2012 Da14 Nasa/jpl Teleconference February 7

[LaurieAG]

February 7, 2013 at 19:00 UTC (11 a.m. PST/2 p.m. EST). For those of you interested in the closest ever predicted Earth approach for an object of this size, NASA will hold a media teleconference to discuss about upcoming asteroid flyby.

 

http://www.nasa.gov/mission_pages/asteroids/news/telecon20130207.html

http://www.nasa.gov/topics/solarsystem/features/asteroidflyby.html

 

The NASA/JPL image on the above link shows that the transit within the geosynchronous ring will start on February 15 at 15:00 GMT and exit at 22:00 GMT.

 

Considering where the moon is and all the evidence points to a 'quasi moon' or 'co-orbital' type orbit what are the possibilities of 2012 DA14 being captured and becoming a satellite?

 

http://www.newscientist.com/article/dn4814-earths-quasimoon-is-wayward-asteroid.html

[CraigD]

Considering where the moon is and all the evidence points to a 'quasi moon' or 'co-orbital' type orbit what are the possibilities of 2012 DA14 being captured and becoming a satellite?

The probability of 2012 DA14 becoming a captive moon of the Earth is, I’m pretty sure, practically zero. It’s in a moderately elongated elliptical (1.110 to 0.8935 AU) orbit around the Sun. At closest approach to Earth (about 40478137 m) on Feb 15 2013, it will have a speed relative to Earth of about 6050 m/s. To have a circular orbit at that distance, it would need to decrease speed to about 3140 m/s. It would take a very high-force interaction, such as a gravitational assist from the Moon, or Aerobraking in the Earth’s atmosphere, for such a velocity change. As 2012 DA14 won’t pass near the Moon or through the Earth’s atmosphere, I can see no chance of such a maneuver.

 

2003 YN107, the smaller (10 to 30 m diameter, vs. 2012 DA14’s 45 m) asteroid mentioned in the NewScientist article linked to last in post #1, with an orbit between 1.018 to 0.997 AU, is better suited purely in terms of required velocity change for capture, but it would still take an unlikely stroke of luck for something like that to happen.

 

My semi-educate guess on how most captive moons get captured is via aerobraking with their primary. Even then, with the big delta-V requirements met, a very lucky break is needed for the other factors to be right for capture.

[Deepwater6]

Hi Laurie,

 

Great topic, I've been watching Da14 with great interest for some time now. I think it's proximity took many scientists by surprise. :o It may also help accelerate politicians to recoginize how vulnerable we are to such an object....yeah right wishful thinking.

 

Reading all the parameters the object would have to achieve to become a "quasi moon" in Craigs reply makes it sound unlikely, But it sure would be cool to have a second or third object up there to spot at night. I'm also surprised over 4.5b yrs chance hasn't pulled some other objects in around the Earth. I guess I'll just keep playing the lottery. B)

[Deepwater6]

http://www.space.com/19684-can-killer-asteroids-be-steered-away-video.html

 

Space.Com had this video up in reference to DA14 and others in the future.

[LaurieAG]

My semi-educate guess on how most captive moons get captured is via aerobraking with their primary. Even then, with the big delta-V requirements met, a very lucky break is needed for the other factors to be right for capture.

Hi CraigD, there was another New Scientist article about quasi moons around the time that said there were a couple of space rocks and even one of the Apollo stage 3's that were in co-orbital relationships. From memory one orbited the sun for 6 years and then orbited the earth for 3 years before the moon pushed it out and it orbited the sun etc.

 

The second reference at the bottom of the following wiki has a link to a PDF from the Australian Bureau of Meteorology (BOM) about Orbital Decay.

 

http://en.wikipedia.org/wiki/Orbital_decay

 

The attached image is from the PDF and shows that the initial orbit of rogue satellites is elliptical, like DA14, and later on they become circular.

[LaurieAG]

The attached image is my plot(s) for the correct trajectory of 2012 DA14.

 

I had to reverse the side elevation, at least it was symetrical, and plot each against each other as the NASA/JPL images and simulation were in opposition.

 

In the movie The Dish, the Australian guy corrected NASA's figures because he said they plotted trajectories for the southern hemisphere from the perspective of the northern hemisphere.

 

http://en.wikipedia.org/wiki/The_Dish_(movie)

 

I said before I don't think it will hit, most likely it will become a satellite, as the NASA guys only said it would not hit the Earth or any other planet although they made no mention of the moon which usually helps to capture quasi moons. BTW, pink is the color you get when you do a negative of a dark background so you don't waste printer ink.

Edited February 15, 2013 by CraigD

[LaurieAG]

30 minutes ago I saw, during our 5:00pm news, that NASA has asked an Australian amateur astronomer to track the asteroid because the Sliding Springs (Australia's largest) Observatory is out of action due to bush fires. The simulated path is shown in red and it looks very much like the calcs were done wrong again.

[Eclogite]

What makes you think capture as a satellite is quite likely. NASA, with a wealth of orbital data, have projected the path of the object and it is clear from that it will not be captured. Oh, and I'm missing what mistake you think is made in the simulation.

[LaurieAG]

Look at the simulation and make up your own mind.

[Eclogite]

I see no problem, so I would appreciate your guidance in pointing out what seems to you to be in error.

[LaurieAG]

Eclogite, look at the basics first.

[CraigD]

In the movie The Dish, the Australian guy corrected NASA's figures because he said they plotted trajectories for the southern hemisphere from the perspective of the northern hemisphere.

I’m a fan of The Dish (as I was an intern at a radioobservatory, it’s not surprising I’d like a movie in which a bunch of non-PhDs at a radioobservatory are portrayed as world heros), but the subplots from it you mention are purely fictional. The power failure, loss of computer data, and subsequent mad scramble to recalculate the Parkes Observatory’s 64 m radio dish to get the signal from Apollo 11 didn’t happen – it was added to the movie screenplay to make it more dramatic.

 

30 minutes ago I saw, during our 5:00pm news, that NASA has asked an Australian amateur astronomer to track the asteroid because the Sliding Springs (Australia's largest) Observatory is out of action due to bush fires. The simulated path is shown in red and it looks very much like the calcs were done wrong again.

Can you find an online source for that that news story, Laurie? I suspect it’s wrong.

 

Siding Spring observatory (no L, no – makes a lot more sense that way, as I’ve seen more springs at sidings than ones that were sliding :)) is up and well since several of its buildings were burned down in January. Due to some good fire prevention work, the main telescopes and their buildings, including the big, 3.9 m one (all optical – I don’t believe Siding Springs has any radio telescopes) escaped damage from the fire.

 

This NASA JPL webpage has a nice animation of 3 images taken yesterday at Siding Spring.

 

I said before I don't think it will hit, most likely it will become a satellite, as the NASA guys only said it would not hit the Earth or any other planet although they made no mention of the moon which usually helps to capture quasi moons.

I’m with Eclogite in thinking the pros at the various NASA affiliated observatories and labs are likely to have predicted 2012 DA14’s future path more accurately than you, Laurie. However, it’s really not worth time, effort, or worry speculating about – in 24 hours, we’ll have pretty good radar telemetry of its actual path, and can know for sure.

 

I think you’re having some terminology trouble with the term “quasi-moon” and “captured moon”. A quasi-satellite (the generic term, which includes not only natural, but artificial bodies) is a Sun-orbiting body that has nearly the same period, plane, and axis alignment as its “quasi-primary”, so stays close to it for many orbits, appearing from the viewpoint of the primary to roughly circle it. Both bodies gravitationally interact mainly with the Sun, not to one another.

 

A captured moon is a body that gets inserted into at least a fairly stable orbit around its primary well after both bodies formed. It gravitationally interacts mainly with its primary, not the Sun. They’re detectable mostly because their orbits are in different planes that moons that formed at the same time as their primaries, so are usually called irregular moons, describing their orbit, rather than captured moons, describing their origin. Most irregular moons are believed to have been captured.

 

Another term and concept related to these is trojan orbit, which is when 2 bodies share nearly the same orbit. These orbits can be very complicated, with the 2 bodies periodically passing near and interacting with one another. Earth has 3 known and 1 suspected Trojan asteroid companions. It’s hypothesized that it once had a very large one, “Theia”, with which it collided about 4,500,000,000 years ago, and which along with ejected material from the Earth, formed our present day Moon.

 

A key orbital mechanical concept about captured moons is that to become them, they must change orbits, and changing orbits requires changing velocity in a way such that it’s total kinetic and potential energy relative to its to-be primary changes. Gravitational interaction with a primary doesn’t produce this kind of velocity change – it essentially give and takes kinetic and gravitational potential energy in a way that the total energy is nearly constant. So to transfer a body into orbit around a new primary, some other interaction must be involved, typically aerobraking with the primaries atmosphere, or a gravitational assist from a third body, such as another moon of the primary.

 

Such velocity changes can happen in many ways, but all are similar in terms of energy and acceleration. In my previous post, I calculated the 3140 m/s needed to insert 2012 DA14 into Earth orbit using the formula for a Hohmann transfer orbit.

 

As I mentioned earlier, I think such interactions are rare. If they were not, Earth would have a lot of 2012 DA14-sized captive moons, as close passes like todays have happened many time in the 4+ billion years that the Earth-Moon system has been in essentially its present state.

[LaurieAG]

balderdash

 

1590s, of unknown origin; originally a jumbled mix of liquors (milk and beer, beer and wine, etc.), transferred 1670s to "senseless jumble of words." From dash; first element perhaps cognate with Dan. balder "noise, clatter" (cf. boulder).

 

Wierd stuff, the Russian meteorite was almost opposite trajectory to 2012 DA14 but I'm not sure.

 

http://www.today.it/mondo/cuba-meteorite.html

http://thewatchers.adorraeli.com/2013/02/16/in-last-2-days-fireballs-were-reported-all-over-the-world-sweden-netherlands-russia-japan-cuba/

http://thelatestworldwidemeteorreports.blogspot.com.au/

 

http://bits.blogs.nytimes.com/2013/02/15/facebook-admits-it-was-hacked/?hp

 

A common saying among security experts is that there are now only two types of American companies: Those that have been hacked and those that don’t know they’ve been hacked.

Edited February 16, 2013 by LaurieAG

[Eclogite]

Sorry? What was balderdash?