Earth and Space Midterm Exam Review PDF

Unit 1 Unit 1 Lesson 1: The Big Bang What is the Big Bang? The big bang is the event which gave birth to our universe. ○ It is described as the rapid expansion of all the space, time, matter, and energy in...

Unit 1 Unit 1 Lesson 1: The Big Bang What is the Big Bang? The big bang is the event which gave birth to our universe. ○ It is described as the rapid expansion of all the space, time, matter, and energy in the universe. ○ It occurred in phases/eras. As the energy from the big bang moved farther and farther, cooling in the process, celestial objects began to take shape. What is a Singularity? A singularity in an infinitely small, hot and dense point which contains all the matter, space, and energy in our universe. With immense heat and pressure, this point rapidly expanded similar to an explosion, releasing all of its contents. ○ After this expansion came a period of cooling, which allowed for subatomic particles to come together and form the simplest of elements. What is the Big Bang Theory? The Big Bang Theory states that the universe began as an extremely small and dense point known as a singularity, which contained all the space, matter, and energy in our universe. This point rapidly expanded to release all of its contents, similar to an explosion. ○ After this, the universe began to cool and developed in stages known as eras and epochs. What was the Timeline of Events following the Big Bang? Radiation Era When What Description 13.7 Billion Years Ago The Radiation Era, made up of different epochs 1. The infinitely dense and hot singularity or “stages” rapidly expands. a. No “modern” matter existed as it was too hot for subatomic particles to come together to form the first elements. 2. A superforce was created made up of all the forces. a. This epoch ended when the gravity force split off from the superforce. 3. The strong force splits off from the forces. 4. The universe rapidly expands. 5. The electromagnetic and weak forces split off.  6. It is still too hot for subatomic particles to form, and this period/epoch is primarily made up of quarks. 7. The universe eventually cools down enough for subatomic particles to begin forming. 8. Quarks ultimately combine to form the first subatomic elements, hydrogen, and the matter era begins. Matter Era When What Description Now The Matter Era 1. The universe cooled down enough for Hydrogen and Helium to form. 2. Galaxies and larger celestial objects begin to form. Evidence to Support the Big Bang Theory Doppler Effect/Red Shift ○ The doppler effect expands on Hubble’s Redshift. ○ The Doppler effect states that when an object moves farther away, its frequency becomes less, its wavelength stretches, which makes it appear to be slower, thus moving towards the red side of the visible light spectrum. ○ When an object moves closer, the frequency of light increases as the wavelength becomes more condensed, making it appear to be faster, thus a blue shifted appearance based on the visible light spectrum. Cosmic Microwave Background Radiation ○ CMB is the residual heat leftover from the big bang, which is just a few degrees above absolute zero. ○ It is considered the oldest observable light in the universe, providing snapshots of the big bang. The Abundance of Lighter Elements ○ The early universe was too hot to form any elements, and after the universe cooled down, was not hot enough to cause the nuclear reactions to form heavier elements, thus the universe became primarily abundant of the lightest elements of Hydrogen and Helium. This was a period known as Big Bang Nucleosynthesis. Predicted ratios of abundant lighter elements coincide with the observations which support the big bang theory, and that the elements we have today come from the lighter elements from the early universe. Unit 1 Lesson 2: Exploring Galaxies What are Galaxies? Galaxies are celestial objects composed of billions to even trillions of stars, gas, dust, and dark matter.  ○ They are held together by gravity and come in various types, shapes, sizes, and structures. Why should we study Galaxies? Studying galaxies will help us understand important astronomical topics such as the origins of our universe, its history, and how it is organized, especially because of cosmic formation. ○ It will also help us understand how forces such as gravity work on interstellar objects. Galaxy Types and Special Features Galaxy types are organized using Hubble’s Tuning Fork Diagram. Galaxy Type Features Spiral (S) Structure: Flat, Rotating Disk with a Central Bulge Spiral Arms, a region of active star formation and younger star concentration, which bends back into the Central Bulge. Spiral Galaxies make up about 60% of the Galaxies in the observable universe. Barred Spiral (SB) Structure: Flat, Rotating Disk with a Central Bulge. A central bar that cuts through the galactic disk. The Spiral Arms do not fully curve into the core. Lenticular (S0) Structure: The Transitional Phase Between Spiral and Elliptical Galaxies, having features of both. Stars are older and formation has mostly stopped. Elliptical (E0-7) Shape: Smooth and Featureless, with an ellipsoidal shape. Classified from E0-E7, from spherical to oval shaped. Population: Mainly made up of older stars. Elliptical Galaxies are thought to originate from the merging of smaller galaxies. Irregular (IRR) Structure: Lack of normal structure. Typically rich in gas and dust. Active Galactic Nuclei (AGN)  Bright and Energetic Regions that are located in the centers of some galaxies, which are powered by supermassive black holes. ○ Ex. Quasars, Seyfert galaxies, blazars. These AGN are amongst the most luminous objects in the universe and are key to understanding black hole growth and galactic evolution. Description of a Galactic Merger When galaxies collide, gravitational fields interact, leading to tidal forces which distort shapes, trigger starbursts, and sometimes result in galactic mergers. For example: The Milky Way and Andromeda Galaxies. ○ As the 2 galaxies move closer together, the Andromeda galaxy will start to appear larger and larger, until it fills the night sky on Earth. ○ Then, as both galaxies begin to pass by each other, the gasses from each galaxy will collide, causing raging storms which fuel star formation. ○ Eventually, when they do pass by completely, their spiral shapes will be warped. ○ Their collision caused increased amounts of star formation due to gas and dust collision, leaving them with 2 new bright cores. ○ In 7 billion years, the process of collision would have completely ended, and as both galaxies exert their gravitational pull on each other, the galaxies merge into 1 huge elliptical galaxy. Galactic mergers are unlikely to cause significant damage to solar systems due to the vastness of space, and the gap between each star and other planets is too huge. What is Dark Matter? Dark Matter is an invisible type of matter in the universe because it does not emit, absorb, or reflect light, but still emits gravitational force. Dark Matter is crucial in forming galaxies due to it providing the necessary gravitational force to hold galaxies together through increasing the rotational force of the outer parts of the galaxies. The presence of dark matter is inferred through galaxy rotation curves, which appears to speed up on the further parts of the galaxies. ○ These show that the outer parts of galaxies rotate faster than can be explained by visible matter alone. Dark Energy makes up 68% of the Observable Universe. Dark Matter makes up 27% of the Observable Universe. Ordinary Matter makes up 5% of the Observable Universe. Galaxy Clusters and Superclusters Clusters are groups of hundreds or more galaxies grouped together by gravity, and are the largest gravitationally bound objects in the universe. Superclusters are large groups of regular clusters connected by filaments of dark matter. Unit 1 Lesson 3: Stellar Classification Properties used to Classify Stars Properties Description Surface Temperature Determines the color of a star  ○ Temperature ranges from 3,000K to 50,000K ○ Coolest Stars: Red 3000-4500K ○ Medium Temperature: Yellow 5000-6000K ○ Hottest Stars: Blue 10000-50000K Stars have several letters of classification based on their surface temperature. Ranging from hottest to coldest: O,B,A,F,G,K,M Our sun is a yellow dwarf type G star. Luminosity The total amount of energy emitted by the star, measured in watts. ○ Brightness: How bright a star appears from Earth ○ Intrinsic Luminosity: How bright the star naturally is. Measured through the use of the magnitude scale to measure the brightness. ○ Absolute Magnitude: True Luminosity of a star based on research and instruments on Earth, removing factors such as distance and debris. ○ Apparent Magnitude: A star's brightness as seen from Earth. Chemical Composition The elements present in the star’s atmosphere. ○ Spectroscopy: The study of spectral lines, crucial for understanding stellar composition and properties. Spectroscopy makes use of 2 methods of chemical detection through spectrums: ○ Emission Spectrum Based on the color of light emitted by glowing gas, as chemicals emit different colors. Appears as colors in a blacked out spectrum. ○ Absorption Spectrum Based on the color of light absorbed by a specific element when light passes through it, because elements absorb specific  colors of light. Appears as a blacked out line in a spectrum. Spectral lines are used to determine the chemical composition of stars, useful for determining the stars age and probable temperature. ○ As these properties are interconnected. Annie Jump Cannon She is known for revolutionizing star classification. Together with a team of Harvard scientists, she developed a spectral classification system that we still use today. She herself classified thousands of stars manually. Unit 1 Lesson 4: The Life Cycle of Stars The life cycle of a star is dependent on its initial mass after being formed. ○ Stars with larger masses generally have much shorter life spans due to a larger surface area and more fuel being needed to fight against gravity. ○ Stars with smaller masses generally have longer lifespans due to a smaller surface area and less fuel being needed. Nuclear fusion is the process by which hydrogen is fused under immense pressure and heat to form helium, creating energy and pressure as a byproduct to fight against gravity trying to pull it apart. ○ Some stars can same themselves from death by utilizing the immense pressure in its core to fuse heavier elements, allowing it to live a little longer. Stages of a Star’s Life Nebulae All stars begin as nebulae, or clumped regions made of gas and dust in space. As gravity pulls the material together, the gasses become denser and hotter, and the nebula collapses to form a protostar. Protostar The protostar is the phase between a nebula and a main sequence star. When the protostar reaches a temperature of 10^7K, nuclear fusion begins to occur and it is the star's first ignition. ○ However, protostars are covered in dust, making them invisible except to infrared. Main Sequence Stars A star spends on average 90% of its lifetime as a main sequence star. These are the stars which are currently in their stable phase of nuclear fusion, being able to combat the gravitational forces trying to collapse it without immediately running out of fuel. ○ Main sequence stars generally have a proportional balance between surface temperature and luminosity.  The End of Main Sequence Stars: Red Dwarf ○ Main sequence stars that live long enough to this point end up as red dwarfs, as they have run out of lighter elements to perform nuclear fusion. ○ These stars are very dim and not visible in the night sky, but are the most common types of stars in the observable universe. Lower Mass Stars Lower mass stars start off as main sequence stars, but run out of hydrogen for nuclear fusion in their cores. When they run out of hydrogen, they expand to become red giants. ○ Helium fusion occurs, while the outer layers of the star cool down. ○ Red giants are much brighter, but also much colder. Planetary Nebula ○ When fusion in the core of a low mass star stops, the outer layers of the star are ejected, forming a beautifully colored planetary nebulae, with gasses fluorescence at different wavelengths. White Dwarf ○ The remains of a planetary nebulae, and the core of the dead star is known as a white dwarf. ○ It is an earth sized remnant, but because nuclear fusion has stopped, it slowly cools down and fades over billions of years. These are the stars most similar to our sun. High Mass Stars High mass stars also start off as main sequence stars, but when they run out of hydrogen for nuclear fusion, they expand to become large blue supergiants. High mass stars rapidly undergo multiple layers of nuclear fusion and create heavier elements. ○ Their large energy usage and output significantly shortens their lifespans and they are extremely unstable. Supernovae ○ When nuclear fusions stops and stars can no longer create enough pressure to withstand gravity, the outer layers explode outwards causing a supernova. The elements released by a supernova help the universe by scattering and enriching the universe with elements for future star formation. Neutron Star ○ When the remaining mass of the remnants after a supernova are between 8-20 solar masses, a neutron star forms. They are extremely dense, composed mainly of neutrons, and their radius is super small but have masses greater than out sun. They rotate rapidly, have strong magnetic fields, and emit pulses of radiation. Black Holes ○ When the remaining mass of the remnants of a supernova are over 20 solar masses, a black hole forms. The core collapses into an infinitely dense point, or a singularity surrounded by an event horizon.  Gravity becomes so strong that not even light is able to escape. Black holes grow by accreting matter, and are crucial in galactic formation. Failed Stars: Brown Stars Brown stars have masses between the largest of planets to the smallest of stars. These stars fail at star formation because they do not have enough mass to undergo nuclear fusion. Why is Stellar Evolution Important? Stellar evolution is important as it helps us in understanding the chemical enrichment of the universe and heavier elements originate in stars and are distributed by supernovae. ○ The elements created through stellar evolution are the building blocks of planets, life, and new stars. Unit 1 Lesson 5: The Sun How is the Sun Imaged? The sun is imaged using NASA’s Solar Dynamic Observatory, or SDO. ○ The SDO is a spacecraft dedicated to studying changes in the sun’s solar activity. The SDO contains 4 atmospheric image array (AIA) telescopes which snap pictures of the sun every 12 seconds in several different wavelengths. Scientists use the electromagnetic spectrum to study the wavelengths of a star as each unique lens is used to interpret different observations of solar activity. ○ The sun emits many different wavelengths of electromagnetic radiation, so by imaging the sun in a variety of wavelengths, they can observe features which could have been unknown before. What are the Layers of the Sun? Inner Layers -> Outer Layers Layer Description The Core The innermost layer where nuclear fusion occurs. Radiative Zone Energy moves outwards from the core via radiation. Convective Zone Heat is transported via convection currents inside the sun Photosphere The visible surface of the sun, this is the layer where sunspots appear. ○ Sunspots appear in the locations in the photosphere where the magnetic fields are powerful. Only made up of plasma because it is too hot for other forms of matter to form. 400 km thick, and the deepest layer of the sun scientists are able to accurately study. Chromosphere The layer towards the exterior of the sun. Sections of plasma shoot out of the sun at rapid speeds and die down quickly.  The chromosphere was created through neutral particles, affected by the magnetic field of the sun. Visible during solar eclipses. Transition Region The transition region is the lowest and shallowest atmospheric region of the sun. Only around 1000 km in distance. There is a significant temperature increase. Corona The outermost layer of the sun. What are types of Solar Activity? Solar Flares ○ Like flashes of light which appear on the sun’s surface. These are the brighter spots visible on the sun. ○ Solar flares are explosive releases of energy, which occur due to magnetic reconnection, and emit radiation across the electromagnetic spectrum. ○ These solar flares are very dense, and can take out satellites if they hit. Classifying Solar Flares ○ Solar Flares are categorized from strongest to weakest: X,M,C,B B-M have a subranking from 1-9, but X class flares can go above 9. ○ The strongest recorded solar flare was in 2003 when an X-45 solar flare was released from the sun. If an X-Class solar flare hits the earth, it could cause satellite destruction, those in planes by the poles could receive high doses of solar radiation from the sun, cause worldwide blackouts, and long-lasting radiation storms. Coronal Mass Ejection ○ Like a solar flare, but a giant ejection mass of energy from the sun, which is hurled towards space. A massive burst of solar wind, high energetic particles, and magnetic fields. When a CME hits the magnetic field of the earth, it causes the northern lights, or the collision between 2 magnetic fields. If the earth was blasted with a stronger CME, it would knock all the satellites off of orbit, and render all electronics useless. Solar Prominence ○ Material which is forced to move due to the sun’s magnetic field. ○ Some of the sun’s energy remains within the corona, and falls back into the sun. ○ It appears like shifting grains of sand. Why is Solar Activity Harmful to Earth? The particles sent to earth by solar activity are dense enough to damage satellites in space, meaning it could potentially knock out our satellite systems.  ○ If a coronal mass ejection was sent towards our direction, it could knock out all of our satellite technology. Energy in the form of radiation is harmful with enough exposure, and a strong enough blast of radiation from the sun could cause skin cancer because of their high energy frequency. What are types of Solar Features? Sunspots ○ Sunspots are darker regions that appear on the sun’s photosphere where magnetic fields are stronger and heat is unable to rise. Sunspots are often correlated with increased solar activity, known as a solar maximum. ○ Sunspots appear in pairs because of magnetic fields. ○ Parts of a sunspot: Umbra: The inner part of a sunspot, where magnetic fields are stronger and temperature is colder due to trapping heat. Penumbra: The outer part of a sunspot, where magnetic fields are weaker and the temperature is hotter due to heat being released after escaping. Coronal Holes ○ Coronal holes are areas of cooler and less dense plasma, which is magnetic, and appears on the corona. Because of the lower density, the magnetic field lines of these regions open up to interstellar space. How does Nuclear Fusion occur in the Core? Stars burn fuel in the form of hydrogen. Isotopes of hydrogen nuclei fuse under immense pressure and temperature to form helium in the core. ○ This process generates immense heat, light, radiation, and pressure. ○ This energy created through fusion is what creates the plasma and light from the sun. The pressure created from nuclear fusion produces pressure, which is strong enough to counter gravitational forces trying to pull the star apart. What is the Kardashev Scale? The Kardashev scale is used to categorize civilizations based on their ability to use and manipulate energy sources. Type 1 Civilizations: A planetary civilization able to harness all the available energy of its home planet, including solar energy. Type 2 Civilizations: A stellar civilization able to harness the total energy output of its star, via a dyson sphere. Type 3 Civilizations: A galactic civilization able to harness the total energy of its galaxy. Project Iter Currently the biggest attempt to generate the power of a star on Earth. It is a huge collaborative effort between lots of countries, but Canada is not one of them.  It is a doughnut shaped “Tokamak” type fusion reactor with magnetic coils. Inside, Plasma is formed and heated up 20x hotter than the core of the sun to overcome the repulsion between atoms to fuse into heavier elements. Unit 1 Lesson 6: Techniques to Observe Stars Ancient Observations of Stars Early civilizations cataloged starts by creating constellations for navigation, agriculture, and mythology. ○ Instruments like the astrolabe were created by the Arabs. Galileo used the first telescope to document stars. Modern Observations of Stars 19th Century: ○ Utilized Parallax measurements by Friedrich Bessel for star distances, and spectroscopy was used to analyze stellar compositions. Modern Space Telescopes: ○ Many space telescopes revolutionized stellar observation, studying star formation and precise mapping. Ground Based Telescopes: ○ Utilize advanced technologies such as adaptive optics and interferometry to overcome the atmosphere. Very Large Telescope in Chile Keck Observatory in Hawaii Methods of Observing Stars Method of Observation Description Parallax Parallax measures the apparent shift in a star’s position against other stars. ○ Observations are taken 6 months apart. Parallax utilizes the angle of the shift to calculate the star’s distance from the earth. ○ A smaller angle indicated a greater distance. The distance is measured in parsecs, and is the inverse of the parallax angle. Parallax can only measure stars up to 100ly in distance accurately. Interferometry Interferometry combines light from multiple telescopes to increase the resolution of images of stars, allowing for finer details. Astronomers use interferometry to analyze size, surface features, and structure of stars. Wien's Law The relationship between peak wavelength of a star’s light is inversely re;ated to its surface temperature. Using  Wien’s law, astronomers calculate the surface temperature by measuring the spectrum. ○ The relationship between color and temperature Cepheid Variables Cepheid Variab;es are types of stars that periodically change in luminosity in a predictable cycle. ○ Their brightness dims and increases over time. Stars with longer periods of brightness/pulsation period are brighter, and can be used as standard candles, or a reference point, to calculate the brightness of nearby stars. Henrietta Swan Leavitt Studied the fluctuating brightness of stars, and identified the regular changes and patterns of cepheid variables. ○ She found out that stars with longer brightness periods are brighter. ○ Edwin Hubble used information from Leavitt to determine the expansion of the universe and the distance of galaxies. Unit 1 Lesson 7: The History of Astronomy Aristotle A member of the ancient civilization, when Earth was viewed as the center of the universe. Aristotle discovered the orbits of our planets revolving around the sun, and proposed that the Earth was not the center of the universe, but something like the sun. Nicolas Copernicus Created the heliocentric model, that the planets all orbit the sun. Johannes Kepler German scientist Johannes Kepler removed the idea that the planet's orbits were perfectly circular, but orbit in elliptical shapes. The Invention of the Telescope The invention of the telescope improved the human sense of sight. Humanity’s view on the universe was expanded, being much bigger than everyone thought it was. The telescope revolutionized astronomy, allowing astronomers to look at space past the naked eye, and just starting at points in the sky. They were able to make out details never seen before, and more accurately observe details on interstellar objects. Galilei Galileo The first person to use the telescope and point it at the night sky. Discovered the moon cycle and planets had earth-like terrains. Also discovered that Jupiter had moons like earth. Invention of Refractive Telescopes Improved upon telescopes, which were able to be built at a certain size without bending the lens. Herschel Mapping of the Milky Way William and Corline Hershel used telescopes to map the milky way. By counting the number of stars visible in the night sky, he could assume the approximate shape of our galaxy. ○ They pointed the telescope at the night sky, and calculated the distance of the stars to earth based on everything having the same brightness. They were able to determine that the Milky Way had a disk-like shape. 60-Inch Telescope Allowed for research of globular clusters, which are collections of stars which developed from the same dust cloud. ○ The 60-Inch telescope helped discover cepheid variables, and that our solar system was not the center of the milky way. 100-Inch Hooker Telescope Hubble used this telescope to measure the distance between stars to earth. ○ Using his telescope, he discovered stars up to 900 LY away. ○ He also discovered that the andromeda nebula was in fact, a galaxy, and that there were more galaxies out there. ○ His discoveries led to humanity understanding that the universe was much greater in size, and possibly infinite. William Hershel Willaim Hershel split light from the sun into a rainbow of colors. He discovered that on the further red side of the spectrum, there was still heat being emitted. ○ William Hershel discovered infrared light, an invisible light of the electromagnetic spectrum. Discovery of Infrared Light ○ Infrared was a massive breakthrough, as it gave scientists a method of seeing past dust blocking the view of stars from normal telescopes, allowing us to finally see the formation and death of stars. Adaptive Optics A technique used to combat night distortion because of the atmosphere on earth. A laser beam is propagated into the night sky, and would be used to calculate the level of distortion by using it as a point of reference. Adaptive optics helped discover the presence of a supermassive black hole. Giordano Bruno Theorized that exoplanets existed with life on them. Exoplanets Searching for pulsars, the aftermath of stars that had gone supernova. These pulsars were used to find orbiting planets, and one pulsar was discovered with 3 planets orbiting them. Many orphan planets were also discovered, which were planets which do not orbit a star. Space Telescopes Space Telescopes were the solution to atmospheric distortion towards ground telescopes on Earth. Stargazer ○ Stargazer revealed that stars were higher than the models stated they were. ○ Stargazer also confirmed that comets are surrounded by vast hydrogen clouds. ○ It also proved the reliability of space observatories. Spitzer ○ The first telescope in a trailing orbit, allowing it to be much colder in order not to deal with the glow coming off of Earth. ○ It discovered distant black holes and newborn stars, things we wouldn't have known if it wasn't a super efficient telescope. Kepler Telescope ○ Nasa’s Kepler Telescope discovered planets within the habitable zone, an area where the distance is just right for planets to support life. An earth-like planet which orbits a red dwarf was found and could possibly support life. As of 2020, 2000 exoplanets were found using the Kepler telescope. Hubble ○ Hubble produced some of the most spectacular images of the cosmos and the sharpest views of the galaxies. It gave us more insight on the details and qualities of stellar objects far away. ○ Hubble produced the most significant images, the Hubble Deep Field. The Hubble Telescope stared at an apparent void in space for days, taking in all the light coming from that direction. The resulting image revealed over 3000 galaxies in high quality. Galaxies came in a variety of shapes, sizes, colors, and ages. James Webb ○ The newest space telescope, which is an improved version of hubble. It was used to refine discoveries made in the past. Overall, The invention and innovation of telescopes have been the lead to challenging new discoveries and finding more information about the universe. Telescopes are the backbone of space observation and astronomy. Unit 2 Unit 2 Lesson 1: The Birth of the Solar System Solar Nebula Theory Solar nebula theory states that the solar system began as a solar nebula made of gas and dust 4.6 billion years ago, which was triggered into collapsing and becoming a protostar by a supernova of a nearby star.  This model states that the planets formed where they are now due to their temperatures and distance from the sun. Factors that Formed our Solar System A Nearby Supernova ○ A theorized nearby supernova kickstarted the gravitational collapse of the solar nebula by swept compressed gas and material being launched into our solar system, forming the early sun. The Spitzer space telescope identified distant planet formation to determine how our solar system could have formed using infrared. Accretion ○ Accretion is the electrostatic force in zero gravity environments which causes particles to gather into larger groups, which is why the planets formed from asteroids and smaller particles. Gravity ○ Gravity exerts an equal force in all directions, no matter the shape of the object. This allowed planets to form into perfect spheres. Comets and Asteroids ○ Comets and Asteroids are the oldest dated objects in our solar system. ○ They originate as the cooled down matter from the accretion disk which formed our sun. ○ The age of all asteroids are dated back to 4.5 billion years old, meaning they originated around the time our solar system formed from the solar nebula. ○ A spacecraft captured particles from a comet passing by, and confirmed the dates of the particle’s age to 4.5 billion years. How were the planets and other objects formed? The distance from the early sun played a crucial role in forming the planets as temperature dictated what type of matter could condense. ○ In high temperatures and planets closer to the sun, only metals and Silicates were able to condense, forming rockier planets. ○ In colder temperatures, planets farther from the sun, only gasses and ice could condense, forming gas/icy planets. Terrestrial Planets ○ The hotter temperatures and closer distance to the sun allowed for the condensing of only metals and silicates. ○ The frequent collisions of asteroids and other particles allowed terrestrial planets to grow in mass. Accretions and gravity played a role in merging matter together into spherical shapes. Accretion Accretion is the electrostatic force in zero gravity environments which causes particles to gather into larger groups, which is why the planets formed from asteroids and smaller particles. Gravity Gravity exerts an equal force in all directions, no matter the shape of the object. This allowed planets to form into perfect spheres. ○ Planetesimals formed from particles due to accretion.  ○ Protoplanets formed from planetesimals due to continued accretion and collisions between planetesimals. ○ Planet differentiate, and the heavier elements sank to form cores, and the lighter elements formed mantles and crusts. ○ Earth exists in the goldilocks zone, which is the perfect temperature for life to exist. Formation of the Moon ○ The moon originates as a fragment of a younger earth, as testing on lunar composition revealed the similarities between moon and earth rock’s elements. It is theorized that around 20 protoplanets existed in the early solar system alongside the planets we have now, and collisions between them cause them to merge together. The moon was created when the early planet, Theia, collided with earth and accreted to form the current earth. The leftover material from this collision resulted in the formation of the moon through accretion and gravity, explaining its similarities in composition. ○ Lunar bombardment from meteorites explains the craters soon on the moon. Jovian/Gas Planets ○ The colder temperatures and farther distance to the sun allowed for only gas and ice to condense. ○ The gas planets originate from the heavy forms of gas and rock formed through accretion and gravity, which exerted gravitational force. Their location in the solar system had plenty of lighter gasses due to being farther away from the sun, and gravity + accretion brought more lighter gas to the planets, causing a snowball effect of absorbing more and more gas, which is why their masses are so big today. ○ The gravitational force of the jovian planets deflects most incoming asteroids from entering the inner solar system, playing the role of “big brother” and protecting the Earth. ○ Molecular hydrogen makes up the outer region of jovian planets. Metallic hydrogen makes up the inner region. Icy Planets ○ Icy planets also formed due to their farther distance from the sun and colder temperatures. ○ Their mantles are much more icy in comparison to Jovian planets because they are much colder, and accumulated more heavy gasses like methane. ○ The location of icy giants does not match the solar nebula theory model. Planetary Orbit The gravitational pull of Jupiter and Saturn is strong enough to move planets, explaining the possibilities of shifting orbits. ○ Jupiter and Saturn were once so close that their gravitational fields nudged each other, known as a 2-1 resonance, which nudged their orbits in the same direction. ○ The size of Saturn happens to be small enough to not cause another resonance between other planets and disrupt the balance of planetary orbits. If 2 planets were the same size as Jupiter in the solar system, planets would be thrown off their orbits due to the strong gravitational forces. It is unknown why asteroids are continuously being sent from the outer solar system towards the inner solar system.  ○ One explanation is that Uranus and Neptune periodically switch places in their orbits, sending asteroids flying everywhere. Asteroid Belt The asteroid belt is a minefield of asteroids between Mars and Jupiter, being held in place by Juptier’s strong gravitational force. It is made up of the leftover debris from the formation of the solar system. ○ THe composition of the asteroids in the asteroid belt reflects the early solar system, which is why scientists are so eager to study it. The Kuiper Belt It is a collection of icy bodies, comets, and dwarf planets like Pluto made from the leftovers of the accretion disk. Its starting point is around 30-50 AU from the sun, but it is unknown where it ends. The Kuiper belt is named after Gerard Kuiper, who speculated about objects farther from pluto. In 2019, the New Horizons spacecraft flew past Arrokoth, a Kuiper Belt Object that is approximately 6.4 billion kilometers away from the Earth, making it the farthest object ever studied in human history. Front Line The distance away from the sun where water, carbon dioxide, carbon monoxide, methane, and ammonia is at the perfect temperature to form and condense. The Oort Cloud The Oort cloud is a hypothetical model based on the orbits of long period comets, which are comets with a return period of greater than 200 years. It is spherical and extends 2,000 to 100,000 AU. It is the outermost region of our solar system, and could have clues about the solar system's interaction with the galaxy and formation. Steps to the Formation of the Solar System 1. Solar nebula collapses due to a nearby supernova and gravity. 2. The accretion disk and protostar form. 3. Material from the accretion disk cools and condenses, forming particles and creating rocky asteroids. 4. Planetesimals in the inner solar system begin to form as particles accrete. a. Planetesimals merge together to form protoplanets, becoming larger and larger due to accretion and gravity. b. Metals and silicates are the only substances able to condense due to the hot temperatures. c. Asteroids and particles collide with the protoplanets, gaining more and more mass. 5. Jivian and Icy planet cores form from gas and rock located in the outer solar system, due to accretion and gravity. a. The colder temperatures cause only gasses and ices to condense. b. Gravity and accretion absorb more and more gas, causing a snowball effect in the gas rich regions of space, allowing the gas and icy planets to gain large masses. 6. Thel eftovers from the accretion disk form the asteroid and Kuiper belt. 7. Comets launched by the outer planets’ gravity form the oort cloud. 8. The moon forms because of the collision between Theia and Earth. Unit 2 Lesson 2: Kepler’s Laws of Planetary Motion First Law - Law of Ellipses Planets do not orbit in circular orbits around the sun, but elliptical orbits with the sun as one of the foci, not its center. Eccentricity ○ Eccentricity measures how stretched the orbis are. A value of 0 = perfect circle, while a value closer to 1 means it is more elliptical. Perihelion ○ The closest point from the sun during a planet's orbit. Aphelion ○ The farthest point from the sun during a planet's orbit. Second Law - Law of Equal Areas In a given time period, a planet will sweep out the same amount of area no matter at what point of its orbit it is in. A planet will sweep out equal areas in equal given time periods. This means that a planet will move faster the closer it is to the sun, and slower the farther away it is from the sun during its orbit. Third Law - Law of Harmonics The square of a planet's orbit (time in AU) is proportional to the cube of the semi-major axis (otherwise known as the orbital radii). This means that the farther a planet is from the sun, the longer it will take to complete a full orbit, and the closer a planet is from the sun, the shorter it will take to complete one full orbit. ○ T^2 = a^3 Applying Kepler’s Laws Kepler’s laws help explain the motion of all planets, moon, and comets in our solar system. Planets with low eccentricity move in nearly spherical orbits, while comets and some asteroids orbit in more elliptical shapes due to their high eccentricity. Unit 2 Lesson 3: Newton’s Laws of Motion Who is Sir Isaac Newton? Sir Isaac Newton is known for his law of universal gravitation and calculus. He sought to understand biblical prophecy and believed that he was chosen to demystify religious texts. He thought that there was life on other planets, and supernovas were the result of the same process happening in other star systems. What are the Four Fundamental Forces? Electromagnetic Force Strong Force Gravitational Force Weak Force Newton’s Laws First Law - Law of Inertia  ○ An object at rest remains at rest, and an object in motion remains in motion at constant speed and in a straight line unless acted on by an unbalanced, external force. Second Law - Law of Acceleration ○ Also known as the law of force, acceleration is produced when a force acts on a mass (F = ma). ○ The more massive an object, the stronger the gravitational force it exerts. Third Law - Law of Action & Reaction ○ Whenever one object exerts a force on an object, the second object exerts an equal and opposite force on the first object. Forces always exist in pairs. ○ The magnitude acceleration is inversely proportional to the object’s mass. Smaller objects on earth will accelerate quickly to the earth, but the earth’s acceleration is negligible. Applying Newton’s Laws Newton’s laws are the foundation for understanding planetary motion, explaining why they move that way. The laws are the same to objects on earth and in space. Newton’s laws are able to predict future planetary positions. Unit 2 Lesson 4: The 8 Wonders of the Solar System Weather and the Sun The heat that comes from the sun plays a crucial role in determining the weather patterns on planets. The atmosphere of a planet becomes more volatile when more energy (in the form of heat) interacts with it, which explains why earth periodically has hurricanes during warmer months. The heat that influences weather can also come from the planet itself, like how Saturn is able to have such strong winds despite being cold and far from the sun. Saturn creates its own heat to power its storms. Mercury Mercury is the most cratered planet in the solar system. It has an unusual orbit, having to orbit the sun twice to complete 1 day on mercury. Its core is also unusual, having much more metal inside than on its surface. Mercury 4.5 billion years ago was seething with heat during its volatile formation, and a crust made up of volatile elements formed. ○ One theory for why mercury no longer had as many metals it should have on its surface is that mercury was actually formed near the earth, and was knocked closer to the sun by a large object. This collision would have removed most of its crust and mantle, explaining its abundance of metals in the core. Earth Earth is the only planet which is guaranteed to be known to have life. ○ For a planet to have life, liquid water needs to appear and remain on a planet. ○ The earth’s atmosphere protects the water on earth, and life now maintains the very atmosphere which allows it to exist. Around 1 billion years from now, complex life on earth will disappear because temperatures will become too hot. Earth’s powerful magnetic fields block solar wind and ionizing radiation, protecting life. Mars Conditions ○ Mars’ MRO sent back data of Mars revealing that it had polar avalanches, shifting sand dunes, and seasonal flows of sand. ○ One particular location was the eridani basin, which was thought to have water a long time ago due to having material which could only form in deep hydrothermal environments. The existence of this material in the eridani basin revealed that Mars once had the conditions to support life. Life on Mars ○ 3.7 billion years ago, Mars became colder and lost most of its liquid water. ○ Mars became volcanically active, leading to rising temperatures and thus lost the environment to support life. ○ Mars also did not have a strong enough magnetic field to protect its water and atmosphere. 4.6 billion years ago, mars formed further away from the sun than earth, meaning it did not have enough rocky material to combine and resulted in a smaller mass. Its core cooled down quickly, meaning it lost heat to create a magnetic field around the planet. Saturn Weather and Conditions ○ Unlike the earth, Saturn’s weather is not being influenced by the sun, which means another heat source is driving the weather. ○ Saturn’s weather is being powered by its own internal energy, not sunlight. Lighting storms are so strong that it transforms methane gas into graphite, and the atmospheric pressure turns the graphite into diamonds and dissolves it. It essentially rains diamonds on Saturn ○ 30,000 km below the surface, gasses turn into liquids similar to liquid metals, which create electricity and release massive amounts of heat. Rings ○ Saturn once had an extra moon made up of ice, but it went too close to Saturn and went past the Roche limit, and was pulled apart to become its rings. ○ Moon sized objects orbiting Saturn along with the rings separate one ring into many. ○ There are vertical structures made of rubble located on the edge of the rings. Uranus Uranus is an ice giant located on the outer planet of the solar system. It is a very cold planet due to its distance from the sun. Uranus also has rings. ○ The moons Cordelia and Ophelia help maintain the rings' shape through gravity. Orbit ○ Uranus is unique because it is the only planet in the solar system which orbits on its side, with the rings orbiting seemingly vertically rather than horizontally. A theory suggests that Uranus was hit by an earth sized object in the past which knocked it on its side, and the impact removed all the internal energy it had, explaining its cold temperatures. Neptune Neptune is almost chemically identical to earth. It is not a featureless planet.  Weather and Conditions ○ Neptune has strong winds and an atmosphere similar to the size of earths’. ○ Neptune is also warmer than uranus despite being farther out. ○ Neptune's winds are viscous, much stronger than Jupiter or Saturns’. ○ Neptune’s weather is thought to originate from its internal heat source. Diamonds are melted in the core because of pressure, which generates heat and rises to the atmosphere. Jupiter Gravity ○ When Jupiter went through the early asteroid belt, its strong gravity scattered the majority of the asteroid belt across the solar system, preventing the possibility of new planets to form. This also prevents Mars from gaining more mass due to scattering the majority of the material needed to increase in size. ○ When Saturn formed, it pulled back Jupiter just enough to spare material for the inner planets to form. ○ Jupiter also flung water rich asteroids towards the inner solar system, supplying an important aspect of supporting life. ○ The asteroid which wiped out the dinosaurs is theorized to have been influenced by jupiter's gravity and sent towards the earth. ○ Jupiter deflects any objects headed towards earth and protects it.