[ad_1]
Remember this cigar-shaped interstellar object that whistled through our solar system the year last? It was pretty weird, right? Well, new research shows that 'Oumuamua is even stranger than we have realized.
& # 39; Oumuamua, pronounced "oh-MOO-ah-MOO-ah" is a comet and not an asteroid, according to a study published yesterday Nature . This is not a huge revelation, as many scientists have already figured it out. What is special about this new document, however, is that it offers hard evidence to support the case.
That seems like a good point, but there is a big difference between asteroids and comets. Both types of objects are remnants of the formation of the solar system, but where asteroids are composed of metals and rocky materials, comets are made of ice, dust and rocks. Generally, comets have elongated orbits that bring them to the confines of the solar system, but when they venture inward, the sun's rays cause shearing of gas and dust, producing a cloud of matter called coma and visible tail.
In the case of "Oumuamua, the dark object of 2,620 feet long was detected on October 19, 2017 using the Haleakala Observatory of Hawaii, and the scientists the have followed since. "Oumuamua has arrived less than 33 million kilometers from Earth before returning to interstellar space – and it seems to be in a hurry." By combining the data collected by NASA / ESA's Hubble Space Telescope, the Canada Telescope -France-Hawaii, ESO's Very Large Telescope and the Gemini South Telescope, a team led by Marco Micheli of the European Space Agency noticed something odd. It's moving faster than Planned.
The extra speed is not absurd, but it is still measurable. "Oumuamua slows down again thanks to the gravitational influence of our Sun, but The reason, say the authors of the new study, is that "Oumuamua always evacuates materials from its surface.Solar heating produces an effect called degassing, and the material ejected from the surface of the Object creates a small amount of thrust. It's like an integrated propulsion system, but that only becomes active in the warm and welcoming realms of a star system.
To ensure that the effect of acceleration was not caused by anything else, the researchers considered scenarios like the solar wind. , a collision with another object, its mass being different from that calculated, and other known or suspected astrophysical phenomena. However, "these explanations are all either physically unrealistic, or insufficient to explain the observed behavior," write the authors of the study.
"In addition, the unlikely theory that & # 39; Oumuamua is an interstellar spacecraft was rejected : the continuous change the speed is not typical for thrusters and the object plummets on all three axes, expressing against it being an artificial object, "according to the Hubble press release. elsewhere, late-last-year research has reached the same conclusion
The suspected presence of degassing was the smoking gun necessary to prove that "Oumuamua is a comet and not an asteroid."
"We think it's a weird little comet," Micheli said in a press release. "We can see in the data that his boost is decreasing as he moves around the world." Sun, which is typical for com . Your "
Now you are probably thinking," Dvorsky it a minute ago you said that comets produce coma and tail visible when & # 39; s it & # 39; approach the sun! But "Oumuamua does not show any of that!" Just point, but there is a good reason for this, one showing how strange this object is.
"Oumuamua, according to the researchers, gives off unusually large coarse dust particles. Micheli's team hypothesizes that small grains of dust, which usually littered the surface of comets, eroded during the epic journey of Oumuamua into interstellar space (We do not know how old this object is, so who knows for how long? The Milky Way, which was formed 13.5 billion years ago). All that remains on this comet are the largest grains of dust. If Oumuamua produces a cloud composed of these large particles, it would be too small for Hubble to see. But the unexpected deviation in its acceleration suggests that these grains are very there, and that "Oumuamua is, or was, in a phase of degassing during its brief time in our solar system.
Unfortunately, this new result means that it's going to be exceptionally difficult for astronomers to understand where this object comes from in the galaxy. If it had been an asteroid with a boring and predictable speed, the scientists should have been able to go back on its trajectory towards its stellar origin system. But with its variable speed, it will now be a physics task of Herculean proportions, and probably something better suited for a future supercomputer.
He came, we saw him, he leaves quickly. But we are still learning incredible things about this messenger from afar.
[Nature]
Source link
