 Good morning, John. I just discovered that the way people used to ask the science side of Tumblr questions, people very, very occasionally ask the science side of Twitter questions. So I just searched for science side of Twitter, and I'm going to answer as many questions as it can in four minutes. Are constellations different in the Southern Hemisphere? Like, is the Big Dipper and the Zodiac down there? The constellations themselves don't change, but you can see different ones depending on where you are on Earth. If you were on the North Pole and the Earth's axis weren't tilted, then you could only ever see just the top half of the constellations, and same for the South Pole. Now, it's a little complicated because it's tilted, so your perspective actually changes a little bit throughout the year. But if you're right on the equator, as the year goes by, you can actually see almost all of the sky, though a lot of it will be really close to the horizon so hard to see. If you find this confusing, it's because it's very confusing. The Earth is revolving while it's rotating, and we're also thinking about us being in different places on a rotating and revolving thing. There are some people who get their heads all the way around this, but they think about it for a living. How do I stop? Look, I don't know. I've been told that you need an equal and opposite force. I haven't found one yet, but I have been assured that they exist. What are these giant quasar-looking stars, though? That's just a star that is in our galaxy. All those background things in this image, those are galaxies that are like billions of miles away. So it's literally millions of times closer, so it looks a lot brighter. And super bright stuff, when seen by the James Webb Space Telescope, has these diffraction spikes, which is caused by the shape of the mirrors. How many calories on average do you burn taking a massive dump? I mean, not zero. Interestingly, the anus is a muscle that is almost always contracting, and so it's always burning energy until it is loosened. In that case, it's burning less energy. But I think that that is more than outweighed by a lot of other muscle contractions that are probably going on during the dump, plus, you know, any anxiety you might be experiencing. I might also burn a little extra calories. Why does ketchup have to be refrigerated? Isn't it primarily vinegar, salt, and sugar, all of which are preservatives? Fascinating question. When we talk about preserving foods, we're talking about two different things. One is preventing bacteria from growing in it, which is going to spoil it and make it dangerous. High concentrations of vinegar, salt, and sugar will all prevent bacterial growth. But we are also concerned about the complicated molecules in the food stuff breaking down into other molecules that might just taste less good. Once the ketchup is exposed to a good deal of oxygen, those reactions are going to happen more quickly, and so we want to slow them down. And one way to do that is by having less heat in the system, so putting it in the refrigerator. Hey, Science Twitter, any tips for reducing eye strain when using a microscope? Using a microscope is absolutely a lot of this, which is like hunch and eye strain. So I suggest you get one of these, which the microcosmos microscope comes with. It's a cell phone holder. You put the eyepiece in here, and then you clamp your cell phone in here, and you put it on, and you're looking through your microscope like there's a screen. Now, you do have to be able to choose which lens your cell phone is looking through, which the iPhone doesn't let you do by default. There are apps that let you do that, though. The one I use is called Procam. And this one is specifically for me. How did I get an actual brain freeze without consuming any liquids purely from pouring cold water over my face? So a brain freeze is kind of nerve pain. It's your brain misinterpreting a confusing signal. Getting suddenly cold will cause all the blood vessels near your nerves to contract, and then when they warm back up very quickly, they will open back up, and that will cause a flood of blood to the area that will just be confusing to the nervous system. And in your face and head, all these sensory nerves are really closely packed together, so it's just more common for signals to get confused, I think. I haven't heard this happening before, but it totally seems like something that could happen. Does sound travel in outer space? Sound is just a bunch of molecules slapping into each other, so you need a bunch of molecules really densely packed together to carry that signal. In an atmosphere, we have that. This is actually a pretty thick soup of molecules, right? In space, there are basically no molecules, so they can't knock into each other to carry sound, which is a good thing, because the sun is so energetic that if space carried sound as well as our atmosphere, it would be a constant 100 decibel roar that we would never not experience. What's a good time to wake up, my friends, because my phone is dying and I need my charger block from their room? What you're gonna wanna do is get two potatoes and a copper wire, and I'm kidding. I've just looked at your tweet, it's from 227AM. You don't need to be on Twitter anymore. Bedtime. It's bedtime. John, I'll see you on Tuesday.