Model your own asteroid
Increase your knowledge of 433 Eros and learn about its formation
Asteroids are small, rocky bodies, most of which orbit the Sun in the asteroid belt between Mars and Jupiter. These space rocks are leftover material from the formation of the Solar System, and although ground-based observations of asteroids can be a little underwhelming due to their low surface brightness, studying them is important for our understanding of planetary formation.
Making an asteroid model allows you to study its morphology in three dimensions and is a fun activity; combining astronomy with crafts is a great way to engage the whole family, especially children. You can make the model using salt dough, which requires only three ingredients and you probably already have these in your store cupboard. At the time of writing, certain kinds of flour may be more difficult to find than usual. The good news is that any kind will work, so just use what you have. You also don’t need any special modelling tools. Just use your hands for the basic shape and then create the details with pens and pencils.
Our model is of the asteroid 433 Eros. It’s an elongated, shoe-shaped object that measures 34.4km x 11.2km x 11.2km with a mean diameter of 16.8km. It was discovered in 1898 and is one of approximately 250 near-Earth asteroids (NEAs). Unlike main belt asteroids,
is an astronomer and dedicated astro imager based in Oxfordshire
NEAs are thought to be either dead comets or fragments from main belt asteroid collisions. In 2000, Eros was orbited by NEAR Shoemaker mission which landed on the asteroid the following year. During this mission Eros was photographed and these high-resolution images can be used as reference photos for the model. An online 3D video animation showing the asteroid from different angles is also helpful.
Make and bake
Salt dough is quite heavy, so we found it best to make this model in two pieces and glue them together once baked. The dough is baked at a low temperature and due to its size the model took nearly 24 hours to bake. However, if you use two parts flour to one part each of salt and water, you can adjust the quantities to make your model smaller. Painting is optional but can give an authentic look; we used a matt grey colour to mimic the low brightness of asteroids.
There are some interesting features on Eros, including different-sized impact craters. Parts of the surface are strewn with rocks and these are thought to have been caused by seismic shockwaves that have turned small craters into rubble. By making this model you can teach the family about planetary and asteroid formation, how impact craters form and how different lighting angles can affect the way these features look. You can also talk about seismological activity within asteroids, and the fact that Eros has enough gravity for a spacecraft to successfully orbit it. Once your model is finished, you can try to recreate NEAR Shoemaker’s photos. After completing this project, you’ll know that Eros is so much more than an unremarkable, faint ‘star’ in our skies.