Do you know about satellites? 🛰️

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Speaker 1: You're listening to sleep Tight Science. Did you know that some satellites orbiting Earth are traveling at incredibly high speeds, much faster than the speed of sound. What The International Space Station orbits at a speed of approximately seventeen thousand, five hundred miles per hour or twenty eight thousand kilometers per hour. Wow, that's super fast. Hello, friends, and welcome back to sleep Tight Science, a bedtime show that answers your questions about science. Did you know that there are giant metal balls up in the sky that help us watch TV and talk to our friends on the other side of the world. They are called satellites, and they are like super interesting cosmic cell phone towers. When you are outside, particularly at night, you might see lights moving across the sky. These moving lights that we see are usually either airplanes or satellites. Sometimes, when we use our imagination, we might think they are aliens from outer space. Unlike flying saucers, airplanes have blinking lights that help other pilots see them and avoid collisions, so you'll often see a steady light and a blue light moving across the sky together. Satellites, on the other hand, reflect sunlight, which makes them appear like moving stars in the night sky. You may also see shooting stars or meteors, bits of space debris that burn up in the Earth's atmosphere and create a streak of light in the sky. In this episode, we will learn about artificial or man made satellites and try to answer some of the questions you our listeners have submitted about this topic and others. So let's learn about some of those moving lights that we see up in the sky. What is a satellite and what does it do? A satellite is an object that orbits a planet. There are several hundred natural satellites in our Solar system. The Moon is Earth's natural satellite, and all the planets except Mercury and Venus have them. Natural satellites, however, are usually referred to as moons, and man made satellites, which are often called artificial satellites, are what is usually meant by the word satellite. Thousands of artificial satellites have been launched since nineteen fifty seven. In fact, over thirty six thousand of them are working in space right now. These have many uses, including taking pictures of the Sun, Earth and other planets, and looking deep into space at black holes distant stars and galaxies. There are also communications satellites, weather satellites, and the International Space Station. These satellites orbit about two hundred to seven hundred miles or three hundred to one thousand kilometers above Earth's surface, and they are usually launched into orbit by a rocket or occasionally by a space shuttle. Once in orbit, the satellite is turned on and will continue to work for several years. All satellites eventually stop, perhaps through the failure of an inside part or the power supply. The failed satellite will in time fall out of its orbit and often, but not always, burn up as it drops through the Earth's atmosphere. In nineteen fifty seven, the space age was started with the launch of Sputnik one, the first artificial satellite. Despite its simplicity, the small aluminum ball, approximately the size of a beach ball, was equipped with four long antennas and powered by batteries. Sputnik contained radio transmitters that released a distinct beeping sound, which could be heard across the globe. The launch of this satellite marked a historic milestone, paving the way for futures space exploration. Modern satellites have become more complex. They are typically made to be very strong and have a lightweight design. In many satellites, a structure known as a bus holds all the primary parts such as batteries, computers, and thrusters. It also includes other devices such as antennas, solar arrays, and payload instruments including cameras, telescopes, and communication equipment. Modern satellites have sophisticated propulsion, power, and communication systems to ensure they will be long lasting. These cutting edge technologies help the satellite orbital stability, enhance data accuracy, and improve communication capabilities. Satellites are placed in particular orbits depending on the job they have to do. Some need to stay above the same part of the Earth all the time. These are placed in a geostationary orbit about twenty two thousand, four hundred miles or thirty six thousand kilometers above Earth's equator. This orbit allows the satellite to always remain over the same point on Earth's surface. Many communication satellites are positioned like this and work together as a global network. Other satellites, such as weather satellites, work in polar orbit, allowing them to watch the whole of Earth's surface as it turns below. Before we continue learning about satellites. Let's answer a few other questions listeners have sent in. And Zov is five years old and lives in Maplewood, New Jersey, and he wants to learn more about eyeballs and what they are made of. Eyeballs are these really amazing things inside our heads that help us to see the world around us. They're like little cameras that take pictures of everything we see. When you look at something, light bounces off of that thing and travels into your eyes. Your eyeballs have these special parts inside them called retinas, and they are filled with tiny little cells called photoreceptors. These photoreceptors capture the light that comes into your eyes and sends messages to your brain about what you are seeing. Your eyeballs also have muscles around them that help them move so you can look around and see everything in different directions. And they have this cool part called the iris, the colored part of your eye that helps control how much light comes in. Your eyeball is made of a tough materia called the sclura, the white part you see on the outside. It's like a hard shell that protects your eye from getting hurt. It's often referred to as the white of the eye. While most of the scleura is white, the front part of the eye has a clear section called the cornea, which allows light to enter the eye. Leela Richardson from Brisbane, Australia would like to know how and where koalas pee and poop. Do they need to climb down from the tree or do they stay up high. Koalas are cute, furry animals that I think we all love. They live in Australia and spend most of their time in trees eating eucalyptus leaves. But just like you and me, they must go pea and pooh when nature calls. Now here is something we did not know. Koalas have a special pouch called a marsupium that's kind of like a pocket on their belly. When baby koalas are born, they're really tiny and not fully developed, so they crawl into their mother's marsupium and stay there for about six months. And while they're in there, the mother koala takes care of all their needs, including cleaning up their pea and pooh. So, just like us, koalas have to clean up after their babies. Now, when adult koalas need to go They usually do it while clinging to the trunk of a tree. They have a special muscle at the bottom of their bladder that allows them to control when they peep, so they can do it whenever they need to without making too much of a mess. As for their pooh, koalas have a unique digestive system that allows them to extract or take out as much nutrition as possible from their eucalyptus diet, so their poop is very dry and small, like little pellets. They usually drop their poo onto the ground or the lower branches of a tree, which doesn't make much of a mess. Just don't walk under a eucalyptus tree when a koala is there. Emma, who is five years old and lives in Belgium, wonders why people burn. When you eat or drink something, you swallow air along with it. This air goes into your stomach and can build up over time. Burping is your body's way of getting rid of that extra air. When the air in your stomach reaches a certain amount, it can create pressure. This pressure causes a muscle at the top of your stomach called the lower esophageal sphincter to open up allowing air to escape through your mouth, So when you burp, you're basically releasing that extra air that's built up in your stomach. And sometimes burping can release some food or drink you've just eaten or drank. It's important to remem remember that burping is a natural bodily function. But that doesn't mean you should go around making burping noises everywhere. Many people feel it's important to be polite and excuse yourself if you must burp in public, and if you do, you should do it quietly. How do satellites get into space? As we now know, satellites are these little machines that we send up into space to orbit around the Earth. They can help us do all sorts of things like take pictures, watch the weather, and even help us communicate with people away. But to get satellites into space, we use really big rockets. When a rocket launches, it uses a lot of fuel to create a powerful force called thrust, which pushes the rocket up up into the sky. Multi stage rockets have stages, which are parts that drop off once they have used all their fuel. This makes the rocket lighter and helps it go faster. Examples of multi stage rockets include the Delta two and the Falcon nine. There are also single stage rockets, which are simple rockets with one main engine that burns all its fuel at once and reaches space in a single stage. They are used for smaller, lighter satellites, such as cubes. Heavy lift rockets are super massive rockets designed to carry heavy payloads, such as large communication or military satellites into space. Examples include the Delta for heavy and the SpaceX Falcon Heavy. Perhaps the coolest of all are space planes, which are rocket powered vehicles that launch like a rocket and land like a plane. They can be used to carry smaller payloads, such as science experiments or small satellites to space. Examples include the Space Shuttle and the Virgin Galactic Spaceship two. No matter what rocket is used, once the rocket reaches the right altitude, it releases the satellite and the satellite starts orbiting around the Earth. It's kind of like how a toy car would go around and around on a racetrack. The satellite goes around and around the Earth. How do satellites stay in space without falling down? Satellites stay up in space without falling down because they are in a state of constant freefall called an orbit. When an object is in orbit, it is moving forward fast enough that the pull of gravity is balanced by the centrifugal force caused by the object's speed and the curvature of the Earth. Or another way to explain this is they stay up in space without falling down because they are moving really fast around the Earth. Just like a racecar on a circular track. When the race car goes around the track, it feels a force pushing it outwards, which keeps it from flying off the track. In the same way, satellites move around the Earth so fast that they feel a force pushing them outwards called centrifugal force, which keeps them from falling back down to Earth. Another force that is important for satellites is gravity. Gravity pulls everything on Earth towards the ground, like apples falling from a tree or a ball you throw up in the air. But when an object is high enough above Earth's surface, like a satellite, gravity becomes weak. So the combination of the centrifugal force and the weaker gravity at the satellite's altitude allows it to keep moving around the Earth without falling down. However, even in space, there is some friction with the very thin atmosphere that can cause the satellite to slow down when this happens. Satellites also have special equipment that helps them stay in the right place in space. They can use thrusters to make small adjustments to their speed and direction so they stay in the same orbit around the Earth. What kind of things or jobs do satellites do. Most satellites are made and operated by commercial companies. There are various types of satellites, including navigation, communication, scientific, military, and Earth monitoring. The first satellites started working more than forty years ago. Communication satellites play an important role in our daily lives, even though we may not realize it. For instance, a sports event or concert happening in one location can be viewed by people on the other side of the world at the same time. Cameras capture the action, transmitting the TV signal to a satellite above the event. The signal is then relayed around the Earth by other satellites until it reaches one above the opposite side of the planet. The signal is finally transmitted back to Earth, where it is received and the event can be watched. Also, millions of telephone conversations and internet connections are helped this way. Our daily weather forecasts use information from weather satellites positioned around the globe. These satellites observe cloud patterns, monitor Earth's atmosphere, record temperature ranges, and track storm systems. Satellites have taken pictures of every part of Earth's surface, many times, gathering valuable information about natural resources such as forests, ice caps, and oceans. By studying the data, scientists can identify our planets short and long term changes. Military satellites can be used for taking pictures of the Earth, listening to signals from other countries, or helping soldiers communicate with each other. They are also used for guiding missiles and being a weapon themselves. Navigation satellites pinpoint any position on Earth and help navigators on land, at sea, and in the air. Without GPS, which stands for Global Positioning System and a mapping application on our phones, I think we would get lost far more than we do now. GPS uses special satellites in space that sends out signals to Earth. These signals are like little messages that contain information about the satellite's location and the time the signal was set. When a GPS device like a phone or a GPS tracker receives these signals. It can figure out how far away it is from the satellites by measuring how long it takes for the signals to reach it. By measuring the distance to several satellites, the GPS device can figure out exactly where it is on Earth and how high up it is too. GPS is helpful because it can help us navigate to different places, even if we've never been there. Fun facts about satellites. Space debris is a term used to describe various objects in space, including outdated satellites and pieces of space material, both natural and man made. The Space Surveillance Network SSN has been tracking objects larger than ten centimeters in diameter since nineteen fifty seven and has recorded more than twenty six thousand objects in orbit. As the number of satellites in orbit increases, so does the risk of collisions. In two thousand and nine, two communication satellites, one belonging to the United States and the other to Russia, collided in space, highlighting the potential danger posed by space debris. The oldest satellite still in orbit is the Vanguard one's satellite, launched by the United States in nineteen fifty eight. It's been orbiting the Earth for over sixty years. Satellites are not always serious business. In nineteen ninety three, a Japanese company launched a satellite called Ozumi, which carried a set of traditional Japanese taicho drums that played in space. In nineteen ninety nine, Pizza Hut became the first company to advertise using a giant pizza shaped billboard sent into space on a Russian rocket. The advertisement could be seen from Earth for several days. The largest satellite ever launched was the Terrestrial planet Finder, designed to search for livable planets outside our Solar system. It was about the size of a baseball field. In twenty thirteen, a group of students at the University of Surrey and England created a satellite called Strand one controlled by a smartphone app. Using the app, they could take pictures of the Earth and send them back to Earth. Nasau's tests transisting Exoplanet Survey satellite is orbiting the Earth to search for new planets outside our Solar system. It's equipped with four cameras, each capable of taking a picture of a twenty four degree square patch of the sky, making it possible to survey the entire sky over time. In this episode, we learned about satellites, what is a satellite and how do they get into space. Satellites can be natural or man made. The Moon is a natural satellite that orbits around the Earth. We looked at some man made ones and talked about the different kinds of rockets that carried them into space. We looked at how satellites stay in space and don't just fall back to the ground, and we learned what satellites are used for. This episode was made with questions from Lincoln, Enzo, Layelah, and Emma. Thank you to a miss A, Lee's and CC. We hope to use your ideas in future episodes. We would love it if you left us a review. Wherever you listen to podcasts, your review might help others decide to listen to our show too. If you'd like to send us your questions, please send them to Hello at sleep tightscience dot com. Thank you