S27E73: Dark Matter Mysteries and Martian Lake Myths Debunked

SpaceTime with Stuart Gary

Join us for SpaceTime Series 27 Episode 73, where we delve into the latest cosmic discoveries and advancements shaping our understanding of the universe.
First, astronomers have developed a new theory of dark matter to explain the mysterious dwarf galaxy Crater 2. Despite its proximity at 383,000 light-years from Earth and its large size—making it the fourth largest satellite galaxy orbiting the Milky Way—Crater 2 has a surprisingly low surface brightness and velocity dispersion. This has led scientists to propose the self-interacting dark matter (SIDM) theory, which may better account for the galaxy's unusual properties.
Next, new research dismisses the idea of a lake under the Martian south polar ice cap. Instead, it suggests that the bright radar reflections previously interpreted as liquid water are likely due to resolution interference between radio waves. This finding, based on computer simulations, challenges the notion of subsurface liquid water on Mars.
Finally, we highlight the development of a new daytime optical telescope, the Huntsman, which allows astronomers to observe celestial objects even when the sun is high overhead. This groundbreaking instrument, located at Siding Spring Observatory, uses an array of camera lenses designed for ultra-sensitive night sky observations but can also accurately measure stars and satellites during daylight.
Follow our cosmic conversations on X @stuartgary, Instagram, YouTube, and Facebook. Join us as we unravel the mysteries of the universe, one episode at a time.
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