The Battle over the Universe’s Age

How can one person making observations for a few years calculate the age of a universe that is billions of years old? It seems to be such an unimaginable thing to calculate the age of a Universe when we cannot even understand everything about it and if we ever will. Edwin Hubble was a brilliant astronomer who took the first step in this huge mystery, but was his first step in the right direction?

Characteristics of a Time Traveler

The key scientists within this episode include Edwin Hubble, Allan Sandage, and Gerad de Vaucouleurs. Edwin Hubble was born in 1889 in Missouri and shortly after moved to Illinois. Although Hubble also succeeded in school with an exception to spelling, he was also known for being a great athlete in his earlier years. After high school he continued his education at the University of Chicago in which he got his bachelor’s degree in science. Hubble spent most of his years studying law as that was his father’s dream, but after his father passed, he went on to teach Spanish, math, and physics at a local high school. After reuniting with a colleague, he re sparked his interest in astronomy and went back to study at Yerkes observatory in which he got his Ph.D. In 1919 Hubble was offered a position at the Mount Wilson Observatory in California where he spent the rest of his career at. This was an amazing job as it had one of the best telescopes during this time in which he had everything at his fingertips.

Allan Sandage was born in Iowa in 1926. Sandage continued his education at the University of Illinois where he earned his bachelor’s degree in physics. He then went on to get his PhD in Astronomy from the California Institute of Technology.  While still in school, Sandage was the assistant to Edwin Hubble until Hubble died in 1953. Allan Sandage was the next in line to run Hubble at Mount Wilson and spent most of his career here. He paid most interest in trying to solve for the Hubble constant or the rate in which the universe is expanding.

Vaucouleurs became quickly interested in astronomy after his mother bought him a small telescope when he was 12. In 1957 he started studying at Lowell’s observatory in which he paid much interest in mars and distant galaxies. He also later continued his observation of distant galaxies at McDonald Observatory with his wife Antoinette.

The Equation that Sparked Curiosity

 With some help from the hooker telescope (see figure 1), Hubble was able to discover Cepheid variables which allowed him to determine the distance between galaxies. In fact, in 1924 Hubble observed the Andromeda nebula in which he observed stars much like those in the Milky way however were too dim and far away to be apart of our galaxy. Based upon the Cepheid variables, Hubble used their radial velocities as well as their redshift to best try and calculate the distance between them. After some time, Hubble found a linear relationship between the radial velocity and the distance between galaxies. This is what we now know as Hubble’s law where HO=V/D where Ho is the constant.  He believed that through this equation the universe was around 2 billion years old.

The Battle over Universe’s Age

In 1956, astronomers realized that there were two varieties rather than one in which they recalculated and found that the Universe was between 7 and 20 billion years old. This left a huge gap for astronomers to try and better estimate the age of the universe. Both Sandage and Vaucouleurs used careful calculations to try and find the age of our Universe and both also seemed certain with their answers.

Sandage began researching and trying to solve for Hubble’s constant in 1958. He worked closely with a colleague named Gustav Tammann. They spent much of their time measuring distant galaxies and when he moved to Hubble space telescope, Sandage observed Cepheids that were used to calibrate the luminosity of a type of la supernovae. Which he used as standard candles to find the distance to the red-giant branch or also known as TRGB. With his methods of measuring distant galaxies and careful calculations, Sandage believed the Universe to be around 20 billion years old.

In 1948 Vaucouleurs studied Hubble’s work in detail. After reading through his work, he found that Hubble had made some mistakes in his photographic photometry. By 1948 Vaucouleur had published his quantitative results which included parameters to measure the size and brightness of nearby galaxies. With his new calculations and measurements, Vaucouleurs believed the age of the universe to be only 10 billion years old. Instead of working together it seemed as if scientists were calculating and recalculating almost in hopes to claim the fame as this was a huge discovery. Eventually, in 2003 a team at NASA at the Goddard Space Flight Center used the Wilkinson Microwave Anisotropy Probe (a far-reaching probe) to get calculations with confidence. NASA was able to announce that the Universe is about 13.7 billion years old.

Conclusion

Edwin Hubble is the one who started it all however he was not the only one who served to find the age of our Universe. Through years of hard work and persistence Hubble was able to prove his theory of galaxies moving away from one another. With the Help of upcoming Astronomers such as Allan Sandage, Gerad de Vaucouleurs, and a team from NASA they were able to build upon one another’s paths to finally discover our Universes age of 13.7 Billion years. We see for many theories that scientists work together and/or continue the work of a previous scientist. Can you think of a time in science, or even in your own life, when people did not work together, and the results suffered? How do you think collaboration may have changed the outcome for you?

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