the Scientia Review
Transcription
the Scientia Review
Exploring Outer Space An E-Book by Peri Michael and Steven Piselli Massachusetts Academy of Math and Science Table of Contents The Universe Page 2 The Big Bang Theory Page 3 Gravity Page 4 Inertia Page 5 The Solar System Page 6 Planets Page 7 Asteroids Page 10 Comets Page 11 Galaxies Page 12 Black Holes Page 13 Nebulae Page 14 Stars Page 15 Glossary Page 18 Image Credits Page 20 About the Authors Page 21 12 The Universe The Universe is the biggest thing that scientists know to exist. It goes on forever in every direction while constantly growing. The universe contains the celestial bodies that make up space, such as solar systems, galaxies, stars, and nebulae. Some organize space into a hierarchy of bodies, with the universe as the top, or largest system. The order is typically planets, solar systems, galaxies, galaxy clusters, and the universe. Sometimes the space part of the hierarchy is included in a longer list that starts with things as small as atoms. 23 The Big Bang Theory The Big Bang Theory is the common theory of how the universe was created. Scientists cannot prove that the universe was created this way, but the vast majority accept the Big Bang. They also do not know what was there before the universe was made, or if there really was anything at all. The Big Bang Theory says that our universe started out as an extremelyinfinitely- small, dense, and hot object, or what scientists call a “singularity”. Over time, it grew bigger and cooler. It expanded out and became less dense and hot. The Big Bang was not one huge explosion, but rather an event that occurred over time. Scientists believe that the universe continues to expand and get cooler even today. Everything in the universe moves away from everything else constantly because the universe expands like a sponge. 34 Gravity In our solar system, everything revolves around the sun. The sun is so large that it pulls everything around it in because of gravity. Gravity occurs when an object attracts another because of their masses. Very large objects, such as those in space, have a gravitational pull on other objects. On Earth, gravity is what keeps everything on the ground, such as people, buildings, and the oceans. It also keeps the moon and the atmosphere around the Earth. Weight Gravity is like depends on the gravity at some the glue of the location, but mass does not because it universe! It is only measures amount of matter. A the reason rock with a certain mass on Earth has everything stays different weights on different planets together. because of different accelerations of gravity. 45 Inertia Inertia keeps all objects in the universe moving because objects in motion stay in motion. While gravity pulls space objects toward the sun, inertia makes them fly outward; when gravity pulls objects in, inertia keeps them moving away. All celestial bodies will keep moving until a force stops them. Law of Inertia Sir Isaac Newton’s First Law of Motion, the law of inertia, states that all objects at rest stay at rest and objects in motion stay in motion until a force changes their movement. The balance between gravity and inertia makes planets and other celestial bodies stay in their orbits. Gravity and inertia work together to keep all of the planets around the sun and solar systems around the galaxy. 65 The Solar System Within the universe there are groups of space objects called solar systems. A Solar System is a collection of planets that orbit around a central gravitational source. This source can be one or even two stars. Others objects in the solar system include asteroids, meteoroids, and comets. In our solar system, there are eight planets that revolve around the sun, which is a star. 67 Planets Planets are large bodies made of either rock or gas that orbits a star. Celestial bodies in our solar system need to meet several requirements for scientists to consider them planets. They need to orbit the sun, be spherical in shape because of their own gravitational pull, and clear their orbital path. That’s an expression that means if the object really is a planet, over time it would have either attracted any smaller solar bodies and debris in its path of orbit, or have pushed them away. The planets are grouped into three categories: Terrestrial, Gaseous, and Dwarf. Our solar system has eight planets, which excludes Pluto because it is actually a dwarf planet. 78 Planets A Terrestrial Planet is a planet that is made of rock. Its core usually consists of a molten metal. They are made from the dust produced by a recently exploded star over the span of billions of years. Terrestrial planets can have features such as canyons, volcanoes, mountains, and valleys. Earth is the most common example of a terrestrial planet. The Earth is the only planet in our solar system that can support life. The other three inner planetsMercury, Venus, and Mars- are also terrestrial planets. Gaseous Planets are planets made mostly of gases. They also have metal or rock cores. The outer ring planets of our solar system are gaseous planets. Gaseous planets form over billions of years from the condensing gases of a nebula. 89 Planets The gaseous planets in our solar system, also called the Gas Giants, are the outer planets: Jupiter, Saturn, Uranus, and Neptune. Uranus and Neptune are also known as the Ice Giants because they mostly consist of ice and other gaseous chemicals. Pluto Dwarf Planets are similar to terrestrial planets but are not large enough to clear all the space debris around them. There are currently five known dwarf planets: Ceres, Pluto, Haumea, Makemake, and Eris. 910 Pluto is a dwarf planet. It was discovered in 1930 and was thought to be a terrestrial planet, but when scientists looked back at it in 2006, they discovered floating debris around it. They then demoted it to a dwarf planet. Asteroids Asteroids are large chunks of space rock that orbit around the sun. They are not big enough to be moons or planets. Their size can range from the size of dust particles to around 600 miles across. In our solar system, there are two large rings orbiting the sun. These Asteroid Belts are large collections of asteroids that orbit the sun. The first belt is between the planets Mars and Jupiter. All of the planets inside the belt are known are inner planets. The planets outside of the belt are called outer planets. The second belt starts after passing Neptune. When an asteroid enters the Earth’s atmosphere it becomes a Meteoroid. 10 11 Comets Comets are large bodies made of ice and space dust. Because their orbits are ovular, comets “grow” a tail when they get closer to the sun. Halley’s Comet Halley’s Comet is the most wellknown comet. It is visible from Earth by the naked eye and passes by every 75-76 years. As the comet moves away from the sun, the tail shrink and the comet refreezes into a giant ball of ice. Because of the large distances comets travel, they are only seen periodically. 1112 Galaxies Galaxies are clusters of stars, planets, and solar systems revolving around a single black hole. The galaxy our solar system is in is called the Milky Way Galaxy. It contains about 400 billion stars and is just under 100,000 light years wide. A Light Year is the distance that light travels in one calendar year. That is approximately 9.460 quadrillion meters, so our solar system is 946.07 quintillion meters wide. Galaxies can attract each other to form what are known as Galaxy Clusters. They can contain up to 1,000 galaxies bound together by gravity. A large portion of these clusters is dark matter. Dark matter is what scientists believe makes up most of the universe. It does not absorb light or radiation so telescopes cannot see it; however, astronomers speculate that dark matter has gravitational effects on visible matter. 12 13 Black Holes A Black Hole is an extremely dense region of space where the gravity is so high that no light can escape. Black holes are often located at the centers of galaxies. They are created from densely compact stars after their life as normal stars finishes. The gravitational force that black holes create is strong enough to hold billions of billions of stars and planets in a very large range that can be over 10,000 light years in diameter. Really large black holes are classified as Supermassive Black Holes. 13 14 Nebulae Some of the most beautiful structures in the universe are nebulae. Nebulae are large clouds of cosmic dust, hydrogen, helium, and gases. They occur after a star explodes in a supernova. After billions of years, the gravitational forces acting on the nebula would pull it all back together resulting the creation of a star or planet. Planetary Nebulae are clouds made mostly of hydrogen that surrounds really hot stars such as white dwarfs, red giants, and supergiants. They are more dense than the common nebulae made from an exploding supernova. A Stellar Nursery is a nebula where stars are forming. They often have lots of ultraviolet (UV) light because of the stars forming inside. 14 15 Stars Stars are giant balls of gas that produce light when they burn. Much like people and animals, stars have life cycles, but their life spans are much longer. All stars are born from nebulae. Many stars seen from Earth are Main Sequence Stars, which are stars in the middle of their life. Gravity holds together the gases that make up the stars. They have a nuclear fusion process where hydrogen atoms become helium atoms and energy makes light and heat. Stars become Supergiants, or Red Giants, when they start to burn out. The stars are much cooler than they were before. When stars burn out, they usually explode and turn into a white dwarf, neutron star, or black hole. 15 16 Stars A Supernova is a giant explosion created by a dying star. As the star starts to decay, the outer shell grows larger and larger. The core of the star cannot hold the rest of it together. The star then violently explodes, and the burning gases shoot across space. The supernova releases about the amount of energy that our sun will produce in its entire lifetime. Not all stars become a supernova. The star has to have enough mass to expand, which is about the mass of 1.4 of our suns. 16 17 Stars White Dwarfs are the cores of remaining stars after a supernova explosion. The mass that a white dwarf has is about the same as the mass of our sun. However, the density is high so the star is about the same size as Earth. Eventually, even white dwarfs burn out and become black dwarfs. When a huge star about 8 times the mass of our sun explodes, the result is usually a Neutron Star or a black hole. With either type of star, the supernova also creates cosmic dust, which forms a nebula. In ten thousand years, the nebula will form a new star. 17 18 Glossary Asteroid Belt- a large collection of asteroids Asteroids- a large chunk of space rock that orbits around the sun Big Bang Theory- the common theory of how the universe was created, which says that the universe expands from a point Black Hole- an extremely dense region of space where the gravity is so high that no light can escape Comet- a large body made of ice and space dust Dwarf Planet- a planet that is not large enough to clear all the space debris in its orbit Galaxy- a cluster of stars, planets, and solar systems revolving around a black hole Galaxy Cluster- a group of galaxies Gaseous Planet- a planets made of mostly gases Gravity- when an object attracts another because of their masses Inertia- objects in motion stay in motion Meteoroid- an asteroid that enters the Earth’s atmosphere 18 19 Glossary Nebula- a large cloud of cosmic dust, hydrogen, helium, and other gases Neutron Star- a result of a explosion of a huge star, formed in the core of the supernova Planetary Nebula- a cloud made mostly of hydrogen that surrounds really hot stars Planet- a large body made of either rock or gas that orbits a star Solar System- a collection of planets that orbit around a central gravitational source Star- a giant ball of gas that produces light when it burn Stellar Nursery- a nebula where stars are forming Supermassive Black Hole- a very large black hole Supernova- a giant explosion created by a dying star Terrestrial Planet- a planet that is made of rock White Dwarf Star- stars formed after a supernova explosion of most medium size stars 1920 Image Credits In-Text Images Pg 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 http://www.dvd-ppt-slideshow.com/blog/wp-content/uploads/2010/08/universe-wallpaper-20.jpg http://www.dailygalaxy.com/photos/uncategorized/2008/04/10/bigbang_2.jpg http://onefreemind.com/wp-content/uploads/2012/01/gravity-02.jpg http://mail.colonial.net/~hkaiter/aa_newest_images/orbitH.JPG http://www.wallsonline.org/wp-content/uploads/2013/01/solar-system.jpg http://blogiceo.nq.pl/czterymuszkieterki/files/2013/01/wenus.jpg http://d1jqu7g1y74ds1.cloudfront.net/wp-content/uploads/2008/04/mercurycomparison.jpg http://planetfacts.org/wp-content/uploads/2011/03/Jovian-planet.jpg http://snowbrains.com/wp-content/uploads/2013/04/pluto.zip_thumbnail3.jpg5873b598-b581-4bdbb8b0-bd3d03ee601bLarger.jpg http://www.wired.com/images_blogs/wiredscience/2013/01/vesta.jpg http://bookingz.net/wp-content/uploads/2013/03/Comet-2.jpg http://www.dailygalaxy.com/.a/6a00d8341bf7f753ef0154331fd9da970c-500wi http://scienceblogs.com/startswithabang/files/2012/05/Black_Hole_Milkyway.jpeg http://nssdc.gsfc.nasa.gov/image/astro/hst_pillars_m16_close.jpg http://world.edu/wp-content/uploads/2011/08/star_20types.jpg http://www.wreckamovie.com/system/task_references/0000/2729/RED_GIANT_001_by_foxd3sign.jpg http://i.space.com/images/i/000/004/210/iFF/080603-iod-supernova-02.jpg?1292268585 http://review-news.ru/uploads/posts/2012-09/thumbs/1346661812_purple-pic4-452x302-10258.jpg Backgrounds Cover http://1.bp.blogspot.com/-9qoKLWRLrnU/UQ1UDfQ56PI/AAAAAAAAG10/ZLnF_vT2W04/s1600/ in_outer_space_by_ifreex.jpg 1 http://static.ddmcdn.com/gif/blogs/6a00d8341bf67c53ef014e6102f233970c-800wi.jpg Cover 2-3 http://nothingoutofnothing.files.wordpress.com/2010/05/bigbang.jpg Pg. 1-2 4-5 http://www.resimbul.com/sonuc/d/uzay/uzay-evren/uzay-evren-87e367.jpg 6-7 8-9 10-11 12 13 14-15 16-17 18-19 20-21 http://www.nps.gov/laro/photosmultimedia/images/PIA12114_NASA.jpg http://www.jpl.nasa.gov/spaceimages/images/wallpaper/PIA10969-1600x1200.jpg http://www.mikebonnell.com/pics/asteroid01_1600.jpg http://blogcache.artron.net/201301/28/447724_13593525520YaW.jpg http://apod.nasa.gov/apod/image/1012/bhlens_riazuelo_big.jpg http://starcraftscience.com/wp-content/up loads/2010/09/supernova_3-1024x768.jpg http://images.fineartamerica.com/images-medium-large/flaming-star-nebula-jim-delillo.jpg http://wallpapersus.com/wallpapers/2012/07/stars-5-485x728.jpg http://www.outerspaceuniverse.org/wp-content/uploads/2009/07/outer-space1.jpg 20 21 About the Authors Peri Michael and Steven Piselli are students at the Massachusetts Academy of Math and Science. Steven is currently a resident of Millbury, Massachusetts. He participates in multiple musical groups affiliated with Millbury High School. He will be a Senior at Mass Academy next year enrolling in Musical Composition and Fundamentals of Music. Peri lives in Ashburnham, Massachusetts, and she will be a senior next year. She loves art including sketching, pottery, jewelry making, and painting. In her spare time, she enjoys drawing and listening to music. 2122