Our Glossary & Fun Facts
Each term includes links to websites with a LOT more information. Have fun exploring!
Jupiter has a long history of surprising scientists – all the way back to 1610 when Galileo Galilei found the first moons beyond Earth. That discovery changed the way we see the universe.
Fifth in line from the Sun, Jupiter is, by far, the largest planet in the solar system – more than twice as massive as all the other planets combined.
Jupiter’s familiar stripes and swirls are actually cold, windy clouds of ammonia and water, floating in an atmosphere of hydrogen and helium. Jupiter’s iconic Great Red Spot is a giant storm bigger than Earth that has raged for hundreds of years.
One spacecraft – NASA’s Juno orbiter – is currently exploring this giant world. –NASA
Find out the 10 You Need-to-Know Things About Jupiter –NASA
Galileo di Vincenzo Bonaiuti de’ Galilei (15 February 1564 – 8 January 1642) was an Italian astronomer, physicist, and engineer, sometimes described as a polymath, from Pisa. Galileo has been called the “father of observational astronomy”, the “father of modern physics”, the “father of the scientific method”, and the “father of modern science.” –Wikipedia
To be called a planet, a planet must do three things: it must orbit a star, it must be big enough to have enough gravity to force a spherical shape, and it must be big enough that its gravity cleared away any objects of a similar size near its orbit. – NASA Space Place
The current count orbiting our star: eight – Pluto is considered a dwarf planet.
There are more planets than stars in our galaxy, the Milky Way. Thousands of planets have been discovered beyond our solar system. Scientists call them exoplanets (exo means “from outside”). – NASA Science
Pages on NASA Science to learn more about each Planet:
Mercury
https://solarsystem.nasa.gov/planets/mercury/overview/
Venus
https://solarsystem.nasa.gov/planets/venus/overview/
Earth
https://solarsystem.nasa.gov/planets/earth/overview/
Mars
https://solarsystem.nasa.gov/planets/mars/overview/
Jupiter
https://solarsystem.nasa.gov/planets/jupiter/overview/
Saturn
https://solarsystem.nasa.gov/planets/saturn/overview/
Uranus
https://solarsystem.nasa.gov/planets/uranus/overview/
Neptune
https://solarsystem.nasa.gov/planets/neptune/overview/
According to the Merriam-Webster dictionary, a star is any one of the objects in space that are made of burning gas and that look like points of light in the night sky.
The nearest star system, the trinary star Alpha Centauri, hangs above the horizon of Saturn. Both Alpha Centauri A and B — stars very similar to our own — are clearly distinguishable in this image. – NASA
In astronomy, a satellite is an object that orbits (goes around) a planet. There are several hundred natural satellites, or moons, in our Solar System. Thousands of artificial (human-made) satellites have also been launched since 1957, like TESS!
The Transiting Exoplanet Survey Satellite (TESS) captures images of our galaxy. TESS is expected to cover more than 400 times the amount of sky shown in this image when using all four of its cameras during science operations. This image, which is centered in the constellation Centaurus, includes dark tendrils from the Coal Sack Nebula and the bright emission nebula Ced 122 (upper right). The bright star at bottom center is Beta Centauri.
The key difference between a planet and a dwarf planet is the kinds of objects that share its orbit around the Sun. Pluto, for example, has not cleared its orbit of similar objects while Earth or Jupiter have no similarly-sized worlds on the same path around the Sun. Like planets, dwarf planets are generally round (Haumea looks like an overinflated football) and orbit the Sun.
There are likely thousands of dwarf planets waiting to be discovered beyond Neptune. The five best-known dwarf planets are Ceres, Pluto, Makemake, Haumea, and Eris. Except for Ceres, which lies in the main asteroid belt, these small worlds are located in the Kuiper Belt. They’re considered dwarfs because they are massive, round, and orbit the Sun, but haven’t cleared their orbital path. –NASA
Our solar system’s small bodies – asteroids, comets, and meteors –pack big surprises.
Asteroids and comets – and the meteors that sometimes come from them – are leftovers from the formation of our solar system 4.6 billion years ago. While the planets and moons have changed over the millennia, many of these small chunks of ice, rock, and metal have not. They are a lot like a fossil record of planetary evolution.
There are currently 1,113,527 known asteroids and 3,743 known comets. –NASA
Perseverance — landed on Mars on Feb. 18, 2021.
With the whirr of a drill, a robotic geologist some 244 million miles away just made history, collecting the first sample of Mars for return to Earth. Sealed in an airtight, ultraclean tube, the sample is an important milestone in a multibillion-dollar effort to finally answer the question: Was there ever life on the red planet? – NatGeo
Find out on NASA what it’s been up to, including helicopter flights!
Basics of Space Flight is a tutorial designed primarily as a quick training guide for mission operations people. But teachers, college and high-school students—anyone interested in the concept of interplanetary spaceflight—may find it useful.
This online textbook offers a broad scope, but limited depth, as a robust framework to accommodate further training or investigation. Many other resources are available for delving into each of the topics related here; indeed, any one of them can involve a lifelong career of specialization. Links to external sites provide further depth to many topics. There are interactive quizzes to let you check your own progress. No records are kept, nor does NASA offer academic credit for this training.
Stars, Galaxies, Black Holes and More
Our Milky Way Galaxy is just one of billions of galaxies in the universe. Within it, there are at least 100 billion stars, and on average, each star has at least one planet orbiting it. This means there are potentially thousands of planetary systems like our solar system within the galaxy! –NASA
The Solar System is the gravitationally bound planetary system of the Sun and the objects that orbit it, either directly or indirectly. Of the objects that orbit the Sun directly, the largest are the eight planets, with the remainder being smaller objects, such as the five dwarf planets and small Solar System bodies.
Our Solar System has 8 planets, 5 dwarf planets, 181 moons, 552,894 asteroids, and 3,083 comets! –SOLAR SYSTEM FOR KIDS – FUN FACTS ABOUT OUR UNIVERSE!, GetLitt
There are many planetary systems like ours in the universe, with planets orbiting a host star. Our planetary system is named the “solar system” because our Sun is named Sol, after the Latin word for Sun, “solis,” and anything related to the Sun we call “solar.”
Our planetary system is located in an outer spiral arm of the Milky Way galaxy.
Our solar system consists of our star, the Sun, and everything bound to it by gravity – the planets Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune; dwarf planets such as Pluto; dozens of moons; and millions of asteroids, comets, and meteoroids. Beyond our own solar system, we have discovered thousands of planetary systems orbiting other stars in the Milky Way. –NASA
A galaxy is a huge collection of gas, dust, and billions of stars and their solar systems, all held together by gravity. –NASA SpacePlace
The Milky Way Galaxy
Our galaxy is the Milky Way. Using infrared images from NASA’s Spitzer Space Telescope, scientists have discovered that the Milky Way’s elegant spiral structure is dominated by just two arms wrapping off the ends of a central bar of stars. Previously, our galaxy was thought to possess four major arms. –NASA
Asteroids, sometimes called minor planets, are rocky, airless remnants left over from the early formation of our solar system about 4.6 billion years ago.Lucy
The current known asteroid count is: 1,113,527. –NASA
Comets are frozen leftovers from the formation of the solar system composed of dust, rock, and ices. They range from a few miles to tens of miles wide, but as they orbit closer to the Sun, they heat up and spew gases and dust into a glowing head that can be larger than a planet. This material forms a tail that stretches millions of miles. –NASA
What’s the difference between a meteor, meteoroid, and meteorite?
They’re all related to the flashes of light called “shooting stars” sometimes seen streaking across the sky. But we call the same object by different names, depending on where it is.
Scientists examining meteorite on snow-covered ground. –NASA
Scientists collecting a meteorite from the Miller Range in Antarctica.
Meteoroids are objects in space that range in size from dust grains to small asteroids. Think of them as “space rocks.”
When meteoroids enter Earth’s atmosphere (or that of another planet, like Mars) at high speed and burn up, the fireballs or “shooting stars” are called meteors.
When a meteoroid survives a trip through the atmosphere and hits the ground, it’s called a meteorite.
The universe is a vast expanse of space which contains all of everything in existence. The universe contains all of the galaxies, stars, and planets. The exact size of the universe is unknown. Scientists believe the universe is still expanding outward. –NASA
A black hole is an extremely dense object in space from which no light can escape. While black holes are mysterious and exotic, they are also a key consequence of how gravity works: When a lot of mass gets compressed into a small enough space, the resulting object rips the very fabric of space and time, becoming what is called a singularity. A black hole’s gravity is so powerful that it will be able to pull in nearby material and “eat” it. –NASA