What may look like a simple star field, reveals one of the most interesting classes of objects in the universe. In the crosshairs is 3C 273, an object known as a "Quasar"...or "quasi-stellar object". All of the other stars in this image are relatively nearby, within our own galaxy. We look across a huge gulf of space and time to see 3C 273. In fact, it is so distant that we are looking at it as it appeared some 2.18 BILLION years ago. It took that long for its light, travelling at 286,000 miles each second, to reach us here. As the universe itself began in the Big Bang 13.77 billion years ago, we are looking back nearly one-sixth of the age of the universe. And this object is some 400 TRILLION times as bright as our Sun.

So, how do we actually know the distance to such objects? Each chemical element that appears in a star's spectrum of light has a "fingerprint"...a system of lines that appear in the spectrum announcing that element's existence in the nuclear reactions going on. We can tell if an object is travelling towards us, or away from us, and how fast, by noting how much an element's fingerprint is shifted either towards the red or blue end of the spectrum. This is similar to how the pitch of the sound of a train's horn changes as it approaches then moves past us.

Astronomer Edwin Hubble nearly 100 years ago noted that entire galaxies also had such fingerprints in their light's spectrum and correlated how far these fingerprints were red-shifted, which tell with how fast they are moving away from us, with their distance. The distances were derived by one of several methods that were calibrated against nearer objects. He noted that the farther away an object was, the faster it was moving away. The universe is expanding! And if we run this movie backwards to its beginning, we find that it all began in a colossal expansion of space (and time) 13.77 billion years ago.

When the spectrum of 3C 273 was first measured in 1963, the astonishing finding was that it was red-shifted to an extent that indicated a distance of several billion light years. The object had actually been known since 1959 as a huge source of radio noise, one of the brightest in the sky, but only when its distance became known did things start to come together. In order to even be detectable at this distance, it has to be extraordinarily bright...estimated at 400 trillion solar luminances. But what kind of object could emit such huge amounts of energy? It was given the name of "Quasar" since it resembled a star, but must be something completely different. It was also noted to vary slightly in brightness over time and this puts an upper limit on its physical size since a change in output has to propagate over the object at less than the speed of light. Since the discovery of 3C 273, thousands more have been detected and studied.

Through the 1960's and early 70's, several theories were put forth attempting to explain how such a huge amount of energy could come from an object that appears to be relatively small. It was speculated that these could be supermassive objects that were not as far from us as their spectrum's indicated. However, as more lines of research came in, the evidence all pointed to their distance being real. The science of black holes was also being refined and the current thinking is that quasars are the result of supermassive black holes at the centers of ancient galaxies gobbling up matter at a prodigious rate. They also appear to be a stage in the evolution of galaxies that no longer occurs since the nearest one found is just under one billion light years away, with most being around 10 billion light years distant. Thus, when we look at the light from 3C 273 in this picture, we are looking at an object that likely has not existed for well over a billion years.