Starting in 2025, the Rubin Observatory in Chile will survey the southern sky every 4 days with a 3.2 gigapixel camera. Statistically, it is expected to discover an interstellar object like `Oumuamua every few months.
The huge question my research team will have to answer is whether technological objects lurk among the enormous population of interstellar rocks that intersect the Earth's orbit around the sun. One way to separate artificial objects from natural rocks is through their anomalous propulsion without a gaseous trace, similar to the non-gravitational acceleration of 'Oumuamua.
Flying close to Earth in 2017, 'Oumuamua showed no evidence of a comet gas or dust breaking away from its surface, which would ensure a natural breakthrough through the rocket effect. The decrease in Oumuamua's non-gravitational acceleration with distance from the Sun has not been measured precisely enough by the Hubble Space Telescope and ground-based observatories.
The scaling was consistent with the excess expulsion being inversely proportional to the square of the distance from the Sun, as expected from the radiation pressure acting on the slim membrane. Another anomalous object detected three years later by the same Pan-STARRS telescope in Hawaii: 2020 YESit exhibited a similar effect by reflecting sunlight and was identified as a thin-wall rocket booster launched by NASA in 1966.
So far, `Oumuamua is one hundred million times fainter than during its closest approach to Earth and cannot be observed with our telescopes. Blindly pursuing `Oumuamua with a spacecraft is impractical given the uncertainty in its trajectory. Alternatively, it would be prudent to operate the Rubin Observatory to hunt for additional objects from its family of “Oumuamua” cousins.
As it fell every 8 hours, `Oumuamua's brightness varied by a factor of 10, suggesting a disk-like shape at a 91% confidence level. Given `Oumuamua's numerous anomalies, there is great interest in learning about another object in its family. If the Rubin Observatory had discovered a cousin of `Oumuamua near Earth, what could we learn about it now?
The key advantage over 2017 is the ability to operate the Webb telescope. I had the honor of serving on the first science advisory committee that designed this telescope thirty years ago, and I look forward to harvesting its fruits in the years to come. The excellent infrared sensitivity would enable the Webb telescope to detect the heat emitted by 'Oumuamua's cousin, and thus infer its surface temperature and surface area with respect to distance.
This area can be used to determine the reflection of sunlight from the surface and potentially the composition of the surface. As `Oumuamua's cousin declines, these properties may be mapped onto its various sides. But most importantly, the Webb telescope will track the trajectory of 'Oumuamua's cousin with unprecedented precision. Let me explain.
There is a good reason why natural selection gave us two eyes rather than one in the context of survival of the fittest. Image data from two separate eyes can be used to judge the distance of an approaching predator by observing it from slightly different directions. In 2017, the precision of measuring the distance of `Oumuamua was constrained by the separation of the Hubble Space Telescope from ground-based telescopes.
Currently, the Webb telescope is one million miles from Earth, about 3,000 times farther than Hubble, which allows us to locate interstellar objects much better. Moreover, Webb's aperture is approximately 2.7 times larger than the size of Hubble's mirror, allowing it to detect fainter objects at greater distances.
In collaboration with my Harvard College student Sriram Elango, I proposed using upcoming Webb telescope imaging data to locate the three-dimensional trajectories of interstellar objects that will be discovered in the coming years by the Rubin Observatory.
We have shown that with a very modest observation time it would be possible to determine with extreme precision the radial dependence of the non-gravitational acceleration of 'Oumuamua's cousin. This will allow us to easily distinguish the rocket effect of comet evaporation from other sources of non-gravitational acceleration, including artificial propulsion of a functional technological artifact.
An anomalous interstellar artifact signaling the existence of superhuman intelligence would give modern context to the concept ofSuperman“, proposed by the philosopher Friedrich Nietzsche.
Why look for interstellar artifacts? Because knowing that we have cosmic neighbors can inspire us to travel to interstellar space. This inspiration was highlighted in an email I received this morning which read:
“Good morning, Avia. I read your book “Interstellar“. The book is currently full of underlined passages. I put the book down and think about many paragraphs. Sometimes it hits me so hard that I just have to sit down and not say anything to anyone for a while. I want you to know that this book made a huge impression on me…
I always say, “Send me in, Scotty, there's no wise life here!” or “why have I been dropped on this horrible rock that makes absolutely no sense? Please take me home!” I think I tell myself both of these things because I really don't feel like I, or many other people, fit in here and that our true home lies elsewhere.
However, when I read the paragraph at the bottom of page 133, I discovered that for the first time in 57 years the prospect of having to move to another planet has become real thanks to what you said there, and I am struggling with how I feel about the prospect of how serious it is. this reality. It may come much sooner than we expected.
It's hard for me to put it into words, but I want you to know that what you say has a huge impact on me and I'm sure on thousands, and I hope, millions of people.
I think that's a big part of what you intended for this book, right? For people to stop and think about the challenges facing our interstellar future.
Adding hope is the fact that this morning the Starship rocket booster was successfully captured by the SpaceX tower.
Image Source: Pixabay.com
