Posted
by
CowboyNeal
from the heavenly-bodies dept.
loconet writes "The BBC is reporting that astronomers have discovered the first object ever that is in a companion orbit to the Earth. Asteroid 2002 AA29 is only about 100 metres wide and never comes closer than 3.6 million miles to our planet."
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You think that's bad? As a student pilot, I've learned that the aviation industry has the biggest problem with unit consistency. Or maybe it's the weather industry... check out a _standard_ weather report...
KGTU 220115Z AUTO 15005KT 10SM OVC005 17/16 A3000 RMK AO1
here's what it all means:
kgtu = georgetown, tx airport
22nd of Oct, 0115Z, automated report
winds 150deg @ 5 KNOTS
visibility 10 STATUTE MILES
clouds overcast at 500 FEET
temperture 17deg CELCIUS, dewpoint 16deg CELCIUS
pressure 30.00 INCHES OF HG
remarks: A01=cannot distinguish liquid from frozen precip...
Anyways, as you just saw, the weather is reported using KNOTS, STATUTE MILES, FEET, CELCIUS, IN of HG. Damn! 3 painfully different systems of measurement.. and it seems the more i learn, the more stuff like this I see... I really wish us stubborn americans would just switch to SI...
I military aviation, we have all of that you mention plus, on the topographical maps, the horozontal distance is in kilometers (metric) and the vertical distance/elevation is in feet! The good thing is the altimiter is in feet too, but still...
I really wish us stubborn americans would just switch to SI...
So what are the S.I. units for a good ol'/.'ing?
Hits?
Sysadmin pagings?
Attempted GB's of transfer?
I'm just imagining what the local newscast tease would sound like, "Scientists at Caltech are reporting a slashdotting of 7.4 on the POSA* scale, centered under poorslashdottedbastard.com. Film at 11."
You think that's bad? As a student pilot, I've learned that the aviation industry has the biggest problem with unit consistency.
There is a series of Discovery channel involving building a light aircraft, one of the first points the presenter made was that the construction involved using strange mixtures of units. You also have fuel load on commercial aircraft being measured as a weight, thousands of pounds; whilst dispensed as a volume; either litres, US gallons or imperial gallons depending where the plane fills up. Messing up the cacluations leading to a flight crew having to test the gliding abilities of an airliner over Canada.
I really wish us stubborn americans would just switch to SI...
The US signed the "Treaty of the metre" a long time ago, the US Congress explicitally has the power to set weights and measures so it's really a political problem.
Americans will NEVER switch to SI (much to my dismay).. Here's why:
Football players' union would demand a proportional increase in salary for the extra distance
Football stadiums are too short to extend to a 100m playing field and still have enough setback behind the end zones to comply with OSHA safety regulations
A quarter pounder sounds bigger than an eighth-kilogrammer, and 100g sounds tiny
Americans couldn't comprehend reciprocating fuel mileage (Liters/100km rather than mi/gal)
Tons of government software would have to be thrown out and/or rewritten for the switch (wait a minute.... they still use FORTRAN77 for stuff)
Having unified units throughout the world might be a threat to our national security (who the hell anywhere else knows what an URG is?)
Sears couldn't sell a 500 piece socket set, half of which is completely useless
What woman would ever admit to wearing a size 32 shoe or having a size 65 waistline? (Although they'd probably love having a size 86 chest or being 168 tall)
The Daytona 500 would become the Daytona 804.672, and that number is too big for NASCAR fans to comprehend (it was only recently that they could start having 600 mile races)
A Wendy's Triple w/ Everything has 810 caliories, which is bad enough. However it has 3,391,308 joules - try selling the biggie-size on that one!
Who wants to pay for gas by the liter? (or shall I say "litre")
Americans don't want to have to start mis-spelling (interject) everything, like "colour" and "litre" and "behaviour" etc
The mile markers on I-85 in Alabama couldn't be so cool anymore - now they go 1,1,2,3,2,4,3,5,6,4,7,8,5,9, etc....
and so on, so as you can see, conversion to SI in America wouldn't be worth the trouble...
I'm curious. How much has the UK really changed? Are road distances Km or miles? And road speeds?
Twenty something years after New Zealand changed to metric I find it interesting and a little disappointing sometimes to observe the results.
Degrees F quickly disappeared because (I assume) of TV weather forecasts. MPH has gone because of car speedos but I think you would get blank looks if you asked a mechanic or tyre installer about pressure in Kpa.
Pounds and ounces seem to be long forgotten except for babies' weights.
Commercial floor space still seems to be advertised in sq ft, land area often in acres although I'm sure the official documentation is metric.
Off the cuff comments on TV by police etc at the scene of some event will often make it clear that feet and yards are still more comfortable than meters.
New born babies' weights are more often than not quoted in the newspapers in pounds.
Some adults still quote weight in stones (14 pounds?) although I doubt that you can even buy scales with stones now.
I really wish us stubborn americans would just switch to SI...
The Carter Administration tried this back in the 1970s. The plan was to gradually ease the U.S. into the metric system; the first step was to put up metric speed limit signs. Patriotic Americans responded warmly by shooting them down. So you could say that the metric system has not caught on very well here, unless you count the increasing popularity of the nine-millimeter bullet. (Paraphrasing Dave Barry.)
1) Thousandths of an inch are useful in measuring machine tolerances, while millimeters are two gross and micrometers too fine.
Millimeters are two gross? As in 2 x 144?;-) I think you mean "too coarse".
2)Celcius is not fine grained enough to figure out how to dress for the weather, while Fahrenheit allows one to easily judge whether or not to wear a jacket.
You have got to be kidding me. Do you wear a hundred layers of tissue paper, peeling them off one by one at 1 Fahrenheit incremements? I've survived so far just by putting on a jacket when it get's close to freezing.
3) In the English System, force is the fundemental unit and mass is the derived unit, while in the metric system, mass is fundemental and force is derived. This works well for science and engineering, but Joe Sixpack thinks in terms of weight on earth -- pounds of force.
Oh please. So you're telling me that everyone who uses the metric system gets terribly confused when they have to speak in precise terms of mass vs. force? You must be denser *grin* than I thought.
One plane crash was due to the crew having loaded so many pounds of fuel when they should have loaded so many kilograms instead...!
This was the Gimli Glider [cadetworld.com], which didn't crash, but did run out of fuel and had to make a dead stick landing on the abandoned RCAFB Gimli. No-one was seriously hurt. The aircraft, registration C-GAUN, serial number 22520, is still in service after $1M worth of repairs. Here [airliners.net] are some photos from earlier this year.
Back in the mid 80's, NPR had a couple of fun articles about the non-celebration of the hundredth anniversary of the US going metric.
This needed a bit of explaining, of course. It turns out that the US, like most countries, actually has no legally-required system of measurements. There are laws (or more often, regulations) that specific items must be measured with specific units. But there is no overall requirement that all measurements be in the same "system".
However, the US government has always had an official standards body. It has had various names and acronyms, such as NBS (National Bureau of Standards) or NIST (National Institute of Standards and Technology). It basically manages the regulations that say "If you use unit U, you must use the official definition of U, which is...."
So how did the US "go metric" in the 1880's? Well, what the national standards bureau did then was to revise the official definition of all terms of measurement. They've done this many times. At that time, they decided that the best system in use by scientists and engineers was the "metric" system centered in Paris. There were already copies of the metric units in the US, and they were used for calibration. What was done was to make this official, and publish definitions of all the common units as multiples of the metric units.
These definitions have mostly continued. Thus, the legal definition of an inch is 0.0254 meters. This is not an approximation. It is exact, because it's the official definition of "inch".
It occurred to me while listening to the NPR articles that what the US has is what we in the computer field would call an "extended metric system". We have all the metric terms, but we also have a whole lot more. This obviously makes the American system more versatile, right?
So it's really an example of "embrace and extend."
Any body of rock that is orbiting the Sun and not another planet, is a minor planet if it is not a major planet like Mercury, or Jupiter. Asteroids are also known as minor planets.
Please, say you pulled that out of something/besides/ those tacky S&M novels thinly disguised as fantasy/science fiction.
Of course, maybe/this/ asteroid has the world where the men are all required to do the bidding of the women... with far fewer stupid sci-fi trappings. Then, the news might actually interest me.
If counter earth were there it would bash into it. And of course the counter-brother planet would bash into us at the same time. So no bizaro world. Bummer.
Not only is it co-orbital but it periodically gets trapped in earth's gravitational field to become a second moon:
General Simon Worden of the United States Space Command described it as a "near Earth object that is close to being trapped by the Earth as a second natural satellite".
...
In 550AD, and again in 2600AD and 3880AD, for a while it will become a true satellite of our planet, in effect Earth's second moon, although technically it will remain under the gravitational control of the Sun.
Not only is it co-orbital but it periodically gets trapped in earth's gravitational field to become a second moon:
Okay, I am no astronomer, nor English major, BUT I am confused all the same.
How can it be "periodically trapped"? Is it like the object orbits Earth a few times and then skips back off through the cosmos?
What about that business of every bit of matter in the universe exerting gravitational force on every other bit all the time? Is this object magically shielded from earth sometimes, except for when it is "periodically captured" by Earth?
Am I confusing periodic capture astronomy in the same way I confuse regular physics with quantum physics?
No, I am not trying to be a wise ass, these terms do not make sense the way they were preseted to me.
the orbit is as such that after orbiting earth for awhile, it builds the momentum to escape earth's orbit and fling itself back out and around the sun.
Interplanetary probes use this method all the time for escaping earth's gravity. After launch, they orbit the earth for awhile building up momentum (this is known as a 'gravity assist') then fling themselves out.
This is actually a much more common cosmic event than actually capturing something in permanent orbit. Doing that requires careful placement in the case of artificial satellites or just random chance in the case of natural ones.
They claim it will be temporarily in earth orbit by 2600 AD. And then they go on to speculate on how important that would be to space exploration, possibly becoming the second object visited by astronauts.
If, in 600 years, we haven't sent astronauts to visit other planets, I have preemptively lost faith in the human race.
Come on, in 600 years we should have a pretty decent Mars colony going.
Detailed observations of its trajectory through space show that 2002 AA29 will reach its minimum close approach to the Earth - 12 times the distance between Earth and the Moon - at 1900 GMT on 8 January 2003.
It will be closest to Earth in 2003, and will be nearby for awhile after. As it is much, much closer than Mars, it very well may become the next body visited.
Well shit, in 600 years I'll take my own goddamm air car and go visit it myself. Needless to say I'm still impatiently awaiting my cure for old age and (naturally) my flying cars but these are pesky details...
I *pray* (and I am not a religious man, so it gets confusing... who shall I pray to tonight?) that we will visit something else before 2600. Preferably in my lifetime, but I guess that's not important in the long-term sense.
If we spent a little money on it (a little compared to, say, what we spend on defense) we could go to mars NOW. Or at least, very soon. All of this bullshit warmongering that we waste our time and money on is really keeping us from greatness. Of course if we didn't spend it on war we'd probably spend it on something dumb like theme parks or big oil.
We should DEFINITELY have gone to Mars and be actively moving colonists there long before 2600, barring some kind of serious event. It's just going to become too lucrative not to for some reason or another.
Keep in mind that the orbital solution is based
on only a short arc: only 28 days, about one twelfth of a complete revolution. Our estimates of the orbital parameters -- and behavior --
could change quite a bit over the next few months.
The Earth of course revolves around the sun completing one revolution every year, but the Moon also revolves around the Earth in its own orbit.
Whether this new planet is actually a satellite of Earth is still to be determined. Also, a similar orbit does not mean that the climate is also known to be similar a priori.
The Earth's ecliptic orbit in summation with the Moon's orbit around the Earth means that the Moon must intersect the ecliptic; in fact, it will have to do so at two distinct points.
Has anyone found these nodal points for "Earth's Little Brother" yet? That's the true test of whether or not we will truly be affected by such circumstances.
Some have speculated that it could be nudged into a permanent Earth orbit where it could be studied at greater length.
I can see it now: "Thanks to a sucessful nudgeing, scientists have been able to determine that Asteroid AA29 is pretty much a big rock. In other news, bizarre tides continue to cause panic and destruction around the world tonight..."
This is a new and interesting experience. I'm genuinely not sure whether you're making a reference to Jonathan Swift or computer architecture. The mind reels.
Can sny rocket scientists out there explain how two bodies in the same orbit can have different velocities, AND how the relative velocities can change over time?
They claim that for 90 odd years, the asteroid will accellerate ahead of us, to catch up with earth from behind, at which point it will fall back and we'll cath up with it. And then it repeats.
weird! I can't figure out how this is comes about, and the article didn't think it worth mentioning.
I mean, come on...if we're as advanced as we seem to think we are, we should have been able to land something on it on jan 8, 2003.
Yeah, I know, that kind of thing is complex, but I feel we should have that spurious launch capability...god knows it would save us if we ever met something like what hit Jupiter a couple of years back.
Yeah, I know, that kind of thing is complex, but I feel we should have that spurious launch capability...god knows it would save us if we ever met something like what hit Jupiter a couple of years back.
I don't think having a spurious (false, unauthentic) launch ability would permit us to escape fiery death at the hands of a rogue shoemaker-levy-like object. Perhaps you mean extemporaneous. All jokes aside, it would be great to have a near-impromptu method for launching, but unfortunately missions are really expensive and require a great deal of planning. With the derth of funds going towards NASA these days, it should be expected that we won't have improvised launches anytime soon.
But despite detailed searches no one has yet found any Trojan objects near the Earth.
"The Greeks built an immense wooden horse and Odysseus, Menelaus, and other warriors hid inside it. After leaving the horse at the gates of Troy, the Greek army sailed away. The Trojans thought the Greeks had given up and had left the horse as a gift."
I wonder how hard it would be to pull that asteroid to earth orbit for mining or as an anchor to a space elevator, a la the [almost] original concept by Arthur C. Clarke (later designs [highliftsystems.com] use a man made anchor).
If we can mine useful materials, we could build some cool, big ass stuff probably cheaper than we would carry all that weight from the surface.
If we are able to collect enough of these "friendly" asteroids, or "trojans" as the article calls them, we can think of establishing colonies on these. Along with space elevators [slashdot.org], there will be micro-colonies on each of these asteroids, between which people can travel, just like between different continents. The only issue is when the asteroids decide to take a different orbit!
The Fermi Paradox [ufoskeptic.org] asks: If intelligent life is common, given the billions of years since the formation of our galaxy, why have E.T.'s not yet reached (and perhaps colonized) Earth?
One proposed resolution [space.com] is the Zookeeper Hypothesis, ie, they could have contacted us but are just waiting and watching for us to evolve, a la 2001.
If so, then wouldn't they want to put a probe near the Earth, which swoops down every few centuries or so for a close look, to see if any thing interesting has happened?
Or rather, a question; who's to say that other intelligent life in the universe is anything like our species? The idea that they can and should colonize us, study us, or even visit us seems like the height of anthropocentric hubris. They might not be "flesh-and-blood." They might have a completely different relation to matter and energy as we understand it. They might live in water. They might have no interest in enslaving us or looting our precious natural resources.
Here [queensu.ca] is Paul Wiegert's [queensu.ca] information on Cruithne, which has much of the same characteristic as this current space body, but his explanation actually makes sense for what appears to be a horseshoe orbit, when in reality it's only a horseshoe orbit from Earth's perspective, and is relatively sane looking when viewed off of the solar system plane.
So just like that it shows up into our lives and we're meant to be all happy about it.
And I suppose we're expected to step in if Mercury or Venus start trying to take it's lunch money. And you know they're just gonna have a bigger brother as well. Don't we have enough problems with global warming and the like, without actively looking for trouble?
EXT. SPACE
2002 AA29:
You better not pick on me or gonna get my brother earth and he'll kick your ass!
MERCURY:
Oh yeah, I'd like to see him try.
EXT. SPACE - LATER
EARTH:
(sigh, to Mercury)
I heard you were giving my little brother shit.
(menacing)
What're you going to do about it now?
MERCURY:
Have you met my brother Jupiter?
From nowhere the gargantuan JUPITER appears.
EARTH:
Oh shit! Ay-Ay run!!!
When will we, the citizens of earth, ever learn that violence never solves anything.
Gosh doesn't anyone read the SF of children's writer Eleanor Cameron?
She wrote "The Wonderful Flight to the Mushroom Planet", but in "Mr. Bass's Planetoid", she created a tiny asteroid that allowed the two young protagonists to view the Earth while having landed their spaceship on this asteroid.
Next thing you know, the BBC will report that we've discovered Lepton! Watch out Mushroom People, we're coming!
I noticed a few people wondering how this would affect our planetary tides, orbit, etc. This would NOT affect the earth at all. Hell, it wouldn't even make that big of a crater if it hit us (why do I think I'm going to get flamed for that?)
The thing is 100 meters wide. Imagine a 100 meter (300 foot) wide ball. If we just grabbed it and brought it to earth's surface (gently), it still wouldn't affect our tides at all. It's small enough to fit in a stadium. It's the size of a big hill. The point is that it wouldn't affect us at all.
Also, the reason it wasn't seen that long ago was that it was too far away and too small to see with the naked eye. (we could barely see it with a scope).
A companion is not the same as a satellite. That's all. A companion describes a similar orbit as another body. The Earth's moons have, necessarily, a slightly different orbit from the Earth if you plot them.
I understand the difference between a satellite and a companion. However Cruithne and this body both follow spiral orbits in resonance with the Earth. Neither body orbits the Earth directly. I wanted to know why 2002 AA29 was described as the "first ever" companion object found when 3753 Cruithne was discovered in 1997, and given the discoveries of 1998 UP1 and 2000 PH5.
Some have speculated that it could be nudged into a permanent Earth orbit where it could be studied at greater length.
Uh, wouldn't that screw up the tidal system?
Yeah, but so what? Our species has a track record of fucking up the environment for the sake of profit. At least now we'd be fucking up the environment for the sake of science.
"In roughly the same orbit around the sun, a much smaller mass has to travel MUCH slower than the Earth to maintain that orbit."
No, any object in the same orbital path travels the same velocity.
Think about it this way. If I have a heavy object and a light object orbiting at Earth's distance from the sun, by your hypothesis one will travel faster than the other. So if I duct-tape them together they should travel at a speed somewhere in-between the fast one and the slow one. But the taped-together object masses the sum of both smaller objects so it should travel faster. It can't travel both faster than and slower than its larger half, so the hypothesis can't be right.
Guys, Galieo had a look at this one, once. Thinks about it. Objects of different masses accelerate at the same rate in a uniform gravitational field. The duct-tape anology is perfectly correct also.
That's only an explanation, not an argument. You're just -illustrating- that two objects would move at the same velocity, not -proving- it. So the other analogies were better.:)
The squares of the periods of the planets are proportional to the cubes of their semimajor axes (http://home.cvc.org/science/kepler.htm).
So the mass of a planet has nothing to do with its orbital period (well, assuming it is small enough that it doesn't make the sun orbit it). So anything placed at Earth's distance from the sun and moving at the same speed would orbit the sun in the same path the Earth does regaurdless of its mass.
roughly the same orbit around the sun, a much smaller mass has to travel MUCH slower than the Earth to maintain that orbit.
Wtf? Orbital velocity is a constant that depends only on the mass of the parent body, as long as the orbiting body is significantly lighter. After all, geosynchronous satellites are all at approximately same height, although they have the same speed (to maintain synch), but different mass.
The formula for calculating orbits is: T=2*pi*(a+h)/v where T = period, a = radius of the parent body, h = orbit height, and v = satellite velocity, which can be calculated from: v = sqrt(g/(a+h)), where g is gravitational acceleration of the parent body. You don't see the mass of the satellite anywhere here.
In roughly the same orbit around the sun, a much smaller mass has to travel MUCH slower than the Earth to maintain that orbit.
Ye gods! This is false.
Hint: why does a low earth orbit -- like the Space Shuttle's -- always take the same time? Orbital period depends only on the mass of the earth and the radius of the orbit, not of the satellite.
So why won't 2002 AA29 ever hit the earth?
Do a google search on the Jovian Trojans. Or look up Lagrange Points. Or just consider the complexity of a three body system.
The reason this discovery is useful and more than 'whoop-de-doo' is because of what was mentioned in the end of the article: it is an extra-terrestrial body that is very close to the Earth. It would not be outside our reach to visit this object with current technology and learn more about the composition of asteroids and other minor planets in the solar system.
It is also intriguing since no 'trojans' have been discovered for the Earth and this could signal that we do in fact have some. Trojans are asteroids that occupy the 4th and 5th Lagrangian points about a larger body (Jupiter has the most, due to its large mass). Because of the physics involved in a 2 body system where any additional bodies have negligible mass compared to the original 2, there are a few 'stable' points where the gravitational forces cancel out...these are known as Lagrangian points. L4 and L5 are co-orbital to the less-massive object (Jupiter, Earth, whatever).
Although this object is not a trojan, since it has a horseshoe orbit and temporarily gets caught up in Earth's orbit, it suggests that there are bodies out there that could be trojans. Perhaps as our detection abilities progress, we will discover some Earth-trojans.
Of course, the part I don't get, *why* can't it hit the Earth? In roughly the same orbit around the sun, a much smaller mass has to travel MUCH slower than the Earth to maintain that orbit...
I don't have the equation for the gravitational attraction between two bodies. But I know it is a function of the SUM of the masses of the two objects. So, how much do you think the sum of the masses of the sun and the Earth differs from the sum of the masses of the sun and 2002 AA29?
There are lots of explanations of horseshoe orbits on the web. Basically, if two objects share the same, or very similar, orbits, they are attracted to one another. That gravitational attraction drains kinetic energy from the leading object, and slightly adds kinetic energy to the trailing object.
The leading object, having lost energy, moves closer to the primary. Its year gets slightly shorter, and its actual velocity relative to the primary speeds up. Similarly, the trailing object moves farther away, and its year grows slightly longer.
So the leading objects closer orbit has it revolve around the Primary more quickly, and it will slowly move away from the trailing object. Eventually the leading object is exactly opposite from the trailing object. According to the BBC article, this takes 95 years.
Once the object that was leading is more than 180 degrees ahead in it orbit from the object that was trailing, their mutual attraction starts to add energy to its orbit, and raise it to a higher orbit. Similarly, the mutual attraction drains energy from the other object.
What we have just seen is the two objects trade places. The object that was the trailing object is now the trailing object.
It seems paradoxical that mutual attraction should tear the two object apart. Until you remember that the Sun's influence on the object's trajectories is much more important than their attraction to one another.
At least that is my understanding of the BBC's article.
How does this mechanism allow 2002 AA29 to be briefly captured by the Earth? I'd welcome an explanation of this.
I don't have the equation for the gravitational attraction between two bodies. But I know it is a function of the SUM of the masses of the two objects.
Err... the force is proportional to the product of the two masses: F = -G M m / r^2;... not the sum.
I don't have the equation for the gravitational attraction between two bodies. But I know it is a function of the SUM of the masses of the two objects.
Maybe if you did have the equation for the gravitational attraction between two bodies nearby you'd realize that it is a function of the PRODUCT of the masses of the two objects.:>
"In roughly the same orbit around the sun, a much smaller mass has to travel MUCH slower than the Earth to maintain that orbit."
Follow along in your copy of Principia Mathematica and repeat after me:
An object maintains linear velocity unless acted upon by an outside force.
Force of sun on asteroid: outside force Force of asteroid on sun: not involved
It doesn't matter whether the mass in question is you, a '57 buick or the Death Star. An object 1 AU away (on the average) from something with the mass of the sun orbits once every 365.2429 days, give or take.
Galileo figured out in the 17th cenutry that all objects reguardless of mass fall at the same acceleration. Where have you been in the past 350 years or so?
I never quite understood the concept that an object in orbit is "falling around the sun (or earth)" until I read a physics book that got me to visualize this:
Imagine you have a cannon. You fire a cannonball out of it, and it follows a parabolic path until it hits the ground (Boom). Now, you get a more powerful cannon, and fire a cannonball even farther. In fact it's so powerful that the cannonball is traveling so fast horizontally that the ground is receding from it, due to the curvature of the Earth, faster than gravity is pulling it down to the Earth!
Tada! So the cannonball just keeps moving, around the Earth. It's in orbit.
I hope that explanation helps at least one person who was like me.
No, it would be idiotic. The moon stores a huge amount of angular momentum. That's energy, folks. Let's see... we could waste a whole lot of energy trying to stop it, or we could leave it as it is so that years from now we may harness it usefully.
Anyone read _Signal to Noise_, incidentally? Great book.
The phases that the moon goes through (waxing and waning and whatnot) has nothing to do with the rotation of the moon
Umm I'm pretty sure that he made the original comment in jest.. I doubt anyone who posts to slashdot is ignorant enough to think that the lunar cycles have anything to do with lunar rotation.
I'm a firm believer in astrology, and I think that this type of object might play some role. [...] Thought?
Apparently not on your end of the connection, there's not. Now, I know we're supposed to be respectful of everyone's beliefs, no matter how crackpot or unfounded they may be, but come on! The URL is "science.slashdot.org," not "stuff-not-subject-to-empirical-proof,reason,or-ex perimentation.slashdot.org". This is a discussion about an asteroid in companion orbit (apparently of the L4 and L5 LaGrange points; see above), and you're wondering what effect it would have if 2002 AA29 were in the fifth house while Jupiter and Venus are in ascendance.
In the immortal words of "Weird" Al Yankovic, "Now, you may find it inconceivable or at the least a bit unlikely that the relative positions of the planets and the stars could have some special deep significance that applies exclusively to only you." I do. 2002 AA29 has been conclusively proven to exist. Has the "like, influence of the planets, man" been subjected to the same rigorous standards?
meters, miles... (Score:4, Funny)
Re:meters, miles... (Score:4, Funny)
Re:meters, miles... (Score:5, Funny)
KGTU 220115Z AUTO 15005KT 10SM OVC005 17/16 A3000 RMK AO1
here's what it all means:
kgtu = georgetown, tx airport
22nd of Oct, 0115Z, automated report
winds 150deg @ 5 KNOTS
visibility 10 STATUTE MILES
clouds overcast at 500 FEET
temperture 17deg CELCIUS, dewpoint 16deg CELCIUS
pressure 30.00 INCHES OF HG
remarks: A01=cannot distinguish liquid from frozen precip...
Anyways, as you just saw, the weather is reported using KNOTS, STATUTE MILES, FEET, CELCIUS, IN of HG. Damn! 3 painfully different systems of measurement.. and it seems the more i learn, the more stuff like this I see... I really wish us stubborn americans would just switch to SI...
To make maters worse... (Score:3, Funny)
Re:meters, miles... (Score:4, Funny)
So what are the S.I. units for a good ol'
Hits?
Sysadmin pagings?
Attempted GB's of transfer?
I'm just imagining what the local newscast tease would sound like, "Scientists at Caltech are reporting a slashdotting of 7.4 on the POSA* scale, centered under poorslashdottedbastard.com. Film at 11."
POSA - Pissed Off SysAdmin
Re:meters, miles... (Score:3, Funny)
"Scientists estimate the site recieved upwards of 4,000 hits in two minutes, or 3,451 hits metric."
Re:meters, miles... (Score:3, Interesting)
There is a series of Discovery channel involving building a light aircraft, one of the first points the presenter made was that the construction involved using strange mixtures of units.
You also have fuel load on commercial aircraft being measured as a weight, thousands of pounds; whilst dispensed as a volume; either litres, US gallons or imperial gallons depending where the plane fills up. Messing up the cacluations leading to a flight crew having to test the gliding abilities of an airliner over Canada.
I really wish us stubborn americans would just switch to SI...
The US signed the "Treaty of the metre" a long time ago, the US Congress explicitally has the power to set weights and measures so it's really a political problem.
Re:meters, miles... (Score:5, Funny)
and so on, so as you can see, conversion to SI in America wouldn't be worth the trouble...
Re:meters, miles... (Score:3, Interesting)
Twenty something years after New Zealand changed to metric I find it interesting and a little disappointing sometimes to observe the results.
Degrees F quickly disappeared because (I assume) of TV weather forecasts. MPH has gone because of car speedos but I think you would get blank looks if you asked a mechanic or tyre installer about pressure in Kpa.
Pounds and ounces seem to be long forgotten except for babies' weights.
Commercial floor space still seems to be advertised in sq ft, land area often in acres although I'm sure the official documentation is metric.
Off the cuff comments on TV by police etc at the scene of some event will often make it clear that feet and yards are still more comfortable than meters.
New born babies' weights are more often than not quoted in the newspapers in pounds.
Some adults still quote weight in stones (14 pounds?) although I doubt that you can even buy scales with stones now.
Re: (Score:3, Informative)
Re:meters, miles... (Score:3, Funny)
The Carter Administration tried this back in the 1970s. The plan was to gradually ease the U.S. into the metric system; the first step was to put up metric speed limit signs. Patriotic Americans responded warmly by shooting them down. So you could say that the metric system has not caught on very well here, unless you count the increasing popularity of the nine-millimeter bullet. (Paraphrasing Dave Barry.)
Re:Why the US will never switch to metric (Score:5, Funny)
Millimeters are two gross? As in 2 x 144?
2)Celcius is not fine grained enough to figure out how to dress for the weather, while Fahrenheit allows one to easily judge whether or not to wear a jacket.
You have got to be kidding me. Do you wear a hundred layers of tissue paper, peeling them off one by one at 1 Fahrenheit incremements? I've survived so far just by putting on a jacket when it get's close to freezing.
3) In the English System, force is the fundemental unit and mass is the derived unit, while in the metric system, mass is fundemental and force is derived. This works well for science and engineering, but Joe Sixpack thinks in terms of weight on earth -- pounds of force.
Oh please. So you're telling me that everyone who uses the metric system gets terribly confused when they have to speak in precise terms of mass vs. force? You must be denser *grin* than I thought.
Re:Why the US will never switch to metric (Score:3, Informative)
Please; just subtract 273:
>298K: t-shirt, shorts
293K-298K:t-shirt, jeans
etc...
Re:meters, miles... (Score:3, Interesting)
This was the Gimli Glider [cadetworld.com], which didn't crash, but did run out of fuel and had to make a dead stick landing on the abandoned RCAFB Gimli. No-one was seriously hurt. The aircraft, registration C-GAUN, serial number 22520, is still in service after $1M worth of repairs. Here [airliners.net] are some photos from earlier this year.
Re:meters, miles... (Score:2)
Re:meters, miles... (Score:5, Funny)
What? What?
Re:meters, miles... (Score:3, Funny)
A compromise has been made. When it is on the left side of Earth, use English units, and when it is on the right side, use metric units.
Re:meters, miles... (Score:3, Funny)
This needed a bit of explaining, of course. It turns out that the US, like most countries, actually has no legally-required system of measurements. There are laws (or more often, regulations) that specific items must be measured with specific units. But there is no overall requirement that all measurements be in the same "system".
However, the US government has always had an official standards body. It has had various names and acronyms, such as NBS (National Bureau of Standards) or NIST (National Institute of Standards and Technology). It basically manages the regulations that say "If you use unit U, you must use the official definition of U, which is
So how did the US "go metric" in the 1880's? Well, what the national standards bureau did then was to revise the official definition of all terms of measurement. They've done this many times. At that time, they decided that the best system in use by scientists and engineers was the "metric" system centered in Paris. There were already copies of the metric units in the US, and they were used for calibration. What was done was to make this official, and publish definitions of all the common units as multiples of the metric units.
These definitions have mostly continued. Thus, the legal definition of an inch is 0.0254 meters. This is not an approximation. It is exact, because it's the official definition of "inch".
It occurred to me while listening to the NPR articles that what the US has is what we in the computer field would call an "extended metric system". We have all the metric terms, but we also have a whole lot more. This obviously makes the American system more versatile, right?
So it's really an example of "embrace and extend."
Brother? (Score:2, Funny)
Re:Brother? (Score:3, Funny)
Since it's not a planet, wouldn't it be more like a cousin than a brother.
More like a red-headed stepkid, from the size of it.
Re:Brother? (Score:3, Funny)
Re:Brother? (Score:3, Funny)
Re:Brother? Yes, it is a minor planet (Score:3, Insightful)
Re:Brother? (Score:3, Funny)
Re:Brother? (Score:3, Funny)
.
Damn! (Score:3, Funny)
Kierthos
Re:Damn! (Score:3, Funny)
Don't let Mr. Ashcroft hear you say that.
Re:Damn! (Score:4, Funny)
Re: Damn! (Score:2, Funny)
> > Don't let Mr. Ashcroft hear you say that.
> Why, is it his secret asteroid base?
No, it's where he hides statues with tits.
Re:Damn! (Score:4, Funny)
They found my secret asteroid base! Now I'll have to move it again before I can continue my plans to take over the world!
You should know by now that all your secret asteroid base are belong to us!
GMDSO WHAT??? (Score:5, Funny)
Not a paradox. (Score:3, Insightful)
Only a 'roid? (Score:2, Redundant)
Re:Only a 'roid? (Score:2)
Of course, maybe
Actually this proves counter earth aint there (Score:2)
Earth's second moon (Score:5, Interesting)
Second? (Score:2)
Re:Earth's second moon (Score:2)
Okay, I am no astronomer, nor English major, BUT I am confused all the same.
How can it be "periodically trapped"? Is it like the object orbits Earth a few times and then skips back off through the cosmos?
What about that business of every bit of matter in the universe exerting gravitational force on every other bit all the time? Is this object magically shielded from earth sometimes, except for when it is "periodically captured" by Earth?
Am I confusing periodic capture astronomy in the same way I confuse regular physics with quantum physics?
No, I am not trying to be a wise ass, these terms do not make sense the way they were preseted to me.
Re:Earth's second moon (Score:3, Interesting)
Interplanetary probes use this method all the time for escaping earth's gravity. After launch, they orbit the earth for awhile building up momentum (this is known as a 'gravity assist') then fling themselves out.
This is actually a much more common cosmic event than actually capturing something in permanent orbit. Doing that requires careful placement in the case of artificial satellites or just random chance in the case of natural ones.
600 years? (Score:5, Interesting)
If, in 600 years, we haven't sent astronauts to visit other planets, I have preemptively lost faith in the human race.
Come on, in 600 years we should have a pretty decent Mars colony going.
Re:600 years? (Score:5, Insightful)
Detailed observations of its trajectory through space show that 2002 AA29 will reach its minimum close approach to the Earth - 12 times the distance between Earth and the Moon - at 1900 GMT on 8 January 2003.
It will be closest to Earth in 2003, and will be nearby for awhile after. As it is much, much closer than Mars, it very well may become the next body visited.
Re:600 years? (Score:2)
Re:600 years? (Score:2)
Re:600 years? (Score:2)
If we spent a little money on it (a little compared to, say, what we spend on defense) we could go to mars NOW. Or at least, very soon. All of this bullshit warmongering that we waste our time and money on is really keeping us from greatness. Of course if we didn't spend it on war we'd probably spend it on something dumb like theme parks or big oil.
We should DEFINITELY have gone to Mars and be actively moving colonists there long before 2600, barring some kind of serious event. It's just going to become too lucrative not to for some reason or another.
31337 413NZ!!! (Score:3, Funny)
See the orbital motion for yourself (Score:5, Informative)
JPL has a very nice tool for looking at the orbits of asteroids. Go to
http://neo.jpl.nasa.gov/orbits/ [nasa.gov]
for the general case. For 2002AA29 in particular, you can use
http://neo.jpl.nasa.gov/cgi-bin/db?name=2002AA29&g roup=all&search=Search [nasa.gov]
Keep in mind that the orbital solution is based on only a short arc: only 28 days, about one twelfth of a complete revolution. Our estimates of the orbital parameters -- and behavior -- could change quite a bit over the next few months.
Better get the calculations right! (Score:3, Insightful)
Earth says... (Score:5, Funny)
Tal
Orbits, nodes, & more (Score:2, Interesting)
Whether this new planet is actually a satellite of Earth is still to be determined. Also, a similar orbit does not mean that the climate is also known to be similar a priori.
The Earth's ecliptic orbit in summation with the Moon's orbit around the Earth means that the Moon must intersect the ecliptic; in fact, it will have to do so at two distinct points.
Has anyone found these nodal points for "Earth's Little Brother" yet? That's the true test of whether or not we will truly be affected by such circumstances.
"Nudge" it? (Score:5, Funny)
I can see it now: "Thanks to a sucessful nudgeing, scientists have been able to determine that Asteroid AA29 is pretty much a big rock. In other news, bizarre tides continue to cause panic and destruction around the world tonight..."
Re:"Nudge" it? (Score:4, Funny)
NASA Guy 2: "I'm in trouble, aren't I?"
NASA Guy 1: "Uhm, yes. Yes you are."
NASA Guy 2: "Well, look on the bright side. We get to land in California this time!"
miniature earth!? (Score:3, Funny)
Or, barring that, could our planets swap all the SUVs?
Re:miniature earth!? (Score:2)
Horseshoe orbit? (Score:3, Insightful)
They claim that for 90 odd years, the asteroid will accellerate ahead of us, to catch up with earth from behind, at which point it will fall back and we'll cath up with it. And then it repeats.
weird! I can't figure out how this is comes about, and the article didn't think it worth mentioning.
Re:Horseshoe orbit? (Score:5, Informative)
This picture [paias.com] illustrates it pretty well.
Re:Horseshoe orbit? (Score:2, Funny)
Yeah, I totally get it now. Thanks.
Re:Horseshoe orbit? (Score:2, Informative)
Doesn't reflect very well on humanity,does it... (Score:2, Insightful)
Yeah, I know, that kind of thing is complex, but I feel we should have that spurious launch capability...god knows it would save us if we ever met something like what hit Jupiter a couple of years back.
Re:Doesn't reflect very well on humanity,does it.. (Score:2)
I don't think having a spurious (false, unauthentic) launch ability would permit us to escape fiery death at the hands of a rogue shoemaker-levy-like object. Perhaps you mean extemporaneous. All jokes aside, it would be great to have a near-impromptu method for launching, but unfortunately missions are really expensive and require a great deal of planning. With the derth of funds going towards NASA these days, it should be expected that we won't have improvised launches anytime soon.
Re:Doesn't reflect very well on humanity,does it.. (Score:4, Funny)
You keep on using that word. I dunna think it means what you think it means.
20K libertareans... (Score:5, Funny)
Forgetting our history? (Score:2, Funny)
"The Greeks built an immense wooden horse and Odysseus, Menelaus, and other warriors hid inside it. After leaving the horse at the gates of Troy, the Greek army sailed away. The Trojans thought the Greeks had given up and had left the horse as a gift."
Re:Forgetting our history? (Score:2, Funny)
wait... what?
BBC, News for Nerds & stuff that REALLY matter (Score:3, Informative)
Re:BBC, News for Nerds & stuff that REALLY mat (Score:2, Informative)
It's the Death Star (Score:5, Funny)
Use it! (Score:4, Insightful)
If we can mine useful materials, we could build some cool, big ass stuff probably cheaper than we would carry all that weight from the surface.
Friendly asteroids - colonisation! (Score:2, Insightful)
Knew this was coming (Score:2, Funny)
Zookeeper Hypothesis (Score:5, Interesting)
One proposed resolution [space.com] is the Zookeeper Hypothesis, ie, they could have contacted us but are just waiting and watching for us to evolve, a la 2001.
If so, then wouldn't they want to put a probe near the Earth, which swoops down every few centuries or so for a close look, to see if any thing interesting has happened?
a real answer to Fermi (Score:4, Interesting)
uh... 'scuse me? (Score:5, Informative)
Couple of comments (Score:5, Funny)
Little brother? At its size, it is more like a booger of Earth.
It has a highly complicated orbit. It must be female.
Some have speculated that it could be nudged into a permanent Earth orbit where it could be studied at greater length.
Better take out *a lot* of insurance before doing something like that.
Little brother planet? Dammit (Score:3, Funny)
And I suppose we're expected to step in if Mercury or Venus start trying to take it's lunch money. And you know they're just gonna have a bigger brother as well. Don't we have enough problems with global warming and the like, without actively looking for trouble?
EXT. SPACE
2002 AA29:
You better not pick on me or gonna get my brother earth and he'll kick your ass!
MERCURY:
Oh yeah, I'd like to see him try.
EXT. SPACE - LATER
EARTH:
(sigh, to Mercury)
I heard you were giving my little brother shit.
(menacing)
What're you going to do about it now?
MERCURY:
Have you met my brother Jupiter?
From nowhere the gargantuan JUPITER appears.
EARTH:
Oh shit! Ay-Ay run!!!
When will we, the citizens of earth, ever learn that violence never solves anything.
Mr. Bass's Planetoid! (Score:3, Interesting)
She wrote "The Wonderful Flight to the Mushroom Planet", but in "Mr. Bass's Planetoid", she created a tiny asteroid that allowed the two young protagonists to view the Earth while having landed their spaceship on this asteroid.
Next thing you know, the BBC will report that we've discovered Lepton! Watch out Mushroom People, we're coming!
Size Matters (Score:3, Informative)
The thing is 100 meters wide. Imagine a 100 meter (300 foot) wide ball. If we just grabbed it and brought it to earth's surface (gently), it still wouldn't affect our tides at all. It's small enough to fit in a stadium. It's the size of a big hill. The point is that it wouldn't affect us at all.
Also, the reason it wasn't seen that long ago was that it was too far away and too small to see with the naked eye. (we could barely see it with a scope).
Confused... (Score:5, Interesting)
How is this object considered a "companion" while Cruithne - Earth's "second moon" - is not?
Earth's Second Moon [slashdot.org]
2nd Moon Orbiting Earth Discovered [slashdot.org]
Google Search: Cruithne [google.com]
Is there an astronomer in the house? Or anybody who could clarify this?
Re:Confused... (Score:3, Informative)
That's all. A companion describes a similar orbit as another body. The Earth's moons have, necessarily, a slightly different orbit from the Earth if you plot them.
Re:Confused... (Score:3, Interesting)
See Weigert [queensu.ca] for more information.
Famous last words... (Score:4, Funny)
Watch for falling rocks (Score:3, Funny)
Just what we need. Someone pushing huge space rocks closer to the planet to get a better look.
Have you never broken a microscope slide by zooming in too far?
Re:Second Moon (Score:2, Insightful)
jason
Re: (Score:2, Funny)
Re:Second Moon (Score:4, Funny)
Some have speculated that it could be nudged into a permanent Earth orbit where it could be studied at greater length.
Uh, wouldn't that screw up the tidal system?
Yeah, but so what? Our species has a track record of fucking up the environment for the sake of profit. At least now we'd be fucking up the environment for the sake of science.
Yes, I'm kidding people. Sheesh...
GMD
Re:Second Moon (Score:2, Informative)
Re:Not quite a planet, eh? (Score:5, Interesting)
No, any object in the same orbital path travels the same velocity.
Think about it this way. If I have a heavy object and a light object orbiting at Earth's distance from the sun, by your hypothesis one will travel faster than the other. So if I duct-tape them together they should travel at a speed somewhere in-between the fast one and the slow one. But the taped-together object masses the sum of both smaller objects so it should travel faster. It can't travel both faster than and slower than its larger half, so the hypothesis can't be right.
Re:Not quite a planet, eh? (Score:2)
Re:Even better explanation: (Score:2)
Re:Not quite a planet, eh? (Score:5, Informative)
The squares of the periods of the planets are proportional to the cubes of their semimajor axes
(http://home.cvc.org/science/kepler.htm).
So the mass of a planet has nothing to do with its orbital period (well, assuming it is small enough that it doesn't make the sun orbit it). So anything placed at Earth's distance from the sun and moving at the same speed would orbit the sun in the same path the Earth does regaurdless of its mass.
Re:Not quite a planet, eh? (Score:5, Informative)
Wtf? Orbital velocity is a constant that depends only on the mass of the parent body, as long as the orbiting body is significantly lighter.
After all, geosynchronous satellites are all at approximately same height, although they have the same speed (to maintain synch), but different mass.
The formula for calculating orbits is:
T=2*pi*(a+h)/v
where T = period, a = radius of the parent body, h = orbit height, and v = satellite velocity, which can be calculated from:
v = sqrt(g/(a+h)),
where g is gravitational acceleration of the parent body.
You don't see the mass of the satellite anywhere here.
Re:Not quite a planet, eh? (Score:2)
Hint: why does a low earth orbit -- like the Space Shuttle's -- always take the same time? Orbital period depends only on the mass of the earth and the radius of the orbit, not of the satellite.
So why won't 2002 AA29 ever hit the earth? Do a google search on the Jovian Trojans. Or look up Lagrange Points. Or just consider the complexity of a three body system.
Re:Not quite a planet, eh? (Score:5, Informative)
It is also intriguing since no 'trojans' have been discovered for the Earth and this could signal that we do in fact have some. Trojans are asteroids that occupy the 4th and 5th Lagrangian points about a larger body (Jupiter has the most, due to its large mass). Because of the physics involved in a 2 body system where any additional bodies have negligible mass compared to the original 2, there are a few 'stable' points where the gravitational forces cancel out...these are known as Lagrangian points. L4 and L5 are co-orbital to the less-massive object (Jupiter, Earth, whatever).
Although this object is not a trojan, since it has a horseshoe orbit and temporarily gets caught up in Earth's orbit, it suggests that there are bodies out there that could be trojans. Perhaps as our detection abilities progress, we will discover some Earth-trojans.
Re:Not quite a planet, eh? (Score:4, Informative)
I don't have the equation for the gravitational attraction between two bodies. But I know it is a function of the SUM of the masses of the two objects. So, how much do you think the sum of the masses of the sun and the Earth differs from the sum of the masses of the sun and 2002 AA29?
There are lots of explanations of horseshoe orbits on the web. Basically, if two objects share the same, or very similar, orbits, they are attracted to one another. That gravitational attraction drains kinetic energy from the leading object, and slightly adds kinetic energy to the trailing object.
The leading object, having lost energy, moves closer to the primary. Its year gets slightly shorter, and its actual velocity relative to the primary speeds up. Similarly, the trailing object moves farther away, and its year grows slightly longer.
So the leading objects closer orbit has it revolve around the Primary more quickly, and it will slowly move away from the trailing object. Eventually the leading object is exactly opposite from the trailing object. According to the BBC article, this takes 95 years.
Once the object that was leading is more than 180 degrees ahead in it orbit from the object that was trailing, their mutual attraction starts to add energy to its orbit, and raise it to a higher orbit. Similarly, the mutual attraction drains energy from the other object.
What we have just seen is the two objects trade places. The object that was the trailing object is now the trailing object.
It seems paradoxical that mutual attraction should tear the two object apart. Until you remember that the Sun's influence on the object's trajectories is much more important than their attraction to one another.
At least that is my understanding of the BBC's article.
How does this mechanism allow 2002 AA29 to be briefly captured by the Earth? I'd welcome an explanation of this.
Re:Not quite a planet, eh? (Score:2)
Err... the force is proportional to the product of the two masses: F = -G M m / r^2; ... not the sum.
Re:Not quite a planet, eh? (Score:2)
Maybe if you did have the equation for the gravitational attraction between two bodies nearby you'd realize that it is a function of the PRODUCT of the masses of the two objects.
F = (G x m1 x m2)/(r^2)
Re:Not quite a planet, eh? (Score:3, Informative)
Follow along in your copy of Principia Mathematica and repeat after me:
An object maintains linear velocity unless acted upon by an outside force.
Force of sun on asteroid: outside force
Force of asteroid on sun: not involved
It doesn't matter whether the mass in question is you, a '57 buick or the Death Star. An object 1 AU away (on the average) from something with the mass of the sun orbits once every 365.2429 days, give or take.
Galileo figured out in the 17th cenutry that all objects reguardless of mass fall at the same acceleration. Where have you been in the past 350 years or so?
Re:Not quite a planet, eh? (Score:3, Interesting)
Imagine you have a cannon. You fire a cannonball out of it, and it follows a parabolic path until it hits the ground (Boom). Now, you get a more powerful cannon, and fire a cannonball even farther. In fact it's so powerful that the cannonball is traveling so fast horizontally that the ground is receding from it, due to the curvature of the Earth, faster than gravity is pulling it down to the Earth!
Tada! So the cannonball just keeps moving, around the Earth. It's in orbit.
I hope that explanation helps at least one person who was like me.
Re:Nudged? (Score:2)
Re:Nudged? (Score:2)
Umm I'm pretty sure that he made the original comment in jest.. I doubt anyone who posts to slashdot is ignorant enough to think that the lunar cycles have anything to do with lunar rotation.
Re:Effect on Earth (Score:4, Interesting)
I'm a firm believer in astrology, and I think that this type of object might play some role. [...] Thought?
Apparently not on your end of the connection, there's not. Now, I know we're supposed to be respectful of everyone's beliefs, no matter how crackpot or unfounded they may be, but come on! The URL is "science.slashdot.org," not "stuff-not-subject-to-empirical-proof,reason,or-ex perimentation.slashdot.org". This is a discussion about an asteroid in companion orbit (apparently of the L4 and L5 LaGrange points; see above), and you're wondering what effect it would have if 2002 AA29 were in the fifth house while Jupiter and Venus are in ascendance.
In the immortal words of "Weird" Al Yankovic, "Now, you may find it inconceivable or at the least a bit unlikely that the relative positions of the planets and the stars could have some special deep significance that applies exclusively to only you." I do. 2002 AA29 has been conclusively proven to exist. Has the "like, influence of the planets, man" been subjected to the same rigorous standards?
Didn't think so. Thank you, please drive through.