Mysterious object believed to be an alien spacecraft has accelerated to leave the Solar System

Since its discovery, astronomers have struggled to find an explanation for the origin of this mysterious object .

In October 2017, astronomers discovered an unexpected visitor to the Solar System: a cigar-shaped rocky asteroid about 100 meters in diameter hurtling toward the Solar System from the direction of the constellation Lyra at a speed of about 26 km/s, almost perpendicular to the ecliptic plane.

This high speed and large tilt suggest that it cannot be an inner Solar System object, but rather comes from a distant star system. This is the first time humans have discovered a celestial body from outside the Solar System in the Solar System . Since this celestial body was discovered from an observatory in Hawaii, scientists from the International Astronomical Union named it 'Oumuamua in the local Hawaiian language, meaning "first messenger".

Further studies showed no trace of a cometary head, so it was reclassified as an asteroid.

'Oumuamua was discovered on October 19, 2017 by Robert Weryk of the University of Hawaii's Department of Astronomy using the Pan-STARRS telescope at Haleakala Observatory on the island of Maui, Hawaii.

The Pan-STARRS program is a project dedicated to monitoring near-Earth objects. It can find potential near-Earth objects by comparing images of the same area of ​​sky taken at different times. When Robert Weryk saw a suspicious bright spot on his computer, he wasn't too excited because such discoveries are so common.

He just looked at the data as usual and looked up the data from a few days ago, but then discovered that this bright spot had actually appeared twice, but it had been missed in the data processing. Using this data, he quickly calculated the orbit of this bright spot and was surprised to see that it did not have an elliptical or parabolic orbit like normal near-Earth objects, but had a dual polar orbit. This meant that this bright spot was not bound by the Sun's gravity, but was moving through the Solar System at an extremely high speed and would never return.

When its orbit was plotted, it became clear that it could not have originated in the Solar System, but instead must have formed from another star system.

Realizing that this could be a very important and rare discovery, Robert Weryk quickly sent this information to the International Minor Planet Center. As soon as 'Oumuamua was discovered, it aroused great interest and curiosity from scientists and the public around the world.

What exactly is it? Where did it come from? Does it have any connection to alien civilizations? To unravel these mysteries, scientists have conducted in-depth observations and analyses of 'Oumuamua using a variety of telescopes and instruments.

However, as 'Oumuamua moved away from Earth, it rapidly faded and became increasingly difficult to observe. Just two months after its discovery, 'Oumuamua was no longer visible to even the most sensitive ground-based telescopes.

During the limited observation period, scientists have collected some data and information about 'Oumuamua, but have also encountered some unexplained phenomena and inconsistencies.

These phenomena and contradictions have stimulated the imagination and creativity of scientists, giving rise to a number of bold and controversial hypotheses and speculations. One of the most prominent and widely discussed hypotheses is that 'Oumuamua could be an alien spacecraft or a type of solar sail (light sail).  The hypothesis was put forward by scientists Shmuel Biali and Avi Loeb of the Harvard Center for Astrophysics.

'Oumuamua is very unusual in length, an unreasonable proportion for an asteroid, but given the structure of the spacecraft, it makes perfect sense to minimize damage caused by interstellar dust.

Precise measurements of 'Oumuamua's orbit by the European Space Agency and others have shown that 'Oumuamua received a weak and continuous additional acceleration as it left the Solar System. This acceleration cannot be explained by the known non-gravitational effects of cometary jets, as 'Oumuamua did not show any jet activity or cometary tails.

Shmuel Biali and Avi Loeb believe that this additional acceleration force could come from sunlight, meaning that 'Oumuamua could be an object that can be propelled by sunlight , similar to a man-made solar sail. A solar sail is a technology that uses the thrust generated by sunlight to propel a vehicle through interstellar space.

Sunlight has no mass but has momentum. When it hits an object, it imparts a very small momentum to that object. If the object is light enough and large enough, this momentum can produce a significant acceleration.

The Indian government launched solar sail missions to support communications satellites in 1992 and 2003. The Japan Aerospace Exploration Agency (JAXA) successfully launched its new solar sail-equipped IKAROS spacecraft in 2010 to study Venus and the Sun. Since then, NASA and the non-profit research organization Planetary Society have both successfully launched solar sail-equipped spacecraft into low Earth orbit.

Light sails are considered a promising interstellar travel technology because they do not need to carry fuel and can continue to accelerate as long as there is enough sunlight.

Avi Loeb has calculated that the trajectory of a light sail with a thickness of slightly less than 1 mm could match the Hubble observations. Observations of 'Oumuamua's brightness variations also show that 'Oumuamua is a very narrow and elongated object , with a long axis to short axis ratio of 5:1 or even greater, also resembling a light sail to some extent.

So, Shmuel Biali and Avi Loeb suggest that 'Oumuamua may not be a natural object. If 'Oumuamua is indeed an alien spacecraft or a type of solar sail, where did it come from? How did it enter the Solar System? What is its purpose? These questions have aroused great curiosity in the scientific community and the public. However, because 'Oumuamua has left our field of view, astronomers have no more opportunities to observe and detect it.

Based on the speed and direction of 'Oumuamua as it entered the Solar System, scientists deduce that it may have come from a star system about 20 light-years away in the direction of Cetus — a star system containing four red dwarfs, two of which have been confirmed to harbor planets orbiting them.

Many conspiracy theorists suggest that if 'Oumuamua was indeed launched from this star system, it could have taken millions or even billions of years to reach us. During its long journey, 'Oumuamua could have encountered various hazards and obstacles, such as stellar winds, cosmic dust, and micrometeorites. These factors could have affected the structure and function of 'Oumuamua, causing it to malfunction or transmit signals. It is also possible that 'Oumuamua itself is a passive detector or beacon that is only activated or sends signals when it is near certain targets.

Even if we don't find any traces of aliens, there's always the chance that we'll find something of scientific value.

In any case, 'Oumuamua offers us a rare opportunity and challenge to think about the possibilities and diversity of celestial bodies and life outside the Solar System. 'Oumuamua also makes us realize that our understanding of the Solar System and the universe is still very limited and partial, and we need more observations and exploration to expand our vision and knowledge. Perhaps in the near future, we will encounter 'Oumuamua or similar celestial bodies. So the question then may still be 'Is Oumuamua a man-made object or a natural celestial body?