Sound Waves and Lenses to Explore the Dark Side of the Universe

Imagine a universe where most of what exists is invisible, dominated by an unseen force driving its expansion and an unseen form of matter shaping the structures. Well, that is precisely what we think our Universe looks like. Join us for an informal discussion of what evidence we have to support this idea.

The story begins with galaxies that rotate faster than they should, hinting at an invisible mass providing extra gravitational pull. As we explore further, we find galaxy clusters that don't have enough visible matter to hold them together, implying a mysterious hidden substance. This invisible mass, known as dark matter, becomes even more evident when we observe how light from distant objects bends around such massive objects.

Our journey continues with the ripples created by sound waves moving through the early universe. These ripples help us understand the composition and proportions of our universe. They can be observed in the typical separation between galaxies and in the cosmic microwave background (CMB), a remnant from the early universe. This is the oldest light we can observe. Minor temperature fluctuations in this light help us understand the distribution of matter after the Big Bang. These patterns suggest that dark matter played a significant role in forming the galaxies and structures we see today.

Pieced together, these different probes support our understanding of how dark matter shapes the universe. Whether you're an avid astronomy fan or just curious about the cosmos, this talk will reveal the fascinating techniques scientists use to uncover the dark side of the cosmos.