Small Solar System Bodies

At the bottom of this entry, I give the Weekly Pondering 8 assignment, for those of you in ASTR 1/2. Any text that you need to read is on Blackboard or linked to here.

8: Small Solar System Bodies

We turn our attention this week to objects in the Solar System other than planets. These include small Solar System Bodies, which are smaller, rocky bodies in the Solar System that aren’t planets, dwarf planets, moons, gas, and dust. You may have heard that Pluto, once considered a planet, was demoted (so to speak) to a dwarf planet. This week, we will discuss Pluto and the reason for its dwarf planet status. We will also talk about comets and asteroids. You may have also read about asteroid impacts on Earth, such as the Tunguska event in 1908. An asteroid is a relatively small, rocky object that orbits the Sun and is not a planet or a moon. They are also generally considered distinct from comets, which are small rocky and icy bodies that sometimes pass close to the Sun. The Solar System is filled with innumerable bits of rock and ice, and some of these hit Earth. Massive impacts are rare, but have in the past killed off vast numbers of living creatures.

Pluto

Let us first discuss Pluto. The below video is an animation of the Solar System. Watch this animation, and answer the following four points:

  1. Note the there are three planets whose labels you can see in the animation. Describe where the other planets are.

  2. Notice that there are four other named objects in the animation: Pluto, Makemake, Haumea, and Eris. Think about what aspects of their orbits are different than the orbits of the three planets that are clearly visible. Try to come up with three.

  3. Based on your answers to the previous question, could you argue that Pluto (and its neighbors with similarly distinct orbits) is a planet? It’s important to note that, although there are only three Pluto-like objects in the animation, there are many thousands of smaller ones.

  4. Watch the video “On Pluto” at the top of the page. In that video, Neil deGrasse Tyson explains why Pluto shouldn’t be considered a planet. Compare your answers to this video.

Asteroids and Comets

As you may know, we (meaning, humans) are discovering asteroids and comets all the time. We have also been able to directly explore asteroids with spacecraft. At the top of this page, there are two videos on asteroids (with a bit of information on comets). Watch both of them. The last one discusses the OSIRIS-REx mission, which collected material from the surface of the asteroid 101955 Bennu and will return with its haul. Do a little research on this mission. Find some photos of this asteroid from the mission.

Conclusion

In a paragraph or so, write your answers to all questions in this assignment, and include one photo of 101955 Bennu from the OSIRIS-REx mission.

Submit WP 8 here:

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