Motion reveals new
dwarf planets
Just like other recently discovered
worlds, the new potential dwarf planet
DeeDee was found by comparing the
sky over several days. The world’s
reflection outlines its surface.We zoom in on
dwarf planets
New technology has brought
astronomers closer and closer to the
dwarf planets. Pluto is a good example.LIGHT IN THE SOLAR
SYSTEM SHIFTS
Scientists study recordings
of the sky made over several days.
Galaxies and supernovas are so far
away that they stand still within
such a short time span, so if a
luminous point is moving, it is within
our Solar System. In order to spot
moving points among all the light in
the sky, scientists use computer
software which can separate images
pixel by pixel, eliminating all
stationary light sources.The new dwarf planet was
discovered by means of
recordings made at the
Cerro Tololo Inter-American
Observatory in Chile.1996 The Hubble
telescope takes photos which
reveal Pluto's surface for the
first time. NASA can measure
Pluto's albedo accurately to
ROCK AND WATER calculate its size.
ABSORB LIGHT.ICE REFLECTS LIGHT.SUNLIGHTSome astronomers describe Ceres as a
“planetary embryo” – a planet which has
not been completed, because Jupiter’s vast
gravity prevented more material from
collecting. Ceres is now the only dwarf
planet located in the Asteroid Belt among
lots and lots of planetary remains.
In 2015, Ceres was the first dwarf planet
to be paid a visit from Earth, when the
unmanned Dawn probe entered into orbit
around it. The probe’s measurements have
shown that the surface includes ammonia-
rich clay, which is not stable at the
temperatures on Ceres, but there is lots of it
in the outer Solar System. According to Dawn
mission scientists, Ceres might have formed
in the Kuiper Belt, but was nudged inwards, as
the large gas planets moved. Ceres could also
have originated in the Asteroid Belt, where it
is now orbiting, the ammonia-rich material
having somehow found its way there from the
outer Solar System.NEW FINDS AWAITING APPROVAL
Whereas Ceres and Pluto are old "friends", the
three other confirmed dwarf planets – Eris,
Haumea, and Makemake – were all discoveredREFLECTION REVEALS THE WORLD'S APPEARANCE
When a new dwarf planet has been
discovered, scientists measure its optical
brightness or albedo and its heat radiation.
The brightness reveals what the unknown
world's surface looks like, because rocks andwater absorb most of the sunlight, whereas
ice reflects almost all light. By comparing
with known world's albedos, scientists can
calculate the recently discovered object's
size and the elements of which it is made up.21 OCTOBER 201423 OCTOBER 201428 OCTOBER 2014DWARF PLANETDEEDEENASA/ESASHUTTERSTOCK
DAVID GERDES/DES/UNIVERSITY OF MICHIGANNOAOTHE SOLAR SYSTEM DWARF PLANETS