When a visitor drops by your home and leaves something on your door step, how do you know if it is someone in your neighborhood or someone from out of town. The most likely answer is that it is someone close by (within the city limit?). But sometimes, you’re not sure so you have to examine the package. Maybe it is from a friend who lives across the city. Or perhaps, it is from a stranger from another country.
The universe as we know it is billions of years old. It is about 13.8 billion years old, give or take a few millions of years. And while the universe is vast and earth is relatively young, how often do interstellar objects enter your star system?
Oumuamua, 1I/2017 U1, was discovered on October 19, 2017 (wiki). Its discovery had awaken interest in the scientific community to wonder what else might be out there and how often is the human solar system visited by objects from another star system. There were even a small number of astronomers who suggest that Oumuamua might be an artificial construct.
I can tell you, given who I am, that it is not an alien ship or artifact. I can tell you, though you will have to prove it to yourself, that the vast “empty space” is more crowded than you can possibly imagine. In the future when humanity finally leave your star system and join us out there, you will find yourself overwhelmed by what just what you can see on your front yard. My suggestion to you is not to go rushing to exploring very rock or even rogue planet.
Look up. Look around. You might see me waiting for you. In a starship.
Until you get out here, you will have the opportunity to see what other interstellar objects that might have visited your world. In fact, a team from Harvard discovered an object, CNEOS 2014-01-08. At1.5 meters (about 5 feet), CNEOS 2014-01-08 crashed in the Pacific Ocean close to Papua New Guinea in 2014. How did your scientists know it was an interstellar object? It was traveling at a speed faster if it was bound by the sun’s gravity or other planets in your star system. With this higher heliocentric velocity, it is likely that the object was from another star system.
Because CNEOS 2014-01-08 could have a stronger magnetism than anything else on the ocean floor, there is a decent chance that efforts to try to recover it can succeed.
Discovered by Gennadiy Borisov in 2019, 2I/Borisov is a rogue comet. Aside from the speed of the Borisov Comet, it has a greater orbital eccentricity than other known comets that have been observed in your solar system. For example, Haley’s Comet has an orbital eccentricity of 0.967 while Borisov is at 3.36. For reference, a perfect circle is zero and 1 is a parabolic escape or capture orbit. Earth’s orbit is a near perfect circle at 0.017. Oumuamua has a value of 1.2 for eccentricity.
All of these interstellar objects was discovered in the last eight years. Imagine what you might have discovered if more effort and technology is dedicated to looking for these visitors from out of town, I mean, out beyond your solar system. At any given time, there could be hundreds of thousands if not millions of objects just floating out there traveling for billions of years and some of them are just waiting to be captured by your sun.
As for Oumuamua being an alien craft, let me tell you something. Imagine you’re a young alien civilization that is curious about the universe, much like you are but way more advanced in terms of technology but is not quite ready to travel on a starship just yet. Maybe creating a robust interstellar explorer with advanced propulsion and sensors and communication systems that can report back what it discovered on its journey. Along the way, it comes across a system with planets orbiting its star within the Goldilocks zone and that one of the planets might have water, the probe decides to it could be a good idea to go in and take a look. Because it has been traveling at such a fast speed, it enters the system at a trajectory that allows it to scan the planet and leave quickly because it still has a lot of other places to visit. As it comes closer, it discovered that one of the planets not only has water, it has a vibrant ecosystem. And whoa, life! As it leaves, it takes additional readings and relays the data back to its creators.
Given the trajectory of the developments of your space programs, that is likely what humanity will do one day. Of course, I can tell you that you humans are closer to exploring other worlds in person than you think.
Pangeaverse 