Angry Birds Space Centripetal Force Achievement Walkthrough

Here is our Angry Birds Space walkthrough video that will help you unlock Centripetal Force (Lagrangian Point) Achievement. You can find info on a Lagrangian Point on Wikipedia.

Update: As of the v1.1.0 (Fry Me to the Moon) update, the Centripetal Force achievement has been fixed and the understanding changed. The concept is no longer to get a bird stuck in a Langrangian Point, but rather to simply pass through one. This is a million times easier. While it doesn’t really need a video, we already have the page created, so why not, eh?

The first level where this achievement is attainable is Pig Bang level 1-5. Simply fire the Red bird above the first planet so that it passes through the overlapping gravitational fields.

If you have a different method for obtaining this that you think is easier feel free to leave a comment below explaining your strategy.

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Comments (148)

By Squeaks McGee

so you can get it so stop in the middle, but you don’t get the achievement?

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By AMslimfordy (@amslimfordy)

Correct; haven’t heard of anyone getting the achievement yet.

By Wrasheed

I am on PC, Played 1-10 , did it one bird:
did it slow like your shot landed 100% between the 2 gravity pullers, split it there destroyed the blocks that gives path to blue bird and waited for a couple of seconds maybe it was at the most between and disappeared
– too bad I am on PC

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By AMslimfordy (@amslimfordy)

Again, we believe the achievement itself is bugged, not that it is impossible to do what we think should trigger the achievement.

By Wrasheed

Did Rovio knew it already

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By AMslimfordy (@amslimfordy)

We have informed Rovio.

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By MVNLA2 (@mvnla2)

Most of the posts before 4/25 (when Fry me to the Moon was released) are OBE. A lot of the discussions of Lagrangian-point physics are interesting, but mostly irrelevant. The achievement is obtained by shooting a bird through 2 overlapping gravitational fields, which is not a Lagrangian point unless the 2 bodies are rotating about each other. None of the planets in ABSp appear to rotate about each other. We could perhaps assume that they are rotating about each other and the frame of reference (or field of view) rotates with them. I think you then need to say that the backgrounds are purely artistic, and irrelevant to physics.
You can especially ignore most of my posts, since I was futilely trying to find a possible solution within the original release, when in reality it was bugged.

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By AngryMiko (@angrymiko)

Yup…..i made it stop, then the blue bird disappear….no achievement

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By Maaz (@maaz)

Same here

By josh senarighi

i did it twice and no achievement:(

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By username12345 (@blahalb09)

Has anyone tried a level with a bomb or ice bird? They never disappear unless they come into contact with something or the screen is tapped.

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By nascarboy (@nascarboy)

Exactly.

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By GFish (@gfish)

That’s a very good idea! Or at least it was if there was a level that meets those conditions…

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By Boo-Boo (@boo-boo)

Danger Zone Level 4 might be the one.
I’ve been aiming for the L4 and L5 Langrangian points, which would be above and below the intersection of gravity circles. I thought that the L1 point with that intersection would be too simple to be an achievement.

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By MVNLA2 (@mvnla2)

@boo-boo I agree that it might be L4 or L5, but haven’t found it yet
@blah All the birds disappear after a while if they are stationary

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By mjr73 (@mjr73)

This is kind of frustrating, must be a bugged achievement, put a bird into here a number of times & got nothing. Same thing on 2-19, very easy to get big green into a steady hover point between the planets, but no achievement

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By sal9 (@sal9)

I even had all three birds jammed in that LP at the same time.
Maybe we’re getting it wrong.
There’s still a secret “hidden” achievement to be uncovered.

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By AMslimfordy (@amslimfordy)

It seems to be “Menu Popper” but I have not yet achieved it

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By sal9 (@sal9)

Something similar to Name popper ?

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By AMslimfordy (@amslimfordy)

Yeah, popping 100 pigs “in the menus” (though the definition of “menu” is not entirely clear).

By TripleXero

My useless temptation to always pop them has reason now!

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By AngryAdvisor (@lesleyg)

Ok so I just did it in level 1-10 and now what? Same as you guys it comes to halt and eventually disapears…maybe were suppose to get all three at one time to sit in there…all though I don’t think so? Is it suppose to appear in GC as an achievment earned and it just isn’t and that’s the bug?

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By AMslimfordy (@amslimfordy)

Probably something wrong with the coding.

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By pianistrevor (@tnatiuk17piano)

Why aren’t achievements like this one on Android yet? I feel like we are missing out, such as not having an app to control your data, like gamecenter, plus not having the mighty eagle and stuff…

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By AMslimfordy (@amslimfordy)

GameCenter does not control or store any data. It only receives information; no storage, no recall, no return.

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By Kathy (@kathy)

I agree trev! Truckdriver and myself have contacted rovio to no avail:( just nnot fair! ( stomp..sstomp)

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By TruckDriver (@truckdriver)

Yeah, whatcha gonna do? Likely the nature of Android, discussed elsewhere, has much to do with it. That’s one of the reasons that I obtained an iPad2.

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By Bill (@dollarbill2208)

I have done this once, allowing the bird to disappear before finishing the level. Then I did this and finished the level before the bird disappeared. Both ways, still no dice.

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By sunshine (@sunshine)

Slim, I got my bird to stop on 1-10the for centripetal force, but no achievement?? Why? :)

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By AMslimfordy (@amslimfordy)

As the post says, it may be bugged.

By elkjar

Are you guys sure this is the point that is seeked?
Mabye its something like the area where bomb is in 2-29?
Didnt manage to get a bird to stay there yet…

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By AMslimfordy (@amslimfordy)

A Lagrangian Point is well-defined. It shouldn’t matter what level you choose.

By Slokar

yes sure.. But the area I mean is between gravity fields.. Was just a thought. :)

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By wrw01 (@wrw01)

On level 1-10 did a slow release (short laser line) off the sling shot with the first blue bird. Right before the blue bird entered the center circle I tapped and released the 3 blue birds. The top bird stayed in the center circle and broke the center of the vertical ice stick and eventually came to a stop. The bird stopped for about 2-3 seconds and then disappeared. The bottom two birds, after the split, went into the bottom circle. I then destroyed the two green pigs on the end structures to complete the game and as a result obtained one star. No Centripetal Force Achievement was provided. The bug lives another day.

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By sammishredd (@sammishredd)

I do not think that stabilizing a bird in a Lagrangian Point is possible in Angry Birds Space,… at least not yet. In all the levels available so far the asteroids are fixed bodies that do not move. A Lagrangian Point occurs only in the gravitational fields of two bodies that orbit around a shared center of mass. If you rotate along with the two bodies they appear motionless relative to your perspective so it may seem intuitive that this movement can be ignored, and that the stationary objects found in Angry Birds will work just fine, but I do not think this is true. The two larger bodies will have to be in motion for a third (the bird is the third!) to be trapped at a Lagrangian Point.  It is likely that in future updates to the game there will be levels involving moving asteroids, and then this trick will become possible. 

In any case, the phenomenon everyone is attempting in level 1-10 and elsewhere is literally missing the point, since the birds pendulate and come to rest at a position BETWEEN Lagrangian Points, which is an oddity of the slightly fudged physics in Angry Birds Space. The center of that lozenge formed by two overlapping gravitational fields is not itself a Lagrangian Point, although it may approximate the L1 position, that would be (along with L2 and L3) an unstable orbit and require correction after launch…which is not really possible in the game. 

 It is nearer the tips of that lozenge that we are after, at Lagrangian points L4 and L5. A moving object that hit these targets just right would stabilize and even if knocked about by pesky debris would auto-correct back into place.  This is why the real-world Lagrangian Points of the larger planets in our solar system are already cluttered with ice-moons and asteroids and similar junk that passed by,  they can’t get back out!  When the friendly folks at Rovio finally release levels with orbiting asteroids we should be able to stuff those sweet spots full of tiny birds. 

:0)
Sammi Shredd

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By Laurence (@laurence)

Nice theory, but from Rovio’s twitter: ‘A few people have had difficulty with this so we are looking into it!’. This implies that it should be possible to obtain it!

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By Bird Leader (@birdleader)

This could be one of the most amazing and informative comments we’ve received in a long time. You inspired me to create a new badge called, “High IQ”, which you have been awarded. Thanks.

I admit, I don’t know a lot about Lagrangian Points, but based on what I’ve read this seems to be spot on.

That said, who knows if Rovio factored in all these points or if they’re going for the “dumbed down” version. I guess time will tell.

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By CougRon (@cougron)

I doubt Rovio would have put the achievement in the launch version of the game unless it was supposed to be possible to get it with the launch version. Rovio may very well add moving gravity points in a future version and then have true Lagrangian points but I doubt the achievement is for that future version–they would have waited for that version before adding it.

So far I haven’t seen anyone definitively define what you are supposed to do for the achievement; all I’ve seen is the not very informative achievement description and our guesses. So far I haven’t even seen anyone who claims to have gotten the achievement or how they did it.

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By sammishredd (@sammishredd)

What? Whoa!

Neat.

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By TruckDriver (@truckdriver)

Of course, what’s likely happening is that the physics of interacting gravitational fields is not within the program. In reality, what would be likely to occur is that the two bodies would have a region where their interacting fields are in flux, with a bias towards the heavier mass, causing an eventual soft landing (a relative term) on its surface.

Another possibility would be a where the more massive object distorts the gravitational fields of the smaller mass, rather than the order and opposite symmetry of fields that we see within the game.

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By Han_Solo1617 (@enrico-carl-andrei)

Actually,there is already a level with moving asteroids.
Like level 2-30.

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By AMslimfordy (@amslimfordy)

But they don’t have a gravitational pull.

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By theanonymoussomeone (@anonymousomeone)

It can be done! I accidentally got a bird stuck in 2 gravitational fields at once and eventually the bird I had launched disappeared in a cloud of feathers, still stuck there.

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By MVNLA2 (@mvnla2)

To add fuel to the physics of ABOS fire, Rhett Alain says the “gravitational” force in ABOS is not 1/r^2! See https://www.angrybirdsnest.com/forum/discussion/855/physics-of-angry-birds-space

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By MVNLA2 (@mvnla2)

Should be Allain, sorry!

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By MVNLA2 (@mvnla2)

Added link to Rhett Allain’s blog on Lagrangian pts to forum on physics of ABOS. Enjoy!

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By MVNLA2 (@mvnla2)

Tweeted PVesterbacka to ask if anyone had done this yet. His response was “impossible is nothing ; )” Maybe would make more sense if not translated into English???

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By MVNLA2 (@mvnla2)

“Impossible is just a big word thrown around by small men who find it easier to live the world they’ve been given than to explore the power they have to change it. Impossible is not a fact. It’s an opinion. Impossible is not a declaration. It’s a dare. Impossible is potential. Impossible is temporary. Impossible is nothing.”
Muhammad Ali
OK, so it’s a dare!

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By TruckDriver (@truckdriver)

I’ll stop using the term when we’ve managed to invent FTL travel.

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By wrw01 (@wrw01)

The European Space Agency presents information on the 5 Lagrange Points in the address listed below. I copied most of the text but would encourage all to view this information because of the pictures that accompany the descriptions provide 4 graphic deplays of the the L1 through L5 scenarios. These pics coupled with the text are written in a manner that I could understand what are the main points of each scenario. One may also get to this page through Google by typing Lagrangian Point.

After viewing this information it started me to wonder about level 1-10. It appears there has to be a rotation component involved around a stationary object. Because I have not completed all the levels there may be another level in this inital release of AB Space that statisfies the general theories of the L1 through L5.

http://www.esa.int/esaSC/SEMM17XJD1E_index_0.htmlESA Home

31-Mar-2012

What are Lagrange points?

Earth and a spacecraft orbiting the Sun

Joseph-Louis Lagrange
Lagrange points are locations in space where gravitational forces and the orbital motion of a body balance each other.
They were discovered by French mathematician Louis Lagrange in 1772 in his gravitational studies of the ‘Three body problem’: how a third, small body would orbit around two orbiting large ones.

There are five Lagrangian points in the Sun-Earth system and such points also exist in the Earth-Moon system.

Descriptions of individual Lagrange points

Spacecraft in ‘sync’ with Earth orbit
L1

Kepler’s laws require that the closer a planet is to the Sun, the faster it will move. Any spacecraft going around the Sun in an orbit smaller than Earth’s will also soon overtake and move away, and will not keep a fixed station relative to Earth.

However, there is a loophole. If the spacecraft is placed between Sun and Earth, Earth’s gravity pulls it in the opposite direction and cancels some of the pull of the Sun. With a weaker pull towards the Sun, the spacecraft then needs less speed to maintain its orbit.

If the distance is just right – about a hundredth of the distance to the Sun – the spacecraft, too, will keep its position between the Sun and the Earth and will need just one year to go around the Sun. This is L1.

L1 is a very good position for monitoring the Sun. The solar wind reaches it about one hour before reaching Earth. In 1978, the International Sun-Earth Explorer-3 (ISEE-3) was launched towards L1, where it conducted such observations for several years. Now the ESA/NASA SOHO solar watchdog is positioned there.

Such spacecraft must have their own rocket engines because the position is unstable: if a spacecraft slips off L1, it will slowly drift away, and some correcting action is needed. In fact, the preferred position is actually some distance to the side of L1, because if the spacecraft is right on the Sun-Earth line, the antennas which track it from Earth are also aimed at the Sun, a source of interfering radio waves. Corrections are needed regularly.

Spacecraft on L2
L2

An effect similar to that which causes the L1 point occurs on the ‘night’ side of Earth (further away from the Sun but about the same distance from Earth).

A spacecraft placed there is more distant from the Sun and therefore should orbit it more slowly than the Earth; but the extra pull of the Earth adds up to the Sun’s pull, and this allows the spacecraft to move faster and keep up with Earth.

At a certain point, the spacecraft’s orbital period equals that of Earth’s. This is L2. It is located 1.5 million kilometres directly ‘behind’ the Earth as viewed from the Sun. It is about four times further away from the Earth than the Moon.

Gaia mapping the stars of the Milky Way
L2 is a great place from which to observe the larger Universe. A spacecraft would not have to make constant orbits of Earth, which result in it passing in and out of Earth’s shadow and causing it to heat up and cool down, distorting its view. Free from this restriction and far away from the heat radiated by Earth, L2 provides a much more stable viewpoint.

ESA has a number of missions that will make use of this spot in the coming years. L2 will become home to ESA missions such as Herschel, Planck, Gaia and the James Webb Space Telescope.

Spacecraft on L3
L3

L3 lies on a line defined by the Sun and Earth, but beyond the position of the Sun.

On the opposite side of the Sun, just outside the orbit of Earth, the combination of the Sun’s and Earth’s gravity would cause a spaceraft’s orbital period to equal that of Earth.

Since the position of this Lagrange point lies behind the Sun, any objects which may be orbiting there cannot be seen from Earth.

L4 and L5

The L4 and L5 points lie at 60 degrees ahead of and behind Earth in its orbit as seen from the Sun. Unlike the other Lagrange points, L4 and L5 are resistant to gravitational perturbations. Because of this stability, objects tend to accumulate in these points, such as dust and some asteroid-type objects.

A spacecraft at L1, L2, or L3 is ‘meta-stable’, like a ball sitting on top of a hill. A little push or bump and it starts moving away. A spacecraft at one of these points has to use frequent rocket firings or other means to remain in the same place. Orbits around these points are called ‘halo orbits’.

But at L4 or L5, a spacecraft is truly stable, like a ball in a bowl: when gently pushed away, it orbits the Lagrange point without drifting farther and farther, and without the need of frequent rocket firings. The Sun’s pull causes any object in the L4 and L5 locations to ‘orbit’ the Lagrange point in an 89-day cycle. These positions have been studied as possible sites for artificial space stations in the distant future.

Copyright 2000 – 2012 © European Space Agency. All rights reserved.

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By MVNLA2 (@mvnla2)

@wrw01 — Thanks! understanding this will take a while.
@Slim, BL — There are other interesting comments in the forum:
https://www.angrybirdsnest.com/forum/discussion/918/ab-space-best-level-to-achieve-a-lagrangian-point
I think that forum has been OBE, but maybe some of the comments should be copied here?

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By MVNLA2 (@mvnla2)

There are some other levels in which motion of the background could be interpreted to indicate orbital motion about an off-screen object:
All PB levels have moving background. Right now my favorite choice is 1-9 (strike that): you can get the blue bird (undivided or divided) to stop at various points in space (aim away from planet), but they/it always pop(s) before achievement awarded (what else is new?) At least the clouds and asteroids move in the same direction. Does the cloud bank at the bottom have any significance?
1-30 seems to have a gravity field that is not centered on the lower planet???
Blah suggested you need a level with a bomb bird or ice bird, since they don’t pop unless they hit something or are triggered.
All cold cuts have a moving background. The stars move at ~60 to 80 degrees to the large ice crystals. Not sure that this is anything other than artistic license. Does this make physical sense?
E-5

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By MVNLA2 (@mvnla2)

@wrw01
http://www.esa.int/esaSC/SEMM17XJD1E_index_0.html
I couldn’t get your link to work; hope this is better.

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By MVNLA2 (@mvnla2)

Very interesting, too bad there isn’t animation of L4 and L5. Which do you suppose we are trying to find?

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By sal9 (@sal9)

Nice article!

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By wrw01 (@wrw01)

Thanks mvnla2
I found this article very understandable in explaining a compled subject

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By loox (@loox)

Hey all… For reference on what I am abou to say, you can visit Danger Zone 12.

Because of the physics in this game (more on this later), I can tell you that @sammishredd post, above, is scientifically accurate. (not to brag but I have a Masters in Physics from GWU, so I know all about Lagrangians). His conclusion is accurate as well: no level on AB: Space (except maybe levels DZ 30, which I haven’t played, and Eggsteroid 6, which I can’t play) provide the conditions necessary to achieve the stability needed to achieve this reward… Based on the true definition of a Lagrangian Point.

Because of this, I believe that in angry birds parlance, by Lagrangian Point, they mean something more akin to a singularity. Not a true one, like a black hole, but the center of gravity… (creating a true singularity requires dividing by zero which would not compile, much less work on our iPads). Either that or it’s a goof.

To see what I think Rovio is referring to, get a blue bird to clear out a sphere in DZ 12 (or another level with planet-less gravity wells), it will slow down and keep slowing down until it stops. In theory, however, this won’t ever happen because
1. the birds ore not precise spheres, and that close to the not-quite “singularity” gravity is extremely strong, which is why they stay there, almost impossible to knock them out. Anyway, because they are not spherical, the gravity source (that’s a good name for it) acts on the farther part of the birds differently, keeping them in motion.

For example, a broken bule bird will retain movement at the center of the gravity well because gravity will act on each of their wings differently since one may stick out farther than another. Again, DZ 12 shows this nicely… But it does slow and remain there… It just doesn’t stop.

Note: I will try letting this level run all night with a bird in the gravity source to see if I get the achievement. And,
2. If you look, the gravity sources have size… Now this could just be animation, but if the blue gravity source in the center has size (ie, is not a single point in space) this too will keep the bird centered within it, but the bird will oscillate within it indefinitely… Which points against my entire hypothesis, which is this:

No one has gotten the achievement because we are looking in the wrong place. With some help from anyone who has gotten the achhievement or a few willing to help test this out on levels like DZ 12, we can learn what Rovio considers a Lagrangian Point.

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By loox (@loox)

Oh, about the physics.., as pointed out, so far no gravity sources in AB Space move… Making a true LP impossible. And the fact that gravity diminishes to zero outside the red circles does not help. Yes it weakens exponentially as you move away, but it never goes to zero. Although the last point may be a nonstarter as there are levels where two fields overlap… But in space (real world space) those intersecting fields don’t simply stop at the red line, they weaken and continue to spread out across the universe like waves in a pond.

Either way, the gravity sources in AB: Space are not in motion… Though they could be if the two fields were allowed to act on each other and create a stable orbit. This is true for both types of gravity sources:

1. massless (which is not possible so already we know AB Space physics is different from reality, and understandably so), as in DZ 12, and
2. Mass generated, like the planet’s field in Level 1-1.

And without the required orbital motion or other stable system of bodies, there are no Lagrangian Points in AB space right now. Based on this, the only two results of this are:
a. The achievement is impossible because there are no LP’s (yet), or
b. The achievement is possible despite the lack of LP’s, which implies a bug, Rovio is using the wrong term and means something else (like the massless gravity source in DZ 12), or has tweaked the math to allow the achievement despite the lack of a true LP….

But since no one has seemed to achieve it, that last clause in ‘b’, above, seems unlikely.

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By MVNLA2 (@mvnla2)

Be interesting to see if you get the achievement after an all-night run.
Your idea may work, in any case, the bird must remain in motion. Thus I think we are looking for L4 or L5. I think there is an off-screen gravitational center in PB and CC. The view on the ABS screen could be motionless in the frame of the birds, and larger on-screen objects. The fact that objects in the background are moving could indicate motion about the center of a larger gravitational field.
Have not found anything that acts like an L4 or L5 (allowing bird to stay in motion).
Despite some earlier comments, all birds expire after about 20 or 30 seconds even if they don’t hit anything, at least if they go off-screen or stop. It is possible to get just about any bird to stop on many levels of ABOS — Just aim it away from everything at the lowest possible speed and the longest possible path.

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By MVNLA2 (@mvnla2)

Gave up on DZ-12 after 1 hr; don’t think it will happen there.

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By loox (@loox)

I think that the background is a red herring. It’s similar to the blossoms and flowers blowing in the background of Angry Birds Seasons.
In other words, just decoration.

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By MVNLA2 (@mvnla2)

Where are the other gravity points? There is one on CC-13 (I give up waiting). So is your conclusion that the Lagrangian achievement is not possible with the current levels? Did you give up on DZ-12?

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By loox (@loox)

Yes. I gave up. I also did the math and arrived at some new conclusions… See my latest post (writing it now). Long story short, I believe Rovio is using the term correctly, the Lagrangian points do exist and they are what we were all originally looking at… My hypothesis that the massless gravity sources are what Rovio meant is thus, unlikely.

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By MVNLA2 (@mvnla2)

If you really want to make your head hurt, turns out there is something called generalized Lagrangian points. It might be more relevant to a future episode. I was trying to find out if the term “Lagrangian point” was applied to greater than 3-body problems. : )

By Ninjynda

Let’s hope the LP is not in D#9!!

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By ANGRYdrummer (@turima)

Easy level to find a fast lagrangian point is danger zone level 28. Still hasn’t given me the achievemt yet tho :/

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By MVNLA2 (@mvnla2)

Please let me know if my assumption about your comment is incorrect.
If you think the Lagrangian point is in the narrow gap between the two planets, that is not actually a Lagrangian point (see discussion above), since a Lagrangian point for a body of relatively very small mass is defined in relation to two bodies that are massive relative to the third AND are rotating about each other. Since the birds in the current levels of ABOS all pop shortly after they stop, they would need to keep moving, which is possible for a body in at least some of the Lagrangian points (there are 5 in a 3-body system). Not clear yet if it is possible to get the centripetal force (Lagrangian point) achievement in the current levels of ABOS, since I think no one (out of 10M???) downloads has done it yet. However Peter Vesterbacka said “Impossible is nothing,” which I learned today should be interpreted as a dare.

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By ANGRYdrummer (@turima)

yes, i was assuming the L-point was a point within the shared orbital area between two bodies (the planets). sorry for the misunderstanding, i couldn’t quite understand wikipedia’s definition of the l-point, still havent taken a physics class! but thanks anyways for the clarification!

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By MVNLA2 (@mvnla2)

If you read through the comments above, there are some reference that are easier to understand. I think the ESA one even has videos to illustrate.

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By kevin (@kcox2116)

Wow, I have learned alot at angrybirdsnest.com today :)

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By f91jsw (@f91jsw)

I think there are a few facts about the physics that are worth pointing out:

1. The physics in ABOS is clearly not the same as real physics, so looking for Lagrangian points in the real sense does not necessarily make any sense.

2. The gravity is different from real gravity because:

3. The fields are truncated.

4. The gravity does not seem to obey the 1/r2 law.

5. The planets/moons are stationary in relation to each other without any orbital motion around each other.

6. There seems to be a region just inside the circle of gravity where the the gravitational force is higher than closer to the centre. Otherwise, it would never be possible to trap objects in the “faux-Lagrangian” point: they would just fall to the moon that happens to be slightly closer.

7. All objects are subjected to friction as they move, even outside gravity fields. They eventually come to rest in the coordinate system that is defined by the frame of gameplay.

8. Objects in orbit seem to obey Kepler’s law (elliptical orbits) with a frictional component that make them spiral closer to the centre. I cannot say what other types of gravity fields (other than 1/r2) give rise to elliptical orbits, that would be interesting to analyse.

Is there a conclusion to be drawn? I don’t know, but for now, the hypothesis that an ABOS Lagrangian point is just a point where an object can be stationary in two or more gravity fields seems as good as any.

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By MVNLA2 (@mvnla2)

6, 7, and 8 are intriguing, especially 6.

Rank: Sling God with 28590 points
By MVNLA2 (@mvnla2)

“Impossible is nothing,” quoting Peter Vesterbacka on centripetal force achievement, who was quoting Mohammed Ali (not talking about centripetal force). This should probably be interpreted as “It’s a dare.” (See entire quote in my comment a ways above.) All the comments on the physics of AB provide food for thought, but may not be conclusive (see also forums on AB Physics and Best Level to Achieve LP). Admittedly, sometimes my optimism gets in the way of objectivity, but I’m not sure all this discussion and listing of facts proves that the centripetal force achievement can’t be obtained, or that AB Space doesn’t obey the laws of physics. Yes, I know what Rhett Allain (I provided link) and others said, but I think some implicit assumptions may have been made that may lead to incorrect conclusions. I’ll be happy to eat my words (especially since they’re electronic) when proven wrong.

Rank: Explosive with 2205 points
By loox (@loox)

I did the math and arrived at some new conclusions…

Long story short, I believe Rovio is using the term correctly, the Lagrangian points do exist and they are what we were all originally looking at… My hypothesis that the massless gravity sources are what Rovio meant is thus, unlikely. My conclusion: to paraphrase @Slim, most likely we can’t get the achievement due to a coding error.

I took the equations needed to calculate the locations of L1 and L2 Lagrangian points and settled in for an entire day of solving them using stationary bodies…. This is not the usual way to approach the equations because in reality the bodies must be in a mutually stable orbit in order to avoid drifting away or colliding. But in AB Space, the bodies are stationary *and* stable.

It was then I realized that Sammy and I were approaching this all wrong. What matters is that the bodies (or, more precisely, their gravitational fields) are stable. And while in nature this implies orbital motion, in AB Space we have stability. Hence, orbital motion is irrelevant for our purposes. The math should still work… And low and behold, it did. As a result any AB level with overlapping fields should have at least an L1 and 2… And probably L’s 3-5 as well, but we don’t need those.
In other words, I was wrong to conclude that there cannot be any Lagrangian Points… there must be at least one in any level where 2 or more fields overlap to form an area larger than the bird. Though the bigger the area the easier it will be to get the bird to slow to a stop inside it.

I used a simple 2 body system (like planet and moon or planet and sun) and wrote out the equations needed to calculate the lagrangian point L1. Put simply, these equations have parameters that account for their mass, gravitational pull, and orbits. For our purposes, we leave out the relativistic component as time dilation doesn’t matter to us (google GPS satellites and General Relativity if you are curious about that); we dont need to communicate with the satellite because the satellite in our case is a bird… This simplifies the equations significantly, but not completely. We still have the Newtonian (Kepler) mathematics to trudge through.

What I found shouldn’t have been surprising… that by zeroing the velocity of the bodies, the integrals governing the orbital motion of the planets drop out entirely. This leaves us with a manageable equation with simple variables… The masses of each planet (I assumed the bird mass to be negligible in comparison to the planetoids), their radii, and the distance between them.

The only remaining variable is on the other side of the equation… The velocity of the satellite bird, and we want that to be zero, just like in nature… so that takes care of that. (mathematically this allows one to “move” a function to the other side of the equation (technically, it’s just subtraction. For example:
A + B = zero. Subtract B from both sides, and you get A = -B.)

-B. Thats good. This is now beginning to look promising as the pull of body A must be negated by the pull of body B. Hmmm how to i explain, gravitational force is a vector… A vector is a number with a direction. Imagine a tug of war with a rope and a person on each side. If both pull the rope with a force of 5 Newtons, the rope won’t move.., this is because force is a vector, and includes direction. So in our tug of war, if person A applies 5 Newtons leftward and person B applies 5 Newtons rightward, the vectors will cancel each other out and the net force acting on the rope will be zero and the tope wont move. Similarly, the force acting on the satellite from the sun must be in the opposite direction of the force acting on the satellite from the Earth. (it’s not quite that simple, but hopefully you get the idea).

So… Using the masses and radii of our sun and Earth, respectfully, I did the math and… it didn’t work; A never equalled B.

Stymied but not stumped, I thought some more… Duh! With no orbital velocity, the earth and sun would collide, or “fall” into each other. But this doesn’t happen in ABoS.

So I then I truncated the fields, which is what ABoS seems to do. And made distance a variable, as distance depends on mass and orbital velocity, which we don’t have here.

I did this deliberately so the fields reached far enough to overlap but not out to infinity and viola… I was able to solve the equation.

What does this prove? Well, the answer is nothing new.

All I was able to conclude is that if we can manipulate the distance between two stationary, massive bodies, and if we can truncuate the reach of their gravitional fields then we get a point at which the pull of one cancels out the pull of the other, creating a point where a satellite, or bird, remains stationary with respect to one of the bodies, matching its rate of revolution around the other… A Lagrangian point.

In closing, while we don’t possess the power to change the laws of gravity and distance between the sun and earth, *Rovio* clearly does have power to manipulate these variables in a game. Whether it made a mathematical error in the math to create an L1 or L2 (for an L2 one field must encompass the other planet and a little beyond), or simply forgot to code the granting of the achievement is irrelevant. The result is the same. Rovio can make Lagrangian Points, and we can get birds to stop ( at least to the naked eye)… Thus, the fact we can’t get the achievement is a bug.

A bug that put the Phun back in Physics for the intrepid nesters who used this opportunity to learn some fun stuff!

Rank: Sling God with 28590 points
By MVNLA2 (@mvnla2)

Wow! Thanks for all the mental effort. Personally, I am voting for L4 and L5.

Rank: Explosive with 2205 points
By loox (@loox)

It was fun. The physics of AB is one reason I love it so much.

On the matter of the achievement, I think the law of parsimony applies and its a coding error.

Either way it made a lot of people think about the depth of physics behind a simple little game. A Lagrangian Point? Rovio certainly didn’t dumb it down. If anything, they are actively using their “little” game to help educate people; to wit, National Geographic and The Daily. It’s commendable. Rovio is turning out to be a real class act.

Rank: Sling God with 28590 points
By MVNLA2 (@mvnla2)

I also like AB because it obeys the laws of physics (I hope).

Rank: Sling God with 70925 points
By wrw01 (@wrw01)

What has been written is very interesting and I have gained a greater understanding of a number of new subjects. What is puzzling is that it appears that no one has obtained this achievement which may lead one to believe there is a code or programming error as was stated previously. When one considers all the other Achievements from the ABs games, Rovio has no history of making “Where’s Waldo” for any of them. They have been straight forward in meaning and intent for the majority of them.

Rank: Sling God with 28590 points
By MVNLA2 (@mvnla2)

I think no one has figured this out yet, and it is not bugged. Start from the point of view that it is possible within all the constraints you know about in ABSp, and what you can learn about Lagrangian points. Then ask yourself how it could be possible. I haven’t figured it out yet, needless to say, but I think it is possible. “Impossible is nothing…. It’s a dare.” (inverted order.)

Rank: Sling God with 70925 points
By wrw01 (@wrw01)

What if this Achievement is off screen like the extra points in Pig Bang 1-17? That possibility just lets one’s imagination go to high gear. Where would you start to look? Where would you aim? What about the egg levels? Considering there are over 3 million folks playing AB Space one will find it.

Rank: Sling God with 28590 points
By MVNLA2 (@mvnla2)

I think it is probably L4 or L5, which would be off the screen. Probably need to do some calculations to find it.

Rank: Sling God with 28590 points
By MVNLA2 (@mvnla2)

Q on LP achievement: If you are not connected to the internet, is there any way to know if you have accomplished it? Does the achievement box still pop up? If you do get it while off-line, will it register in GameCenter the next time you connect?

Rank: Sling God with 21285 points
By AngryAdvisor (@lesleyg)

In my experience you do have to be connected to internet for the achievement box to pop up and if you’re off line, the next time you log on while connected to internet, the answer is yes, it will show then in GC.

Rank: Explosive with 2205 points
By loox (@loox)

My experience jives with what @AngryAdvisor said. On iPad I dont see the achievement unless I am connected to the Internet. They always show up the next time I am online AND playing the game… Sometimes several. And it could take a minute if your connection is slow.

Rank: Sling God with 28590 points
By MVNLA2 (@mvnla2)

So specifically for LP achievement, is there any way you will know you have achieved it if you are off-line?

Rank: Explosive with 2205 points
By loox (@loox)

If you are in iOS that would be a definite “No”.

You should read this entire thread, however, as it may be bugged. I wouldn’t want you to waste your time.

Rank: Explosive with 2205 points
By loox (@loox)

Meaning it is my unserstanding that Rovio us looking into the issue and it may not be doable at all.

Someone correct me if I am wrong, but no one of he tens of millions of players has achieved it.

Rank: Sling God with 45310 points
By Kathy (@kathy)

Sorry to interupt. Can’t get achievements due too android but a couple levels I have got the bird to stay in place without moiving…the bluebird I folrget what level it was …but on eggsteroid 5 lazer bird stayed in middle of star without moving..he rotated a bit in a tiny circle then just stopped..don’t know if this helps at all I hope it does if not please forgive me for interupting.

Rank: Sling God with 28590 points
By MVNLA2 (@mvnla2)

You are not interrupting. All comments welcome, at least if they are about LP achievement. Actually what you found is probably not a Lagrangian point. There are several levels on which you can get a bird to stop in the intersection of two gravity fields, or at a “gravity point” (my term for those little blue centers of a gravity field), but once the bird stops, it disappears in a few seconds. There are 5 Lagrangian points (in a 3 body gravitational system), see references above. L4 and L5 would allow the bird to continue moving and therefore not disappear. L4 and L5 are off the screen in the existing levels, and therefore will be difficult to find.

Rank: Sling God with 45310 points
By Kathy (@kathy)

o.k. yes it was a small blue spot on the screen ..thought I was onto something, it is very interesting..at the same time frustrating that android users can’t participate in aceivements:(

Rank: Sling God with 28590 points
By MVNLA2 (@mvnla2)

LP is one achievement you may be glad you can’t try to get : )

Rank: Sling God with 45310 points
By Kathy (@kathy)

Lol so I’ve heard..I’m actually scared to even get dz I thought cc was hard enough:) I am starting pb again and it seems so simple lol:)

Rank: Sling God with 28590 points
By MVNLA2 (@mvnla2)

Sorry if I haven’t paid attention — Can’t you get DZ? If you can, you should do it. It’s difficult, but fun, i.e. challenging.

Rank: Sling God with 45310 points
By Kathy (@kathy)

@mvnla. No the dz update is not available yet on android..I don’t understand why it makes no sense 2 weeks later it should be. Android users typically get ripped off (for lack of better words) we don’t get dz, we don’t get mighty eagle..and our updates are usually put on the back burner to the ios or other more advanced platforms..can’t even get gamecenter…I and truckdriver have contacted rovio about tbis issue to no avail….feel like a second class citizen lol:) patience is a virtue but……

Rank: Sling God with 28590 points
By MVNLA2 (@mvnla2)

My belief is that the LP achievement is possible in the current game, and that no one has proven that it is bugged. I think people aren’t looking it the right place. As I said previously, I think it is L4 or L5, and off-screen. There’s a lot of real-estate off screen, and I certainly am not going to waste my time looking for it if there is not way to know if I’ve found it.

Rank: Sling God with 32120 points
By AMslimfordy (@amslimfordy)

Let’sadd an important distinction in AB:Space where offline achievements will NOT register when you reconnect. This is a known bug and has been reported to Rovio.

Rank: Sling God with 21285 points
By AngryAdvisor (@lesleyg)

Good to know, thanks Slim;-)

Rank: Explosive with 2205 points
By loox (@loox)

Agreed.
Oh, and @Kathy I was convinced Rovio meant the small blue gravity wells, too.
And you didn’t ask, but I’ve always respected your input, and as far as I am concerned, you could never interrupt.

Rank: Sling God with 45310 points
By Kathy (@kathy)

Thank you so much loox that really means a lot to me you just made my day:)

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