Universe Today
"Our first interstellar guest appeared to be weird and unlike anything we have seen before. By the time we realized it, the guest was already out the door with its image fading into the dark street, so we did not have a chance to get a second look at its mysterious qualities. We have limited data, most recently the lack of detection by the Spitzer Space Telescope, which implies that `Oumumua is small and at least ten times more shiny than the typical asteroids in the Solar System.
"We do not have a photo of `Oumuamua but its brightness owing to reflected sunlight varied by a factor of 10 as it rotated periodically every eight hours. This implies that `Oumuamua has an extreme shape with its length at least 5-10 times larger than its projected width. Moreover, an analysis of its tumbling motion concluded that it would be at its highest excitation state as expected from its tumultuous journey, if it has a pancake-like geometry. The inferred shape is more extreme than for all asteroid previously seen in the Solar System, which have an axes ratio of at most 3."
"This yields roughly one such object (of a hundred meter size) per the volume defined by the Earth's motion around the Sun. In total, each planetary system needs to eject about 10^{15} such objects during its lifetime... Out of those a small fraction is trapped by the Solar System, as objects pass close to Jupiter and lose energy through their gravitational interaction with it. The Sun-Jupiter system acts as a fishing net that hosts a few thousand captured objects at any time. The objects eventually get kicked out of the system, but new ones get captured, and so there is a steady population.
"This will be revolutionary, as it will demonstrate that we are not alone and will shed light on advanced technologies beyond our own. It holds the potential for being the most important result in science and technology for centuries to come."
