Researchers believe they’ve debunked a theory that a giant cigar-shaped object travelling through the far reaches of our solar system was an alien spacecraft, even though it remains a mystery.
In November, researchers at Harvard published a paper in which they speculated a 400 metre-long object that passed through our solar system between October 2017 and January 2018 may have been a “fully operational probe sent intentionally to Earth vicinity by an alien civilization,” in part due to its unique, fast-moving travel.
Now, an international research team co-led by Matthew Knight, an associate research scientist at the University of Maryland, indicates the object -- named 'Oumuamua, or "scout" in Hawaiian -- is of “purely natural origin.” The findings are published in the July issue of Nature Astronomy.
"We have never seen anything like 'Oumuamua in our solar system,” Knight wrote in a news release. “It's really a mystery still, but our preference is to stick with analogs we know, unless or until we find something unique. The alien spacecraft hypothesis is a fun idea, but our analysis suggests there is a whole host of natural phenomena that could explain it."
Scientists first discovered 'Oumuamua in October 2017 using the Pan-STARRS 1 telescope and had just a few weeks to analyze the object before it left the range of the best telescopes on Earth.
'Oumuamua’s unique method of travel is what separates it from other comets and asteroids and led researchers to speculate it could be alien. 'Oumuamua’s motion, for example, is not determined by a gravitational pull, which is the case with asteroids and doesn’t have a gas tail, typical of a comet.
Knight adds what made the object particularly puzzling was the speed at which it travelled through our solar system. 'Oumuamua moved at an estimated 26 kilometres per second and was accelerating, though there weren’t any gaseous emissions to explain the acceleration.
“The motion of 'Oumuamua didn't simply follow gravity along a parabolic orbit as we would expect from an asteroid," he said. "But visually, it hasn't ever displayed any of the cometlike characteristics we'd expect."
The research team believes 'Oumuamua could have been ejected by a gas giant planet orbiting another star, which could explain how it escaped its solar system and emerged in ours.
Knight suggests Jupiter may have done something similar to create a massive grouping of small objects on the outer edges of our solar system. Some of these objects would look similar to 'Oumuamua if they escaped the sun’s gravitational pull and became interstellar.
"We tend to assume that the physical processes we observe here, close to home, are universal,” Knight said. “This thing is weird and admittedly hard to explain, but that doesn't exclude other natural phenomena that could explain it.”
Back in November, the Harvard researchers suggested 'Oumuamua’s unique travel could be the result of solar radiation pressure, which could in theory be able to harness solar energy to propel a spacecraft.
“If radiation pressure is the accelerating force, then ‘Oumuamua represents a new class of thin interstellar material, either produced naturally, through a yet unknown process… or of an artificial origin,” they wrote.
A FUTURE OF INTERSTELLAR STUDY
While ‘Oumuamua is believed to be the first interstellar visitor to our solar system, a new telescope slated for operation in 2022 could open the door for the study and discovery of more interstellar objects.
The Large Synoptic Survey Telescope (LSST), under construction in northern Chile, will be able to photograph the entire sky every few days using the largest digital camera ever constructed. The telescope’s photos will be completely available to the public at launch.
“The LSST will be leaps and bounds beyond any other survey we have in terms of capability to find small interstellar visitors," Knight said. "We may start seeing a new object every year. That's when we'll start to know whether 'Oumuamua is weird, or common.”
With files from CTVNews.ca writer Jackie Dunham
