Weird cosmology? Twin neutron stars.

[RangerWickett]

If two neutron stars rammed into each other, would there potentially be enough mass to create a black hole?

If beforehand these two neutron stars were in a decaying orbit with each other as a weird sort of binary pair, would there be any odd interactions of the gravity between them? I imagine the tidal effects would be enormous at some points. Would light be shifted in a particular direction between them, or at the edges of their orbits?

Could planets still theoretically orbit these stars, albeit at a distance where the tidal influence wouldn't tear them to pieces?

 

[Rodrigo Istalindir]

Yes, sort of. From Wikipedia:

Candidates for stellar-mass black holes were identified mainly by the presence of accretion disks of the right size and speed, without the irregular flare-ups that are expected from disks around other compact objects. Stellar-mass black holes may be involved in gamma ray bursts (GRBs); short duration GRBs are believed to be caused by colliding neutron stars, which form a black hole on merging. Observations of long GRBs in association with supernovae[3][4] suggest that long GRBs are caused by collapsars; a massive star whose core collapses to form a black hole, drawing in the surrounding material. Therefore, a GRB could possibly signal the birth of a new black hole, aiding efforts to search for them.

Large neutron stars are around 2 solar masses and have an escape velocity of around .5c, so two of them colliding could conceivable result in a stellar-mass black hole. These are tiny compared to the ones thought to be at the center of galaxies.

It's generally believed that there are a number of binary systems where one of the pair is a neutron star or black hole, so I suppose neutron binaries are possible.

Since neutron stars are the end result of supernovae, I doubt you'd find any with planets as they would have been consumed in the process.

 

[RangerWickett]

Since neutron stars are the end result of supernovae, I doubt you'd find any with planets as they would have been consumed in the process.

Thanks for the info. I was thinking, though, that the aftermath of a supernova, if it were in the proximity of a nebula, would result in enough material that new planets could form, right? If conditions were just right, some sort of ambient heat from the nebula could keep planets habitable even if they were drifting in erratic orbits around a neutron star.

 

[Rodrigo Istalindir]

Thanks for the info. I was thinking, though, that the aftermath of a supernova, if it were in the proximity of a nebula, would result in enough material that new planets could form, right? If conditions were just right, some sort of ambient heat from the nebula could keep planets habitable even if they were drifting in erratic orbits around a neutron star.

In an infinite universe, anything is possible. Might be infinitely improbable, though, especially in a binary system which have really screwy dynamics anyway. With a gravity a hundred billion times that of Earth, it'd clear a might big swath through the area. I'd think anything that got captured would have to have a hell of a lot of momentum to fall into orbit instead of making a dash down the gravity well. Excape velocity of .5c is hard to get away from. Consider, too, that neutron stars are pretty darn small (1/50,000th the size of the sun), so even if something managed to orbit it, they'd have to be be so far away (gravity inversely proportional to the square of the distance) and it would be so tiny, people on the hypothetical planet would probably never know it was there.

Someone with real math skills could probably figure out if it were possible for a binary neutron system to have stable planetary orbits.

Speaking of neutron stars, ever read 'Dragon's Egg' by Robert Forward?

 

[DerHauptman]

ENWorld never ceases to amaze me - the sheer power of intellect in this community put together in one place could salve the worlds ills.

That is of course as long as one of those ills is not the AoO or 4e lol.

Seriously though it amazes me what people around here know.

I am not an intellectual at all I am a soldier and as one have a different set of skills but this kind of here in this post amazes me its real intelligent stuff.

Kudos to you two. I am totally serious now this is not a smart ass post - I find it amazing you guys can whip like this out.

Coolness. And my dad said D&D would eat my brain - I evidently didn't play enough. I can't write code, do math beyond the big 4 (+, -, x, / ), set up a network or a fire wall, and I certainly don't know what a solar mass or escape velocity is.

I can plan a decent raid though and shoot like Wyatt Erpp - yea like that will sell in a year after I retire - LOL

Kudos guys makes me proud to be a member of this group.

 

[RangerWickett]

*grin*

I bring this up because my next game is going to be in such a world. I'm trying to think up interesting astronomical phenomena that would amaze primitive people, but which could theoretically be understood, because one of my players is an astronomy professor, and I've got a feeling he's going to want to try to figure out the motions of the heavens. He might not grasp gravity, but he should be able to figure out that the world is orbitting something distant and (practically) invisible.

Also, he might just figure out that the planet is headed to destruction in the not too distant future. Hell, even if he doesn't figure it out himself, I'd like to be able to explain it all later on, and have him approve of my whacky science.

Now I need to figure out how a planet would be affected by passing through the rings of a gas giant.

 

[Steve Jung]

Most light given off by a neutron star is in the X-ray range with some in the visible spectrum. So that might be a slight problem.

 

[Zamtap]

*grin*

Now I need to figure out how a planet would be affected by passing through the rings of a gas giant.

Lots and Lots of meteors

Gas giant rings are made of dust and ice particles (ok particles means up to small house sized and small "shepherd" moons are needed to keep the rings spread out), when particles like these from comets hit our atmosphere they cause meteors.

What is the tidal effect of the gas giant is going to do? Io is melted inside by the tidal interaction with jupiter.

So Volcanos are going to flare and stars fall from the sky very end of the world as we know it.

Zamtap

 

[Rodrigo Istalindir]

Most light given off by a neutron star is in the X-ray range with some in the visible spectrum. So that might be a slight problem.

Would be significant gravitational redshift, too, I think.

Some other things to think about with your hypothetical planet, RW:

Radiation from the neutron star is going to be intense. You could give your planet a high density molten metal core with a very high rotational period. This would give it a very strong magnetic field to shield the planet from the radiation. You'd end up with constant and vivid auroras, a really short day/night cycle, and rampant vulcanism.

From a human point of view, any danger from colliding with the neutron star or the binary pair degrading into each other would be impossibly far in the future. By the time the situation became observable by primitive peoples, it would be too late. (Or maybe not, come to think of it, since they might experience a time dilation effect as they fell towards it; if it were a black hole they definitely would.)

Getting whacked ala When World Collide would be much more likely and more dramatic I think.

 

[RangerWickett]

You'd end up with constant and vivid auroras, a really short day/night cycle, and rampant vulcanism.

Well, in a nebula, day/night would not be light/dark, but rather the spinning of the heavens, which would have distinct visuals. But I think I'll skip a bit of physics, and just have a strong molten core thanks to magic, and not require fast days. I like the idea of auroras, though.