The phrase
"ring plane" refers to the flat, disk-like region where the rings of a planet or object in space are located. It is like a horizontal plane where the rings form a circle around the planet/object.
Full definition
The last
ring plane crossing was a triple (it was seen three times over a few months), and occurred during 1995 to 1996.
The new belt lies at the far reaches of the Saturnian system, with an orbit tilted 27 degrees from the
main ring plane.
Paradoxically a «
ring plane crossing» such as this gives astronomers a chance to unlock some of the secrets of the ring system and the moons that chaperone these lanes of ice and dust.
The ring plane includes a lot of particles.
So, as Cassini flies through
the ring plane, its high - gain antenna will be oriented to provide a shield for the rest of the spacecraft and its instruments.
However, it is thought that the risks of a significant dust hit in
the ring plane are low.
Our arguments were successful, garnering several extensions and ensuring, for example, that we witnessed the rare illumination conditions of Saturn's equinox in August 2009, when the sun's shallow rays on Saturn's rings revealed the presence of vertical structures protruding above
the ring plane that cast long, easily seen shadows.
Along the sharp outer edge of the most massive ring (the B ring), we found an incredible 20,000 - kilometer - long continuous string of spiky shadows betraying the presence of «ring mountains» — waves of particles extending three kilometers above
the ring plane.
This natural - color view, captured by the Cassini spacecraft in 2007, shows the dark side of the rings from an angle slightly above
the ring plane.
Because that gap is a region no spacecraft has ever explored, Cassini will use its dish - shaped high - gain antenna (13 feet or 4 meters across) as a protective shield while passing through
the ring plane.
-- 2 a.m. PDT (5 a.m. EDT) on April 26: Cassini crosses
the ring plane during its dive between the rings and Saturn.
This view looks toward the sunlit side of the rings from about 10 degrees above
the ring plane.
The best models for the region suggested that if there were ring particles in the area where Cassini crossed
the ring plane, they would be tiny, on the scale of smoke particles.
Cassini was exploring the Saturnian system during the planet's 2009 equinox, when
the ring plane aligns with the center of the sun.
This view looks toward the sunlit side of the rings from narrowly above
the ring plane.
This view of Saturn's moon Enceladus above the planet's
ring plane was captured by the narrow - angle camera of NASA's Cassini spacecraft at a distance of approximately 630,000 miles (1 million kilometres) from the tiny water world.
The spacecraft captured this image from roughly 1.7 million miles, at 16 degrees above
the ring plane using its wide - angle camera.
This view looks toward the sunlit side of the rings from about four degrees above
the ring plane.
Cassini will next cross through
the ring plane Tuesday, May 2, at 12:38 p.m. PDT (3:38 p.m. EDT) in a region very close to where it passed on the previous dive.
The RPWS team expected to hear a lot of pops and cracks on crossing
the ring plane inside the gap, but instead, the whistles and squeaks came through surprisingly clearly on April 26.
A dustier environment in the gap might have meant the spacecraft's saucer - shaped main antenna would be needed as a shield during most future dives through
the ring plane.
The antenna was used as a protective shield during the crossing of Saturn's
ring plane.
RPWS detected the hits of hundreds of ring particles per second when it crossed
the ring plane just outside of Saturn's main rings, but only detected a few pings on April 26.
The sun was expected to cross
the ring plane of Uranus on December 7, 2007.
This event is known as
a ring plane crossing.
We now know that it his confusion was caused by the rings, and possibly by
the ring plane crossing.
On April 20 (Friday), Cassini will make its final flyby of Titan, Saturn's largest moon, using its gravity to fling itself through Saturn's
ring plane (on April 26) between the innermost ring and the planet's cloudy upper atmosphere, revealing a view that we've never before seen.