Starts With A Bang #112 - Galactic Archaeology

When we look out at our home galaxy, the Milky Way, we have to recognize that even though it's been growing and evolving for 13.8 billion years, we're only observing it as it is right now: a snapshot in time determined by the light that's arriving in our instruments right now. However, just like we're living "right now" in human history but can, through the science of archaeology, learn about historical events that happened many thousands of years ago (before recorded history) or even earlier, we can learn about the Milky Way's history through the astronomical equivalent: galactic archaeology. How do galactic archaeologists do it? They look at as much data as possible, across many wavelengths of light, including at many rare and obscure species of stars, in as many locations as possible and to the greatest precisions possible all at once. By combining these different lines of evidence, we can arrive at a coherent and compelling picture for how our little corner of the Universe grew up, including by reconstructing the merger history of the Milky Way. Surprisingly, it isn't only the "big data" missions that are contributing to this understanding, but even smaller, less heralded (and more accessible) telescopes, with the right equipment and sets of observations, can make a huge impact. Join us for this episode, where astrophysicist and observatory director Elaina Hyde joins us, helping us better appreciate the wonders of our own cosmic past! (This illustration of our Milky Way shows an ancient galactic stream wrapped around our galaxy's plane at nearly a 90 degree angle: evidence for a recent and even ongoing merger in our galaxy's history. Credit: NASA/JPL-Caltech/R. Hurt (SSC/Caltech))