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Asteroid Apophis to Pass Within 20,000 miles of earth in 2029
#1
   

Impact threat from asteroid Apophis cannot be ruled out
June 26, 2017 by Tomasz Nowakowski, Astrowatch.net
Read more at: https://phys.org/news/2017-06-impact-thr...s.html#jCp

Quote:In just 12 years, NASA predicts that the 1,000-foot wide space rock will pass within 18,500 miles of Earth, which is less than one-tenth the distance between the Earth and the moon. As Earthlings recognize global Asteroid Day on Friday, it’s a salient reminder that this is startlingly close, but scientists are certain that it will miss our tranquil planet and carry on its endless orbit around the sun. Herein lies the problem: Apophis will return, and when it does, not all scientists are sure that it will miss again.
Link: https://www.inverse.com/article/33554-ap...cle-footer

I wonder if these predictions take into account the following: According to Wikipedia, the two Van Allen belts extend from about 500 to 58,000 kilometers. That means they extend out to 36,039 miles from earth. So those charged particles held in the earth's magnetic field, would surely produce some drag on the incoming asteroid, perhaps enough to divert it into a trajectory striking the earth. And what about the effect of earth's magnetic field on any iron in the rock? NASA had better start making plans to divert the asteroid!

On another website, the asteroid is said to be 370 meters, which is about 405 yards, or 1,215 feet. Link: https://phys.org/news/2017-06-impact-thr...ophis.html Earth has probably been hit by larger asteroids in the past and survived, but that is still going to be a disaster (that word means "bad star").

The odds are 4-1 that it would strike in the ocean, since 4/5 of the earth's surface is covered by water. That would mean tremendous tsunamis. But God promised He would not destroy the earth again with water. There is an even chance it would strike south of the equator, or in the Pacific. It would probably cause the least global damage if it struck in Antarctica. But the impact waves traveling through the earth's crust could set off earthquakes, volcanoes (watch out for the supervolcanoes like Yellowstone!) and random heating effects. And what if it caused the earth to change its axial tilt?

Also--if the asteroid impacts in Antarctica, would that possibly throw millions of tons of ice chunks into the air, to fall as deadly hail in many places around the globe, like the hail weighing a talent in Rev. 16:21? (Some authorities say a talent weighed about 75 pounds.)
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#2
That does it - I'm moving!
I know you think you understand what you thought I said,
but I'm not sure you realize that what you heard is not what I meant!
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#3
Where to, Mars? Actually, there may be a chance of a habitable area on Mars in some caves beneath the 5-mile deep Mariner valley. You might find air at much greater pressure there than on the surface, and you might find water underground. Then again, Mars is much closer to the asteroid belt, where impacts would likely be much more common.

Or you could take up residence in a space habitat constructed at the L-5 point. That might work, if your habitat has the capability of moving itself out of the way of incoming asteroids. Unfortunately no O'Neill type L-5 facility has yet been constructed.

Maybe some enterprising corporations will orbit space hotels as vacation retreats--especially beneficial for those with heart problems, or bad arthritis. As long as they can move out of the way of incoming space rocks, they might be great places to live. You would still need to import your food from earth though. So if earth is wiped out, so are you.
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#4
No. You don't need to import food from Earth. Just use the replicators used on Star Trek. Everything else that Roddenberry envisioned is mostly already in use. We czn't use magic wands to create food, either, because Hermione Granger from Harry Potter explained the Fifth rule of exclusionary magic said food can't be created out of nothing.
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#5
I used to think pretty much along the same lines as you guys. That mars was the answer. But its not, and never will be in my humble opinion. The best bet are space habitats, which can be moved anywhere in the system. But that is going to have to wait for the cheap and easy production of "Carbon" framing. Once that is possible, who the hell needs an uninhabitable planet?

Just build your own habitat, and live on the inside. I'm a firm believer in this. We could accommodate billions of people in space with all of our natural resources available. But we will have to wait for the development of "Carbon" as a building element. After that, its Katie Bar the Door. S22
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#6
None of the options mentioned so far, including space habitats, Mars, etc., are viable at present, as long as we depend upon the highly inefficient, wasteful, and expensive technology of rocket propulsion to get us anywhere off the earth. Until we develop a cheaper and much more efficient method of interplanetary transport, like manipulated kinetic energy where heat is converted into one-directional kinetic energy (like what Star Trek called "impulse drive"), space travel will remain impractical. To establish any kind of serious space habitat anywhere, we need to be able to move large numbers of people, not just the tiny crew that will fit in a Space Shuttle. Rocket propulsion just is not good enough, and never will be. Unless we can travel to the Moon or Mars at no more cost than it takes to fly in an airliner from NYC to Los Angeles, large-scale space travel will remain out of our reach. And I do not think "bean stalks" will prove to be a practical answer, either, even if they can be built. It is hard to consider seriously the possibility of colonizing the Moon by using what amounts to taking an elevator to orbit.

We need a whole new technology if we are going to make space travel in large numbers possible. Something that goes beyond the simple physics and immense expense of rockets.
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#7
The space ladder makes sense as the best way to build Lagrange habitats, but such constructs need to be fairly mobile for protection from incoming fire.

The latest Star Trek movie Beyond shows a great habitat, Yorktown, that looks to house millions of inhabitants. Artificial gravity is a great thing.

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#8
The space elevator does have some problems of its own.  For example, geostationary orbit is slightly over twenty-two thousand miles up.   Even traveling at a thousand miles per hour, it would take over 22 hours to get from one end to the other.  In other words, humans would have to wait a long time between trips, which could get quite boring.  Freight up and down the ladder would be no real problem.  

The question would be to decide which point humans could safely exit the elevator and use other vehicles to get them out into space much quicker.  But how would ships be able to land and exit that point safely, since that particular point would be moving much slower and gravity would have a lot of pull.  

Anybody have any good ideas?

I'll still go with the O'Neill as the best space habitat from a practical standpoint. Its spin automatically creates its own gravity, and it may be a good while before anti-gravity is discovered.
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#9
Apparently, NASA has a big "proof of concept" test coming up in 2022.

... wonder if they have a "plan B" .... ?
"Democracy is the theory that the common people know what they want and deserve to get it good and hard."
-- Henry Mencken
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#10
Using KEW to impact and deflect incoming bodies is certainly possible, and all revolves around simple math: Size of body, size of impactor, vector, frangibility of the body, and necessary footprint of impact to overcome frangibility. Test are certainly required, but getting info on incoming bodies is also necessary.
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#11
What kind od tests are necessary to discover the frangibility of the body? A KEW could just put a hole through some asteroids without much deflection.

Plan B may be a soft landing of a propulsion platform of some kind.
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#12
(07-08-2017, 01:01 PM)WmLambert Wrote: What kind od tests are necessary to discover the frangibility of the body? A KEW could just put a hole through some asteroids without much deflection.

Plan B may be a soft landing of a propulsion platform of some kind.

Agreed. Ideally that would be the best route. However, asteroids rotate as they move. Using a propulsion system would first require it to halt the asteroid's rotation before activating the propulsion unit. The propulsion has to be pointed in the right direction. That's the hairy part of the operation.

However, the strike of a revolving asteroid will work best if it approaches at a wide angle. If it hits it head-on, its effect will be almost negligible.
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#13
I believe some may tumble and some may have picked up spin by colliding with others, but most don't spin do they?
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#14
(07-08-2017, 07:45 PM)WmLambert Wrote: I believe some may tumble and some may have picked up spin by colliding with others, but most don't spin do they?

They all tend to rotate, some more than others. Consequently, the firing of the rocket designed to push them away from a collision course must be either computer controlled once its characteristics are know, OR it's rotation must be halted in order to be certain the rocket will accomplish its mission.
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#15
It would require too much input of kinetic energy to stop a body weighing a million tons or more from rotating. The inertia involved is immense. A spacecraft the size of a refrigerator would not be able to input that much energy, unless you could accelerate it to an impossibly high velocity. But if they hit it straight on as close to the center of gravity as possible, they might deflect the overall course slightly. If they did not hit straight on, but rather struck it obliquely, or struck it toward one end, they might do no more than just affect the rate of rotation slightly, which would not deflect the overall course.

A likely alternative might be to harpoon the asteroid with an umbrella device, that would open up into a solar sail. That would exert a continuous pull on the asteroid, so long as the rotation of the asteroid did not wind up the solar sail, which might have unpredictable effects.

A little note on the name "Apophis."

"Apep (Aapep, Apepi or Apophis) was the ancient Egyptian spirit of evil, darkness and destruction who threatened to destroy the sun god Ra as he travelled though the underworld (or sky) at night." Link: http://www.ancientegyptonline.co.uk/apep.html
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#16
(07-08-2017, 09:32 PM)Ron Lambert Wrote: A likely alternative might be to harpoon the asteroid with an umbrella device, that would open up into a solar sail. That would exert a continuous pull on the asteroid, so long as the rotation of the asteroid did not wind up the solar sail, which might have unpredictable effects.

It's considered here.  One interesting aspect is that they've known about this for about 13 years.  Another is that they actually have calculated odds of 3% for an impact.   S11

It's not spelled out, but given that they will actually be doing an actual test on a kinetic device in the next few years, it's likely that somebody defined this as "Plan A" a while ago.  It certainly fits the mitigation criteria listed for a small asteroid.

The other thing that pops out is the significant hazard of not knowing what we don't know (aka Rumsfeld's Unknown Unknowns).  Unfortunately, this is one of the many things that the last administration managed to make worse.   S28  The key in defending against these things [NEOs], regardless of the method used to defend, is finding them [much] earlier.  I hope somebody in the global genius corps manages to realize this ... the sooner the better. Pity the fool that has to explain that for all the untold Billion$ spent on climate change, they couldn't spare a teeny bit of chump change on a telescope/spectrometer (and a vehicle to get it out into space) that might have actually saved humanity. Thankfully, there is a glimmer of hope.
"Democracy is the theory that the common people know what they want and deserve to get it good and hard."
-- Henry Mencken
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#17
In impact never just imparts rotation. There will always be a change in vector. as well. Think of a pool ball with English on it.
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#18
Better would be to think of an already spinning gyroscope. Of course, most asteroids do not just spin (unless they are big ones, like Ceres), mostly they tumble. So the effects of hitting any asteroid are going to be largely unpredictable. The key is to aim for the center of mass. That is about the best we can do.
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#19
Any chance that Apophis stays in orbit around Earth after coming that close, but not close enough to crash?



And... why did they build Manhatan style skyscrapers on a space platform? Doesn't make sens to me.

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#20
Earth getting a second moon would be cool!

Good observation about the sky scrapers on the space platform. How could a species so insane build a space platform? I think 99.99999% of all aliens who pass by would be repelled--likely flee in fear of such lunatics. That might actually be the purpose, if those who build it are paranoid.
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