What is Ceres?
Ceres is a dwarf planet and the largest body in the asteroid belt between Mars and Jupiter. Its dimensions are 975×909 km, making it about a quarter the size of the Moon. Ceres orbits at 3 AU from the Sun. Its mean surface temperature is approximately ~167 K (-159 °F), although at high noon its temperature may rise to 235 K (about -38°C). Ceres likely has a tenuous atmosphere accompanied by surface frost. When it was discovered by the Italian astronomer Giuseppe Piazzi on 1 January, 1801, Ceres was considered a planet, but in 1850 the astronomical community reclassified it as an asteroid. This designation persisted for over 150 years, until 2006 when it was reclassified as a dwarf planet by the International Astronomical Union, along with the trans-Neptunian objects Pluto and Eris. Ceres is named after the Roman god of plants. Ceres is not classified as a true planet because it fails to meet one of the necessary criteria for planets; to have cleared the neighborhood around its orbit. L
CERES – Clouds and the Earth’s Radiant Energy Sytem – is a high priority scientific satellite instrument which is now orbiting the Earth as part of NASA’s Earth Science Enterprise (formerly known as Mission to Planet Earth). Scientists are using it to study the ways in which clouds may affect the Earth’s climate. You can find detailed information on CERES at: http://asd-www.larc.nasa.gov/ceres/ASDceres.html. A NASA lithograph (photo with explanation), and a NASA Fact Sheet about CERES are also available. There are a number of CERES instruments flown in different orbits to obtain measurements over the entire globe. The first CERES instrument was launched on Thanksgiving Day, 1997. It was carried to orbit on a Japanese rocket as part of the Tropical Rainfall Measuring Mission (TRMM) spacecraft. You can see an animation of some early results from CERES on TRMM, which shows how the instrument measures Scene Type over the course of a day. The second and third CERES instruments were launched
Ceres is (or now we can say it was) the largest asteroid, about 1000 km across, orbiting in the asteroid belt between Mars and Jupiter. Ceres now qualifies as a dwarf planet because it is now known to be large enough (massive enough) to have self-gravity pulling itself into a nearly round shape. (Thomas, 2005) Ceres orbits within the asteroid belt and is an example of the case of an object that does not orbit in a clear path. There are many other asteroids that can come close to the orbital path of Ceres. Q: Didn’t Ceres used to be called an asteroid or minor planet? A: Historically, Ceres was called a planet when it was first discovered in 1801, orbiting in what is known as the asteroid belt between Mars and Jupiter. In the 19th century astronomers could not resolve the size and shape of Ceres, and because numerous other bodies were discovered in the same region, Ceres lost its planetary status. For more than a century, Ceres has been referred to as an asteroid or minor planet. Q: Why
