Recent content by Norseman

This is a very good question. The simple answer is that cells die just like how anything else dies: something permanently damages them in a way that prevents them from continuing to function. Unsurprisingly, cells can die in many different ways, just like how the people who are built up from...

Very cool. While I was waiting for a reply I checked some Wikipedia articles regarding non-black body radiation (it didn't even occur to me to check for that!) and found Kirchhoff's law of thermal radiation, Low emissivity, and Thermal radiation which indicate that for any material, the...

True, but the back of the mirror is a black body. Heat would be conducted from the blackened exterior to the reflective interior, right? Or does the mirror actually emit less energy even if it's at the same temperature?

If it helps, let's try something that just seems wrong: a perpetual motion device. Imagine you place a blackened cap on the end of the parabola to absorb the heat, and you thoroughly insulate the cap so that it can get quite hot. Then, you use the hot cap to run a heat engine at room temperature...

Right, it wouldn't be precisely focused. But it would be more focused than ordinary. If I understand you correctly, this might be the explanation. Are you saying that reflective surfaces tend to emit less radiation, or tend to emit a different spectrum of radiation?

No, but a somewhat focused beam. If you imagine a line going from the center of the parabola and extending outward, I think most of the energy would be focused to within 60 degrees of that line. Parabolas tend to reflect light away from themselves in mostly the same direction, right? I...

Preface: I understand that regardless of any further details, the correct answer is "No, it does not, because..." I'm looking for an answer because clearly I don't understand something about either thermodynamics, mirrors, or black body radiation. In my mind, the scenario I describe follows the...

Okay. How do I estimate using bond formation energy? Also, how imprecise are you talking about? ±50%? An order of magnitude? More?

Background: I've seen many different values for enthalpy of formation on Wikipedia, such as the following: MgO: -602 kJ·mol−1, Fe2O3: -826 kJ·mol−1, NO: 90.29 kJ·mol−1. I'm curious about these values, but I have no idea how they were determined and I've only taken an introductory course in...

Ah, yes this is correct. I was thinking that using the signs of sin and cos would only give you precision to within 90°, and I thought there would be some edge cases where that wouldn't work with a rectangle. You can't use it to accurately determine which side of the four is the one that you...

I've solved the problem of finding which line to use. If anyone Googles this later, here's the solution: Get the coordinates for all of your corners. Get the angles for all of your corners. Start with the smallest angles, and work your way up. Assuming your x and y-axis are normal, then you...

Looking at the signs of the sin and cos would only work if this were a square. Originally, I was using a similar approach that worked very well because I was using a square display surface. However, once I tried to go fullscreen with a hardware-supported resolution, everything got messed up, and...

I tried that approach already. The problem is that there are two valid intersections, as shown in the picture below. So, I need to work out which intersection is the right one. To do that, I need to determine which of the four lines I should intersect with, which brings us back to my...

Context: I'm making a fairly simple 2D game with spaceships that build up velocity, with no artificial speed limits. This means they go very fast, so they tend to go off screen unless I zoom out a lot. When they go off screen, I want an arrow at the edge of the screen to point in their...

So then energy required to cause two objects to move away from each other increases exponentially as velocity increases. These two objects might be things like a cannon and cannonball, or a rocket and rocket fuel, right? And, if we take a rocket as an example again, it doesn't matter if both...