There is a lot of excitement in the world of astronomy at the moment, because a strange visitor has appeared in the night skies. A mysterious object detected flying past our sun could be the first space rock traced back to a different solar system, according to astronomers tracking the body. While other objects have previously been thought to have origins from deep space, experts say the latest find, an object estimated to be less than 400m in diameter, is the best contender yet.
What Dr Edward Bloomer, astronomer at the Royal Observatory Greenwich, finds particularly exciting is that this may be essentially be a visitor from another star system, which is what make it special. If its origins are confirmed as lying beyond our solar system, it will be the first space rock known to come from elsewhere in the galaxy. Published in the minor planet electronic circulars by the Minor Planet Center at the Harvard-Smithsonian Center for Astrophysics, the observations reveal that the object is in a very special orbit which suggests that it is going fast enough to escape the gravitational pull of the sun.
Objects originating from, and on long-period orbits within, our solar system can end up on such orbits and be ejected into deep space, for example, if they swing close by a giant planet, since the planet’s gravity can cause objects to accelerate. But Dr Gareth Williams, associate director of the Minor Planet Center, said that wasn’t the case for the newly discovered body. By studying its orbit, Dr Bloomer noticed that there were no close approaches to any of the giant planets that could have given this thing a kick, so, he suggests that it is coming from deep space and it is going to deep space. His calculations are very clear on that.
He is not the only interested party. According to observations made by several other astronomers, the object entered our solar system from above, passing just inside Mercury’s orbit and travelling below the sun, before turning and heading back up through the plane of the solar system towards the stars beyond. At its closest, on 9 September, the object was 23.4m miles from the sun. It was first spotted earlier this month by a telescope at an observatory in Hawaii, and astronomers around the world are now following the path of the object.
Among them is Professor Alan Fitzsimmons from Queen’s University Belfast. He feels that it is fairly certain we are dealing with our first truly identified alien visitor. His team is currently working on measuring the objects’ position better to improve calculations of its trajectory, and to gather information relating to its chemical makeup, and size. The team is anxious to learn as much as they can about this visitor. Early results suggest that the object might be similar in make-up to many of those of the Kuiper belt. This is a region of space, which is past Neptune in our solar system, that contains a large number of small bodies.
It would not be too surprising if it does indeed turn out to have come from elsewhere in the galaxy. With large quantities of material thrown out into interstellar space, it was expected that there would be objects travelling between the stars. In fact, astronomers have been expecting a sighting such as this for some time. But a puzzle still remains because the Kuiper belt bodies are believed to be icy, and so this would give rise to an atmosphere and tail if brought close to the sun, because the ice would melt. There is no evidence that this object has behaved like that, and all the data shows it as an unresolved point of light, implying it is more like a rocky asteroid than an icy comet. As with all things planetary, there are mysteries to be solved here, which is half the fun.