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Have you ever wondered how all the chemical elements are made? Then join me as we are lifting all the star dust secrets to understand the cosmic origin of the chemical elements. We talked a lot about the lighter elements that are made in fusion processes in the cores of stars but what about all the other elements from the bottom half of the periodic table? We haven't really talked about those yet -- Let's do that! What we need are so-called seed nuclei. We have an iron nucleus, here, and if we are in a situation where there is a strong neutron flux available (we'll talk about where that happens in second) then if we have little neutrons here and this seed nucleus is getting bombarded with these neutrons then it's going to swell and turn into a much larger nucleus that is radioactive and neutron-rich and it's an isotope that has lots of neutrons in it. What's happening then, because it was radioactive, it doesn't like to stay in this way, it wil...

Have you ever wondered how all the chemical elements are made? Then join me as we are lifting all the star dust secrets to understand the cosmic origin of the chemical elements. We just talked about fusion processes and how elements are made in stars, mostly for energy generation purposes. Now let's look at how that actually manifests in a star as a whole because as astronomers, we can observe stars but we can't really look inside of stars. We can only see the surface. There are a number of ways we can get clues from the surface of the star as to what's going on in the core. Of all that, a really nice example of how nuclear physics and astrophysics -- nuclear and astrophysics -- come together because the nuclear physics governs what's happening inside the core, and then the astrophysics provides what we can actually observe and both kind of need to come together and work out. So over the last several decades, a lot of progress has been made to put these tw...

Have you ever wondered how all the chemical elements are made? Then join me as we are lifting all the star dust secrets to understand the cosmic origin of the chemical element. Let's look at the early chemical evolution. Some 14 billion years ago, everything started with a Big Bang. And it left behind the universe level made from just hydrogen and helium gas. I mentioned before there's a tiny tiny little trace of lithium but we're not going to worry about it. So we had a universe but they were no stars yet. It was actually dark, and some people call that the cosmic Dark Ages. But structure began to form and gas began to clump, and so eventually, in a gas cloud the very first stars formed. Here are two of the first stars. And they were made just from hydrogen and helium because the gas was just hydrogen and helium but for energy generation purposes, these stars needed to have nuclear fusion go on in their cores to produce energy. The first elements heavier than...

Have you ever wondered why the word Ambulance is printed as its mirror image on the front an Ambulance truck? The word is written this way so that drivers can read the word in their rearview mirror signaling them to pull over if necessary. In chemistry and biology, molecules can also be mirror image of each other and have very different functions. This video is part of the Structure-Function-Properties video series. The structure, function and properties of a system are related and depend on the processes that define or create the system. Hi, my name is Brad Pentelute, and I am a professor of chemistry at MIT. My research focuses on the biological properties of mirror-image proteins and how these macromolecules may be used in pharmaceutical applications and therapeutics. Before watching this video, you should be familiar with: Molecular Geometry, the structure of the 20 naturally occurring amino acids, as well as have an understanding of what a protein is and its three-di...