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Is it possible for a earth-like planet to orbit a neutron star & have intelligent life-forms, even if said neutron star 'moves' through different galaxies?

as seen in this video - https://www.youtube.com/watch?v=tlTSXr4PfSg where a neutron star destroys Earth, only in my universe it wouldn't destroy a earth, but just different planets of roughly the same size, up to 5x the mass of earth.

Would my earth-like planet be safe & able to sustain life?

I've seen - Earth-like planet orbiting neutron star? - but the answer only explains that it isn't possible, mainly due to radiation, and assumes that Sol is a neutron star, my question isn't about Sol being a neutron star but about a earth-like planet orbiting a neutron star that devours planets.

I've asked a question about this before - Can a star orbit around a planet? and am now asking this question because I'm looking for a source of extreme heat / energy, such as an 'extra' star or 'neutron star'

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  • $\begingroup$ Are you preparing to write a book / story? $\endgroup$ – i486 May 31 '16 at 12:08
  • $\begingroup$ What do you mean by "moving through galaxies"? This makes me feel you are actually lacking of basic orbital principles. when a neutron star is moving through diferent galaxies, it would earlyer or later stick to one of them or they have a common center of mass making it beeing just a usual neutronstar inside a usual galaxie. where AFAIK the other "galaxies" wouldn't be galaxies yet. I might be wrong. But I don't think so yet. $\endgroup$ – Zaibis May 31 '16 at 12:40
  • $\begingroup$ say two galaxies are quite close to one another, and the Neutron Star would have sufficient velocity to pass through the first, it could technically get into the second, no? $\endgroup$ – Gerwin May 31 '16 at 12:48
  • $\begingroup$ @i486 I have a idea for a story in my head $\endgroup$ – Gerwin May 31 '16 at 12:49
  • $\begingroup$ You could have an earth-like planet orbit a small (red dwarf) star, and then have that star orbit a neutron star with a large mass. That might work, but you would still have the problem of keeping your dwarf-star and earth-planet from hitting the same things that your neutron star is destroying. Seems pretty dicey. $\endgroup$ – RBarryYoung May 31 '16 at 18:07
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I'd say no, it's not possible according to our understanding of physics.

From "moves through different galaxies", I assume you mean that the star moves at relativistic speed, so that it will see more than one or two galaxies before the heat death of the universe. I also will assume the planet somehow ended up in an orbit around this star intact.

Together, they will be crashing through any matter in their way. The neutron star is so tiny and dense that it could likely fly straight through a planet without slowing down. Interstellar gas clouds and gravitational influence from nearby stars and planets are barely noticed at all.

The planet, having a tiny density compared to its star, will be bombarded with all those particles and slow down, destabilizing its orbit until it either spirals into the neutron star or flies off into deep space.

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    $\begingroup$ Not to mention the significant blueshift of any EM radiation when moving at relativistic speeds, making "habitable" a relative term. Starlight could be downright lethal... $\endgroup$ – DevSolar May 31 '16 at 13:17
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    $\begingroup$ "more than one or two galaxies before the heat death of the universe" -- well, the Milky Way is on course to collide with Andromeda, and the Sagittarius Dwarf Spheroidal Galaxy is involved in a series of collisions with us as we speak. That's at least 3 galaxies Earth could "pass through" in a mere 4 billion years (granted, we're not sure the Sun won't have toasted us by then). The questioner may have another timescale in mind, though, and can compare that timescale with the distances to other galaxies in the local group. $\endgroup$ – Steve Jessop May 31 '16 at 18:06
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First of all, it's interesting to note that the first extra-solar planets that were discovered orbited a neutron star (well, a pulsar, which is a fast-spinning neutron star). There are only a few pulsar planets known but they include some of the smallest planets we know of outside the Solar System (see wikipedia "pulsar planets" page)

One big mystery regarding neutron star planets is: where do they come from? Neutron stars are the central leftovers after a star goes supernova and ejects most of its mass. Any primordial planets are probably destroyed. We think that neutron star planets form from the parts of the star that were thrown off.

To maintain life a planet would have to orbit very close to a neutron star. For typical neutron star parameters, the luminosity is about a million times lower than the Sun's (for a temperature of ~50,000 K). So the habitable zone would have to be one thousand times closer than Earth's orbit, about 0.001 Astronomical Units from the neutron star. There would be danger from high-energy radiation like X-rays as well as from tidal heating due to the neutron star's gravity.

Alternately, a planet on a more distant orbit could potentially maintain a warm surface if its atmosphere was thick enough (see here for an extreme example: https://aeon.co/essays/could-we-make-our-home-on-a-rogue-planet-without-a-sun).

To summarize, I don't think it's impossible to imagine a life-bearing world orbiting a neutron star. But it only makes sense with certain assumptions.

More references for world building (on my blog): https://planetplanet.net/real-life-sci-fi-worlds/

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Life with the same type of biochemistry to us is unlikely to be able to survive on a planet orbiting a neutron star however life with alternative biochemistries may be able to survive. Carbon based life would be destroyed by the radiation but if the life was based on a different element or elements then it may be able to survive the radiation.

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  • $\begingroup$ Can you add any examples of elements that would be able to survive the radiation? $\endgroup$ – Gerwin May 31 '16 at 9:29
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It is very unlikely that a planet orbiting a star going supernova survives this event, but suppose an Earth-like world that encounters a neutron star passing really nearby, the planet could be captured. Some pretty uncommon orbital mechanics would need to be involved (a second planet, probably a Jupiter-sized gas giant in the right place could do the trick) The velocity of the intruding neutron star cannot be too high however, capture requires velocities that are comparable to each other. If the disrupting object goes too fast, only orbital disruption can take place.

If an actual collision with the Sun would happen, the neutron star would pass through unharmed, but the Sun will experience such a hefty energy outburst that any Earth like planet will be burned and boiled bone dry.

After being snagged by the neutron star, the planet will experience some really big tidal effects, and it will freeze over. That would be a big extinction event, but not total sterilization.

Imagine an advanced technological civilization that has survived such a cataclysm by sheltering on the bottom of the oceans, deep under a thick ice crust that shields the deadly radiation from the neutron star. The planet remains heated internally because of the elliptical orbit, so a layer of water remains liquid underneath the ice.

Maybe this advanced civilization could also have bio-engineered a totally new ecosystem that can exist under the dark conditions known on Earth around "black smokers", and possibly on other worlds in our own solar system such as Europa, Titan and Enceladus. And bio-engineered themselves to be able to live permanently under high-pressure conditions. Living to the surface is possible only with technological help.

Travelling through different galaxies is possible if the neutron star and its captured planet(s) exceeds the escape velocity of the home galaxy, but reaching another galaxy will take millions of years at relativistic speed. Which is ruled out by the capture requirement, so count on billions of years in intergalactic space with absolutely nothing to encounter.

Much more interesting is the wandering neutron star and its companion passing through a region with extremely high star density, such as a globular cluster. Every few centuries, a new star can be passed by.

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