EXPLORING SPACE: The Universe • Define key vocabulary terms associated with the study of our universe. • Describe the life cycle of stars. • Describe theories about the origin of the universe. Vocabulary 1. Nebula - Huge clouds of gas and dust between the stars. Stars are born within these clouds. 2. Galaxy - Giant groups of stars often with billions of members. 3. Solar system - A sun with planets, moons, and other objects in orbit around that sun. 4. Light-year - The distance light travels in one earth year. Light travels at 186,000 miles per second, so a light-year is very long. Scientists round it to six trillion miles. 5. Nuclear fusion - The combining of hydrogen atoms to make helium atoms deep inside a star. A tremendous amount of heat is released. 6. Supernova - An explosion in which a star tears apart releasing energy and elements. 7. Prominences - A huge storm on the sun that appears as an arch of gases. 8. Spectroscope - An instrument used to break light into its color spectrum. It can be used to tell what elements are present in distant stars. 9. Sunspot - A dark spot on the sun’s surface; interferes with radio transmissions on earth. 10. Black hole - The remains after a supernova. The gravity is so strong that light can’t escape, thus the name black hole. Space Shuttle The shuttle is meant for low altitude earth orbit use. It could never land on another planet because it lands on a runway just like an airplane. It doesn’t carry enough fuel to travel out of orbit. Space Walk A space walk is a dangerous procedure because space is lacking things necessary for life, such as oxygen. Astro nauts must be protected from radiation and the lack of air pressure, so space suits are essential. The space suit provides pressure, protection, and oxygen. Lunar Landings From examining rocks and satellite pictures of the moon, scientists now believe that the moon formed when an object the size of Mars collided with earth. Astronauts who visited the moon had to take oxygen and pressurized suits because there is no atmosphere on the moon. They also took all their food and water because neither of those are found on the moon. In the future, we may use the moon’s resources to construct space stations in earth orbit. Also, humans may build colonies on the moon for research and scientific investigation and industrial manufacturing. The Hubble Telescope Ground-based telescopes must look through the earth’s atmosphere. This causes problems related to weather conditions and dirt particles in the air. In earth orbit above the atmosphere, a telescope would not have to deal with those problems. Life Cycle of Stars Stars form in dust and gas clouds called nebula. As the gases come together, gravity and pressure increase. When the temperature exceeds 20 million degrees, a nuclear fusion reaction occurs and the star's internal power plant begins. Energy is released and the star is born. Stars are found to be of different sizes and temperatures. They live through a stable life that is actually related to their mass. The more massive the star, the shorter its life cycle. When a star has used up almost all of its hydrogen atoms, it begins to collapse. This collapse creates a buildup of heat and the helium atoms begin to change to carbon atoms. The heat buildup causes the hydrogen outer layers to expand to tremendous sizes creating what is called a red giant. In the case of our sun, the outer atmosphere will expand to past the orbit of the earth. A star of small mass will then lose this outer atmosphere and become a white dwarf and eventually a black dwarf, or dead star. A more massive star goes through a different death. When a star that is many times larger than our sun turns into a red giant, it doesn’t evolve into a white dwarf. Instead, because of its terrific gravity, it fuses the carbon atoms made from fused helium atoms into heavier elements. Then the star explodes in a violent explosion called a supernova. The core of a star that has exploded in a supernova can end up as either a neutron star or a black hole, depending on its original mass. Neutron stars are very massive. These stars spin very fast. If the star is more massive, it may become a black hole. The gravity is so strong that nothing can escape its pull. Observatories When we study the night sky, we are actually looking into the past. This is because the stars are so far from each other that the light from them takes hundreds, thousands, millions, and billions of years to travel to our eyes. The distances in space are measured in light- years. This is the distance light travels in one earth year. The closest star to our sun is 4.3 light-years away, so the light from that star takes 4.3 years to travel the distance between the two stars. Scientific Notation Try writing these numbers in scientific notation: a. 1 x 105 b. 3 x 103 c. 6 x 104 d. 2.44 x 105 e. 2.345 x 106 f. 4.5 x 104 Change these numbers from scientific notation: a. 1,000,000 b. 30,000 c. 23,400 d. 100,200 e. 5,000,000,000 f. 34,000 Try changing these numbers to scientific notation: a. 3 x 10-5 b. 5.8 x 10-2 c. 3.056 x 10-3 Change these numbers from scientific notation: 1. 150,000,000,000 2. 384,000,000 3. 1,390,000 4. 1,990,000,000,000,000,000,000,000,000 5. 5,976,000,000,000,000,000,000 6. .0000000000000000000000000016749 Calculate the answer to these problems: 1. (3 x 107) x (4 x 104) = 12 x 1011 2. (4.6 x 105) / (2.3 x 10-3) = 2 x 108 3. (5 x 105) / (2.5 x 104) = 2 x 101 = 20 Name_____________________________________ Pd. ____ Date _________ Exploring the Universe Video To be completed as you view this video, or after as directed The unaided eye can see about ______ stars. Actually most stars are bigger than our own star the sun. Our sun may look small but it is actually large enough to hold a __________ planets the size of our earth. The sun looks small because it is ____ million miles away from us. A light-year is the distance light travels in ____ earth year. Light travels at the incredible speed of 186,000 miles per second. The closest star to our planet, besides the sun, is called Proxima Centauri. It is _____ light- years away, which is about 26 trillion miles. Stars are grouped together in collections called galaxies. The galaxy that our star is found in is called the _______________________. It is a spiral galaxy with an estimated _____ billion stars arranged in a giant pinwheeled disk with a bulge in the center. The Milky Way is about _______ light-years across. Scientists estimate that it takes 200 million light-years for our sun to orbit the center of the galaxy once. Scientists believe that there may be as many as _____ billion galaxies in the universe. Within galaxies are clouds of gas called nebulae. These are the __________ of stars. Stars actually have a life cycle. They are born, evolve and change over a period of time, and then die. Scientists believe our sun began giving off energy about ______ billion years ago. The star is considered a red giant. Then it will blow away its outer atmosphere and collapse to what is called a white dwarf. The star shrinks to planet size as more and more of the helium is fused into carbon. It becomes a white dwarf, which gives off a white cool light. White dwarfs are extremely ______________. How long a star takes to evolve is determined by its starting ________. The more massive a star is, the shorter its life. Our sun is an _________________ -sized star, so it will take about 10 billion years from birth to death. A smaller star might take 100 billion years, while a larger star may shine for only a few billion years. As mentioned before, stars begin in dust and gas ________________ called nebulae. Gravity pulls hydrogen gas in the nebula into a spinning cloud. As more and more atoms of hydrogen are brought into the cloud, they begin to strike each other creating greater and greater amounts of heat. When the temperature reaches 20 million degrees Fahrenheit, a nuclear reaction begins. Atoms of hydrogen are fused, or ______________, to form helium atoms. A great deal of energy is released as this happens. The energy is given off as heat and light in all directions. The star is born. This fusion happens deep in the ___________ of the star where temperatures and pressure are unbelievable. When a star that is many times larger than our sun turns into a red giant or a super giant, it doesn’t evolve into a white dwarf. This star explodes in a violent explosion called a _______________________. Our _____________ is made up of the remains of a supernova that exploded billions of years earlier. So everything found within our solar system--the sun, planets, moons, asteroids, and everything found on our planet-is made of the stuff of stars. Sometimes a neutron star gives off radio waves as it spins. These are called ______________. A black hole has such strong ______________________ that everything that comes near is swallowed into it. Nothing can escape the black hole, not even _______________________. The most popular theory that explains the beginning of the universe is called the “________________________.” It says that about ten to twelve billion years ago, all the matter of the universe was contained within an area no larger than an atom. A way to think about this expansion is to consider a balloon with stars pasted on it. As the balloon is blown up, the stars move farther apart. It is actually the space between the galaxies that is stretching just as the material that the balloon is made of stretches as it is inflated. According to the latest information from the Hubble telescope, this expansion has been going on for ______ billion years. Scientist know that galaxies are moving away because of a ______ shift in their color. This is also called the Doppler effect. As light moves away from us, it becomes elongated and shifts to the ___________ wavelengths, or the red end of the visible spectrum. Some civilizations worshipped the sun and stars as ___________. Some early people even built giant structures to help them observe the sky and determine proper planting seasons. Telescopes on earth can’t be used when the ________ is covered with clouds. The particles in the atmosphere cause light to be scattered and clear pictures are difficult. Also, the sun releases a great deal of energy that is found in different wavelengths besides the wavelengths of visible light. The atmosphere __________________ out much of this energy. So the best location for a telescope and other instruments would be in orbit above the atmosphere. The energy of the sun comes from the nuclear ____________ reactions occurring in its core. The outermost layer of the atmosphere is called the corona, which is seen only during an eclipse. Solar flares are another solar storm seen as bright bursts of light. Every _________ years there is a great deal of sunspot activity. These sunspots interfere with ________________________________ systems on earth. The solar _____________ is a steady flow of high-energy particles given off by the sun’s corona. The color of a star can tell us something about its surface ________________. Metals glow with different colors as they are heated. The metal glows first dull red, then bright red, then orange, yellow, and white as the temperature increases. (ROYGBIV backwards) Stars glow with different colors, and from those observations scientists can tell what the temperature of the star’s surface is. They have organized the stars into classes by color. Another way scientists have gathered information about the stars is to use a __________________________. This device splits the light from a star into a spectrum. The spectroscope uses a ______________to bend light given off from stars so that it can be analyzed. Every element has its own spectral pattern that can be used to identify it. It’s like an element’s fingerprint. It is always the same and each element has its own characteristic pattern. The most common element in stars is _________________, and the next most common element is helium.
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