NASA has released a new image of Ceres yesterday; this new image offers a detailed view of the landscape of the celestial object, which is classified both as a dwarf planet and a giant asteroid. To date, no other mission has managed to observe such an object so closely.
The image in question has also put light on the significant of “crescent” shape to science and our culture.
For those who don’t know: crescent is an extremely recognizable icon as far as astronomy is concerned. It is widely known as the signature element of the Nebra Sky Disc, a four thousand year old representation of the space. In addition, the shape also appears on several national flags. You must have also observed them in many children’s books. For scientists, the significance of crescent is much more than all of the shape’s above mentioned applications.
For observing a crescent, the distance between the viewer and the sun must be more than the distance between the viewer and the object he or she is viewing. This means, for people on Earth space probes are the only way for viewing the crescent.
Let us come back to the main topic of this news i.e. the image of Ceres that NASA has managed to capture recently. It’s a job done by the space agency’s Dawn spacecraft, a voyager that has already paid a successful visit to another asteroid Vesta. Thus, Dawn other than being the first spacecraft to take such a close look at Ceres, is also the first probe to perform the job of circling two different extraterrestrial objects
Dawn managed to complete the feat so easily as a result of being equipped with an unusual variety of engine, an engine that generates thrust from a series of hasty xenon ions. For those who don’t know: regular engines generate thrust from chemical propellants.
Unlike regular engines, ion engines are known for their ability to stay active for a long period of time that too at extremely high efficiency. The only problem with these engines is that they produce weak thrusts.
Dawn had to face serious troubles due to this demerit of its ion engine; it had to face an unexpected engine shutdown. This forced the scientists to plan a fresh trajectory to the dwarf planet. However, still the probe managed to capture an amazing image of Ceres.