However, Professor Monica Grady, earth and space science researcher at the UK's Open University, said the cigar-shaped object Oumuamua shows why we may need a new classification system.
By Monica Grady, Professor of Planetary and Space Sciences at the UK's Open University and Research Fellow at the Natural History Museum in London and CEO of MonicaGrady MeteoriteLady a company that produces educational resources and scientific events for schools and the public. Translation: Avi Blizovsky
Ever since astronomers first spotted the strange cigar-shaped object known as 1I/' Oumuamua in the sky, they have been debating what exactly it is. Suggestions included an asteroid, a comet and even an alien spacecraft. A new study published in the journal Nature claims that this is a comet, but an unusual comet.
The fascinating findings add to the recent discoveries that show that now is the time to think beyond the traditional division of asteroid versus comet.
Gravity is what keeps our feet on the ground, the moon orbits the earth and the planets orbit the sun. It is also the main factor that controls the trajectory of comets as they travel through the solar system. Newton's laws of gravitation allowed the astronomer Edmund Halley to predict the return of the comet known as Halley's Comet. The same laws allowed the Rosetta spacecraft to synchronize and fly alongside Comet 67P/Churyumov-Gerasimenko.
There are other non-gravitational factors that can affect a comet's orbit, but they are so weak compared to gravity that they are usually negligible. But in the case of the object 1I/'Oumuamua, its orbit is so unusual that non-gravitational phenomena may play a role in its geometry.
1I/' Oumuamua was first observed in October 2017. Calculations based on the laws of gravity showed that its orbit was not elliptical like that of a comet or circular like that of an asteroid. Instead this object appears to have a hyperbolic orbit, meaning it is not gravitationally bound to the Sun. This means that it is almost certain to be a visitor from outside the solar system. And so the 1I" part of his name means the first intergalactic body.
Oumuamua's orbit in the solar system
Oumuamua approached a quarter of an astronomical unit from the Sun (an astronomical unit is the distance between the Earth and the Sun). He should have developed a comet nucleus and a comet tail, but although all possible telescopes were directed at him, no trace of these was discovered.
Indeed measurements of its composition have shown that it has more in common with asteroids than with comets. A low light reflectance of the surface indicates that there is little if any ice on it. It also reveals material that has undergone changes due to exposure to cosmic radiation, such as many asteroids.
Along with these observations, was the strange shape of the bone. Although it could not be seen directly, a model of its light curve showed that it was a long, thin, cigar-shaped object rather than the usual rounded appearance of asteroids and cometary cores. This has led many to speculate that Oumuamua may be an artificial object visiting the inner solar system. Maybe an alien spacecraft.
If we were to fly a spaceship to another solar system, we would stop to examine the signals coming from a star from the planet, leaving the question of whether it is a comet or an asteroid. The researchers who used all the large ground telescopes and the Hubble Space Telescope came to the conclusion that a significant release of gas through the takeoff process was the main mechanism that causes the orbit of the object and therefore it is a comet from the solar system and it loses water and dust at a rate of 2.4 kg per second. This is compared to 20 kg per second that evaporates from comet 67P (Rosetta's comet). So, the question is what holds the dust back from a higher release rate? Perhaps the dust is bound to the surface through organic compounds.
Until recently, the division between comets and asteroids in the solar system was clear. Asteroids have circular orbits, are made of rock and subsurface and are mostly found in the asteroid belt between Mars and Jupiter. The orbits of comets are elliptical and they are made of rock and ice and came from afar.
But in recent years we have discovered asteroid families scattered all over the solar system. We also discovered comets with short and long orbits and saw unusual features on objects we thought we knew well. A collapsed asteroid (now a dwarf planet), for example, contains salts left after the ice evaporated from their surface via mirroring, a process common to comets but not asteroids.
Oumuamua, with its unusual small solar system bodies and interstellar guests, appears to exhibit a spectrum of dynamic properties and compositions. It's time to think beyond the asteroid versus comet division and look for a new way to classify these objects. Perhaps an additional category of small entities is required. Obviously - Oumuamua showed Nan that we still haven't discovered the variety of objects that can be discovered in our neighborhood.
to the article on The Conversation website
More of the topic in Hayadan:
4 תגובות
A. Ben Ner
Wikipedia has a lot of detail about this object. In particular, it says that it is about 230 meters long, and about 35 meters wide. There is also data on the shape and rate of its rotation.
In addition, there is a detailed explanation of why it is thought to originate, probably, from outside the solar system.
And there are a lot of links, so it seems very reliable.
Despite the hyperbolic orbit of the Oumuamua, it is possible (and even probable) that the origin of the object is in the asteroid belt and not outside the solar system (!!!).
According to this hypothesis, it was formed as a result of a collision between asteroids.
Therefore, it is a fragment of an asteroid that, as a result of a collision between asteroids, was thrown into a hyperbolic orbit that will later cause it to be ejected outside the solar system.
Regarding the dimensions of the Oumuamua:
In articles on the websites: The Conversation and Arxiv, it is estimated that its diameter is over 100 m.
The measure of length is not indicated, but, according to the proportion seen in the illustration, it can be estimated that the measure of length is 12 to 17 times the measure of the diameter.
Therefore, it can be estimated that the dimensions of Oumuamua are approximately:
Length-(2000-2500) m~ Diameter-(130-200) m~
Another figure that appears: self-rotation time - about 7 hours.
I did not find any further details of the rotation data.
Avi Cohen
I understand that to show that your theory is right - you fit the observations to the theory? Let's, with your permission, go over what you wrote:
1. "The trajectory of the object points to an origin outside the solar system". All it means is - that the "origin is outside the solar system". It does not show in any way that it is an unnatural object. Does the fact that the dove has wings prove that the dove is a dragon? I hope you agree not.
2. "The shape is different...". Right. Does it follow that it is not something natural? The answer is no.
3. "The object changed its course contrary to the calculations of gravity" - yes - it changed its course, as a result of the emission of gases near the Sun (as expected from a comet).
4. "The object uses the slingshot effect with the sun" - where did you come up with that? The object moves in the path expected from any object coming from a distance.
5. "The object did not release a tail of material and gas as expected from a passing comet" - you mean they did not see such a tail with their eyes. But the change in its trajectory corresponds to the expected release of gases.
6. "What if...". But if the object is just the result of a collision between bodies in space, then the ILO is not needed.
7. "There is a specific point in the slingshot effect where our probes activate engines to maximize the energy from the effect" - we have already said that the object performs a simple ballistic trajectory... but when you are trying to prove your point, then why refer to the facts?
8. This is nonsense. 1) So what if someone else agrees with you? 2) He really doesn't agree with you, but if we're already distorting reality...
My father - you ignored the fact that the body turns over all the time. Do you think a spaceship would do that? A spacecraft that uses its engines for minor orbit corrections?
I looked for the explanation why it couldn't be a spacecraft or a probe from another solar system and the only explanation I found was: "If we were flying a spacecraft to another solar system, we would stop to examine what the signals are coming from the planet..."
Is it really so? Are we able to send probes to the nearby star Proxima Centauri B and steer them to the planet that emits radio signals?
The only program we currently have STARSHOT talks about sending nano probes with the help of a laser beam - I don't think they will have much navigational ability.
Unless we are stuck in circular reasoning: "The chance that it is an alien object is slim because we have never encountered such an object before, but we have encountered asteroids and comets, so it is likely one of the two." Accordingly, an object of this type will never be classified as "alien" if it does not perform a maneuver similar to something from science fiction... Who said that alien probes perform such maneuvers? Perhaps they use our star's gravity in a similar way to how we use our probes to create the slingshot effect?
The reasons why it could be a probe from another solar system:
1. The orbit of the object indicates an origin outside the solar system.
2. The shape of the object is different from the shapes of all the comets and asteroids we know so far.
3. The object changed its trajectory contrary to gravity calculations, did it correct its trajectory by activating engines?
4. The object uses the slingshot effect with the sun similar to what our probes do when passing between the planets. A proven technique for moving space and saving energy.
5. The object did not release a tail of material and gas as expected from a comet that passes at a distance of less than one astronomical unit from the Sun, despite a change in its orbit.
6. If the unusual shape of the object was caused by material not solid enough to form a circular shape as previously explained, the object should have broken up or given off a comet tail in passing by the Sun, or at least changed its shape.
7. There is a specific point in the slingshot effect where our probes activate motors to maximize the energy from the effect. Who will pick up the glove and calculate whether the object made the change in trajectory at the point that would maximize the energy?
8. And if you made it to this section, bonus: Neil DeGrace Tyson agrees with me (of course not directly, but it will be hard for him to avoid it). Before the present discovery he stated that it was a natural artifact in Kobert's plan because it obeyed the laws of gravitation. So, since we know he doesn't follow the rules, Tyson believes it is now "at least interesting" - search on YouTube: Neil DeGrasse Tyson: Is This Thing A Spaceship.