Posted by
CowboyNeal
on 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."
Earth's second moon
by
EggplantMan
·
· Score: 5, Interesting
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.
--
?-|||-----x<*))))><
600 years?
by
cybermace5
·
· Score: 5, Interesting
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.
Re:Not quite a planet, eh?
by
jamie
·
· Score: 5, Interesting
"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.
See the orbital motion for yourself
by
StupendousMan
·
· Score: 5, Informative
JPL has a very nice tool for looking at the orbits of asteroids. Go to
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.
-- Michael Richmond "This is the heart that broke my finger." mwrsps@rit.edu http://stupendous.rit.edu
Earth: "MOMMMMMMM! AA29 won't leave me alone! Please tell him to play on the other side of the solar system?!?"
Tal
--
"Study your math, kids. Key to the universe." -The Archangel Gabriel
Re:Not quite a planet, eh?
by
ocie
·
· Score: 5, Informative
Interesting physics, but Kepler's third law says:
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.
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..."
-- _sig_ is away
Re:Not quite a planet, eh?
by
targo
·
· Score: 5, Informative
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.
20K libertareans...
by
Anonymous Coward
·
· Score: 5, Funny
... now have the perfect candidate for their "free" state.
Re:Not quite a planet, eh?
by
GreenPhreak
·
· Score: 5, Informative
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.
-- I drink to prepare for a fight; tonight I'm very prepared.
-Soda Popinksi
Re:meters, miles...
by
bongholio
·
· Score: 5, Funny
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...
Re:Horseshoe orbit?
by
Link310
·
· Score: 5, Informative
Zookeeper Hypothesis
by
gnarly
·
· Score: 5, Interesting
The Fermi Paradox 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 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?
Here is Paul Wiegert's 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.
--
IBM had PL/1, with syntax worse than JOSS, And everywhere the language went, it was a total loss...
Couple of comments
by
Tablizer
·
· 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.
Is there an astronomer in the house? Or anybody who could clarify this?
-- My other sig is also a.Porsche
Re:Why the US will never switch to metric
by
weiyuent
·
· Score: 5, Funny
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.
Re:meters, miles...
by
EmagGeek
·
· Score: 5, Funny
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...
Slashdot Mirror
Wake me up when Earth's little sister is found, and you've got some decent JPEG's.
Is this truly the only Earth I can live on?
?-|||-----x<*))))><
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.
...
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.
JPL has a very nice tool for looking at the orbits of asteroids. Go to
http://neo.jpl.nasa.gov/orbits/
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
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.
Michael Richmond "This is the heart that broke my finger."
mwrsps@rit.edu http://stupendous.rit.edu
Earth: "MOMMMMMMM! AA29 won't leave me alone! Please tell him to play on the other side of the solar system?!?"
Tal
"Study your math, kids. Key to the universe." -The Archangel Gabriel
Interesting physics, but Kepler's third law says:
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.
JET Program: see Japan, meet intere
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..."
_sig_ is away
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.
When men used to be men
... now have the perfect candidate for their "free" state.
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.
I drink to prepare for a fight; tonight I'm very prepared. -Soda Popinksi
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...
http://www.paias.com/paias/home/Science/Newton/New t8Fig5Orbits.htm explains it. From what I understood, it's actually orbiting the L4 and L5 Lagrange points of earth.
This picture illustrates it pretty well.
"That's no moon"
What? What?
My deviantArt site
One proposed resolution 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?
Here is Paul Wiegert's 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.
IBM had PL/1, with syntax worse than JOSS,
And everywhere the language went, it was a total loss...
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.
Table-ized A.I.
How is this object considered a "companion" while Cruithne - Earth's "second moon" - is not?
Earth's Second Moon
2nd Moon Orbiting Earth Discovered
Google Search: Cruithne
Is there an astronomer in the house? Or anybody who could clarify this?
My other sig is also a
1) Thousandths of an inch are useful in measuring machine tolerances, while millimeters are two gross and micrometers too fine.
;-) I think you mean "too coarse".
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.
and so on, so as you can see, conversion to SI in America wouldn't be worth the trouble...