GeminiFocus January 2018 | Page 6

John Blakeslee

Gemini North and South Join in Welcoming the Solar System ’ s First Interstellar Emissary

Two months after the first electromagnetic counterpart to a gravitational wave detection caused Gemini to “ pull out all the stops ” in its effort to follow the event as long as possible , the Observatory reprised its performance , but this time for a few nights only , when the first known interstellar object streaked through our Solar System . Observations were carried out with both the Gemini North and South telescopes during late October 2017 and enabled astronomers to characterize the peculiar properties of this exotic visitor .
Note : Parts of the following article are adapted from the Gemini Observatory press release issued on November 20 , 2017 . The original release is available online .
Planet formation is a messy , sometimes violent , affair . The evidence is imprinted in the countless impact craters that pockmark the face of our Moon and the other airless , rocky bodies that retain the scars of the distant past . It is believed that numerous asteroids and comets were ejected entirely during the early stages of our Solar System as a consequence of interactions with the giant planets Jupiter and Saturn . The same should be true of all other planetary systems with giant planets , which may comprise the majority of the systems around stars in the Milky Way . Doing the numbers , one finds that trillions of objects must be wandering the vast expanses between the stars . However , the likelihood that any one of these wanderers would make a close approach to another planetary system is tiny .
On October 19 , 2017 , a small near-Earth object discovered by the Pan-STARRS1 survey telescope on Haleakala was found to be moving away from the Earth at a speed so high that the Sun ’ s gravity was insufficient to prevent the object from escaping . Thus , the object was on
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