How can you tell the difference between a spaceship and a space rock?
For astronomers like me, this question turns out to be misleading; It was so misleading that we were almost fooled when it was named after the first recorded interstellar object. ‘OumuamuaIt was spotted passing through the inner solar system in 2017.
Astronomers once thought that any object that moves at its own speed, with no apparent driving force, must be moving. artificial technology. We knew how ‘Oumuamua should behave if it were an interstellar space rock, or so we thought, but in every respect it did the exact opposite.
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‘Oumuamua speeding by solar system, we only had a few weeks to watch it with our world-class telescopes. These observations showed that the object came from outside the solar system and was extremely elongated and rounded. ‘Oumuamua didn’t have a comet-like tail, but still moved with its own driving force.
comets they also move under their own propulsion, but exhibit beautiful tails caused by dust and ice blowing from their surfaces, causing a rocket-like recoil. ‘Oumuamua was different. Its mysterious flight through our solar system sparked whispers of an artificial origin. Even some astronomers He named him Rama.
The real explanation, which we determined from its motion and the amount of energy it received from the sun, is just as strange: a completely new type of object. We call them “dark comets.” Since detecting ‘Oumuamua, we have found a population of seven dark comets hiding among our solar system. asteroids. They get their name because they move like comets but do not exhibit a dust tail.
Visitors from beyond the solar system (interstellar travelers) have long been predicted by science fiction writers Arthur C.Clarkebut it’s not so easy to determine what we’re actually seeing or how many interstellar space rocks or spacecraft are near Earth at a given time. This challenge came to a head when we rushed to understand ‘Oumuamua, but James Webb Space Telescope (JWST) and the upcoming Rubin Observatory Ancient Space and Time Survey (LSST) In the Atacama Desert in Chile, we will have the tools we need to understand future interstellar travelers and expand our understanding of the universe.
If only we had had JWST when ‘Oumuamua was discovered, we would have been able to take more detailed images of the object and get information about what light looks like at different wavelengths. By doing this, we could better understand what propels it through space. We could see molecules like water or carbon dioxide that only appear at certain wavelengths and do not reflect sunlight. We routinely see normal solar system comets being pushed as their surfaces warm and their water and carbon dioxide ice turns into gas. We would immediately identify it as a dark comet-like object. The good news is that if we detect another ‘Oumuamua, we already have a confirmed JWST schedule to track it.
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In the future, JWST will not be the only powerful tool in our toolset. LSST, scheduled to be operational within the next year, will detect many more interstellar objects and be able to identify dark comets in our own solar system. Located in the Atacama Desert, a prime spot for viewing the skies, LSST will begin scanning the entire Southern Hemisphere sky nearly every night. LSST will be able to detect much fainter objects than our surveys, which currently monitor the entire sky for fast-moving objects. It will be able to detect mysterious objects that are fainter because they are smaller or farther from Earth, such as ‘Oumuamua. Soil. LSST will also be able to find much smaller asteroids and determine whether they are dark comets and whether they are moving under their own propulsion.
Once the LSST is at first light, it is possible that we will begin detecting interstellar objects on a monthly or even weekly basis. Some of these may be dark, like ‘Oumuamua, and some may be brighter with beautiful tails, like the second interstellar comet. 2I/Borisov.
The near-Earth sky may turn out to be full of hitherto unseen interstellar objects even smaller than ‘Oumuamua. These tiny interstellar visitors could quite conceivably be constantly zipping through Earth’s neighborhood within the solar system. If this happens, LSST could detect an interstellar target close enough for a special space mission.
Close encounters with an interstellar visitor will no longer be the preserve of science fiction writers.
We have the tools to tell the difference between an application with LSST and JWST. smart visitor and a dark interstellar comet. Let’s not be fooled.
Darryl Seligman is a research assistant professor in the Department of Astronomy at Cornell University. His research focuses primarily on theoretical and computational planetary science and astrophysics.