On the 19th of October, astronomers at the University of Hawaii detected a new object in the night time sky. At first the object was believed to be a comet, but as more observations were made it was determined to be an asteroid and some extraordinary things came to light. Firstly the asteroid was traveling at a very high speed, and it was approaching from way above the usual orbit of our solar system. This could only mean one thing: the asteroid had come from outside our solar system, making it the first ever detected interstellar asteroid. The second weird thing about it was its shape, which wasn’t the usual roughly spherical asteroid. This asteroid was shaped like a cigar, about 400 metres long by 40 metres wide. The third weird thing about the asteroid was its high rate of spin, which given its shape would mean that it’s made of incredibly tough material, otherwise the high spin rate would cause it to disintegrate. The asteroid was named ‘Oumuamua’, which is the Hawaiian word for “messenger”, and it became the first designated interstellar asteroid in the history of human science. In light of all this I’m surprised that Oumuamua hasn’t received more press coverage.
The gravitational pull of the Sun caused Oumuamua to speed up and it made its closest approach to the Sun (known as perihelion) on 9th September. It made a partial orbit of the Sun and is now whipping away out of the Solar System at an incredible speed, and at an angle of 66° from the direction of its approach. It will take many thousands of years before Oumuamua reaches interstellar space again, and there’s talk of sending a rocket after it so that close observations can be made. However, the high speed of Oumuamua means that its chaser would have to be the fastest rocket ever built; so don’t hold your breathe on that one. Tomorrow, though, the Green Bank telescope in West Virginia, which is one of the largest telescopes in the world, will start listening for radio signals being broadcast from Oumuamua. If Oumuamua is the product of beings from another galaxy, beings capable of traveling interstellar distances, it seems highly unlikely they would use something as antiquated as radio waves, so we’ll probably never know if Oumuamua is a natural object or an alien technology.
One thing in all this, though, has been puzzling me: there’s consensus among the scientists that Oumuamua’s high velocity and rate of spin means that it can’t be captured by the Sun’s gravity, so why didn’t it by-pass the Sun? (I should add at this point that I’m no expert on astronomy) What Oumuamua did is a text book example of how space vessels use the gravity of large celestial bodies to greatly increase speed, and then shoot off in whatever direction they want to go. When Oumuamua was first detected in October its speed was 58,900 mph (which is way faster than any Solar asteroid). After its slingshot around the Sun in September Oumuamua’s speed had greatly increased to 196,200 mph.
If Oumuamua is a natural object, a natural object with a velocity and spin that allows it to escape the Sun’s gravitational pull, why was it heading for the Sun? The odds on this happening naturally are absolutely astronomical (if you’ll forgive the pun); or maybe Oumuamua was deliberately aimed at the sun. If this all sounds crazy to you it should be noted that just as Oumuamua was reaching perihelion there was an absolutely massive X solar flare. Was this another coincidence? or was Oumuamua taking on fuel..?