Astronomers are buzzing with excitement this week about a newly discovered object that apparently originated in interstellar space. The official confirmation that this object labeled C / 201
A statement from NASA called the object a "comet" and said:
The new comet C / 2019 Q4 is still heading for the sun, but will remain further away than the orbit of Mars and closer to Nr Earth as about 300 million kilometers.
After the Comet's first discoveries, the scout system, located at NASA's Jet Propulsion Laboratory in Pasadena, California, automatically marked the object as potentially interstellar. Davide Farnocchia of the NASA Near-Earth Object Studies Center at JPL worked with astronomers and the European Space Agency's Coordinating Center for Near-Earth Objects in Frascati (Italy) to obtain additional observations. He then worked with the NASA-sponsored Minor Planet Center at Cambridge, Massachusetts, to assess the comet's exact trajectory and determine if it came from our solar system or from any other location in the galaxy.
The Comet The current speed is high at 93,000 miles per hour (19459029), far beyond the typical speeds of objects orbiting the Sun at that distance. The high speed not only indicates that the object probably comes from outside our solar system, but also that it will leave the interstellar space and return.
Do we know what C / 2019 Q4 looks like? No, it's mostly a moving spot for us, though it seems a bit blurry. Its orbit resembles the orbits of long-period comets. NASA called it a comet in its announcement, but in another announcement by the European Space Agency, astronomers used the more neutral word "object." The NASA statement explained the results of the observations made by Karen Meech and her team at the University of Hawaii, indicating that the cometary nucleus has a diameter of between 2 and 16 km:
2019 Q4 was considered to be a blurred image Classified as a cometary body, indicating that the object has a central ice body that produces an ambient cloud of dust and particles as it approaches the sun and heats up.
"Established" is a strong word, and we assume that not every astronomer will agree. And of course, science fiction fans like me hope it's more exciting than a comet, even a (probably) interstellar one.
Could the object be something other than a comet? With "Oumuamua," some astronomers speculated that the object might be an alien artifact, perhaps similar to the two Voyager spaceships now racing away from our solar system with their golden records. Astronomers searched for signals from Oumuamua, but found none. "Oumuamua has made his way with many unresolved puzzles, as this object will reach its sunniest point – its perihelion – on December 8, 2019, at a distance of about 300 million km. If it is really interstellar, it will – like Oumuamua – flee back into the space between the stars.
According to NASA, C / 2019 Q4 will be within range of professional telescopes in the coming months. Farnocchia said:
The object will gain brightness in mid-December and will continue to be observed with mid-size telescopes until April 2020. After that, it will only be observable with larger professional telescopes until October 2020.
NASA said that astronomers will continue to gather observations to further characterize the comet's physical properties (size, rotation, etc.) and to better identify its trajectory.
So the second known interstellar object has invaded our solar system, and we will undoubtedly hear more about it in the coming months while astronomers continue to investigate it.
By the way [SPOILER ALERT AHEAD] If you never read Rendezvous with Rama – a science-fiction book by Arthur C. Clarke in 1973 about an object that enters our solar system from interstellar space and turns out to be an alien spacecraft – then perhaps you will not appreciate the words:  And on the far earth had dr. Carlisle Perera still does not tell anyone how he awoke from a restless sleep, and the message of his subconscious mind still echoed in his brain: The Ramans do it all in threes.
If you've read it … you know why I mention this quote (yearning)!
Conclusion: Astronomers discovered the second interstellar object on August 30, 2019. They described it as C / 2019 Q4. If confirmed as interstellar, it would be the second such object discovered in 2017 after "Oumuamua".
Read more from NASA / JPL
Read more from ESA