Although confirmation here can't be considered a full proof, two nearby craters appear to have come from the impact of a binary asteroid. See article below. http://www.bbc.com/news/science-environment-26172181
Uh oh! Double trouble! There's nothing to fill up the human heart with terror greater than to witness three moons in the sky! And than, I imagine, over several days or weeks, watch them move in closer and closer, until you notice that your head is the general target! Oh Boy! That's just like this one stray meteor I saw several years ago... It was a beautiful, bright shooting star... Then I noticed it didn't burn up in the safety zone way high up there in the atmosphere, and I also noticed, uncomfortably, that its path was basically straight towards my head!!! I jumped up and ran away, I heard something ricochet loudly and violently behind me. Fortunately, by chance, it didn't bounce into my back, but instead into the bushes. Because at that speed it would have been like a bullet. I'm lucky to be alive! I personally think the idea of "binary" asteroids is neat and I love space rocks, and I wish I could be more enthusiastic about this, but overall I'd say this is just an average day in space. And than once, after a very long time of misses, the Earth just happens to get in the way. Fortunately some of those impacts were not global, extinction level events. And, for all their problems, they at least left behind some interesting features in the landscape.
Speaking of extra moons in the sky, isn't Apophis supposed to be visible even to the naked eye during its coming close pass? That would be a far-out sight, especially through a good pair of binoculars.
I didn't know about that one. I've not had a decent telescope for years or astronomy binoculars, and I wasn't paying attention. I got lost in the Egyptian Mythology story behind the name... Interesting stuff... But I've become suddenly uneasy about this concept of Gravity Keyholes! Very strange stuff. I've tried to dig into it, but I'm having all sorts of problems really understanding it in my mind.
All I know about that is if this thing is perturbed by Earth's gravity to just the right extent, its course around the sun could be altered just right for it to end up on a collision course with our planet on its next close pass. That is, even outside of the keyhole its course will be affected by our gravity to some extent, but the keyhole describes just the right amount of gravitational force (thus just the right distance between the asteroid and the planet) for the asteroid's course to be so affected that it becomes a future earth impactor.
Okay, I looked up Yarkovsky effect... It looks like the affect is caused by thermal photons, in other words heat and infrared emissions, in essence forming tiny thrusters ... Specifically: the Diurnal effect. This is specifically for rotational bodies above 100m. Since the Apophis asteroid is larger than this and rotates, as far as I can tell, this is what we want. During the absorption of radiation (again this is that infrared, heat stuff) there is a lag time between absorption and release. Surprisingly this causes the heat spot to be slightly offset to the 2PM position of the object. Even more interesting is that the location of the heat spot, in relation to the orbital direction, can actually cause an object to move inwards or outwards in its orbit!!! In other words add some heat/infrared to specific points on the surface of a rotating body, in orbit, and you can steer! Since we are dealing with infrared I decided to look up the Astronomy optics of this... It appears that MOST telescopes deal with regular light and near-infrared, basically color. And they deal with details like Magnatude, something ALSO based on light NOT infrared. But, if we really wanted to see what is going on with the Apophis asteroid and these strange orbit changes wouldn't we want to look at it through the infrared, and similar parameters, but not anything through plain light? We want to see the heat/infrared. In fact we ALREADY use infrared in Astronomy, but only to look at distant objects like stars. I don't know if we thought to turn one of our space telescopes, that can see infrared, towards Apophis? (I'm not sure if this 2PM offset is also important to cleaning up the view of the temperature reading we receive?) Also, To track down the cause of thermal lag, I looked up Infrared. It looks like the actual absorption and emission is caused by vibrations in the molecules. Specifically Molecular dipoles. And these represent inequalities in the electric field? Possibly related to Chemical Polarity. So now we're back to polarized fields and charges, but I don't know what's next, I'm lost. I'm also SO sorry because I saw an article on Wikipedia about a method to map an arbitrary shaped object of, I forget, Heat/temperature/infrared/ thermal particles, or polarization, or something like that? The thing was that I saw that one of the problems with Gravitational Keyholes and problems mapping Yarkovshy's problem in 3D were solved.... And now it's lost and gone forever! My browser doesn't have a history feature and I can't find it again to save my life. I HOPE an expert in temperature or particle mapping might know what I saw?
Granny says dem space aliens flingin' `em at us aim ain't too good... Ex-Astronauts: Only Blind Luck Saves Earth's Cities From Asteroid Strikes April 21, 2014 - Earth is being bombarded with three to 10 times more asteroids than previously acknowledged, say three former NASA astronauts, and the only thing preventing a catastrophe from a city killer-sized asteroid is blind luck.
Uncle Ferd got his tin-foil hardhat on just in case... Risk of asteroid hitting Earth higher than thought, study shows 23 Apr.`14 - The chance of a city-killing asteroid striking Earth is higher than scientists previously believed, a non-profit group building an asteroid-hunting telescope said on Tuesday.
If it weren't for blind luck I'd have no luck at all -- gloom, despair, and agony on me (from the television show Hee-Haw . . . with one word change.)
Effects from light of any kind are very small. Individual atoms are pushed, but much more than a tiny dust particle. The solar sails people talk about are extremely thin, like plastic wrap, and many square miles/kilometers in area, and that is just for a small push. The orbit of an asteroid is constantly being changed by gravity from a number of other objects at once. An asteroid near the earth is going to be changed by the gravity of both earth and the moon, which is complicares because it depends on where the moon is in its orbit. Then, even the gravity of Jupiter will have some effect, depending also on where Jupiter is.
One doesn't have to be gloomy to support adequate research. We can't do much about an asteroid now. However, it would only be a matter of money to do additional research and develop a base in space which could protect earth from asteroids by doing something to alter their courses. We spend a lot of money on fighting wars, which could be avoided if people wanted make peace a basic value of humanity in a real sense. We could easily spend a lot of money to protect earth from asteroids, which we can't prevent just by making peace a value we actually would begin to follow.
The affects of light may be small, but the rocks in space are being exposed to the full intensity of the sun, it's not just light that's shining on the asteroids. The heat release's affect on movement is still small, but it exists. And in the long term, combined with gravity, it could move the asteroid in towards a path to impact Earth or send it out into space. You're right that gravity is the strongest, most important player regarding where an asteroid ends up. And that may be why there are only 2 orbits of worry regarding Apophis NEA, 2029 and 2036. I guess the change in planetary bodies in the solar system will prevent the third pass from being a problem, at least as far as we know of for now.
Personally I don't think we'll ever be able to do all that much to protect the planet against asteroids. Too much mass to divert and if we manage to break it apart instead then according to physicists the effect of all that rubble entering the atmosphere in pieces would actually be much worse. Anyway that's why I've been an advocate of establishing off planet colonies. Get enough people planted elsewhere and if the planet gets wiped clean of life again, at least the species survives.
It would be difficult, and if we protect earth from some asteroids, another large one might still get through. Orbital space communities would be better protected because if a large asteroid were detected on a collision course, the space community vehicle could fire up its engines and move out of the way. It wouldn't even have to move all that far. A few kilometers would take it out of a collision course with most large asteroids. Then, although such bodies seem likely to be extremely rare, a space community could also move out of the way of a very fast approaching body from beyond the solar system. Unless we develop a seriously better propulsion system, such as the anti-gravity which is supposed to be impossible under the Theory of Relativity, it will be very expensive to move into space, Yet, we can do it if humanity becomes motivated enough.
Do you honestly think that would be less difficult than launching a few satellites and hooking them up to a few computers? You only have to push the asteroid a little bit if it's discovered far enough away and we have several rockets that could do that rather easily
Aleksander Ulyanov... ... Uncle Ferd says he sounds like one o' dem Russian physicists... ... better lissen to him... ... he might know whereof he speaks.
Do we? Is it just that simple? We are unlikely to miss something? We are unlikely to encounter something with enough mass to laugh at our 'fleets' of little rocket motors? Best solution? Do a bit of both. Develop the ability to alter the trajectory of smaller masses first -- about the mass of say the Empire State Building -- while ALSO working at establishing scattered colonies in space. Now all of this is just 'It's a good idea' stuff with me as I am an old man (in relative terms) and so in the not too distant future it's all going to be moot where my personal existence is concerned. So it's sort of a wistful and sentimental 'loyalty' to the concept of survival of the species itself that motivates my opinions on this stuff. But from a personal perspective . . . well the macro cosmic ALL ends with my existence anyway and so none of this is any really big deal to me.
I know I'd much rather give a chunk of the money the stupid IRS is after right now to this and other scientific projects.
