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  • In October of 2017, our solar system had a very strange visitor.

  • We now call this oblong mass 'Oumuamua, which simply translated means 'scout' in Hawaiian.

  • When it passed by our Sun, it brought more questions than answers.

  • What is it? Where did it come from? Why is it here now?

  • A brand new study may finally bring answers to all these questions.

  • Initially, many thought the unusually elongated interstellar object, or ISO, was a comet.

  • But it was missing several key characteristics of a comet, like the coma and the tail.

  • So, of course, it's gotta be aliens, right?

  • One key piece of the puzzle that made 'alien spaceship' jump to mind was just how freakin' fast it was going.

  • It zipped past the Sun at about 87.3 kilometers per secondthat's way over the legal speed limit.

  • I mean, way faster than it would be going if it were solely influenced by the Sun's gravity.

  • The team that published this proposed hypothesis for 'Oumuamua's origin story

  • may be able to explain everything about it that has mystified us for the past three years.

  • The idea goes like this: once upon time, some body in another solar system got a little too cozy

  • with its system's star and BAM, it was ripped to shreds by the tidal forces from that star,

  • a process called tidal fragmentation.

  • The scientists tested this idea out in simulations that modeled what would go down

  • if three kinds of bodies got too close to their host star.

  • One: kilometer-sized comets from the Oort cloud, the very farthest region of our solar system;

  • two: kilometer-sized planetesimals, which are like little baby pre-planets;

  • and three: full on planet-sized bodies called super-Earths,

  • even farther away from their star than we are from our Sun.

  • The results of these simulations were clear:

  • if any of these items came within roughly 350,000 kilometers of their star,

  • the tidal forces exerted by that star would tear them to shreds.

  • Tidal forces in space are the result of gravity pulling on stuff.

  • Just like the moon's gravity pulls on the Earth's oceans and causes our tides,

  • stars pull on all of the things around them, too.

  • Like, did you know that our Sun also affects our ocean tides?

  • Not as much as the moon does because of how much closer the moon is to us, but still.

  • So, between any two objects, both are exerting gravitational pull on each other

  • and the gravitational force increases with mass.

  • So smaller bodies, like the comet-like objects, have to get closer to their host star to be ripped up.

  • But for big objects, it's much easier to get torn up at a distance by that tidal fragmentation,

  • all just because of the way gravity works.

  • This proposed explanation takes care of the strangest and most inexplicable parts

  • of the interstellar mystery we've had on our hands.

  • Based on these simulations, 'Oumuamua's distinctive elongated shape

  • matches how objects would look if they broke apart due to tidal fragmentation.

  • And the speed at which it passed us by could be explained by that fragment

  • being forcibly ejected by its host star after being shredded.

  • The team behind this study hopes they'll get to observe more ISOs like 'Oumuamua

  • so they can gather more data and shore up their models.

  • And studying bodies like 'Oumuamua will tell us more about their composition,

  • and could even indicate if they could possibly host any life.

  • And that's important because one of the main scientific hypotheses for how life began on Earth

  • is that it may have been brought to our planet by an interstellar object.

  • So studying one flying by could give us more insight into our own origins!

  • So unfortunately, it's probably not an alien spaceship.

  • At least, not this time.

  • I'm not giving up hope.

  • And a piece of a planet that was banished by its star is pretty cool too

  • and at least we got to wave as it went by.

  • Keep coming back to Seeker for all your earth shattering astrophysics news,

  • and if you have another astronomical headline you want us to covernot astrological, we don't do those

  • then leave us a comment down below.

  • I'll see ya next time and as always, thanks for watching.

In October of 2017, our solar system had a very strange visitor.


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恒星間訪問者の謎が解けたかもしれない (The Mystery of Our Interstellar Visitor May Have Just Been Solved)

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