Speaker 1: Welcome to Brainstuff, a production of iHeartRadio, Hey brain Stuff,
Speaker 1: Lauren bob Obam. Here lurking near the orbit of Jupiter
Speaker 1: is an asteroid like no other. It's an alien from
Speaker 1: another star system. This visitor may have arrived at our
Speaker 1: solar system billions of years ago and didn't buy a
Speaker 1: return ticket. It's now a permanent resident, trying to blend in.
Speaker 1: Alas blending in is hard to do when you're orbiting
Speaker 1: the Sun the wrong way, it's also a possible sign
Speaker 1: that the asteroid wasn't born here. It was first discovered
Speaker 1: in twenty fourteen by astronomers working at the Leakala Observatory
Speaker 1: on Maui and given the designation twenty fifteen b Z
Speaker 1: five h nine. It's since been given a Hawaiian name, Eavela,
Speaker 1: and is affectionately called Bezed. To understand why Bezed's retrograde
Speaker 1: orbit is a old hill sign that it isn't from
Speaker 1: round these parts, we first must realize why the planets
Speaker 1: all orbit the same way around the Sun. Our star
Speaker 1: was born from a dense region inside a stellar nursery
Speaker 1: also known as a molecular cloud, as the gas and
Speaker 1: dust clumped together under gravity to spark the first nuclear
Speaker 1: reactions that would become our sun. The cloud spun increasingly
Speaker 1: faster around that protostar as the material collapsed of physical
Speaker 1: consequence of the conservation of angular momentum. Over time, a
Speaker 1: protoplanetary disk of material formed, all spinning in the same direction.
Speaker 1: Everything that was born from this disc, all of our
Speaker 1: planets and asteroids, orbited in the same direction like clockwork.
Speaker 1: Buta orbits the wrong way, a sign that's something strange
Speaker 1: is afoot. And it's not just the asteroids retrograde orbit
Speaker 1: that reveals that it came from another star. It's also
Speaker 1: the length of time that it's been living in that orbit.
Speaker 1: For the article, this episode is based on How Stuff Works.
Speaker 1: Spoke with fatid Na Muni, an astronomer at the Cote
Speaker 1: Diazor Observatory in France and the lead author of a
Speaker 1: study looking into the asteroids orbit that was published in
Speaker 1: twenty eighteen. He said, it's not the fact that the
Speaker 1: asteroid now has a retrograde orbit that makes it of
Speaker 1: interstellar origin. It's the fact that it had the same
Speaker 1: orbit four point five billion years ago. That is the
Speaker 1: only evidence, and it is incontrovertible. Namuni and co author
Speaker 1: Helena Morris of Sal Paulo University in Brazil ran sophisticated
Speaker 1: computer simulations of BEZ to figure out that it was
Speaker 1: likely captured over four and a half billion years ago
Speaker 1: by the gravity of our young son when it was
Speaker 1: starting to evolve with its stellar siblings. They found that
Speaker 1: it wasn't just an asteroid born from the Sun's protoplanetary
Speaker 1: disc that was gravitationally disturbed by a massive planet and
Speaker 1: flipped into retrograde orbit. Nope, it had to come from
Speaker 1: outside the Solar System, and like a gravitational catcher's mit,
Speaker 1: the Sun caught the interstellar orphan and adopted it as
Speaker 1: its own. More I said in a press statement. Asteroid
Speaker 1: immigration from other star systems occurs because the Sun initially
Speaker 1: formed in a tightly packed star cluster where every star
Speaker 1: had its own system of planets and asteroids. The close
Speaker 1: proximity of the stars, aided by the gravitational forces of
Speaker 1: the planets, help these systems attract, remove and capture asteroids
Speaker 1: from one another. There are a handful of known retrograde
Speaker 1: objects in our Solar System, and the researchers think that
Speaker 1: alab isn't the only one. To have originated from another star.
Speaker 1: During the earliest epoch of our solar system, many asteroids
Speaker 1: were likely transferred from star to star, and the researchers
Speaker 1: are in the process of identifying other interstellar adoptees that
Speaker 1: were captured by our solar system and have orbits near
Speaker 1: massive Jupiter. Namuni said, from our work, we see that
Speaker 1: if objects similar to be Z were captured by Jupiter
Speaker 1: at the same time and had slightly different orbits, they
Speaker 1: do not stay with Jupiter like BEZ for four and
Speaker 1: a half billion years. They tend to leave Jupiter's orbit
Speaker 1: and go beyond Neptune and assume polar orbits, that is,
Speaker 1: orbits that are perpendicular to the ecliptic. We are currently
Speaker 1: studying the known asteroids of that type to see if
Speaker 1: we can link them to be Z. A one exciting
Speaker 1: thing about Okavleb is that it's staying local and thus
Speaker 1: could be a potential target for a future spacecraft mission.
Speaker 1: If we could directly sample material from BEZ, we could
Speaker 1: study the composition of an ancient exoplanetary system. In doing so,
Speaker 1: we might learn surprises about the evolution of our own planet.
Speaker 1: For example, depending on whether we found water with a
Speaker 1: similar isotopic composition to Earth's water on the asteroid, we
Speaker 1: might be able to figure out whether interstellar asteroids contributed
Speaker 1: to the delivery of water to our planet, a discovery
Speaker 1: that may have profound implications for the origins of life
Speaker 1: on Earth. Although exciting, some experts aren't convinced of Beza's
Speaker 1: interstellar beginnings, arguing that it might instead be an extinguished
Speaker 1: comment whether or not it's truly interstellar. More research is
Speaker 1: needed to study its chemical composition, perhaps via a sample
Speaker 1: return mission, to see whether it's made from the same
Speaker 1: material that's seated our solar system billions of years ago.
Speaker 1: Today's episode is based on the article and alien asteroid's
Speaker 1: been lurking in our solar system since the beginning on
Speaker 1: houstofworks dot com. Written by Ian O'Neill. Brainstuff is production
Speaker 1: of iHeartRadio in partnership with Hastuffworks dot Com and is
Speaker 1: produced by Tyler klang A. Four more podcasts from my
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