Slashdot Mirror
A Rock Moves In Space
theBrownfury writes: "The BBC is reporting here that
a very large Earth collision course asteroid has been discovered. This asteroid, NT7,
was first observed on July 5th and current data suggests an impact date of
February 1st, 2019. NT7 is 2kms wide and on date of impact will be approaching
Earth at 28km/s. An asteroid of this size is large enough to cause continent
wide destruction. However astronomers are still cautious in reporting this
asteroid as the orbit of NT7 has not been fully verified. Current data on
NT7's orbit suggests it orbits the Sun every 837 days and travels in a tilted
orbit from about the distance of Mars to just within the Earth's orbit." The BBC article's headline (and accompanying illustration) are more alarming than the story itself seems to warrant: this asteroid has been given a 0.06 on the Palermo technical scale, which means it shouldn't bump getting run over by a llama off your list of worries.
What's that? hm.
:))
I remember at one point in the distant past whenever they used a term in an article it was unlikely anyone would have heard of, like "Palmero Technical Scale", the slashdot editors would put a little [?] box with a link to the appropriate entry on the public collaborative encyclopedia everything2. (OK, so everything2 doesn't have an entry on palmero technical scale, but i'm sure it would pretty soon after slashdot linked it
Why did slashdot stop doing that? It would eliminate a lot of confused, unnecessary discussion. Did the everything2 people just ask slashdot to stop, or something, because they were sick of getting hordes of slashdotters who would start posting stuff without reading the FAQs directed to them?
The Mayan calendar ends on December 21, 2012. If 1. the projections are a bit off as far as the arrival date and 2. it does hit the Earth, I'd say this might be a good reason to end your calendar.
Check out the 3d view here.
Just fast-forward to Feb-1 2019, set the center on earth, and zoom in.
1. mine it for data;
...and, well, you get the point. If it's coming close enough, let's turn it in to something useful.
2. use it as a platform for whatever;
3. sell pieces of it to whomever;
4. mine it for whatever minerals it may carry;
5.
Everything in the Universe sucks: It's the law!
The higher-precision text-based orbital calculator is more accurate. (And overloaded right now.) It has 2002 NT7 in its database. Both claim January 28, 2019 is the date of closest approach. Both claim closest approach around 0.8 AU. Remember, this is projecting many orbits ahead, and small-object orbit projection is inherently noisy because minor disturbing forces matter.
Either we'll know it's a definite miss in a few weeks, or this will be a worry for some time to come.
No, no, no... You mean it is time to break out Larry Niven's book "Lucifer's Hammer" (1977)... which predates Clarke's book (published in 1993) by decades. Niven's book is much better than Clarke's IMO.
A Palermo value of 0.06 means that the risk from this object is elevated above the background risk for such objects by about 15%. (The 0.06 is the log of the ratio of the risk to the background risk.) So however worried you were yesterday about collisions with 2 km asteroids, you can be 15% more worried today.
In short, not worth losing sleep over.
http://neo.jpl.nasa.gov/neo/close.html
give distances both in AU and LD (lunar distances) for the dozen or so close passes that happen each month or so.
Not that you should be alarmed.
"It is a greater offense to steal men's labor, than their clothes"
The impact on the Earth of NT4 and NT5 was bad enough...
I am not interested in articles about life extension advancements.
Actually there are contingency plans that we as a planet can do with this much advanced warning.
Most asteroids such as this one are almost black in color and reflect very little incident light; this coupled with their small size make them very difficult to detect. There is a property in physics called albedo (no, not libido) which is basically the 'reflectivity' of an extraterrestrial object (the moon has an albedo of ~.1, ie it reflects ~10% of incident light). If we could find a way to change one side of an earth-collision asteroid to have a higher albedo, perhaps by icing it with water ice, then we have effectively made a motor to push the asteroid off its normal orbit. More light would be reflected on one side than the other, causing a slight difference in the number of photons absorbed on one side compared to the other. This absorption differential would be enough over time to significantly alter the orbit of an asteroid. But this is the sort of thing that won't work in 18 days, it would have to be several years for the photon force to make a real change in the orbit. That is why we have the NEAR program, to determine orbits of near-earth asteroids in advance so we have a lot of time to figure out an appropriate way of dealing with them.
Something like icing an asteroid is much easier than landing a manned crew on it to put a rocket on it or blow it up or the other things suggested in this thread. It could be done using entirely automated systems.
Oh, and I don't believe that methods for avoiding the extinction of our species should be patented...
I drink to prepare for a fight; tonight I'm very prepared. -Soda Popinksi
I'm a lot more worried about the asteroids that are discovered just AFTER missing earth. :-/
Don't worry about the alarmist graphic. You'll note that they BBC online site uses that "giant asteroid destroying the Earth" image every second on third asteroid story they run. Here's a few recent favorites with the scary image:
Asteroid Impact Centre Site Selected
Earth at Lower Risk of Impact
UK Centre to Study Asteroid Threat
So, yeah, basically you should ignore that image. It's not related to the story in any but the most basic level; it's a picture of an asteroid hitting the Earth... a stock one.
--
RumorsDaily
So, their error is tens of millions kilometers, or several 10^10 meters. The radius of earth is roughly 10^6 meters. The chance of the asteroid hitting us with this data is proportional to the AREA, which means the ratio of these quantities squared. So the chance is (10^6/10^10)^2 = 10^-8, which is 0.000001%. I wonder if I have a better chance of winning the lottery?
When will Microsoft learn... Here's an excerpt from some computer magazine's review of the new "enhanced" version of NT... "In one review the editor had this to say about Microsoft's new version of WindowsNT: "All in all it was a massive undertaking. Massive in scale. It ran quite fast in all test's, giving a maximum of 28km/h (kilo-mips/hertz). But when it crashes... it takes most everything down with it....""
--Kevin
I don't know which is more scary -- the idea of an asteroid hitting the Earth, or the name "NT7".
Currently the odds of being hit by 2002-NT7 is about 1 in 100,000
:)
For those of you playing at home, those odds are about 70 times better than the advertised odds of winning the Washington State Lottery.
Think about that next time you plop down your dollar for a Lotto ticket.
Buy asteroid collision insurance with it instead.
Someone you trust is one of us.
Hmm. I'm surprised noone's read Niven & Pournelle's "Lucifer's Hammer". I suppose slashdotters are too busy reading Star Trek novels and watching crappy movies like Deep Throat^H^H^H^HImpact. If you're going to be a geek, read real sci-fi. Pournelles a fascist bastard, but Niven's a genius, and together the do good sht.
The first half of Lucifer's Hammer is all about the scientists saying "It won't hit us" because they know the statistical unlikeliness of it all. Meanwhile, all the survivalists and sensationalists are getting ready. Then when the Hamner/Brown comet hits (on Hot Fudge Tuesdae, as named in the funniest part of the book) half the world is unprepared 'cause they new how sensationalist it all was.
Its even got the required Space Mission - but they're just up there to study the damn thing, and are as surprised as everyone else when they watch it clobber the earth (and then the confused Chinese try and nuke the USSR - this was written in the 80s).
Good book.
Actually, I believe that most asteroid threats lie in the plane of the eccliptic, which means you see them coming from pretty much anywhere on the planet.
According to the article, the obit of this asteroid is quite inclined to the ecliptic, which is why it wasn't detected earlier.
Anything NOT coming from the plane of the eccliptic is probably interstellar and thus likely moving WAY too fast to get to and divert without some major advances in technology.
Not so. This object is in a high inclination orbit. A southern herisphere observatory might be critical to detecting an object in an orbit that spends most of its time in the southern sky.
It's because there isn't a global inertial frame of reference.
The rock may be moving quite slowly wrt the place that it departed from, but the sun is moving also, and so is the earth. To expect them to encounter something from "out there" that happens to share their inertial frame of reference... if it did, you wouldn't encounter it. So it will have an inertia more aligned with some other star. Could be quite different from anything local. (It might not, also, but that's not the interesting case.)
I think we've pushed this "anyone can grow up to be president" thing too far.
From the AP wire:
Scientists said if it had hit a populated area, it would have released as much energy as a large nuclear weapon.
Forgive my ignorance of modern scientific theory, but why does the density of people affect the amount of energy released? Would it have been less energy if it hit the ocean?
Maybe there is some human fission reaction anticipated here? If so, I think I know how to solve our energy woes... It's time for Carousel. Renew!
Please mod me up. My grandma might not make it to the weekend and she always wanted me to hit karma cap.
You are asking a good question. The reason why the close approaches occur on the same day of the year is because 2002-NT7's orbit is closest to Earth's orbit at one point. That point does shift around. The current model suggests the closest approach occurs at:
The path of 2002-NT7 will next cross earth's orbit plane going upward at a point about 132.1708757 degrees from the Fall Equinox. Now 132.1708757 degrees / 360 degrees = 0.3671413214 of a circle. Using 365.2564 days (Earth's year), 0.3671413214 of a circle * 365.2564 days = about 134.1 days from the Fall Equinox. 134.1 days from Sep 23 (~06 hr UTC) lands one near 1 Feb.
Take a look at this 2002-NT7 orbit diagram. The dark blue part of 2002-NT7's orbit is below Earth's plane. The light blue part is above Earth's plane. The yellow line from the Sun (red dot in center) going down and to the right is the 0 degree fall equinox line. The vertical yellow line, 132.1708757 degrees from the equinox line (as measured in the plane of Earth's orbit, not the plane shown on your screen) shows where 2002-NT7 crosses Earth's orbit plane. That crossing spot (the place where the dark/light parts of 2002-NT7's orbit meet near the yellow line), you will notice, is very close to Earth's orbit. That spot is the place where Earth is found on/near Feb 1. No other place on Earth's or 2002-NT7's orbit comes as close.
You ask another good question about deflection:
Not every object that gets within 35000km of Earth enters a geostationary orbit. The reason why 2002-NT7 is not captured by earth is that it is moving about 26.25 km/second as it crosses Earth's orbit plane. It is moving too fast to be captured by Earth and pulled into a orbit around our planet.
FYI: An object orbiting the Earth once a day 35,000 km above the surface is moving about 3 km/second with respect to the center of the Earth. The 26.25 km/second speed of 2002-NT7 is much faster.
BTW: Earth DOES deflect 2002-NT7. The crossing point and angle in inclination do shift a but after a close approach, but not by a huge amount. These close passes make the 2002-NT7 orbit tricky to model.
On a different question that somebody else asked:
Your typical astro/solar system display program that runs on your PC (XEphem, RedShift, TheSky, or even that Java app on the JPL site) uses simplified assumptions that are OK for general approximation of objects that do not have significant encounters. They frequently use point size masses and only take into account the Grav pull of the Sun and major planets. High precision models must use much much much more complex models. For example, in addition to accurate 2002-NT7 observations (to measure its position) one must use a non-point Earth model. That gravity lump called EurAsia has a slightly different "tug" than the Pacific Ocean, for example. Normally that difference is not critical, but when one is trying to predict with high precision year in the future, such details can become important.
Permit me to end with a note about critical NASA mission called GRACE.
There is a very critical mission (largely ignored by the general press) known called GRACE. GRACE stands for Gravity Recovery and Climate Experiment. The mission will obtain obtain accurate global and high-resolution determination of both the static and the time-variable components of the Earth's gravity field. This goal will be achieved by making accurate measurements of the inter-satellite range change to within one micron between two co-planar, low altitude polar orbiting satellites, using a microwave tracking system.
GRACE will provide us with an accurate Gravity map which will improve the modeling of very close approaches. I am looking forward to the day with GRACE's gravity maps can be used to establish more detailed close approach orbit models. I wish the GRACE team all the best!
IAACM (I Am A Celestial Mechanic) :-)
and I hope this helps.
chongo (was here)
If you have been following the recent articles about the "Interplanetary Superhighway" discovered by NASA researcher Martin Lo (I have been scouring the net for papers recently) you will realize that there may be a good case for early deflection. In fact NASA re-released the story about this with a little more data just this morning (jpl mailing list). This is hot stuff!
Lo is trying to map the low energy trajectories through the Solar System which result from calculating n-body gravitational problems for all the objects in the System. Apparently there are tube-like trails between the Sun and the Oort Belt along which objects can travel theoretically without thrust, and the dinosaur killer is thought to have come down an "offramp" to the Earth much like Shoemaker-Levy apparently did with Jupiter.
This technology was used in the Genesis Mission and chaos theory applies to the low-energy halo orbit around a Sun-Earth libration point. After orbitting around this point a few times the robot will (without thrust) return to a sample capture point in Earth orbit.
While I do not yet understand the math itself, it seems likely that this Rock is in a somewhat chaotic orbit and that small nudges can have very large effects on its trajectory down the way. A decade or two may not be long enough, or we might even set up a pattern which will smash us on a later orbit, but the technology is being developed right now.
Lots of civilization ending threats face us. Race ending threats face us. Life on Earth ending threats face us. For most of them the odds are basically impossible to calculate. Will we end civilization? Render the human race extinct? Render the Earth unfit for anything but the most primitve life through poisoning the Earth with our waste? It is incalculable, because it depends on making a subjective judgement of whether we can learn to be wise, instead of clever. We are clever enough to build things that could kill us as a side-effect. Are we wise enough not to? That is incalculable.
Astronomical disasters are ones about which we can make reasonable, defensible judgements, and start to enter into actuarial calculations.
Yes, a close enough Supernova burst could destroy civilization. Slashdot has discussed this recently, and again here. 160 to 200 light years was suggested to be the distance beyond which civilization would be safe from a supernova. NASA's picture of the day site has half a dozen articles about eta carinae, a large variable star that they state is a good candidate for the next supernova in our neck of the woods. It is well beyond that 200 ly limit.