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The Solar System Missions
Astronomers discover 'new planet'
Astronomers have detected what could be the
Solar System's 10th planet.
It was first seen by astronomers using California's
Palomar Observatory, and has been given the name
"Sedna" after the Inuit goddess of the ocean.
Observations show it measures about 1,1802,360km (730-1,470 miles) across, making it similar
in size to Pluto.
Astronomers now say they have evidence that
Sedna has its own moon, although this needs to be
confirmed, and is also very red in colour.
There is likely to be some debate about whether it
qualifies as a true planet, but some scientists are
already saying it re-defines our Solar System.
BBC News – March 15, 2004
Astronomers discover 'new planet' - Sedna March 15, 2004
What’s New??
NEW YORK (AP) -- One of the nation's leading science museums has quietly
shaken up the universe by suggesting that Pluto is not necessarily a planet at
all but just a lump of ice.
The startling suggestion comes from scientists at the Rose Center for Earth
and Space, which opened last year at the American Museum of Natural
History in New York.
Comparative Planetology – Dwarf
Planets Pre June 2008
Name
Ceres
Pluto
Eris
Clasification
Dwarf Planet
Dwarf Planet
Dwarf Planet
Diameter (km)
975 x 909
2306
2400
Mass compared to earth
.00016
.0022
.0027
Radius compared to earth
.0738
.180
.19
Date of Discovery
01/01/1801
02/18/1930
01/05/2005
Comparative Planetology – Plutoids
and Dwarf Planets Post 2008
Name
Ceres
Pluto
Eris
Makemake
Haumea
Clasification
Dwarf
Planet
Plutoid
Accepted as
Plutoid*
Accepted as
Plutoid*
Accepted as
Plutoid*
Diameter (km)
975 x 909
2306
2400
1500
1150
Mass
compared to
earth
.00016
.0022
.0027
.0007
.00074
Radius
compared to
earth
.0738
.180
.19
.23
.18
Date of
Discovery
01/01/1801
02/18/1930
01/05/2005
03/31/05
12/28/04
* Unclear if is in hydrostatic equilibrium
Comparative Planetology – Plutoids
and Dwarf Planets Post 2008
Name
Ceres
Pluto
Eris
Makemake
Haumea
Clasification
Dwarf
Planet
Plutoid
Accepted as
Plutoid
Accepted as
Plutoid
Accepted as
Plutoid
Diameter (km)
975 x 909
2306
2400
1500
1150
Mass
compared to
earth
.00016
.0022
.0027
.0007
.00074
Radius
compared to
earth
.0738
.180
.19
.23
.18
Date of
Discovery
01/01/1801
02/18/1930
01/05/2005
03/31/05
12/28/04
Beyond a doubt, more to come (there are
many candidates)…
Comparative Planetology – Plutiods
and Dwarf Planets
Comparative Planetology – Plutoids
and Dwarf Planets
Note: 2003 UB313 is now called Eris
Ceres
Goddess of Plants (Roman)
Discovered: 01/01/1801
Classification: Dwarf Planet
Remains classified as a Dwarf Planet, and
is believed to be the only object of its kind
Ceres
The International Astronomical
Union has reclassified Ceres, the
first asteroid to be discovered
(and the largest and most massive
object in the asteroid belt between
Mars and Jupiter), as a "dwarf
planet". Ceres was discovered on
January 1, 1801 (technically the
first day of the 19th Century) by
Giuseppe Piazzi at Palermo,
Sicily. He named it after Ceres,
the Roman goddess of agriculture
and grain.
Ceres was originally considered a
planet, but when dozens of
asteroids came to be discovered,
it was reclassified in an asteroid. (I
have an astronomy guide from the
1830s that lists 11 planets, the
seven from Mercury to Uranus,
plus Ceres, Pallas, Juno, and
Vesta, the first four asteroids to be
discovered.) I took this photo with
a Canon Digital Rebel in late July
when Ceres was in the
constellation Piscis Austrinus;
Ceres is between the marks at
upper right.
Comments
Ceres
Pluto
Discovered: 02/18/1930
Pluto was discovered in 1930. Pluto's satellite Charon was discovered in
1978. Pluto is a low-density planet made up of 97% nitrogen. The
combined mass of Pluto and Charon is 450 times less than Earthís
mass. It rotates once every 6.39 Earth days and it revolves around the
sun for 247.7 Earthís years.
As of 2011 – Pluto is now known to have 4 objects in orbit around it. The
moons are Charon, Nix, Hydra and P4 (newest, still to be named as of
07/21/11
Pluto
Ruler of the Dead
Pluto is known as the ruler of the dead and lives in the underworld
and his name Pluto meant the giver of wealth since many precious
gems and metals were found were he lived. His Greek name is
Hades, which means the unseen. He owns a giant three-headed
dog that guards the gates of the underworld. There is a myth of
how Hades got his wife. When Hades got bored of the underworld,
he wanted a wife. So he went up to earth to kidnap Persephone,
the daughter of Demeter. When Demeter found out that her
daughter was kidnapped, she became furious and went up to
Jupiter. After a while, Jupiter decided that six months, Persephone
would spend time with her mother, and another six months she
would become queen of the dead. Whenever Persephone went
down to the underworld, Demeter would be said and her tears
would be the falling leaves of autumn. She would be so sad that all
the crops would stop growing and everything would turn cold.
When she saw Persephone, she would happy again and everything
would come back to life, this is the mythological theory of the
seasons. Pluto has a helmet of darkness that made him invisible
during battle. In astrology, Pluto rules your private life.
Pluto
Pluto Facts Sheet:
Classification: Plutoid
Mass of planet (Earth=1) = 0.002
Mean density (grams/centimeter³ ) = 2.03
Interior: Ice??
Surface:
Water:
Atmosphere: mostly nitrogen gas, just like
that of the Earth and Saturn's moon Titan, with
the addition of carbon monoxide (CO - what
comes out of your car) and methane (CH4).
Moons: 4
Pluto
This is the clearest view of Pluto and its satellite Charon seen by the Hubble
Space Telescope and taken by the European Space Agency's Faint Object
Camera on February 21, 1994.
Pluto
Puto and its moons. HST in 2011.
Eris (Formerly 2003 UB313)
Goddess of Strife and
Discord
First observed: 2003
Classification: Plutoid
Formal identification: 01/05/2005
About 10 Billion kilometers from the sun (96.7 AU)
Aphelion: 97.56 AU
Perihelion: 37.77 AU
The name Eris was chosen because of the strife and discord in the
astronomical community over the official designation of Eris and,
maybe more popularly, the designation of Pluto as a planet.
Eris
A view of the solar system from the north down. The four circles show the orbits of Jupiter, Saturn, Uranus,
and Neptune. The yellow dot in the center is the sun. The earth, if it were shown, would be inside the
yellow dot representing the sun. The orbits of the two outermost planets, along with their current positions,
are also shown. If you are worried because the sun appears to not be the focus of the orbital ellipse you
are very observant! But it is just a projection effect.
Sedna
Spirit of the Sea
Sedna is the spirit of the sea according to the
peoples of northern Canada and Greenland,
named Inuit. Sedna resides at the bottom of the
sea and has power over all animals. Her control
of the sea, which the Inuit people depend on for
their survival, gives Sedna an enormous power.
Inuit people believe that success or failure in
hunting depend on her unpredictable mood.
Sedna
Discovered: 11/14/2003
Classification: ???
About 10 Billion kilometers from the sun
Aphelion: 975.56 AU
Perihelion: 76.156 AU
It is not presently known if Sedna is in Hydrostatic
equilibrium (condition 3 of the IAU planetary
definition), so its classification is currently not
finalized.
Sedna
The discovery of Sedna resurrected the question of which astronomical objects should
be considered planets and which should not. On March 15, 2004, articles in the
popular press reported that "the tenth planet has been discovered". This question was
answered under the new International Astronomical Union definition of a planet,
adopted on August 24, 2006. It is unknown whether or not Sedna is in hydrostatic
equilibrium. If, as currently suspected,[16] it is, then it would qualify as a dwarf
planet. Sedna has a Stern–Levison parameter estimated at between 8 × 10-5 and
6 × 10-3 times that of Pluto,[17] and therefore cannot be considered to have cleared
the neighbourhood of its orbit, even though no other objects have yet been discovered
in its vicinity.
Image above: These three panels show the first detection of the faint distant
object dubbed “Sedna.” Imaged on Nov 14 from 6:32 to 9:38 UT, Sedna was
identified by te slight shift in position notes in these three pictures taken at
different times. Image courtesy: NASA/Caltach.
Sedna
Astronomers have announced the discovery of a large new planetoid named Sedna. Mike Brown of the
California Institute of Technology, Chad Trujillo of the Gemini Observatory in Hawaii, and David
Rabinowitz of Yale University in Connecticut discovered Sedna in November 2003. The astronomers
cannot be certain of the exact size of the new planetoid, but they believe it is the largest object
discovered in our Solar System since the discovery of Pluto in 1930. Sedna is also the furthest object
from the Sun that has been found within our Solar System.
Sedna is probably a huge ball of ice somewhere between 1,280 and 1,760 km (800 and 1,100 miles) in
diameter. Sedna is remarkably reddish in color. Astronomers think that exposure to radiation over
extremely long times may have altered the chemistry of some of the compounds within the ice, turning
them red.
Sedna orbits on the fringe of the known Solar System. It is currently at a distance of about 90
Astronomical Units (AU) from the Sun, more than twice as far away as Pluto. Its orbit is highly elliptical,
and carries it around the Sun once every 10,500 years. It will reach perihelion (closest approach to the
Sun) in 72 years at a distance of 76 AU, then slowly move away towards its extreme aphelion distance of
900 AU. Numerous similar icy planetoids, known as a group as Kuiper Belt Objects (KBO) or TransNeptunian Objects (TNO), have been found in the last decade. However, the TNOs seem to orbit within
about 50 AU from the Sun, thus Sedna appears not to belong to that group. An area much further from
the Sun, called the Oort Cloud, is thought to exist and be the source of many long period comets. Sedna
does not seem to orbit quite far enough out to be part of the Oort Cloud, however, and scientists are
trying to figure out how this new planetoid fits in to their big picture views of our Solar System.
Comparative Planetology – Plutoids
and Dwarf Planets
The study of objects in the solar system
that are not classified by the IAU as
planets is still evolving and will continue
to evolve into the future.