If You Could See Gravitational Waves, the Universe Would Look Like This

By Brian Koberlein - September 22, 2023 09:00 AM UTC | Physics
Our biology limits our vision. Our eyes can only perceive specific wavelengths of light. But what if we could see the Universe in gravitational waves? A new NASA simulation mapped out hundreds of collisions between dense objects, like white dwarfs, neutron stars, and black holes. These collisions happen within galaxies, sending ripples of gravitational waves across the Universe, and would allow astronomers to recreate the shape of galaxies over time. Upcoming observatories will detect tens of thousands of ultra-compact binary stars, providing even higher resolution—an entirely new way to observe the Universe.
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We Can't See the First Stars Yet, but We Can See Their Direct Descendants

By Brian Koberlein - September 21, 2023 09:43 AM UTC | Stars
The first stars in the Universe were enormous, made of primordial hydrogen and helium from the Big Bang. They lived short lives, exploded as supernovae, and seeded nearby nebulae with heavier elements that began the next generation of stars. Our telescopes aren't powerful enough to see them yet, but have astronomers found their direct descendants? The metal-poor stars in the galactic halo seem to show the imprints from those first stars and could offer valuable clues about the first stars in the Universe.
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First Contact Could Turn Out Well for Humanity

By Brian Koberlein - September 20, 2023 10:35 AM UTC | Astrobiology
Most science fiction portrays the first contact between humanity and alien civilizations as a disaster. That's probably because our history hasn't turned out so well. But does it have to end poorly for us? A new paper looks at the game theory of first contact. It shows that the rational response to another civilization is to be cautious, with both groups understanding the other before taking decisive action. Communication would be difficult but not impossible. Since we share a physical Universe and have reached a technology level that allows us to detect each other, we could assume some of their characteristics in advance.
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