The Case of the Backwards Orbiting Asteroid
Illustration Video Credit & Copyright:
Western U.,
Athabasca U.,
Large Binocular Telescope Obs.
Explanation:
Why does asteroid 2015 BZ509 orbit the Sun the backwards?
As shown in the featured animation, Jupiter's
trojan asteroids orbit the
Sun in two major groups -- one just ahead of
Jupiter, and one just behind -- but all orbit the
Sun in the same direction as Jupiter.
Asteroid BZ509 however, discovered in 2015 and currently unnamed,
orbits the Sun in retrograde and in a more complex gravitational dance with
Jupiter.
The reason why is currently unknown and a topic of research --
but if resolved might tell us about the early
Solar System.
A recently popular hypothesis holds that
BZ509
was captured by Jupiter
from interstellar space billions of years ago,
while a competing conjecture posits that BZ509 came from our Solar System's own
distant Oort cloud of comets, perhaps more recently.
The answer may only become known after more detailed models of the likelihood and
stability of orbits near Jupiter are
studied, or, possibly, by observing direct properties of the unusual object.
To watch the video, Click here.
Source: NASA