Explanation:
Could this close-by asteroid ever hit the Earth?
Eventually yes -- but probably not for a very long time, even though the asteroid
is expected to pass inside the orbit of the Moon next century.
However, to
better understand
the nature and orbit of all near-Earth asteroids, NASA sent the robotic
Origins, Spectral Interpretation, Resource
Identification, Security, Regolith Explorer
(OSIRIS-REx) to investigate this one: the 500-meter across asteroid
101955 Bennu.
Launched in 2016,
OSIRIS-REx
is now approaching Bennu, and is first scheduled to map the
minor planet's rough surface.
The
featured time-lapse video taken earlier this month compacts
Bennu's
4.25-hour rotation period into about 7 seconds.
Bennu's diamond-like appearance is similar to
asteroid Ryugu currently being visited by the
Japanese spacecraft
Hayabusa2.
The exact future orbit of
Bennu is a
bit uncertain due to close passes near the Earth and the
Yarkovsky effect:
a slight force
created by an object's rotationally-induced, asymmetric
infrared glow.
If all goes
according to plan,
ORISIS-Rx will actually touch the asteroid in 2020, collect soil samples, and
return them to Earth in 2023 for detailed analyses.
