‘Oumuamua, the first object to visit our solar system from interstellar space, still hasn’t shown signs of having intelligent origins. However, scientists have found a few interesting things about its surface.
Artist's impression of 'Oumuamua [Photo by ESO/M. Kornmesser]
The chances that ‘Oumuamua is a probe sent by an intelligent extraterrestrial civilization is growing slimmer and slimmer (and let’s face it, they weren’t really that big to begin with). For one thing, the object is drifting farther and farther away from Earth, and it may eventually leave our solar system. Once it gets far enough away, it may become more difficult for our astronomers to study it. Still, as the first known object from interstellar space to penetrate our little bubble in the universe, it does still hold some mystique.
New analyses have found that the object has a reddish, carbon-rich coating of cosmic gunk over a foot thick. This layer likely developed due to the radiation found in interstellar space.
Comets have tails, but 'Oumuamua didn't.
A new study details the analysis of wavelengths of light recorded in observations of ‘Oumuamua made by two telescopes in late October. The study confirms a couple of important things. One is the confirmation that the object did not indeed produce a tail of gas as it swung close to the sun. Another is that there are no wavelengths that indicate the presence of rocky minerals that characterize asteroids.
At first, astronomers thought that ‘Oumuamua was a comet. However, comets have tails, and ‘Oumuamua didn’t. So then, scientists began considering ‘Oumuamua to be an asteroid. However, these new findings put that classification in doubt as well.
The observations also concluded that the object’s carbon-rich layer formed when the radiation in between stars battered the carbon dioxide, methane, and methanol that make up ‘Oumuamua. This outer layer formed over what could be billions of years of travel through the cosmos. Thus, ‘Oumuamua may have come from a much older star system.
It’s also possible that the object does have ice, but that ice is located deep under its surface. The ice on its surface could be long gone, likely due to a close encounter with its home star or perhaps a supernova. Calculations show that the heat of our sun could penetrate only up to about 40 centimeters under the surface,which may explain the absence of a comet tail. This also means that the object’s possible icy core is still intact.
The Hubble Space Telescope will be keeping an eye on 'Oumuamua.
‘Oumuamua is becoming less and less strange the longer that astronomers observe it. The object’s measurements, for example, also show that it has a resemblance to Trojan asteroids near Jupiter and objects in the Kuiper belt beyond Neptune. Thus, it’s not so unique after all.
Sooner rather than later, ‘Oumuamua will be too far away to observe from Earth. However, there are space telescopes that may be able to continue observing the object. Scientists are also gearing up to determine the object’s trajectory by using the Hubble Space Telescope in January 2018. There’s also another project that seeks to use the infrared lens of the Spitzer Space Telescope to determine what exactly ‘Oumuamua is made of. However, these researchers better move fast.
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