How Do We Solve the Riddles of Our Universe?

When stars collapse and explode in supernovae, they scatter heavy elements like oxygen, carbon and iron in every direction in the form of what Dr. Casey Papovich calls “cosmic pollution,” creating the building blocks for more stars and galaxies to form over time.

Papovich’s work revolves around the oldest observed galaxies, formed about one billion years after the Big Bang. While cosmologists expect these galaxies to contain some heavier elements, Papovich and his team have reason to believe they can observe some of the first “polluted” galaxies.

“That means there were even earlier generations of stars forming and dying in that first billion years to produce those heavy elements,” he said. “Those stars would have been very short-lived, dying quickly and generating lots of heavy elements to end up in the galaxies we see.”

By studying the formation of early galaxies, Papovich and his team hope to bridge fundamental knowledge gaps about our universe’s origins.

Black holes defy our everyday understanding of space and time. They are places where a gravitational collapse has compacted vast amounts of matter into a single, infinitely dense point, creating a region where gravity is so strong that not even light can escape. There are billions of black holes scattered throughout the universe.

“Empirical evidence demonstrates that black holes have a significant impact on how galaxies evolve,” Dr. Jonelle Walsh said, “but we don’t know the details behind this process.”

So far, scientists have observed a supermassive black hole (“supermassive” signifying a black hole millions to billions of times the mass of the sun) at the center of every large galaxy, including our Milky Way.

Most current data comes from the closest, largest and most easily detected black holes, but Walsh is studying more obscure black holes to better comprehend how these enigmatic voids could help propagate the stars and, indirectly, the building blocks for life.

With an astronomer’s curiosity and an engineer’s precision, Dr. Darren DePoy heads the Texas A&M Munnerlyn Astronomical Instrumentation Lab, where instruments for ground-based telescopes like the ambitious Giant Magellan Telescope take shape.

On occasion, he uses some of his own tools to extensively study exoplanets, or planets outside our solar system. Due to their distance from Earth and low visibility, astronomers discover most exoplanets by measuring their gravitational influence on nearby stars. “Studying those planets presents some of the big challenges in astronomy today,” he said.

DePoy is working with his team to build an instrument that can detect whether exoplanets have atmospheres and measure what those atmospheres are made of if they do. Many exoplanets will probably bear little resemblance to Earth, but examining their attributes can clarify how unique our solar system truly is.

Since the Big Bang, the universe has been expanding at a measurable rate. “In the 1970s, scientists came close to the correct value,” Dr. Lucas Macri said, “but they could not reliably account for the expansion rate’s margin of error.”

Calculating the expansion rate, or Hubble constant, is about much more than satisfying a cosmological curiosity. Scientists are scrambling to understand dark energy and dark matter—two invisible components that make up 95% of our universe.

These properties must exist to account for the universe’s rapidly accelerating expansion rate, but that is about all of which the scientific community is sure. Thus, measuring the constant accurately is pivotal for progress.

In December 2021, an international research team including Macri and astronomy Ph.D. graduates Samantha Hoffmann ’13 and Wenlong Yuan ’16 announced the then-most-accurate Hubble constant measurement with a total uncertainty of only 1.4%.

With help from new tools like the James Webb Space Telescope, he and his peers hope to get a few steps closer to understanding dark energy, dark matter and the true nature of everything.

Learn how you can support Aggie astronomers in their exploratory research by contacting Ian Wilson '13, assistant director of development, at the bottom of this page.

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