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Scientists have learned more about 'Oumuamua, the piece of matter that is the first known interstellar object to be detected by scientists within the confines of the solar system. Specifically, observations made by researchers using the Spitzer Space Telescope and published in The Astronomical Journal have shown that previous observations probably established an overly generous upper limit on its size.
While earlier observations made by the University of Hawaii's Pan-STARRS 1 telescope, NASA's Hubble Space Telescope and ground-based observation stations had determined Oumuamua was no more than 800 meters long, NASA said in a statement, the Spitzer Space Telescope recently failed to see the object in the infrared spectrum during a two-to-one investigation month. Based on various models of what exactly corresponds to 'Oumuamua' and its degree of reflection, this sets a new upper limit of 440 meters (1,440 feet), which could actually not exceed 100 meters.
These numbers refer to the "spherical dimensions" of the object or the size of that object if it were a sphere, although it is currently considered to be shaped like a cigar.
NASA wrote:
The fact that "Oumuamua was too weak to be detected by Spitzer imposes a limit on the total area of the object. However, since the non-detection can not be used to derive a shape, the size limits are presented as what the Oumuamua diameter would be if it were spherical. Using three distinct models that emit slightly different assumptions about the composition of the object, the "spherical diameter" of Oumuamua, undetected, allowed to limit the "spherical diameter" to 1,440 feet (440 meters), 460 feet (140 meters) or perhaps as little as 320 feet (100 meters). . The wide range of results stems from assumptions about Oumuamua's composition, which affect the visibility (or fainting) that it would seem to Spitzer of a particular size.
As noted by Ars Technica, the new observations on 'Oumuamua support the theory that it is indeed a natural object, rather than an odd interstellar probe that searches for relevant data for its unknown extraterrestrial masters. Scientists have found that 'Oumuamua seems to have slowed down less than expected as it moved through the solar system and was affected by the gravity of the sun.
This could be explained by the fact that solar radiation warms the frozen gases on its surface and evacuates them when it rocks in a vacuum, a process called degassing that could serve as a de facto propulsion mechanism. This latest discovery establishing a lower upper limit on its size makes this explanation more likely because, as NASA noted, "Oumuamua is" relatively smaller than the comets of the solar system ". The study also revealed that the object "could reach 10 times more reflective than the comets that reside in our solar system," writes NASA, because the degassing could have swept away the accumulated dirt and reveal the ice and the underlying snow.
"Oumuamua has been full of surprises from the first day, so we can not wait to see what Spitzer could show," said lead author David Trilling, professor of astronomy at Northern Arizona University, in a statement from NASA. "The fact that Oumuamua is too small to be detected by Spitzer is actually a very valuable result."
According to NASA, this is probably the last time scientists Earth will learn more about this object, because there is no way to see it.
"Usually, if we get a weird measure of a comet, we measure it again until we understand what we see," co-authored Davide Farnocchia of the Center for Studies on a Comet. objects close to Earth from NASA's Jet Propulsion Lab. , said in the statement. "But this one is gone forever; we probably know as much as we will ever know. "
[NASA via Ars Technica]Source link
