1. Did the 40,000-Year-Old Mammoth Tusk Boomerang Return?
A boomerang made from a mammoth tusk was found in the Oblazowa Cave in southern Poland. It is about 72 cm (28 inches) long. A study in 2025 dated it to approximately 40,000 years ago, making it one of the oldest in Europe and possibly the world [4]. Its shape is close to a crescent moon, similar to the "non-returning" boomerangs used by some Indigenous peoples in Australia. Researchers estimate that while it would fly when thrown, it would not come back. This is not based on actual flight tests [5].
Boomerangs come in two main types: those that return and those that do not. Returning types are thin, light, and have wing cross-sections shaped like airplane wings. Non-returning types are heavier and flatter, designed to fly straight and hit hard targets [3]. In Australia, some groups used only non-returning hunting sticks, while others used both returning and non-returning styles [8]. Whether a boomerang returns seems to depend on its shape. So, what exactly is different about the returning kind?
2. What Shape Do Returning Boomerangs Have?
A typical returning boomerang has two wings joined at an angle of 80 to 120 degrees. Newer designs may have three or more wings [2]. They are thin and light, with wing cross-sections resembling airplane wings, which helps generate lift from the air [3]. Sizes vary widely, from under 10 cm (4 inches) to over 180 cm (71 inches). The typical flight distance for returning models is cited as 20 to 40 meters (about 65 to 130 feet), though this depends on conditions [8].
If the wings are like airplane wings, the boomerang should experience an upward force called lift from the air while flying. However, a boomerang is also spinning. As it moves forward while rotating, what happens at different parts of the wings?
3. Why Does One Side of a Spinning Boomerang Lift More?
Imagine throwing a boomerang so it spins almost vertically. It moves forward while rotating. When the top edge of the spinning wing moves in the same direction as the forward motion, its speed relative to the air is the forward speed plus the rotational speed, making it very fast. The bottom edge moves against the forward motion, so its speed relative to the air is the forward speed minus the rotational speed, making it slower. Here, "top side" refers to the upper tip of the rotating wing, not the top surface of the wing itself.
The top edge, cutting through the air faster, experiences greater lift than the slower bottom edge [2]. The wing shape creates lift, and the combination of rotation and forward motion makes this lift uneven between the two sides [2]. If the lift is stronger at the top, the boomerang might seem like it would fall down or sideways. Instead, it curves back toward the thrower. This involves a specific movement characteristic of spinning objects.
4. How Does Precession Turn the Boomerang's Spin Axis?
When a sideways force is applied to a spinning object, its axis of rotation moves in a direction different from the force. This is called precession. In diagrams of boomerangs, this movement is shown as being roughly 90 degrees away from the force direction [1]. It is similar to how a spinning top slowly wobbles its axis while rotating.
For a boomerang, the greater lift at the top edge creates a torque that tilts the axis. The axis moves in a direction roughly 90 degrees away from that torque. For a right-handed throw, viewed from above, the boomerang precesses counter-clockwise. This causes the flight path to curve back toward the thrower [1]. Other sources also explain the return mechanism as a combination of "lift" and "precession." Uneven lift caused by rotation and forward motion twists the natural rotation at right angles, resulting in a curved flight [2]. The fact that the object moves in a direction offset from the applied force is central to why it returns. So, what is the boomerang’s posture while it is flying?
5. Why Does a Returning Boomerang Flatten Out in Flight?
Returning boomerangs gradually lie down as they fly. This happens because the center of lift is ahead of the center of gravity, creating another force that tilts the body [2]. A boomerang thrown vertically is nearly horizontal by the time it returns.
Scientists have studied this motion. Dutch physicist Felix Hess analyzed the forces on boomerangs using computers and verified them with field experiments. He published a paper titled "The Aerodynamics of Boomerangs" in Scientific American in November 1968 [7]. In 2019, research from the University of California San Diego and others included calculations where the direction of air and angle of attack reversed for each part of the wing during rotation. They considered the effects on lift and moments. Their numerical calculations reproduced the boomerang’s side-lying motion (nutation) and elliptical flight path. It was reported that the results did not contradict observed flight patterns [6]. This theory is said to apply to small, light, fast drones as well.
You can view this as earlier research on precession followed by studies adding finer details. It is not a case of previous explanations being wrong.
6. Three Questions to Explore How Boomerangs Fly
If you want to explore this topic yourself, consider these three questions. First, why do non-returning types fly straight? Focus on the differences in shape and weight compared to returning types [3]. Second, how does the throw affect the difference in lift between the left and right sides? Specific throwing techniques, such as "nearly vertical, slightly tilted," are not covered in this note. Third, how are the flight patterns of small drones similar to boomerangs? [6]
When actually throwing a boomerang, use a wide open space and throw in a direction where there are no people. Start by looking for information about boomerangs on museum websites. about boomerangs or museums.