Blake Hole Near Earth

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Blake Hole Near Earth

Postby kdrake » Sun Jul 15, 2018 2:22 pm

So how can one model a Black Hole? Some suggested to me the book "The Krone Experiment" a few months back. I finally fetched it for my Kindle (there is also a DVD). I just started it yesterday and find the concept interesting. A Russian Carrier is damaged by what the Russians believe is an American space based weapon. This brings them to near war. Several other events happen and a CIA guy and a computer sim gal start to piece it together. With the help of a small think tank of scientists, they think a Black Hole is captured by Earth, orbiting with a perigee of ~10,000 miles. We're talking 10 million metric tons the size of a nucleus. I'll finish the book tomorrow.
So, I could not figure out how to model this thing in AstroGrav. I sent a note to Russ Calvert (author of AG). He created a sim and sent me some detailed directions on how to do my own. If you want the sim he crafted, let me know so I can send it to drop box.
His reply.........and instructions

Hi Kenneth,

This is an interesting problem!

The short answer is that you can’t model this with AstroGrav. The reason is that once the particle is inside the Earth, the Earth’s gravitational attraction is pulling the particle in all different directions instead of just towards the centre, so that all the normal ideas of elliptical orbits, fixed orbital periods, etc, break down. I’ve no idea what the correct physics is to cover such a situation, but I imagine that somebody somewhere has studied it and published papers about it.

However, you can model a particle orbiting within the Earth, but the physics won’t be correct. Try the following:

(1) Open the ‘Planets, Moon’ sample simulation.
(2) Close the ‘Structure’ and ‘View From New York’ windows, as they just get in the way.
(3) Select the ‘Edit / Add Object…’ command and choose the Earth as the parent. You should then see a ‘Editor of ‘Earth/2’’ dialog.
(4) Edit the ‘Type’ to ‘Asteroid: Small’ (it will do), and OK the window asking about updating various other fields.
(5) Change the ‘Semi-Major’ to 3186km, which is slightly more the half the Earth’s radius.
(6) Change the ‘Eccentricity’ to 0.999.
(7) Leave the other fields as they are for now, and OK the dialog.
(8) You should now have added your particle orbiting (mostly) within the Earth. If you check its orbital period in the table, you should see a figure of about 0.02 days, which is about half and hour, so use the ‘Evolve / Settings…’ command to change the time step to 1 minute, which should be just about ideal to see what’s going on.
(9) In the ‘View’ window, zoom in on the Earth using Ctrl+drag, fixing on the Earth, and reducing the brightness until you have a nice big Earth filling up most of the window. You might want to make the window much bigger too.
(10) Use the ‘Edit / Find…’ command to find and select the particle. [You can’t select the particle simply by clicking on it, because it’s inside the Earth, and you’ll select the Earth itself!]
(11) Start the simulation running. You might or might not see the particle popping out of the Earth at apogee depending on exactly how you’ve got the Earth oriented.
(12) Choose the ‘View / Show All / Objects’ command to hide the objects and effectively make the Earth transparent. You should now able to see the particle orbiting.
(13) Use the ‘Ctrl+Alt+Shift+G’ and ‘Ctrl+Alt+Shift+L’ commands to display the Earth’s coordinate grid and the locations that you see with the ‘Tools / Edit Locations…’ command. [Two Easter eggs that you might not already know about.]
(14) Play around rotating the Earth and editing the particle’s orbital parameters as you want.

Here’s my version:
kdrake
 
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Joined: Wed Sep 26, 2012 5:12 pm

Re: Blake Hole Near Earth

Postby todd-murray » Sun Jul 15, 2018 3:51 pm

Could the simulation fail because when the black hole makes contact with the Earth, there's matter converting to energy and all kinds of radiation pressure from the crazy continuous explosion? I am well beyond under qualified to speak on these matters, but it seems to me like there would be lots forces in action that might overwhelm pure gravity.
todd-murray
 
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Re: Blake Hole Near Earth

Postby kdrake » Sun Jul 15, 2018 9:57 pm

One mistake I made in the info was that the apogee, NOT PERIGEE, is ~10,000 miles. I'm in the dark ages on Black Hole science but this novel simply yanked a bit of interest out of my skull. I'm sure in my sim, I have the mass correct but not the size. It's an interesting experiment. You can create the sim following the instruction given or pick up the file to run directly in AstroGrav at https://www.dropbox.com/s/02yt5x6c4nfs3 ... h.ast?dl=0

I think that most of the energy and surrounding matter simply gets eaten. Hence the centimeter sized hole in literally everything. Some structure will simply collapse upon itself (water, air, etc). Total orbital period is in the upper 80 minutes range. This is the most fun I've had with gravity in a while. Check out the book. There is areas where the author seems to know his science.
kdrake
 
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Re: Blake Hole Near Earth

Postby kdrake » Tue Jul 17, 2018 10:47 pm

todd-murray wrote:Could the simulation fail because when the black hole makes contact with the Earth, there's matter converting to energy and all kinds of radiation pressure from the crazy continuous explosion? I am well beyond under qualified to speak on these matters, but it seems to me like there would be lots forces in action that might overwhelm pure gravity.
Just getting into the sequel and it seems to get into some of that. Death by radiation poisoning. If the Black Hole were in the vacuum of space it might radiate over 100MeV gamma-ray at a furious rate - Hawking Radiation. Since this BH is not in a vacuum and is accreting matter, somehow the Hawking Radiation is suppressed - space time is distorted. Remember, this is fiction but I think the author has a pretty good understanding of the physics. The accretion, the matter falling down the BH should produce heat and radiation but it appears to fall into the gravity well of the hole.Radiation output is reduced due to the cocoon around the BH.

I added another version of the sim to https://www.dropbox.com/s/i27cuu8y0txqp ... 2.ast?dl=0
It might be a good idea to switch off general relativity with this sim to avoid orbit jump each time it passes the center of the earth. The mass and size have also been changed. Orbit time is 276 minutes vs 88 by author. Two 100 minute sweeps when outside earth and two 38 minutes when passes through. Unlike in the book. Comes from this page -- https://www.livescience.com/50312-how-l ... earth.html
kdrake
 
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Joined: Wed Sep 26, 2012 5:12 pm


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