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Our first confirmed interstellar visitor was a tough nut to scissure. Scientists puzzled over 'Oumuamua when information technology appeared in the sky concluding twelvemonth. The nomenclature flipped back and forth a few times before somewhen landing on "comet," but it'south a weird comet. At present, researchers from the Harvard Smithsonian Center for Astrophysics accept revived the thought that 'Oumuamua could be an conflicting spacecraft.

While we've recategorized 'Oumuamua a few times, we tin can say with utmost certainty that information technology came from some other solar system. It has an orbital eccentricity of 1.20, which is far by the sun's escape velocity. Nothing in the solar system could reach that speed naturally without a cataclysmic release of free energy that we would have noticed.

'Oumuamua was already on its way out of the solar system and moving at high speed when we spotted it, so at that place was no time to build and launch a mission to intercept it. Nosotros haven't even gotten a very proficient wait at the object. Scientists believe 'Oumuamua is cigar-shaped and up to 120 meters in length. That's an unusual shape for an asteroid (at to the lowest degree in this solar system) so the discoverers initially categorized it as a comet. Then, scientists looked closer and saw no coma, the cloud of dust and gas that surround a comet when it nears the sun. So, an asteroid? Upon fifty-fifty closer exam, researchers found 'Oumuamua's orbit was being nudged by a force consistent with gas release. Currently, 'Oumuamua is considered a low-action comet.

The newly released paper (which hasn't been peer-reviewed yet) suggests another option. What if the small force acting on 'Oumuamua is not from gas release? The study suggests that 'Oumuamua could have an odd orbit because information technology'due south an alien space probe with a solar sail. A solar sail is a concept for a depression-power propulsion system currently in testing at a number of companies and space agencies effectually the world. The sail would utilize the pressure of the solar radiation to propel a craft forward continuously. Over time, a solar sail could reach loftier speeds, maybe fifty-fifty leaving the solar organization.

'Oumuamua'southward path through the solar arrangement in 2022.

The researcher making this proposal are not presenting bear witness that 'Oumuamua actually has a solar sail — in that location'south no fashion to know that with current technology. Instead, they seek to demonstrate that it is possible based on what nosotros know of the physics of solar sails and the orbit of 'Oumuamua. The study concludes that information technology's possible that 'Oumuamua is being dragged along by a solar sail, just that doesn't necessarily hateful it'southward an active alien probe.

Researchers scanned 'Oumuamua back in 2022 to wait for any electromagnetic emissions, finding nothing. At that signal, they deemed it not an alien ship. The new report suggests 'Oumuamua could be not-functional droppings with a bit of light canvas material clinging on. Alternatively, it could be a probe in a low-power mode that we cannot characterize. Unfortunately, nosotros'll probably never know for sure what 'Oumuamua is — information technology's already long gone.

At present read: Breakthrough Listen Launches Unprecedented Try to Detect Aliens, NASA: Gas Behemothic Ejected 'Oumuamua Into Interstellar Space, and Interstellar Visitor 'Oumuamua Came From 1 of 4 Nearby Stars