First Alien Moon Detected Outside Our Solar System May Be As Large As Neptune

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An artist's impression of what could be the first moon outside our solar system ever found, via NASA’s Hubble and Kepler space telescope observations. (Credit: L. Hustak/NASA/ESA/)

Over the last couple of decades, astronomers have identified thousands of planets outside our solar system. However, they have been unable to find confirmation of a moon revolving around any of the distant worlds, mainly because the generally smaller satellites are harder to spot. Now, some researchers from Columbia University believe they have found evidence of an alien moon orbiting a gaseous exoplanet which, lies almost 8,000 light years away.

For their study, astronomers Alex Teachey and David Kipping, who have been searching for alien moons for nearly a decade, focused on the 284 exoplanets discovered by the planet-hunting Kepler spacecraft. The distant worlds were considered the best candidates for potential exomoons due to their relatively wide orbits that span more than 30 days.

Specifically, the scientists were searching for two dips in light – one caused by the exoplanet as it passed in front of its star and the second by another, most likely smaller, celestial body. After sifting through the data collected by Kepler, the researchers were able to identify one exoplanet, Kepler-1625b, that looked promising. “We saw little deviations and wobbles in the light curve that caught our attention,” Kipping said.

Animation showing the corrected WFC3 images of Kepler-1625. The star is located in the center and is spread out horizontally due to the instrument’s grism, giving the observer’s color information about the source. (Credit: Alex Teachey & David Kipping)

To confirm their suspicions, the team used the Hubble telescope to monitor the planet before and during its 19-hour-long transit across the face of its star. Sure enough, about 3.5 hours after the Kepler-1625b had passed, Hubble detected a second, much smaller decrease in the star’s brightness, which Kipping said was consistent with “a moon trailing the planet like a dog following its owner on a leash.”

Their exomoon hypothesis was further confirmed when the planet began its transit 1.25 hours earlier than predicted. This happens only when an orbiting moon pulls at the planet and causes it to wobble, as is the case with our own moon. “An extraterrestrial civilization watching the Earth and Moon transit the Sun would note similar anomalies in the timing of Earth’s transit,” Kipping explained.

Artist’s impression of the exoplanet Kepler-1625b transiting the star with the candidate exomoon in tow. (Credit: Dan Durda)

The researchers, who published their findings in the journal Science Advances on October 3, 2018, estimate that the newly-discovered moon has a diameter of 30,600 miles (49,000 km). In comparison, our solar system's biggest moon - Jupiter’s Ganymede – boasts a diameter of about 3,270 miles (5,260 km). However, the exomoon is tiny compared to Kepler-1625b which is believed to be several times bigger than Jupiter. The researchers estimate the satellite's mass to be just 1.5 percent that of the planet it orbits, about the same ratio as the Earth and our moon. Though the host planet and its moon lie within the solar mass star’s (Kepler 1625) habitable zone, which has moderate temperatures and hence the possibility of water on planets that feature a solid rocky surface, there is no chance of finding aliens. As Kipping explains, “Both bodies are considered to be gaseous and therefore unsuitable for life as we know it.”

The team’s conclusion still has to be verified by follow-up Hubble observations of the moon’s transit. If confirmed, the discovery could provide vital clues about the development of planetary systems and may cause experts to revisit theories of how moons form around planets.

smithsonianmag.com, nationalgeographic.com,sciencemag.com

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confirmationconsistentdecadesdetecteddiameterexoplanetextraterrestrialgaseoushabitablehosthypothesismoderateorbitssatellitesspecificallytransitverified
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Reading Comprehension (12 questions)

  1. Why has the search for exomoons proved elusive for scientists?
  2. How far away is the exomoon discovered by Columbia University researchers?
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Is it surprising that the exomoon is as big as Neptune? Why or why not?

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Vocabulary in Context

“To confirm their suspicions, the team used the Hubble telescope to monitor the planet before and during its 19-hour-long transit across the face of its star.”

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790 Comments
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  • donuts4ever
    donuts4everSunday, December 9, 2018 at 3:53 pm
    Watch the video its awesome!!!
    • woSaturday, December 8, 2018 at 7:26 pm
      cool awsome
      • heyFriday, December 7, 2018 at 4:12 pm
        It was so cool! i literally drooled when i read this! my classmates were like, "cool, dude"
        • clfav<SFriday, December 7, 2018 at 4:10 pm
          cool people
          • blaFriday, December 7, 2018 at 4:07 pm
            i really belive there aliens. this is weird but cool. i love it! cant wait to learn more
            • blaFriday, December 7, 2018 at 4:04 pm
              OMG!!! this is so cool. great for current events. everyone was so curious! i love this... hope i can do it again! but my teacher says it matters about date too...
              • VotivePhonez!Friday, December 7, 2018 at 2:10 pm
                No, there has not been a sighting of aliens. "Alien" does not only mean another bean on a different planet it also means "not part of our group such as our solar system.
                • creepyboi23
                  creepyboi23Friday, December 7, 2018 at 10:25 am
                  NICE... THAT WOULD MEAN THAT ALIENS CAN BE REAL!!!!!!!
                  • big bFriday, December 7, 2018 at 10:02 am
                    this is a gret article
                    • FORTNITEFriday, December 7, 2018 at 8:12 am
                      this is so cool What if there are aliens???????

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