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4 crazy stars that might exist + Space aliens may be trapped in underground oceans - C C - Mar 26, 2021

Four crazy stars astronomers think might really exist
https://astronomy.com/news/2021/03/four-crazy-stars-astronomers-think-might-really-exist

EXCERPTS: From stars made of dark matter to stars literally living inside their partners, these stellar systems are theoretically possible. Every day, we bathe in the glow of a giant, burning ball of gas that sustains life on our planet. At night, we look up at a sea of stars, which come in a staggering variety of sizes, colors, and ages. These objects all shine thanks to the same nuclear fusion that powers our own Sun. But they might not be all the universe has to offer.

Some astronomers think there are so-called "exotic stars" out there, composed of particles other than the typical electrons, protons, and neutrons that make up our Sun and all of its cousins. And while these exotic stars are still hypothetical, scientists are starting to find evidence that some of them might actually exist. Here, we’ve compiled a list of four of the weirdest and most exotic stars that might be floating in space.

Dark matter stars. Dark matter stars would have existed before the first normal stars were born. And if they are real, they might even still exist today. Contrary to what you might imagine based on the name of these theoretical stars, they would mostly be made of normal matter. Namely, hydrogen and helium, like our own Sun. However, these dark stars would also have significant amounts of something called “neutralino dark matter.”...

[...] Boson stars. ... some scientists think that dark matter could have its own boson. These dark bosons could be dark matter itself, or they could simply cause its interactions with regular matter. Dark matter bosons also might be able to coalesce into dark matter stars, though they’d behave rather strangely. ... the fermions in normal stars behave like people. Two people can’t occupy the same physical space at the same time, and they have to take turns standing in a given spot. But bosons act more like waves in water. And when waves come together, they don't push each other out of the way. Instead, they add together and make a bigger wave. In physics, this is called a Bose-Einstein condensate. A dark boson star would be like a giant, dense Bose-Einstein condensate in outer space. And it might resemble another extremely compact object — a black hole...

[...] Quark stars. Neutron stars are truly bizarre objects that are common across our universe. ... But there’s another type of hypothetical star that could make even these extreme objects look tame. They’re called quark stars. Quark stars are theoretical objects that sit somewhere between the density of a neutron star and a black hole. They're made of quarks, an elementary particle that serves as a building block for matter by coming together to form the protons and neutrons in atomic nuclei.

[...] Thorne-Żytkow objects. Thorne-Żytkow objects are a truly bizarre kind of binary star. These theoretical, hybrid stars harbor a neutron star inside a puffy giant star, making them essentially stellar Russian nesting dolls. They are thought to form when red giant or red supergiant star collides with a neutron star... (MORE - details)


Where are all the aliens? Maybe trapped in underground oceans
https://gizmodo.com/where-are-all-the-aliens-maybe-trapped-in-underground-1846545540

EXCERPTS: A planetary scientist says subterranean water worlds are likely common in the galaxy and probably even better for life than Earth-like environments. Should an intelligent species arise beneath the frozen crust, however, they’d find themselves in perpetual isolation, in what is a possible solution to the Fermi Paradox.

Several moons in our solar system feature vast oceans of liquid water covered in a thick layer of ice. These include Europa, Titan, and Enceladus, and they represent tantalizing targets in the search for extraterrestrial life in our solar system. Indeed, these moons, in orbit around Jupiter and Saturn, have warm interiors, the result of immense tidal forces caused by the gravitational tugging of their gigantic host planets

[...] Excitingly, there’s a lot of complex chemistry going on inside these liquid oceans ... Another exciting thing about these interior water ocean worlds, or IWOWs, is that they’re located outside of our solar system’s habitable zone ... Earth is parked inside the circumstellar habitable zone, but so are Mars and Venus, so a seat inside this area is certainly no guarantee of external oceans or life...

[...] Given the surprising prevalence of these worlds in our solar system, S. Alan Stern, a planetary scientist at Southwest Research Institute, says they “are likely to be common in extrasolar planetary systems as well,” as he wrote in a new report [...] What’s more, Stern makes the case that “interior oceans worlds can be more conducive to life than worlds with surface ecosystems” and an “advantage for the development and maintenance of life.”

In his one-page report, Stern argues that the habitability of such worlds isn’t dependent upon specific types of stars, the need for host planets to avoid eccentric orbits, or the distance to host stars, among other factors. In fact, Stern says underground ocean worlds don’t even need a Sun at all to be habitable, in reference to moons in orbit around rogue planets...

[...] Interior water ocean worlds also have a built-in defense system, according to Stern. Any life that emerges in these watery worlds is protected, not by an atmosphere, but by a thick frozen crust that can measure tens of miles deep. This layer confers “environmental stability against external threats,” offering protection from numerous existential dangers, whether they be asteroids, solar flares, space radiation, extreme climate cycles, and nearby supernovae explosions, according to Stern.

Frustratingly, however, this same protective shell could make it next to impossible for astronomers on Earth to detect any life beneath the frozen surface... (MORE - details)


RE: Where are all the aliens? Maybe trapped in underground oceans - Zinjanthropos - Mar 26, 2021

https://europa.nasa.gov/europa/life-ingredients/