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1 Ceres

Page history last edited by gemma 15 years, 2 months ago

 

1 Ceres

By James McCarrick and Gemma Tierney

 Ceres, largest asteroid - artwork © Mark A. Garlick

Artistic rendering of Ceres (Credit: Mark Garlick)

 

Overview of Information

  

Ceres was discovered on 1 January, 1801 by Giuseppe Piazzi. Piazzi was a Sicilian monk and astronomer who founded the Polemo Observatory. It was discovered where many astronomers predicted another planet should be according to the Titius-Bow law, which claimed that there should be a certain amount of space between each planet. According to this law, another planet should be between Mars and Jupiter, and Ceres fit in that gap. But over the next couple of centuries, hundreds more asteroids were discovered and the area in which they reside is now known as the asteroid belt.

  

Ceres’ year is 4 years and 220 days and its day is 9 hours in Earth terms.

  

Ceres Information chart (Credit: Solarviews)

 

Ceres’ diameter is about 7.5% of Earth’s diameter, making it as big as some of Saturn's moons, and its mass is about .016% of Earth’s mass. This makes it the biggest asteroid in the asteroid belt. Its size also exerts enough gravitational force to form it into a round shape. Also because of its size, it is also considered a dwarf planet.

 

 

Comparison of Earth, Ceres and the Moon (Credit: Walter Myers)

Credit: Galileo, NEAR Shoemaker, HST

It also has a very low density despite the gravitational force of its mass. This has been explained by the fact that contains a lot of water ice. Its mass may be even 25 % water, which would mean that it has more water than Earth. It is also most likely made up of three layers, a dense rocky core, a low density mantle made of water ice, and a low density, dusty crust. Its temperature is about -38 degrees C.

Model of the interior of Ceres

 

 

 Ceres' layers (Credit: McCord and Sotin, 2005)

 

Recent pictures of Ceres taken by the Hubble Space Telescope show dark and light surface features on Ceres. These are assumed to be craters, other theories include them to be either low and high topographical points or different substances in the soil that have different colors.

 

A better Hubble image of Ceres.

Credit: HST

 

 

Proposed Experiments

 

All information we have about Ceres has been gathered through observations from Earth. There is no way to determine how accurate this information is unless we have more direct observational methods. Fortunately, there is a space probe called Dawn that is set to observe Ceres in 2015 after observing Vesta, another large asteroid, in 2011. This means that most of the experiments we conduct would be to confirm or refute the current stats on Ceres.

 

Some of the experiments we would conduct would be to determine the following information:

-Mass

          This can be determined by measuring Ceres' pull on nearby asteroids, planets, and even the Dawn probe, as it will be orbiting Ceres for five months, making observations. Its gravitational pull on other objects is directly proportional to its mass.

-Volume

          This can be determined by observing Ceres' eclipse effect on astronomical bodies behind it. This would be like a lunar eclipse where Ceres is Earth and the other astronomical body is the moon. By flying further out in the solar system, we could also see how much of the sun it blocks, similar to a solar eclipse, with Ceres being the moon in this situation. Through both of these methods, the mass would be determined by seeing how much less light the sun or the other astronomical body (being lit by the sun) shines.

-Density

          An overall density can be determined by knowing the mass and volume. However, Ceres most likely has different layers with different densities. There is no way to determine specific densities besides landing on the asteroid. This is something that Dawn will not be doing.

-Temperature          

          The current temperature attributed to Ceres has been determined through infrared telescopes. It can be determined more accurately by Dawn's infrared instuments.

-Presence of an atmosphere

          It is likely that Ceres has a weak atmosphere. The presence of an atmosphere, as well as its composition, can by direct observation of the planet. This will allow us to see what spectrum of light reaches the planet. Certain spectrums are absorbed by the presence of certain chemicals, so if these spectrums do not reach the planet, those particular chemicals are part of the atmosphere.

-Composition (including the amount of water and what the dark and light spots on the surface are)

          Many of Ceres' surface features will be able to be determined by Dawn's close proximity to it (about 125 miles). We will get our first clear photos of the planet and will be able to see whether the dark spots are valleys or just a different substance. The probe also has equipment to determine the presence of different elements on Ceres, which will determine whether it has water.

 

     In the future we can send a lander similar to the Pheonix Mars Lander to collect and analyze the soil and what we think is potentially ice. The Lander would have a drill and scoop just like the PML, the drill being used incase the surface is to hard to just scoop. Once the ice is scooped you can watch for changes like melting or sublimintation to determine whether it truely is ice. The Lander would also be able perform chemical analysis on dirt or ice found by bringing it back to the landers deck which contains instuments such as microscope which takes images to send to Earth used to analize chemical composition of substances. This Lander would also be able to travel to parts of Ceres to determine whether the color differences are soil color or craters and this can teach us more about the history of Ceres. The Lander would also take pictures of the landscape of Ceres and these can be used like the pictures from Mars which showed the possibility of water in the past to determine whether Ceres was once covered in water. A major challenge of the Lander would be landing on the Ceres, with Ceres having a weak atmosphere the Lander would need to slow down very quickly  without the help of a strong atmosphere buy using parachutes and strong breaking rockets, to successfullly land it would need to drop to about 5 mph at landing and then the breaking rockets would turn on to make the safe fnal decent. The Lander could also use giant balloons to bounce and take the fall and protect the Lander on the inside of the balloons. The Lander will then last a long time on Ceres because it can be solar powered and  would be powered longer in the summer because of longer days. The Ceres Lander mission would be a very interesting mission if attempted because it would teach us a lot about dwarf planets and the asteroid belt.

 

Works Cited:

http://www.planetary.org/explore/topics/asteroids_and_comets/ceres.html

http://www.space.com/scienceastronomy/050907_ceres_planet.html

http://www.solarviews.com/eng/ceres.htm

http://www.usatoday.com/tech/columnist/aprilholladay/2006-09-25-measuring-planets_x.htm

http://www.kabrna.com/cpgs/programme/images06_07/ceres_asteroid.jpg

http://space-art.co.uk/pages-en/debris/Asteroid-King.htm

http://rst.gsfc.nasa.gov/Sect19/Sect19_22.html

http://www.arcadiastreet.com/cgvistas/images/ceres_earth_compared_600.jpg

http://www.spacedaily.com/reports/UCLA_Professor_Leads_NASA_Dawn_Mission_999.html

 

 

 

Comments (3)

Jess Yarnall said

at 10:10 pm on Jan 7, 2009

There were a lot of experiments, but since they all involved Dawn, if Dawn crashed or combusted or ran out of film, you wouldn't accomplish anything. Maybe if you did a separate experiment not involving Dawn, if one failed, you'd still have some success.

kevin kearney said

at 6:43 pm on Jan 6, 2009

You had alot of experiments which seem like they could be possible. You gave alot of information showing that you researched the concepts of your experiments. Project is GREAT!!

Kelly Tran said

at 11:30 pm on Jan 4, 2009

The proposed experiments were quite elaborate. Pretty open-minded, good job.

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