Summary
Highlights
An astronomer discusses the challenge of finding dark matter, an invisible substance that makes up nearly 80% of the universe's mass. Scientists investigate patterns in the natural world, from small-scale phenomena to distant cosmic events, to understand its indirect effects on normal matter.
The Milky Way, our galaxy, appears as a pale strip of light in the sky. It's a giant disk of stars, with red regions indicating star birthplaces shrouded in dust, and blue regions showing young stars that have cleared their surrounding gas. Gravity triggers star formation, but these processes are often hidden by gas and dust.
Astronomers face challenges similar to navigating fog when trying to see through the gas in galaxies. Visible light is blocked, but radio waves can penetrate it. Radio telescopes, like the Parkes telescope in Australia, are used to peer through this thick gas, revealing structures and processes that visible telescopes cannot.
The ASKAP telescope, under construction in Western Australia, will consist of 36 dishes spread over six kilometers. Its advanced phased array feeds will allow it to view 30 times more of the sky in a single snapshot and survey the sky ten times faster than existing telescopes, generating an unprecedented amount of data.
Astronomers use supercomputers to simulate the universe, creating models of stars and entire galaxies. These simulations act as laboratories where scientists can test physical theories and observe galaxy collisions in various ways. They help link observations and theories to understand galaxy formation over billions of years.
Simulations show galaxies forming from gas after the Big Bang. Galaxies rotate so fast that their visible matter alone cannot explain their stability; stars should be flung into space. This indicates a massive, unseen amount of dark matter provides the extra gravitational force to keep galaxies together.
Dark matter is thought to form long, interconnected filaments stretching across the universe, much like a cosmic web. Galaxies are distributed along this web. Simulations illustrate how dark matter forms these enormous filaments, along which galaxies are strung. ASKAP will aid in mapping this cosmic web and learning about the underlying dark matter structures.
The ASKAP telescope, with its dishes already on site and collecting data, will help answer fundamental questions about star formation, organic molecules in exoplanet atmospheres, the distribution of galaxies on the cosmic web, and the ultimate nature of dark matter—the mysterious substance composing 80% of the universe's mass.