【正文】 re iron meteorites, or the stony iron kind, even though they only make up about 5 percents of the meteorite material on the ground. 。re easier to spot by eye. So most of the meteorites in collections, uh, in museums, they39。re made of rock, so they end up looking almost indistinguishable from mon terrestrial rocksonce that originated on earth. So it39。re trying to find metal? Student: Oh! Metal detectors! Professor: Right, thank you. At least that39。s rare to ever find one. I mean, it39。ve analyzed enough of them to learn a lot about their position, most e from asteroids, though a few may have e from ets. So essentially they are rocks, and like rocks, they39。re called meteors. Most of them are very small, and they burn up soon after entering earth’s atmosphere. The larger ones that make it through the atmosphere and hit the ground are called meteorites. So meteorites are the ones that actually make it through. Now we39。s orbit, temperatures are low enough to permit ices to form out of water and…and out of gases like methane and carbon dioxide. Loose collections of these ices and small rocky particles form into ets. So ets are similar in position to the gas giants. Both ets and asteroids are...typically are smaller than plas. And even smaller type of interplaary debris is the meteoroid. And it39。ll just cover some basic info about them. OK, ets and asteroids. It might help if you think of...remember we talked about the two classes of plas in our solar system? And how they differ in position? The terrestrial plaslike Mars and Earthposed largely of rocks and metals, and the large gas giants, like Jupiter. Well, the solar system also has two analogous classes of objects, smaller than plasnamely, asteroids and ets. Relatively near the sun and inner solar system, between Jupiter and Mars to be precise, we’ve got the asteroid belt, which contains about 90 percents of all asteroids orbiting the sun. These asteroids are…uh…like the terrestrial plas, and they39。m not going to go into any depth on the ets and asteroids now, but we39。s especially interesting about meteoroids is that they e from interplaary space, but they consist of the same chemical elements that are in matter originated on earth, just in different proportions. But that makes it easier to identify something as a meteoroid, as it opposed to…to just a terrestrial rock. So to talk about where meteoroids e from, we need to talk about ets and asteroids, which basically...they’re basically made up of debris left over from the origin of the solar system billion years ago. Now I39。 many troubadours were able to make a living being full time poets which should tell you something about the value of that profession during the medieval times. TPO 13 – Lecture 4 Narrator: Listen to part of a lecture in an astronomy class. Professor: OK, I wanna go over the different types of meteoroids, and what we39。 these were more like long stories. I mean one of them must all about love, but the other one the Chan…Chan…whatever it called, the other one。t want to miss anything, you know, and it is probably already started watching it... Manager: No problem, we39。t want to miss out everyone es in a once. Manager: Oh, no, we have several copies of each tape of Spanish accident series. We usually have multiple copies for everything for each video collection. Student: Super. So...how many rooms are there total in the lab? Manager: 20. They are pretty small. So, we normally get one person or no more than a small group of people in their watching the video together. Actually, someone else for your class just came in and took the first Spanish video into watch. You could probably run in a watch with them. Of course, you are wele to have own room. But, sometimes students like to watch with classmate, so they can review the material with each other afterwards. For example, it was with some content they didn39。t. Manager: Ok, well, you have to watch the videos here. You need to sign in to reserve an open room and sign out the video you need, just start with the first one in the series, each video have an hour long. Student: So, it is a video library, basically? Manager: Yes, but unlike the library, you can39。m taking the first year Spanish this semester. Our professor says that we need to e here to view a series of videos. I think it is called Spanish Working onYourAccident. Manager: Yes, we have that. Err...They are on the wall behind you. Student: So, I can just take....err.....Can I take the whole series home? I think there are three of them. Manager: I guess you haven39。 imagine if we still have all those beavers around, all those wetlands. What would our water supply be like then? Part 2 Script: TPO 13 – Conversation 2 Narrator: Listen to a conversation between a student and the language lab manager. Student: Hi, I39。s the cr