Our cosmological models have been written and rewritten so many times, if another advanced species were observing us they would have to wonder if us Earth humans are ever going to get it right. First, the Earth was the center of the universe, and then it was one of the heavenly bodies that revolved around a pretty interesting but relatively stationary and lonely star within the great cosmos (which at that point was just the solar system). And then came along three celestial mechanics giants and our consciousness jumped exponentially with each one of their entrances to the conversation.
Henrietta Swan Leavitt attended the Society for the Collegiate Instruction of Women in Massachusetts, which would later be known as Radcliffe College. After her graduation she found a post at the Harvard College observatory under the direction of Charles Pickering. Over her career she discovered and made a thorough study of over 2000 stars, specifically a grouping of stars known as the Cepheid Variables.
 Using Cepheid variables to measure distance
Leavitt noticed that these stars contracted and expanded in a very predicable way and this rate was directly related to the maximal brightness of the star. By closely observing these stars she was able to deduce what is known as the Cepheid Variable Period Luminosity. These data allowed researchers to begin to measure cosmic distance and was integral to the contribution made by the next gargantuan researcher. In addition to these contributions Leavitt also developed a 17 scale measurement tool for star brightness through the usage of logarithmic equations and data from 299 stars and 13 telescopes.
Edwin Hubble, after which NASA’s Hubble telescope is named, studied physics at the University of Chicago and astronomy at Cambridge. Shortly after leaving Cambridge he received a post at the Mount Wilson Observatory in California, where he remained until his death in 1953. Using the newly constructed Hooker telescope he also made a study of the Cepheid variable stars.
 RS Puppis – one of the brightest Cepheid Variables
His early research led him to conclude Andromeda was not merely a spiral of the milky way but a galaxy in its own right . His further research allowed him to not only put to death the theory that our galaxy is the only one in the universe but he was able to correlate spectral data with distance. His theory, and what has been used in the astrophysics community since, is that red-shift in galaxy light emissions is related to distance between galaxies in a linear fashion . This research lead Hubble to the conclusion that the cosmos is expanding. If most people had a hard time accepting that the universe was made up of an non-quantifiable number of other galaxies their minds had to have just blown-up when it was also demonstrated that the universe is expanding.
So 1 star became 10^11(100billion) and that morphed into at least 10^23 . Maybe our estimates are a bit off and its really 6.022 x 10^23 (gotta give my chemistry guys a shout out). So whats the next step? Each jump is so unimaginably large that it boggles the mind to think there could be more but….is there a chance that we will discover the universe is finite and just one of many within the multiverse? Does it ever end or do we just get to a point where we can perceive another boundary limit more distinctly? Utterly mind-bending…
The last of the gargantuan astronomers for today is the man who characterized the planet Uranus in this age, William Herschel (1783-1822), but that was far from his greatest contribution, in my opinion. I could imagine that astronomers of deep antiquity all the way up to the 18th century were convinced that our stars existed without partner. After all it is Newton’s theory of gravity that gives proof of the attraction of bodies at a distance. Without his theory, heavenly bodies were just pretty stationary objects. And then came Herschel. From his mind came the colossal works the “New General Catalog” and “Catalog on Double Stars”. It is this final work that has me truly fascinated. He discovered that certain stars existed quite close to each other and his observations led him to the conclusion that gravity exists outside of our solar system and that these stars were in fact gravitationally attracted to each other. His was a strong career that lead to a personal cataloging of more than 2500 stars and 145 double (or binary) stars . Some of these systems are incredible to say the least. According to the Binary Research Institute astronomers from the United Kingdom working on Hawaii with an Infrared telescope just recently discovered four pairs of binary systems in which the stars orbit each other in under four hours . Imagine the short distance that must exist between them…
So this all begs the question, does solar system sol have a binary companion around which it dances? In the Milky way approximately half of all stars are binary stars so the chances are quite high! Surely William Herschel must have thought that the binaries were rarities but he couldn’t have been more wrong. Amazingly a physicist from Berkeley and a radio astronomer from Harvard are suggesting that all stars are formed in pairs . Perhaps our sun did have a dancing partner but instead of a social companion it was a nemesis which had to be vanquished. So naturally us Earth humans living so long after the formation of the binary system would not have any knowledge of its existence. What a warrior sun we had! Well anyways our sun seems to be quite unique in the universe in that it has a planet that can support life. Did its former twin also have this ability? Perhaps more scans of the sky with the Hubble telescope will yield the answers to these late night metaphysical musings.