6567306
Description
Flashcards by Bilal Khan, updated more than 1 year ago
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Created by Bilal Khan
about 8 years ago
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| Question | Answer |
| What are stars? | A star is a luminous ball of gas, mostly hydrogen and helium, held together by its own gravity. Nuclear fusion reactions in its core support the star against gravity and produce photons and heat, as well as small amounts of heavier elements. The Sun is the closest star to Earth. |
| What is the closest star to our sun? | Alpha Centauri A (Alpha Centurai A and B are 2 stars that orbit eachother this is known as a binary system it is the closest binary system to our solar system) |
| What happens when a star runs out of fuel? | The core finally cools into a white dwarf, then a black dwarf. This is what happens when a normal-sized star dies. If a really huge star dies, it has so much mass that after the helium is used up, it still has enough carbon to fuse it into heavy elements like iron. When the core turns to iron, it no longer burns. Some stars that are large enough naturally end their lives by exploding in a supernova. Throughout their lives, stars are fighting against the crushing force of their own gravity. Inside, nuclear reactions fuse together smaller elements, like hydrogen, to create bigger ones and release energy. |
| Phases of the moon | |
| How did the moon form? | The moon was formed ~4.5 billion years ago, about 30–50 million years after the origin of the Solar System, out of debris thrown into orbit by a massive collision between a smaller proto-Earth and another planetoid, about the size of Mars |
| Why is the moon important? | Perhaps the most important effect of the Moon is the way it stabilizes our rotation. When the Earth rotates it wobbles slightly back and forth on its axis. It's like a top, which doesn't simply spin in a vertical position on a table or the floor. But without the Moon we'd be wobbling much more. |
| What is a galaxy? | a system of millions or billions of stars, together with gas and dust, held together by gravitational attraction. |
| Types of galaxies | |
| What is the Milky Way? | The Milky Way is the Galaxy in which we live. It is a spiral shaped galaxy that contains several hundred billion stars, including our Sun. It is about 100,000 light-years across and about 10,000 light-years thick. |
| What are planets? | a celestial body moving in an elliptical orbit round a star. |
| What is a solar system? | A solar system is a star and all of the objects that travel around it — planets, moons, asteroids, comets and meteoroids. Most stars host their own planets, so there are likely tens of billions of other solar systems in the Milky Way galaxy alone. |
| What are the terrestrial (rocky) planets of our solar system? | |
| What are the Gas Giants of our solar system? | |
| What is a dwarf planet? | a celestial body resembling a small planet but lacking certain technical criteria that are required for it to be classed as a planet. |
| What is the biggest planet in our solar system? | Jupiter |
| What is the smallest planet in our solar system? | Mercury |
| what are satellites? | Earth is a satellite because it moves around the sun. The moon is a satellite because it moves around Earth. Earth and the moon are called "natural" satellites. But usually when someone says "satellite," they are talking about a "man-made" satellite. |
| What are artificial satellites? | An artificial satellite is an object that people have made and launched into orbit using rockets. There are currently over a thousand active satellites orbiting the Earth. The size, altitude and design of a satellite depend on its purpose. |
| What is a meteoroid? | A meteor is a meteoroid – or a particle broken off an asteroid or comet orbiting the Sun – that burns up as it enters the Earth's atmosphere, creating the effect of a "shooting star". Meteoroids that reach the Earth's surface without disintegrating are called meteorites. |
| What is the asteroid belt? | The asteroid belt is a region of space between the orbits of Mars and Jupiter where most of the asteroids in our Solar System are found orbiting the Sun. The asteroid belt probably contains millions of asteroids. ... The largest asteroid is called Ceres. It is about one-quarter the size of our moon. It is a dwarf planet. |
| What is the Kuiper belt? | a region of the solar system beyond the orbit of Neptune, believed to contain many comets, asteroids, and other small bodies made largely of ice. |
| What is a comet? | a celestial object consisting of a nucleus of ice and dust and, when near the sun, a ‘tail’ of gas and dust particles pointing away from the sun. |
| What is the most famous comet? | Halley's Comet is arguably the most famous comet. It is a "periodic" comet and returns to Earth's vicinity about every 75 years, making it possible for a human to see it twice in his or her lifetime. The last time it was here was in 1986, and it is projected to return in 2061. |
| What are constellations? | a group of stars forming a recognizable pattern that is traditionally named after its apparent form or identified with a mythological figure. |
| What are astronomers and what do they do? | An astronomer is a scientist who focuses primarily on the study of space, which includes the stars, the planets and the galaxies above us. |
| What is the Geocentric model? | In the geocentric system, the Earth is considered to be the center of the solar system. The Moon, the planets, the Sun, and the stars all rotate around the Earth (which stays still). |
| What is the Heliocentric model? | Heliocentrism, or heliocentricism, is the astronomical model in which the Earth and planets revolve around the Sun at the center of the Solar System. |
| Who first proposed the theory of the Heliocentric model? | The theory was first proposed by Nicolaus Copernicus. |
| Who first proposed the theory of the Geocentric model? | The theory was proposed by the Greek astronomer Ptolemy. |
| What is the retrograde motion? | This retrograde motion is entirely an illusion caused by the Earth passing the slower moving outer planets. |
| Who invented the telescope? | Originally the first person to invent the telescope was Hans Lippershey, Galileo, though, was the first person to use a telescope for astronomical purposes after hearing about Lippershey's work in 1609. He improved on Lippershey's design and using his new telescope in 1610, he discovered the four largest moons of Jupiter (Io, Ganymede, Callisto and Europa) and physical features on the Moon. |
| Who was the first man to land on the moon? | Neil Armstrong |
| What are the Zodiac Symbols? | |
| What is Gravity? | the force that attracts a body towards the centre of the earth, or towards any other physical body having mass |
| What is a Gravitational force field? | In physics, a gravitational field is a model used to explain the influence that a massive body extends into the space around itself, producing a force on another massive body. Thus, a gravitational field is used to explain gravitational phenomena, and is measured in newtons per kilogram (N/kg). |
| What is an orbit? | the regularly repeated elliptical course of a celestial object or spacecraft about a star or planet. |
| What is an eclipse? | an obscuring of the light from one celestial body by the passage of another between it and the observer or between it and its source of illumination. |
| What is a solar eclipse? | an eclipse in which the sun is obscured by the moon. |
| What is an umbra? | the fully shaded inner region of a shadow cast by an opaque object, especially the area on the earth or moon experiencing the total phase of an eclipse. |
| What is a penumbra? | the partially shaded outer region of the shadow cast by an opaque (not able to be seen through; not transparent.) object. |
| What is a lunar eclipse? | an eclipse in which the moon appears darkened as it passes into the earth's shadow. |
| What are tides? | the alternate rising and falling of the sea, usually twice in each lunar day at a particular place, due to the attraction of the moon and sun. |
| How are tides formed? | The gravitational attraction of the moon causes the oceans to bulge out in the direction of the moon. Another bulge occurs on the opposite side, since the Earth is also being pulled toward the moon (and away from the water on the far side). Since the earth is rotating while this is happening, two tides occur each day. |
| What is an axis? | an imaginary line about which a body rotates. |
| What is a day? | each of the twenty-four-hour periods, reckoned from one midnight to the next, into which a week, month, or year is divided, and corresponding to a rotation of the earth on its axis. |
| What is a revolution? | a single orbit of one object around another or about an axis or centre. |
| What are the seasons? | each of the four divisions of the year (spring, summer, autumn, and winter) marked by particular weather patterns and daylight hours, resulting from the earth's changing position with regard to the sun. |
| What is a year? | An Earth year is 365 days. It's the time that it takes the Earth to orbit the Sun. |
| What is a leap year? | A common year has 365 days and a leap year 366 days, with the extra, or intercalary, day designated as February 29. A leap year occurs every four years to help synchronize the calendar year with the solar year, or the length of time it takes the earth to complete its orbit about the sun, which is about 365¼ days. |
| THE END |
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