Last year the interstellar space intruder space Moimoi passed through the inner Solar system. Initially it was assumed that a comet, then an asteroid, and then the alien ship — this visitor had properties that are unusual for typical space rocks. He was moving too fast and at a weird angle to have the roots of our system; neither Jupiter nor Neptune or the Oort cloud could not send us the object with such properties. In detail after studying the asteroid, scientists came to the conclusion that his icy insides coated with something like carbon, and the asteroid does not leave the tail, despite the temperature of 290 degree Celsius. The strange thing is, that cigars with a ratio of width to length is 1:8. Offered a variety of explanations, but eventually came to the very simple: journey through the milky Way for billions of years turned the asteroid into the object that we are interested in.
Looking at the Solar system today, you can find the solid inner worlds, outer gas giants, and a handful of smaller objects, grouped in four different folk:
- asteroids are rich in minerals objects formed near Mars and Jupiter at the boundary where the solar radiation will allow to form ice in the clear light of the sun;
- the Kuiper belt objects, ice-rich objects that formed beyond Neptune that become comets to enter the inner Solar system;
- centaurs are hybrid objects between the orbits of Jupiter and Neptune;
- the objects of the Oort cloud, which lies beyond the Kuiper belt and is a remnant from the formation of the Solar system.
Although the Kuiper belt objects and the Oort cloud are similar in composition and are extremely numerous in the early days of the formation of the Solar system there were more.
Over billions of years, the mutual gravitational interaction between objects and planets emit a huge amount of the first interstellar space. For every star that exists in the galaxy, we will have thousands or millions of objects flying through the Universe, not bound to any star. And just as the stars are moving relative to the Sun at the speed of 20 km/s, moving average, and the majority of these interstellar intruders.
From a certain point of view it’s amazing what we’ve been looking for your first interstellar asteroid. Probably, such meetings should occur many times a year, but very rarely such large objects appear close enough to the sun that we were able to capture them. And when we discovered this asteroid, we were immediately surprised by its properties: its rotational movement, the curve of his blackouts, the composition of the surface and subsoil, and a strange elongated shape. The spin doesn’t surprise, since in the absence of a massive object, which could resolve, an asteroid of this form will spin. But other properties remained a mystery.
We had never seen interstellar objects, so astronomers and physicists are seriously thinking how to explain Muamua. Some try to track his movement in the past, because there is a possibility that the asteroid was thrown out of the system recently. Others seek an explanation of how such an elongated object that is protected by carbon, could be formed, especially in the midst of these shapeless objects that we see everywhere. The simplest explanation is that the ice object was flying through the galaxy billions of years, and its interaction with the interstellar medium has turned it into what we see today.
We believe that space is emptiness, but actually it has a lot of dust particles, neutral atoms, ions, and cosmic rays, even where no stars. While the object is moving through space at speeds of hundreds of kilometers per second, it is constantly bombarded by numerous small fast particles. Just as water and sand are smooth and eroded pebbles and boulders in the ocean, the space environment acts similarly on the ejected ice body.
Because objects are rarely spherical, they tend to elongate in one direction more than in others, which leads to an elongated oblate forms. The lightest molecules are cleared quickly, and the heavy with a more durable grate can hold. The presence of carbon components, the bombarded particles means that they can be heated to form a more stable molecular configuration, and then freeze again. So over billions of years could form a “cigar”, which took over the alien ship.
If such an object does not fit close enough to the star to his inside broke through the crust, we won’t see no tail, no coma, no behavior. In addition, over billions of years, most of the external volatile substances will evaporate. It’s just unusual for the bodies of the Solar system. Simulation of new observations and gathering of statistics on this new feature class will eventually provide us with the answer, but until then we can only guess where “it” came.