By Emily Levesque, University of Washington
When it comes to astronomy, we’ve made new discoveries that stretch the limits of our imagination. And yet, we have only just begun unravelling the mysteries of black holes, dark matter, and dark energy, and are now in a position where we can comprehend how the universe began and how it will end.
The Harvard Computers
Much of what we know about the stars today began with the ground-breaking work of a group of astronomers known as the Harvard Computers: women employed by the Harvard College Observatory to process and analyze the cutting-edge astronomical data of the era.
Women like Annie Jump Cannon and Williamina Fleming, and other early Harvard astronomers like Cecilia Payne-Gaposchkin made some of the most foundational discoveries about stars in the history of astronomy.
They developed methods for classifying stars that are still used today, and discovered that stars are primarily composed of hydrogen and helium. They broke down barriers for women in astronomy.
Henrietta Swan Leavitt
One Harvard Computer, Henrietta Swan Leavitt, made a particularly compelling stellar discovery with ramifications that are still shaping astronomy. She discovered Cepheid variables, stars whose rate of pulsation is directly correlated with how bright they appear.
It may seem like no more than a curious discovery, but Cepheid variables wound up drastically altering our picture of the universe. By measuring these stars’ pulsation rates and determining how bright they should be compared to how bright they appeared, Leavitt had given us a new and powerful tool for measuring the distances to faraway objects, and her work directly led to Edwin Hubble’s discovery of galaxies beyond our own.
This article comes directly from content in the video series Great Heroes and Discoveries of Astronomy. Watch it now, on Wondrium.
Edwin Hubble
Hubble’s most indelible contribution to astronomy was a famous and deceptively simple equation describing the expansion of our universe. However, as with many details of our universe, the discovery isn’t as simple as it seems.
Georges Lemaitre, a Belgian priest and astronomer, had published a similar result several years earlier. Other physicists and astronomers also had speculated about an expanding universe based on implications of Einstein’s general theory of relativity that were still being explored.
Hubble Constant
Hubble’s famous equation is a source of continued debate as teams of astronomers engage in a century-long mission to determine the exact value of this equation’s constant—the so-called Hubble constant—and work to reconcile different observations into a single answer that can best explain the expansion of our universe.
Hubble’s legacy also lives on in the space telescope that bears his name. The heroes of the Hubble Space Telescope range from astronomers who dreamed of space telescopes long before humankind ever launched its first satellite, to the NASA personnel who tackled daunting scientific and bureaucratic hurdles to make the telescope a reality, to the astronauts who opened (and sharpened) the telescope’s eyes, to the teams of scientists today that have kept the telescope running and making remarkable discoveries for over 30 years.
Radio Astronomy
It’s also important to remember that astronomy involves much more than the light that we detect with our eyes. What we call visible light occupies just a tiny fraction of the electromagnetic spectrum, and fully understanding the universe requires the ability to detect energy across this entire spectrum to get a complete picture of the cosmos.
Over in the radio regime—at wavelengths far too long and energies far too low to be detected with our eyes—physicist Karl Jansky made a groundbreaking discovery in 1932. He became the first person to detect radio waves from space while working at Bell Labs.
A few years later, Grote Reber created the first dedicated radio telescope, an antenna specifically designed to detect radio waves from the sky. Since then, the field of radio astronomy has grown exponentially.
We have radio astronomy to thank for one of the most exciting astronomy discoveries, when in 2019, astronomers synchronized radio telescopes across the entire planet to take the first ever picture of a black hole.
The Cosmic Microwave Background
Another radio antenna at Bell Labs also made an incredible, if accidental, discovery in 1964. It detected the cosmic microwave background, the faint leftover remnant of the Big Bang.
Observable only as a quiet but persistent hiss in the background of the telescope’s data, this radio signal from the birth of the universe led to a Nobel Prize for its discoverers, Arno Penzias and Robert Wilson.
Today, several dedicated space telescopes have been launched to study the cosmic microwave background, and teams of scientists are focused on collecting data from the universe’s earliest moments in the hopes of explaining how space and time have evolved to what we have today.
Decades after Hubble’s discovery of galaxies beyond our own, and just three years after the discovery of the cosmic microwave background, there came a shift in how we studied the nature of our universe.
Dark Matter
An astronomer named Vera Rubin uncovered strange inconsistencies in how the stars in nearby galaxies moved. Years of careful observations revealed that these galaxies appeared to contain huge amounts of invisible mass, what we now call dark matter.
The existence of dark matter fundamentally changed our entire cosmological model and spawned an entire new field within astronomy, focused on studying dark matter in the hopes of explaining what exactly it is and how it affects our universe.
Each of these discoveries presents an immensely compelling story: they’ve changed what we know about the universe, and expanded our picture of what we can understand, opening up our view of the cosmos with every step.
Common Questions about Astronomy: Making New Discoveries
The Harvard Computers was the name given to a group of women employed by the Harvard College Observatory to process and analyze the cutting-edge astronomical data of the era.
Edwin Hubble’s famous equation is a source of continued debate as teams of astronomers engage in a century-long mission to determine the exact value of this equation’s constant—the Hubble constant—and work to reconcile different observations into a single answer that can best explain the expansion of our universe.
In 2019, thanks to radio astronomy, one of the most exciting astronomy discoveries was made when astronomers synchronized radio telescopes across the entire planet to take the first ever picture of a black hole.
