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    Introduction

    Ceres is a good example of how challenging it can be to categorize bodies in our solar system. When Giuseppe Piazzi first spotted it in 1801, he assumed Ceres was the "missing" planet between Mars and Jupiter. Within a few years, Pallas, Juno and Vesta were also discovered in the region, and they too were called planets. Starting in the 1840s, astronomers discussed reclassifying the increasing number of bodies in this area, since they didn't quite fit the definition of a planet.

    By 1860 a total of 62 bodies had been discovered in the space between Mars and Jupiter. And by 1863 astronomers accepted the classification of these objects as asteroids and called the area the asteroid belt. That's the way it stayed for over 140 years.

    Then in 2006, astronomers designated Ceres a dwarf planet, since it matched the criteria used to classify Pluto and similar-sized objects in the outer solar system.

    Ceres holds the honor of being the first dwarf planet to be orbited by a spacecraft. Dawn reached it in 2015 to study its surface, composition and history.

    Significant Dates

    Significant dates

    • 1801: Giuseppe Piazzi discovers Ceres while searching for a star and calls it a planet.
    • 1802: John Herschel coins the term "asteroid."
    • 1850: Alexander von Humboldt first uses the term "asteroid belt."
    • 1863: Wide acceptance that Ceres be classified as an asteroid.
    • 2006: Ceres is classified as a dwarf planet.
    • 2007: The Dawn spacecraft launches.
    • 2015: Dawn arrives at Ceres, marking the first time a spacecraft has orbited a dwarf planet.

    Notable Explorers

    Missions

    Careers

    10 Careers That Explore Space

    1

    Astronaut

    Astronauts pave the way for human exploration beyond our Earth. They are pilots, scientists, engineers, teachers, and more.

    2

    Project Manager

    Project managers guide missions from concept to completion, working closely with team members to accomplish what they set out to do.  

    3

    Rover Camera Operator

    A camera payload uplink lead writes software commands that tell a rover what pictures to take.

    The first thing that fired my imagination for planetary science was when the NASA Voyager spacecraft discovered active volcanoes on Jupiter's moon Io.

    4

    Artist

    Melding science with design, artists create everything from large-scale installations to the NASA posters hanging in your bedroom. 

    5

    Media Specialist

    Media specialists tells stories across social media and help feature missions and people on TV and in films, books, magazines, and news sites. 

    6

    Writer/Producer

    Writers/producers capture the incredible stories of NASA's missions and people and share them with the world. 

    7

    Administrator/Director

    Administrators and directors work out of NASA headquarters, prioritizing science questions and seeking to expand the frontiers of discovery.

    8

    Educator

    Whether it's introducing kids to space or teaching physics to PhD candidates, educators help share their knowledge with the public.

    9

    Engineer

    Engineers design and build all types of machines, from what a spacecraft looks like to the software that directs where a rover goes each day. 

    10

    Scientist

    From an astrophysicist to a volcanologist, scientists of all types pose questions and help find answers to the mysteries of our universe.

    The important thing about being a scientist or an engineer is learning how to think critically, learning how to be creative, learning problem solving and learning how to learn.

    Explore in 3D

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    › Explore in 3D

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