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I’m going to be quoting from an article entitled Exploring ‘Oumuamua’s Perihelion Date by British physicist and astronomer Adam Hibbert. His findings are quite interesting.
What Hibbert maintained is that the only thing that could theoretically be variable about ‘Oumuamua is its arrival time—that is, the timing of three key events:
1. Its entry into our solar system,
2. Its closest approach to the Sun (perihelion), and
3. Its closest approach to Earth (perigee).
Before we get into those details, let’s briefly cover the strange things ‘Oumuamua did during its visit to our solar system.
For one, at the time of its encounter, ‘Oumuamua was traveling at a speed and on a trajectory consistent with the Local Standard of Rest (LSR). This means it was moving at a speed that matched the average motion of stars around it within the galaxy. In other words, relative to its stellar neighborhood, ‘Oumuamua was essentially stationary.
This is very unusual. In fact, it would be highly useful for a probe meant to explore stars across the galaxy. If you’re stationary in the LSR, the natural rotation of the galaxy will bring stars toward you over time, allowing close encounters without using any propellant. This kind of passive travel would be highly efficient.
The odds of a natural object just happening to match the LSR are approximately 500 to 1—not impossible, but extremely unlikely. This already raises questions about an artificial origin.
On top of that, ‘Oumuamua was highly reflective, and it rotated at a very consistent speed. While the rotation itself isn’t unusual, what’s truly strange is that as it left the solar system, it began to accelerate—without any visible means of propulsion.
The only natural objects we know of that can do this are comets, which can accelerate due to outgassing (jets of gas erupting from their surface). But when comets outgas, their rotation also changes due to the shifting mass distribution.
In ‘Oumuamua’s case:
• Its rotation didn’t change, and
• No outgassing was detected, even though the world’s best telescopes were watching closely.
It was essentially a comet with no tail, and that means it couldn’t have been a comet at all. No natural object we know of can accelerate like that without any visible exhaust or gas release, especially with the level of acceleration observed—over 100,000 kilometers off-course in just a few weeks.
Hibbert’s article then addresses the fact that ‘Oumuamua passed so unusually close to Earth—apparently just by chance.
So he asks: what happens if we keep all of ‘Oumuamua’s orbital parameters fixed (its trajectory through the solar system), and only change its perihelion date—the date of its closest approach to the Sun?
He ran simulations using a range of perihelion times spread throughout 2017, and he plotted the effect this had on the perigee distance (its closest approach to Earth). The results were striking:
“Apparently purely by chance, ‘Oumuamua came ridiculously close to Earth. If it had come at any other time, it would have passed at a much greater distance than it actually did.”
Hibbert continues:
“We find that the true perihelion date of ‘Oumuamua was such that its resulting closest approach to Earth (perigee) was nearly as close as it could possibly have been.”
He notes that had the perihelion occurred just 10 days later—on September 19—the perigee would have been even closer, at just 0.095 astronomical units.
So then he poses a provocative hypothetical:
“Let’s suppose ‘Oumuamua chose its perihelion date deliberately—on September 9th. What would be the reason?”
The article then plots not only perigee distance versus perihelion date, but also the Sun-Earth-object angle—the angle between the Sun and ‘Oumuamua as viewed from Earth.
If this angle is less than 90°, then ‘Oumuamua would pass Earth on the sunward-facing side, harder to observe. If it’s greater than 90°, it would pass on the night side, making it more visible to telescopes. The larger the angle, the more favorable the conditions for Earth-based observation.
What Hibbert finds is that ‘Oumuamua’s actual perihelion date (September 9–10) resulted in one of the largest possible Sun-Earth angles at the moment of perigee—maximizing visibility from Earth.
So again we ask: what are the odds of all this happening by random chance?
• A natural object traveling at the Local Standard of Rest: 500 to 1
• That same object just happening to pass so close to Earth, and at just the right time to be easily observed: 1 in 250,000
But if ‘Oumuamua was an artificial probe, capable of decelerating (as well as the acceleration we already observed), then all of this behavior would make perfect sense.
What Hibbert maintained is that the only thing that could theoretically be variable about ‘Oumuamua is its arrival time—that is, the timing of three key events:
1. Its entry into our solar system,
2. Its closest approach to the Sun (perihelion), and
3. Its closest approach to Earth (perigee).
Before we get into those details, let’s briefly cover the strange things ‘Oumuamua did during its visit to our solar system.
For one, at the time of its encounter, ‘Oumuamua was traveling at a speed and on a trajectory consistent with the Local Standard of Rest (LSR). This means it was moving at a speed that matched the average motion of stars around it within the galaxy. In other words, relative to its stellar neighborhood, ‘Oumuamua was essentially stationary.
This is very unusual. In fact, it would be highly useful for a probe meant to explore stars across the galaxy. If you’re stationary in the LSR, the natural rotation of the galaxy will bring stars toward you over time, allowing close encounters without using any propellant. This kind of passive travel would be highly efficient.
The odds of a natural object just happening to match the LSR are approximately 500 to 1—not impossible, but extremely unlikely. This already raises questions about an artificial origin.
On top of that, ‘Oumuamua was highly reflective, and it rotated at a very consistent speed. While the rotation itself isn’t unusual, what’s truly strange is that as it left the solar system, it began to accelerate—without any visible means of propulsion.
The only natural objects we know of that can do this are comets, which can accelerate due to outgassing (jets of gas erupting from their surface). But when comets outgas, their rotation also changes due to the shifting mass distribution.
In ‘Oumuamua’s case:
• Its rotation didn’t change, and
• No outgassing was detected, even though the world’s best telescopes were watching closely.
It was essentially a comet with no tail, and that means it couldn’t have been a comet at all. No natural object we know of can accelerate like that without any visible exhaust or gas release, especially with the level of acceleration observed—over 100,000 kilometers off-course in just a few weeks.
Hibbert’s article then addresses the fact that ‘Oumuamua passed so unusually close to Earth—apparently just by chance.
So he asks: what happens if we keep all of ‘Oumuamua’s orbital parameters fixed (its trajectory through the solar system), and only change its perihelion date—the date of its closest approach to the Sun?
He ran simulations using a range of perihelion times spread throughout 2017, and he plotted the effect this had on the perigee distance (its closest approach to Earth). The results were striking:
“Apparently purely by chance, ‘Oumuamua came ridiculously close to Earth. If it had come at any other time, it would have passed at a much greater distance than it actually did.”
Hibbert continues:
“We find that the true perihelion date of ‘Oumuamua was such that its resulting closest approach to Earth (perigee) was nearly as close as it could possibly have been.”
He notes that had the perihelion occurred just 10 days later—on September 19—the perigee would have been even closer, at just 0.095 astronomical units.
So then he poses a provocative hypothetical:
“Let’s suppose ‘Oumuamua chose its perihelion date deliberately—on September 9th. What would be the reason?”
The article then plots not only perigee distance versus perihelion date, but also the Sun-Earth-object angle—the angle between the Sun and ‘Oumuamua as viewed from Earth.
If this angle is less than 90°, then ‘Oumuamua would pass Earth on the sunward-facing side, harder to observe. If it’s greater than 90°, it would pass on the night side, making it more visible to telescopes. The larger the angle, the more favorable the conditions for Earth-based observation.
What Hibbert finds is that ‘Oumuamua’s actual perihelion date (September 9–10) resulted in one of the largest possible Sun-Earth angles at the moment of perigee—maximizing visibility from Earth.
So again we ask: what are the odds of all this happening by random chance?
• A natural object traveling at the Local Standard of Rest: 500 to 1
• That same object just happening to pass so close to Earth, and at just the right time to be easily observed: 1 in 250,000
But if ‘Oumuamua was an artificial probe, capable of decelerating (as well as the acceleration we already observed), then all of this behavior would make perfect sense.
