780, its spiral form was immediately recognized as unique.
M-77 has captured the imagination of scientists for many decades because of the unusually high amount of energy pouring from its central region. Following years of intensive investigation, observations with the Hubble and Spitzer Space Telescopes confirmed the presence of a powerful jet pouring copious amounts of material into inter-galactic space at enormous speed. It is now believed that the source of this commotion is a super-massive black hole, ten million times more massive than our Sun, in the process of absorbing material that has ventured too close.
Over time, the orbits of gas, dust and stars near a black hole will slowly decay thus causing the stellar objects and material to grow closer to the event horizon. As they approach, the speed of their orbit will increase until it reaches incredible velocity. Instead of being drawn beyond the point of no return, some material will, instead, be flung outward far away from the black hole in a massive jet of matter and energy.
The radiation emitting from the center of M-77 is constantly changing- it can be observed to brighten and dim over a period that spans just a few days. This picture cannot show the jet because it is not detectable in visible light. However, the material that is shot from the center eventually falls back onto the galaxy's broad circular plane- and that is something you can see in this image (above) where the color and contrast has been severely exaggerated.
On the right, (I believe) copious amounts of dust falling from the central jet create enormous, ruddy colored clouds and dust lanes encircling the galaxy. On the left, furious star formation give the outer arms a bluer cast as the light from the new, hot, bright suns is reflected off the nearby clouds of dust.