Sometimes I feel like Peter Parker. (You know, Spider-Man.) I have real work to do, but then I hear these sirens on the internet and I must go to action.
Well, what about this kid being carried away by an eagle? What can be done with this video? Here is the evidence I will present. Let me just say that I sure hope it's fake. I would hate to have all our babies snatched away by flying eagles. That would just suck. Although, maybe the eagle is just pumped up about the movie The Hobbit and thinks that kid is actually a hobbit.
Analysis of Camera Shake
This is my first go-to tool when looking at videos. One of the tricks fakers use is to record the video with a tripod. A steady video makes it much easier to add in special effects later. Of course, who records with a tripod? That seems unrealistic. To account for this, the fakers will add "fake shake" to the video.
How do you detect a fake shake? The first step is to use a video-analysis tool like the awesome and free Tracker Video Analysis. With this, I can track the motion of the background in the video to see how the camera moves. Here are four samples of background motion.
Which, if any, of these background motions do you think correspond to a real person with a real camera? Here are the answers:
- A: This is the background motion from the Human Birdwings video. In case you missed it, a guy posted a video of his homemade wings that let him fly like a bird. It was fake.
- B: This is from the eagle-kid video. Real or fake?
- C: This is fake shake from this fake spinning water video. You can see how the camera takes similar pixel size jumps. It's faker than Sweet 'N Low.
- D: This is a real video recorded from a real person (me). What does this background look like? To me, it looks like a random walk. Maybe that's just me.
For this eagle video, which case does it look like? It doesn't look as bad as the other two known fake videos. However, it doesn't look like my video either. One of the things I haven't looked at (yet) is the stabilizing video features that YouTube offers for videos.
I would say that this shake analysis is mostly inconclusive.
Acceleration of a Falling Object
Next, let's look at the part of the video where the eagle drops the kid. The drop distance is small enough that air resistance should be negligible. This means that the vertical acceleration should have a value of -9.8 m/s2 if this eagle and kid are on the surface of the Earth. Here is a plot of vertical motion of the kid after he (or she) is dropped.
I put the arrow to indicate the part of the data where the kid was dropped. Now, I don't know the scale – but it might not matter. Does this look like constant acceleration? No, it looks like constant velocity. I'm not even going to use the quadratic fit in this case to find the scale.
Instead, let's look at the time of the fall. From the video, the child was falling for 0.367 seconds. If the child was dropped from rest (or close to it), how high would the kid have to be to fall for this time? Normally, I break down the kinematic equations and show where this comes from, but let me just skip right to it.
Putting in my value for the time, I get a dropped height of 0.66 meters. OK, that's not as bad as I thought it would be. However, the position function should still be a parabola and not a straight line.
Center of Mass
Here is a shot of the kid while being carried by the eagle.
Look at the angle that the kid is "swinging" back. It could be as high as 30° - but that is just an "eyeball" guess. So what? This actually shows a common misconception. It shows the idea that if something is moving at a constant velocity, there must be a constant force on it. However, at low speeds with no air resistance there wouldn't need to be a force pulling the kid forward.
If the bird were accelerating, then the kid would swing back. From the swingback angle, you can figure out the acceleration. You can find all the details on how this works in my Iron Man 3 post. Here also is a diagram of a person hanging from something that is accelerating.
The kid hanging back at an angle couldn't be moving at a constant speed since the horizontal forces don't add up to zero. If I use an angle of 30°, then the bird would have to accelerate at 5.6 m/s2. That's pretty high for a bird carrying a kid.
How Much Can an Eagle Lift?
Bigger-mass birds need bigger wings, right? Also, a larger wingspan bird could lift more "cargo". So how much could an eagle lift? Here is my favorite graph showing the relationship between a bird's wingspan and mass.
Bigger-mass birds need bigger wings. Seems obvious. So, what about a Golden Eagle? Wikipedia lists these as having a mass of about 6.5 kg and a wingspan of about 2.3 meters. What about the kid? Let's say the kid is 2 years old with a mass of about 13 kg. That is about double the mass of the eagle! Sure, eagles can pick stuff up – but not something this big.
OK – I think we can all agree this video is fake.
