Neutron Star vs Earth - Effects of a Collision

[kindaroomy]

Firstly, I would like to say hello to everyone as this is my first post.

I am an artist working a personal project that will be a visual investigation into the effects of a collision between a Neutron Star and Earth.

The star would have a fully collapsed core at 1.5 solar masses (maybe 15km diameter), with it’s poles not pointing towards earth… or if you think it would be more interesting, pointing towards earth.

I was hoping to get some feedback on the sequence of events that people think would transpire as the star approached our planet, events like: gravitational effects, radiation, tidal forces, weather effects, seas would boil, Earth would stop spinning, etc.

I have included an image I hastily put together as an initial talking point. If you would like to reply with what do believe to be accurate and/or inaccurate about the scene, that would be great. Or include any comments as you wish.

Thank you for your time,
CJ
[PLAIN]http://www.kindaroomy.com/blog2/wp-content/uploads/2010/06/Earth_vs_Neutron-Star.jpg

 

[nismaratwork]

There would be a great deal of seismic activity, increasing to the point where the Earth began to be torn asunder. Those heated fragments would form an accretion disc, around the neutron star.

As to effects of radiation or magnetic fields, unless we were staring down the barrel of a pulsar, I think because of range gravity would do the damage first. By the time the magnetic field overwhelmed our puny field, we'd already be shredded like cheddar.

Remember that a neutron star spins about its axis VERY VERY rapidly, so infalling matter is going to form a disc with a great deal of angular momentum. Rather than your "linear suction" image, you would have an ever-thinning ribbon of hot plasma spiraling inward. The rest would be a function of how close the star gets, and what type of neutron star it is. I cannot imagine the damage the magnetic field of a Magnetar would do.

 

[kindaroomy]

Thanks for the comment nismaratwork,

I will make the addition of an accretion disk. Agreed, the earthquakes would be tremendous.

I wonder if it would stop Earth rotation about its axis? Someone mentioned to me that if Earth stopped rotating the atmosphere would continue spin and strip the surface down to bedrock. But i feel the atmosphere would be as much subject to gravitational affect as the rest of the planet would, ie. slow at the same rate. Would you agree?

CJ

 

[berkeman]

Does a neutron star travel in the plane of its accretion disk? I'm wondering how you should orient the accretion disc for the approaching neutron star...

 

[Max™]

The plane of rotation shouldn't influence the direction of travel too significantly.

For comparison, the solar system is plowing through the galactic medium at a steep angle:

So the accretion disc could be at all sorts of different angles relative to it's trajectory, as far as I can determine.

A magnetar would likely create visible aurora like effects along it's field lines as it hauled material around, it would probably be painfully beautiful.

 

[nismaratwork]

The plane of rotation shouldn't influence the direction of travel too significantly.

For comparison, the solar system is plowing through the galactic medium at a steep angle:

So the accretion disc could be at all sorts of different angles relative to it's trajectory, as far as I can determine.

A magnetar would likely create visible aurora like effects along it's field lines as it hauled material around, it would probably be painfully beautiful.

Emphasis on painful!

 

[kindaroomy]

Thanks Berkeman, that is a fantastic point. Because the star would be on the move it means it wouldn't equatorially locked with any companion. It and its accretion disk could approach at any angle making for some interesting possibilities!

 

[kindaroomy]

I have added the accretion disk and decided to dirty-up the atmosphere a little. I am assuming there would be jets coming from the neutron star, if anyone could confirm this that would be great.

Please chime in with any observations or comments as to the accuracy of the illustration, I would be happy to hear what people think. Good and bad of course.

CJ
[PLAIN]http://www.kindaroomy.com/blog2/wp-content/uploads/2010/07/Earth_vs_Neutron-Star-r2.jpg

 

[Chronos]

It would be an awful mess. Planetary orbits would become chaotic and Earth would have an interesting new orbit by the time the neutron star drew near enough to become a serious player. The sun, as resident mass king of the solar system, would take the brunt of it.

 

[kindaroomy]

I wonder if Earth's poles would align with the star, ie. pointing at the accretion disk? Is this feasible? or is Earth's magnetic field not an issue in this scenario?

 

[nismaratwork]

I wonder if Earth's poles would align with the star, ie. pointing at the accretion disk? Is this feasible? or is Earth's magnetic field not an issue in this scenario?

Definitely not a factor, it's too weak and as has been pointed out graviity not EM is the winner in this game.

 

[kindaroomy]

Would the jets of a Neutron Star always be a right angles with the accretion disk?

 

[nismaratwork]

Would the jets of a Neutron Star always be a right angles with the accretion disk?

Yes, because the accretions disc is aligned with the axis of rotation, and the jets are perpendicular to that.

 

[kindaroomy]

Thanks nismaratwork, so then why does a Pulsar 'pulse'? am I missing something?

 

[nismaratwork]

Thanks nismaratwork, so then why does a Pulsar 'pulse'? am I missing something?

There are three types of pulsars that I know of, ones which depend on accretion (like a black hole), magnetars, and rotational pulsars (think of a really REALLY fast dynamo). Beyond that, I offer this quote:

Werner Becker of the Max Planck Institute for Extraterrestrial Physics said in 2006, "The theory of how pulsars emit their radiation is still in its infancy, even after nearly forty years of work."

So, I really don't know. Maybe there is rotation on more than one axis, with the extremely rapid rotation around the axis (perpendicular to magnetic field lines/accretion disk) and slower rotation or a wobble leading to the lighthouse effect. Beyond that, it's really not something I know more about than you'd find online or from other members here.

 

[Max™]

It occurs because the magnetic axis is tilted from the rotational axis, rotating the jets like some hellish lawn-sprinkler of doom.

 

[kindaroomy]

So with reference to my artwork, to be more accurate the accretion disc would be flopping around as like a unbalanced gyroscope possibly tearing material of the planet in a wavy sort of motion. Am I describing the effect on the in falling material properly?

 

[nismaratwork]

So with reference to my artwork, to be more accurate the accretion disc would be flopping around as like a unbalanced gyroscope possibly tearing material of the planet in a wavy sort of motion. Am I describing the effect on the in falling material properly?

Your accretion disk looks good to me, but the planet itself... I would make the attentuation of the mater more gradual. The planet would be torn by tidal forces, so instead of a globe partly turning into plasma the way you have it, I would have less "whole" planet, in a roughly conical spiral of debris, then hotter material stretching into the disk. I wish I could draw worth a damn so I could do more than describe it...

Something like this, but with you dynamic flair that makes it more visually appealing:

http://www.cosmographica.com/gallery/portfolio2007/content/bin/images/large/131_BlackHole.jpg

and

http://www.awesomeoff.com/images/entries/mainview/black_hole_Accretion_disk.jpg

Now those are (drawings) of stars. The stram of infalling matter alone would be larger than the Earth. Instead of a streamer from a spherical object, or a distorted sphere, it would be tearing, and ripping. The portions of the planet closest to the neutron star would be experiencing more intense gravity that that further away. Does this make any sense?

 

[kindaroomy]

Thanks nismaratwork, Yes I believe I can picture what you mean. I will try it out and post a new image soon. Thanks again for helping me on this, your comments are appreciated.

CJ

 

[nismaratwork]

Thanks nismaratwork, Yes I believe I can picture what you mean. I will try it out and post a new image soon. Thanks again for helping me on this, your comments are appreciated.

CJ

I like your art, so it works for everyone! I look forward to your next image.

 

[kindaroomy]

[PLAIN]http://www.kindaroomy.com/blog2/wp-content/uploads/2010/07/NeutronStar_vs_Earth_final2.jpg

 

[berkeman]

Wow, nice image. Have you thought about animating it? How fast is all of that stuff moving? Crazy!

 

[Mu naught]

Until the Earth gets very near the surface where you have a very large "acceleration gradient" so to speak, I don't see why it should be getting torn apart other than for dramatic effect for your drawing...

 

[kindaroomy]

Thank you Mu Naught,

I very interested in your feedback for this scenario. I am trying to create an accurate depiction of what would happen to Earth as a Neutron Star came near.

Please have a look at my initial drawings earlier in this thread to see if any aspects are closer to what you believe would happen.

Thanks.

 

[kindaroomy]

Berkeman,
How I wish I could animate this scene... but unfortunately I seem to be missing the basic fundmentals on how a scenario like this would play out in the first place. Let's see what some other comments might reveal.

CJ

 

[mjacobsca]

Berkeman,
How I wish I could animate this scene... but unfortunately I seem to be missing the basic fundmentals on how a scenario like this would play out in the first place. Let's see what some other comments might reveal.

CJ

The atmosphere and water would be sucked off the planet long before it started to get ripped apart. Your original picture showed oceans on the side of the planet not being torn asunder, but I believe your latter picture is much more accurate. The tidal forces on the Earth would cause massive earthquakes, and water would gather on the side of the Earth closest to the neutron star causing immense changes in water height (e.g. massive tsunamis). The Earth would probably spin while it was approaching, so the water surges would circle the globe as the Earth spun. Eventually, when the neutron star got close enough, I would imagine it would cause a drag on the Earth's rotation, possibly causing a tidal lock on it. A large percentage of people on Earth would probably be killed by the earthquakes and tsunamis, before the coolest effects started to happen. Tidal forces might also cause mass eruptions of volcanoes as the friction from the tidal stresses superheats the magma and pushes lava up the lava tubes faster than normal. Air and water would be sucked away next, suffocating anyone who wasn't killed by the massive earthquakes. After this, the neutron star would suck up all the people and non-fixed objects on the surface of the planet (except for my TV, which is heavy as hell). Top-soil would be stripped away as well until all that is left is chunks of the rocky crust, which would soon thereafter be picked off one rock at a time until all that was left was the softer mantle. There would definitely be a deformation of the Earth after this point, with the last (and rather quick) stage being the Earth itself being torn apart. If I was to make any modifications to your drawing, I think the final stage you are showing should probably show a more elongated Earth rather than a perfect sphere. By the time the Earth was being torn apart like you are showing, it would definitely be far more deformed than what you have drawn.

That's how I see it happening. When is the movie coming out?

 

[IsometricPion]

I found a Youtube http://www.youtube.com/user/jguillochon#p" of a ~0.5 solar mass star disrupting a jupiter-mass planet (there are 5 videos in the channel in total, all relating to this subject). Depending on the situation, this may or may not be similar to what a neutron star would do to the Earth (so food for thought rather than a blueprint, I guess).

 

[GoodUniverse]

mjacobsca, do you mind if I come over and hang onto you TV set?