On October 19 2017, Robert Weryk, a Canadian astronomer working at the University of Hawaii, discovered the first-ever known interstellar object in our solar system. If that sounds a bit strange, what with all the relatively regular sightings of asteroids and comets popping up in the news, it’s important to understand the significance of the phrase ‘in our solar system’.
Unlike previous interstellar objects, ‘Oumuamua which means ‘a message from afar arriving first’ in Hawaiian) had entered the zone controlled by the sun’s gravity. What’s potentially more alarming is that ‘Oumuamua had come closer to Earth than any other known interstellar object, and we still don't know much about it.
So what do we know? 'Oumuamua, a shining object that measured approximately 400-800 metres in length, entered our Solar System travelling 57,000 miles per hour (that's 16 miles per second). It sped straight down towards the Sun but curled underneath due to the star's gravitational pull. This sent the object off on a new trajectory, which was once again altered slightly as it passed Mercury. At its closest point, 'Oumuamua was 15 million miles away from the Earth, which may seem like a lot, but can be classed as a near-miss in the grand scheme of things. The whole process lasted forty days.
But no-one knows what 'Oumuamua really was. An asteroid comprised of metal and rocks, a comet made up of rocks, dust and ice, or a spinning, intensely bright, cigar-shaped (or 'prolate ellipsoid' to give it the technical description) alien probe?
The popular conclusion that ‘Oumuamua was most probably a cosmic iceberg, a mass of frozen hydrogen, is based upon observed findings that ‘Oumuamua couldn’t have contained any water, carbon monoxide or carbon dioxide, as found in asteroids and comets, because they would have been visible phenomena.
Perhaps more contentiously, astronomers also discovered that the object was accelerating as it left the solar system, yet it had no antitail as one might expect to find on a comet. The theory was that tails on comets and asteroids (though less common) act like rocket engines, but a frozen lump of hydrogen could have rocket-engine like propulsion, while the tail remained invisible from the gaze of the telescope.
Based on this, the general conclusion is that ‘Oumuamua was a highly luminescent, half-billion old chunk of planet from outside the Solar System., However, the theory is in a perpetual case of dispute. There are also a growing number of high-profile voices, such as Harvard astrophysicist Professor Avi Loeb, that claim ‘Oumuamua might have been an alien spacecraft from the far reaches of space.
His theory that ‘Oumuamua was a fully operational probe sent intentionally to the Earth’s vicinity by an alien civilization, was based on exactly the same observations that deemed it a cosmic iceberg.
In the series finale of Craig Charles: UFO Conspiracies, Craig Charles and astrophysicist Sarah Cruddas investigate ‘Oumuamua in an attempt to get one step closer to the answer. They speak to Professor Loeb who warns that the object could be a ‘message in a bottle telling us we’re not alone’. Sarah and Craig also speak with members of the SETI Institute who offer their hypotheses about the event and ponder the existence of intelligent life outside of Earth.
Is Oumuamua an alien probe sent from another galaxy, as Professor Loeb believes or a cosmic glacier? We’ll probably never know for sure, but let's leave you with this: the Drake Formula. Formulated in 1961 by Dr Frank Drake, this provides the formula for a probabilistic argument to estimate the number of communicative extraterrestrial civilizations in our galaxy. The answer is 12,600, and that’s just in the Milky Way. The Hubble Telescope has revealed an estimated 100 billion galaxies in the universe and the James Webb Telescope will probably double that…