Across the Universe Trivia Quiz

Answer:

Subrahmanyan Chandrasekhar - White dwarf

In the early 1930s, Subrahmanyan Chandrasekhar asked this question: What happens to a star after it burns through its fuel? Using quantum mechanics and special relativity, he found that white dwarfs (the dense remnants left behind by Sun-like stars) can't grow indefinitely massive. Above about 1.4 times the Sun's mass, the pressure from degenerate electrons can no longer support the star's weight. It meant some stars are headed for a catastrophic collapse.

This limit changed how we understand stellar death and the violent events that shape the cosmos. Stars exceeding the limit don't fade away. They implode, triggering supernova explosions that forge heavy elements and leave behind neutron stars or black holes. The physics behind this limit also drives Type Ia supernovae, the 'standard candles' later used to discover dark energy. Chandrasekhar's insight opened the door to some of the biggest breakthroughs in modern cosmology.

Henrietta Swan Leavitt - Period-luminosity relation

When working at the Harvard College Observatory, Henrietta Swan Leavitt identified a precise link between a Cepheid variable star's true brightness and how long it takes to pulse. Her 1912 work showed that the longer a Cepheid's cycle, the brighter the star actually is.

This turned Cepheids into cosmic measuring sticks. Astronomers could finally calculate distances to remote galaxies and work out how big the universe really is. By using Cepheids to measure galactic distances, astronomers eventually determined that the universe is expanding. Leavitt's discovery became the foundation for that breakthrough and reshaped modern astrophysics.

Albert Einstein - General relativity

Albert Einstein's general theory of relativity was published in 1915. It described gravity as the curvature of spacetime rather than a force acting at a distance. This theory became the foundation for modern cosmology and for understanding black holes, gravitational lensing, and the large-scale structure of the universe.

The theory was confirmed during the 1919 solar eclipse, when astronomers saw starlight bending around the Sun exactly like Einstein predicted. That observation turned general relativity into one of the biggest physics breakthroughs ever and made Einstein a worldwide celebrity.

Cecilia Payne - Stellar composition

In her 1925 doctoral work, Cecilia Payne showed that the Sun and other stars are made up primarily of hydrogen, with helium second. This overturned the assumption that they had an Earth-like composition and proved that hydrogen dominates the universe.

Her insight changed how scientists understood stars. They weren't just distant lights; they were chemical records of cosmic history. This helped researchers trace how the first elements formed after the Big Bang and how later generations of stars built the heavier ones we find today.

Georges Lemaître - Expanding universe theory

In 1927 Lemaître figured out that the universe is expanding, using general relativity and redshift data to derive what we now call Hubble's law. In 1931, he proposed the 'primaeval atom' hypothesis, an early version of the Big Bang theory that the universe started from a super-dense, hot state.

His ideas didn't get much attention at first, but once Edwin Hubble's observations confirmed the universe was expanding, Lemaître's work started getting the recognition it deserved. Over the next few decades, evidence like the cosmic microwave background radiation established the Big Bang as the leading theory, with Lemaître's early insights forming its foundation.

Edwin Hubble - Discovery of other galaxies

In 1923, Edwin Hubble identified a Cepheid in the Andromeda Nebula, proving that Andromeda is a separate galaxy far outside the Milky Way. By 1929, he showed that galaxies' recessional velocities increase with distance, providing observational evidence that the universe is expanding.

Hubble's discoveries transformed astronomy by revealing that the Milky Way is only one galaxy amongst countless others, and that the universe itself is changing, not fixed. His work established the observational foundation for modern cosmology and an expanding universe.

Arno Penzias & Robert Wilson - Cosmic microwave background

In 1964, Arno Allan Penzias and Robert Wilson detected an isotropic microwave glow across the sky. They later identified it as the cosmic microwave background (CMB). The CMB provided strong evidence for a hot Big Bang origin of the universe and opened the era of precision cosmology.

This discovery allowed scientists to study tiny temperature fluctuations imprinted on the early universe. These variations revealed how matter first began to clump together, giving a blueprint for the formation of galaxies and large-scale cosmic structure.

Vera Rubin - Dark matter in galaxies

In the late 1970s Vera Rubin and Kent Ford measured rotation curves of galaxies such as Andromeda and found that stars in the outer regions rotate as fast as inner ones, contrary to Newtonian expectations from visible matter alone. This was compelling evidence that galaxies are embedded in massive halos of unseen dark matter, which dominates the universe's matter content.

Rubin and Ford's work did something bigger: it made dark matter real. What had been just a wild idea became essential to understanding how the universe actually works. Their measurements proved this invisible stuff doesn't just exist, as it shapes how galaxies form, grow, and crash into each other. That foundation is still used to map out the universe's structure today.

Alan Guth - Cosmic inflation

In the early 1980s, Alan Guth proposed inflation, a split-second burst of exponential expansion right after the Big Bang. This solved some major puzzles, such as why the universe looks so uniform in every direction, why it's geometrically flat on large scales and where those tiny ripples in the CMB came from.

Inflation tied quantum physics to cosmology. During that brief but intense expansion, quantum fluctuations, normally microscopic, got stretched to cosmic size. Those became the seeds for everything we see now, like galaxies, galaxy clusters, and the whole web-like structure of the universe.

Saul Perlmutter & teams - Accelerating expansion and dark energy

In the late 1990s, Saul Perlmutter's team used distant Type Ia supernovae as standard candles and discovered something shocking: the universe's expansion is speeding up, not slowing down. This meant there had to be something else out there (dark energy) which now appears to make up about 70% of the universe's total energy.

The discovery completely overturned cosmology's biggest question: how will the universe end? Instead of gradually collapsing back under gravity's pull, the cosmos seems headed for endless expansion, with galaxies drifting further and further apart. Dark energy went from unknown to the main puzzle in understanding the universe's fate.

Stellar parallax measured, Discovery of Neptune, Universal gravitation, Moons of Jupiter, Laws of planetary motion and Heliocentrism were not twentieth century discoveries.