Dorothy is a light sail craft? Very unlikely, humans may send a probe to chase

Something particularly interesting is happening all the time in the universe, such as the visit of a comet, or a young star rising in a planetary system.

Or, perhaps, a hidden celestial visitor is heading for another planet.

Of course, this celestial visitor is not some sci-phi movie alien or spaceship.

It is just a small celestial body that is wandering, Dorothy.

The name sounds strange, right, but it's its Hawaiian name, "Oumuamua," which means "first come, first served messenger.

In October 2017, a team of astronomers from the University of Hawaii searched for an unusual object during an observation, as it was the first interstellar object to visit our solar system.

After completing the basic nomenclature, NASA's Near-Earth Object Observation Program funded a study of its long-term observation, with a related program focused on discovering and tracking asteroids and comets near Earth.

Although the object was initially classified as a comet, during the initial observations, it was found that the object did not behave simply.

Later observations revealed that the small object was still accelerating slightly, which led to its classification as a comet.

Observations and conclusions about Dorothy's trajectory came mainly from the U.S. astronomical telescope in Hawaii, in addition to data from the Space guard survey mission, and the Canada-France-Hawaii telescope.

Dorothy should have entered the solar system from the far side of the Milky Way.

From direct telescopic observations, Dorothy is so small and not very bright that it was not even detected during the initial observing campaign.

Because its magnitude is so low, with a brightness limit of 13.5 mags, Dorothy had decayed to 23 mags by October 2017.

In follow-up observations, spectral analysis by the Herschel telescope showed that Dorothy's spectrum is predominantly red, similar to a comet nucleus.

The Wilhelm Herschel Telescope record indicates that it has no characteristic signal-to-noise ratio, and a variety of observations show that Dorothy's spectrum resembles that of a D-type asteroid.

Also, its motion trajectory is very unusual, Dorothy has no rotation axis of its own, and it probably moves in a tumbling state.

Scientists believe that Dorothy's unique motion may have originated from a collision in the celestial system in which it is located.

And the dissipation time scale of this motion is very long, requiring at least a billion years of consumption to terminate, so it also keeps showing a tumbling state.

After observing the light-change curve of Dorothy, astronomers have found that it has a huge variation in the light-change curve.

The light curve allows us to roughly deduce what Dorothy looks like, but research observations suggest that it could be anything.

Dorothy could be flat

Cosmic cigar or large pancake

The light curve of Dorothy shows that it is stretched out in height, possibly like a cigar-shaped object, and that the stretched length of Dorothy is even more exaggerated compared to similarly stretched objects in the solar system.

Dorothy also exhibits a flattened state, which makes it likely to have the appearance of a pancake or a flattened round sphere.

In short, such peculiar morphological manifestations and large changes in the light-change curve suggest that Dorothy is in a very unstable state of motion.

In a 2019 paper, however, researchers modeled it.

They found that the best model representation of Dorothy was cigar-shaped, or with a 1:8 aspect ratio.

Dorothy's ability to exhibit such bizarre forms has also led some scientists to suggest that this extreme shape may be the result of evaporation.

Theoretically, it should not have been like this before it entered the solar system and should have been at least 2:1 in shape.

A month after it reached perihelion, it evaporated 92% of its mass due to the Sun's energy.

In addition to that, Dorothy's light-change curve observations suggest that it may contain dense metallic rocks.

Due to the long exposure to cosmic rays in interstellar space, these metal-laden rocks eventually turned red.

It is thought that the surface of Dorothy may contain Tomlin, an organic compound spawned by irradiation during prolonged exposure to the solar system, which could help scientists determine the age of the surface.

The performance of Dorothy's trajectory is also a place where scientists are very puzzled. During the 80-day-long study, scientists found that its orbital eccentricity is 1.20, which means that it is moving faster than the escape velocity of the Sun.

So, in this respect, Dorothy will only be a visitor to the solar system.

The speculation that it is a comet comes mainly from the non-gravitational acceleration of Dorothy, which behaves in line with the push of the solar radiation pressure.

During its closest position to the Sun, the resulting change in velocity totals about 17 meters per second.

It is due to this variation that scientists point it initially to the comet.

As a distinctive feature of the comet's tail, Dorothy appears to evaporate as it approaches the Sun, and the volatile material inside the object brings about a comet-like effect.

But this outgassing process causes a change in spin due to Dorothy's elongated shape, which eventually tears the object.

But Dorothy's spin stability suggests that it is not affected by this condition, which is all the more puzzling to scientists.

To say where it came from, astronomers believe Dorothy's home would be in the Vega system, probably part of one of the galaxies inside.

Studies have shown that Dorothy is moving close to the local stationary standard, which means he has orbited the galaxy several times, and may even have originated from a completely different part of the galaxy.

For the moment, scientists do not know exactly how long it has been marching through the universe.

However, the boldest speculation scientists have about Dorothy is a light sail craft. Some scientists believe that Dorothy's possible flat shape, and its state of being pushed away by the sun, resembles a light sail in general.

And it tumbles every 8 hours making people think about the laws of motion inside, which is too similar to a flying machine.

However, the hypothesis of the light sail craft proposed by American scientists was soon denied by Lou Shanghai, a professor of astronomy at Sun Yat-sen University in China.

In his opinion, if this thing is a light sail craft, then it should have more than one reflected light point, but there is more than one enemy thin at existing reflective points, so in line with the performance of light sails in the universe.

In addition, if Dorothy is a light sail craft, it should be very bright, but the observations have shown that the surface of Dorothy is dark and difficult to be found.

For now, all the possibilities of Dorothy being a shaped probe are highly speculative based on existing observations, and it would not hurt to just find this conclusion interesting.

But to better explain Dorothy's behavior and performance, scientists say better scientific data should be collected to explain the situation.

Currently, the UK's Interstellar Research Initiative has launched the Lyrae project, which will launch a probe to Dorothy for a re-evaluation that is expected to be completed in the next 5 to 25 years.

Now that the discussion about Dorothy is becoming clearer, scientists are putting more discussion into celestial research.

Based on past observations, it appears that Dorothy's nitrogen ice could explain why it has no outgassing process of its own.

Dorothy carries nitrogen ice of its mass that can survive 500 million years in the interstellar medium and can reflect two-thirds of the sunlight.

If this is true, Dorothy could be a dwarf planet or a fragment of an exoplanet like Pluto.

Future probes will test it

Based on the theory of nitrogen ice, the possibility of hydrogen ice has also been suggested. Dorothy may have a large amount of hydrogen ice, which, if true, suggests that it originated in the core of an interstellar molecular cloud.

The heat from the Sun causes hydrogen to sublimate, which in turn drives Dorothy's motion.

However, this phenomenon is difficult to observe directly due to the influence of the Earth's atmosphere. But in a later demonstration, the hydrogen ice of Dorothy cannot be composed of small particles.

It would have to have formed in the vicinity of the solar system 40 million years ago if it was to remain vaporized in interstellar space.

More and more scientists think it is just an ordinary object compared to possible extraterrestrial probes.

But the truth will only be clear once it is truly understood, and while it is still completely away from us, the mystery may continue and wait for the answer to emerge.