This quasi-satellite
is constant
companion of Earth !
companion of Earth !
NASA: A small
asteroid has been discovered in an orbit around the sun that keeps it as a
constant companion of Earth, and it will remain so for centuries to come.
As it orbits the sun, this new asteroid, designated
2016 HO3, appears to circle around Earth as well. It is too distant to be
considered a true satellite of our planet, but it is the best and most stable
example to date of a near-Earth companion, or "quasi-satellite."
"Since 2016 HO3 loops around our planet, but
never ventures very far away as we both go around the sun, we refer to it as a
quasi-satellite of Earth," said Paul Chodas, manager of NASA's Center for
Near-Earth Object (NEO) Studies at the Jet Propulsion Laboratory in Pasadena,
California. "One other asteroid -- 2003 YN107 -- followed a similar
orbital pattern for a while over 10 years ago, but it has since departed our
vicinity. This new asteroid is much more locked onto us. Our calculations indicate
2016 HO3 has been a stable quasi-satellite of Earth for almost a century, and
it will continue to follow this pattern as Earth's companion for centuries to
come."
In its yearly trek around the sun, asteroid 2016 HO3 spends about half
of the time closer to the sun than Earth and passes ahead of our planet, and
about half of the time farther away, causing it to fall behind. Its orbit is
also tilted a little, causing it to bob up and then down once each year through
Earth's orbital plane. In effect, this small asteroid is caught in a game of
leap frog with Earth that will last for hundreds of years.
The asteroid's orbit also undergoes a slow, back-and-forth twist over
multiple decades. "The asteroid's loops around Earth drift a little ahead
or behind from year to year, but when they drift too far forward or backward,
Earth's gravity is just strong enough to reverse the drift and hold onto the
asteroid so that it never wanders farther away than about 100 times the
distance of the moon," said Chodas. "The same effect also prevents
the asteroid from approaching much closer than about 38 times the distance of
the moon. In effect, this small asteroid is caught in a little dance with
Earth."
Asteroid 2016 HO3 was first
spotted on April 27, 2016, by the Pan-STARRS 1 asteroid survey telescope on
Haleakala, Hawaii, operated by the University of Hawaii's Institute for
Astronomy and funded by NASA's planetary Defence Coordination
Office.. The size of this object has not
yet been firmly established, but it is likely larger than 120 feet (40 meters)
and smaller than 300 feet (100 meters).
The Center for NEF Studies website has
a complete list of recent and upcoming close approaches, as well as all other
data on the orbits of known NEOs, so scientists and members of the media and
public can track information on known objects.
Watch the video here by clicking the image below:
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