The Universe and Its Stars

1. The Universe and Its Stars We still do not understand everything about the universe. Ex. We do not know what causes gravity, only how impacts things. Scientific knowledge is based on the assumption that natural laws operate today as they did in the past and they will continue to do so in the future.

2. As we develop new instruments (ex. telescopes & particle accelerators), we will gain more information about our universe and the quantum forces involved in it. Telescopes • Telescopes gather more light than our eyes can, and provide greater clarity. • Radio telescopes use a dish to reflect radio waves to a focus where an antenna collects them. • Refractors: Use lenses to refract (bend) light into a focus to form an image. No modern professional telescopes use this design. • Reflectors: Use mirrors to reflect light into a focus to form an image. • Radio Telescope in Puerto Ricodish 300 m wide

3. Space Telescopes Why put telescopes in Space? …To get above the atmosphere Which image do you think is the one taken from space? • Advantages of having a telescope in space: • No atmospheric blurring. • The sky is darker. • To see light blocked by the atmosphere. • Mirrors do not flex under their own weight as they do on the ground.

5. Other theories for the Origin of the Universe Steady state theory Oscillating model In this model, the universe began with expansion. Over time, the expansion slowed and the universe contracted. Then the process began again, oscillating back and forth. • It suggests that the universe always has been the same as it is now. The universe always existed and always will. As the universe expands, new matter is created to keep the overall density of the universe the same or in a steady state.

6. Big Bang theory occurred approximately 13.7 billion years ago. • we are reasonably certain that the universe had a beginning. • According to the standard theory, our universe sprang into existence as a "singularity" around 13.7 billion years ago. • Prior to the singularity, nothing existed, not space, time, matter, or energy - nothing. We don't know where it came from, why it's here, or even where it is. All we really know is that at one time it didn't exist. • At a singularity, space and time cease to exist as we know them. • The laws of physics as we know them break down at a singularity, so it's not really possible to envision something with infinite density and zero volume

7. Big Bang Theory - The Premise. Begins with SINGULARITY- everything in the universe formed at this time Big Bang/ INFLATIONRapid expansion outward • After its initial appearance, it apparently inflated (the "Big Bang"), expanded and cooled, going from very, very small and very, very hot, to the size and temperature of our current universe. • It continues to expand and cool to this day • an expanding universe that began as an infinitesimal singularity which appeared out of nowhere for reasons unknown. • Big Bang theory occurred approximately 13.7 billion years ago.

8. BIG BANG THEORY Videos- • Big Bang- How the Universe Works- http://www.youtube.com/watch?v=I-nSdxAjljA • Inflation- http://www.youtube.com/watch?v=_LGia74lu70 • Expanding universe- http://www.youtube.com/watch?v=CcJ2u1BAL4I- NOVA • Cosmic microwave backgroundradiation-http://www.teachersdomain.org/resource/ess05.sci.ess.eiu.microwave/ Video 15 min. • The Elements: Forged in Stars- PBS Nucleosynthesis= http://www.youtube.com/watch?v=uKqvjEE0wFg

9. Universe formation • Universe forms from the gravitational attraction of molecules in a nebulae. • As the mass increases due to gravity, it clears out the space around it. If there is enough material pulled inward it forms a star, it not it may form a planet. • The pressure from the gravitational attraction in a star begins the FUSION reaction where Hydrogen atoms combine to form helium (and eventually heavier atoms), releasing the energy of the star that eventually reaches Earth in the form of radiation. • The mass rotates. It is believed that our galaxy has a black hole in the middle.

10. Nebulaesnursery of stars & planets

11. Recycling Matter • The matter in stars is recycled many times. • Spectrographs have shown that the Sun contains some carbon, iron, and other heavier elements.

12. Solar System Began • A large nebula, or cloud of material, was rotating slowly in space. Shock waves, perhaps from a nearby exploding star, might have caused the cloud to start condensing about 5 billion years ago • Steps • Gravity attracts molecules in a Cloud of dust & gas • Cloud rotates & matter clumps in center due to gravity • protosunchanged into sun (if enough gravity & mass)

13. Origin of the Solar System • Most of the condensing material was pulled by gravity toward the center to form an early Sun. • remaining gas, ice, and dust in the outer areas of the nebula condensed, collided, and stuck together forming planets, moons, and other components of the solar system. • Motion involves spinning

14. Evidence of the Big BangHS-ESS1-2. Construct an explanation of the Big Bang theory based on astronomical evidence of light spectra, motion of distant galaxies, and composition of matter in the universe. • Red shift of light galaxies appear to be moving away from us at speeds proportional to their distance. This is called "Hubble's Law," named after Edwin Hubble. (The Doppler shift) indicates the universe is expanding faster rates. If a star is moving toward Earth, its wavelengths of light are compressed. If a star is moving away from Earth, its wavelengths of light are stretched. • Cosmic microwave backgroundradiation- In 1965, Radio astronomers discovered Cosmic Microwave Background radiation (CMB) which pervades the observable universe, thought to be the remnant of predicted heat which scientists were looking for. • Composition of elements; ordinary matter of the universe; Stars, produce elements nucleosynthesis based on the mass of a star and the stage of its lifetime. The Big Bang produced two chemicals, hydrogen and helium. (75% H & 25% He by mass).Heavier elements were produced later by stars through nuclear fusion or when certain massive stars achieve a supernova stage and explode to produce the heaviest elements known(HS-ESS1-2),(HS-ESS1-3) In nuclear processes, atoms are not conserved, but the total number of protons plus neutrons is conserved.

15. The study of stars’ light spectra and brightness is used to identify compositional elements of stars, their movements, and their distances from Earth. The Red Shift is based on the Doppler Effect • When a spectroscope is used to study light from galaxies beyond the Local Group, a red shift occurs in the light.

16. Composition: NUCLEOSYNTHESIS – • Elements are made in the stars through the process of fusion: H + H  He. • Nucleosynthesis, and therefore the different elements created, varies as a function of the mass of a star and the stage of its lifetime. In medium size stars elements combine to produce elements up to Fe. Iron). Heavier elements are produced in a SUPERNOVA.

17. Today astronomers believe that around three quarters of the mass of the Universe consists of dark matter • Dark Matter neither reflects, emits or obstructs light (or indeed any other type of electromagnetic radiation • It cannot be observed directly. However, Hubble studies of how clusters of galaxies bend the light that passes through them lets astronomers deduce where the hidden mass lies. This means that they are able to make maps of where the dark matter lies in a cluster. • Cosmologists speculate that the dark matter may be made of non-baryonic matter particles, produced shortly after the Big Bang • Hubble studies of the expansion rate of the Universe have found that the expansion is actually speeding up. • Astronomers have explained this using the theory of dark energy, as a sort of negative gravity that pushes the Universe apart ever faster. • in the early moments following the Big Bang, the universe itself acted as a particle accelerator.

18. Uses light to separate substances and identify. • Electromagnetic Radiation; Atoms of each element emit and absorb characteristic frequencies of light. These characteristics allow identification of the presence of an element using a spectrograph, even in microscopic quantities. • temperature: Brightness/color – hottest- blue- white- yellow - red (coolest star) • movements (elliptical); • Distances from Earth. (Parallax) Parallaxes give us distances to stars up to perhaps a few thousand light years.

19. Measurement in SpacePARALLAX • How do scientists determine the distance from Earth to nearby stars? One way is to measure parallax—the apparent shift in the position of an object when viewed from two different positions.Used to determine distance of star from earth • Closer- greater apparent change in position • Extend your arm and look at your thumb first with your left eye closed and then with your right eye closed. Your thumb appears to change position with respect to the background. • Now do the same experiment with your thumb closer to your face. What do you observe? The nearer an object is to the observer, the greater its parallax is.

20. Brightness The brighter the star, the smaller the number that describes its magnitude Brightest have negative magnitudes Distance is measured in AU 1 AU is Distance from earth to sun Units= light-years Distance that light travels at a speed of 310 000 km/sec will cover in 1 year = 9.5 trillion km Apparent magnitude- brightness as it appears from Earth Absolute magnitude- brightness if stars were a standard distance from Earth- 32.6 light-years. Magnitude of Stars

21. Star Brightness & Size • H-R Diagram

22. The Main Sequence • Stars seem to fit into specific areas of the graph. • Most stars fit into a diagonal band that runs from the upper left to the lower right of the graph. • This band, called the main sequence, contains hot, blue, bright stars in the upper left and cool, red, dim stars in the lower right

23. A Star Is Born • When the temperature inside the core of a nebula piece reaches 10 million K, fusion begins. • The energy released radiates outward though the condensing ball of gas • As the energy radiates into space, stars are born.

24. Star Life cycles • The star called the sun is changing and will burn out over a lifespan of approximately 10 billion years. • Larger stars burn out faster and have a shorter life-span. • If they are about 3 X the size of our sun they may go super nova and form a black hole.

25. Evolution of Stars • When hydrogen fuel is depleted, a star loses its main sequence status. • This can take less than 1 million years for the brightest stars to many billions of years for the dimmest stars • The Sun has a main sequence life span of about 10 billion years. • We estimate that we are about ½ way through this cycle.

26. The larger the star, the faster the H burns. For all stars, when most of the hydrogen is fused, *used up, the… core collapses outer layer expand crash inward/explosion Dwarf Stage (final stages) fusion slows, cooling occurs gravity causes collapse inward may become black dwarf- burned out w/no visible light Supernova- most violent event core remains/ becomes neutron star extremely dense/may form black hole High mass Star Life cycle • Supernova • Death of a star

27. Supernova atoms found on Earth--such as gold, uranium, and many essential to life--were created in a nearby supernova

28. So dense its gravity is so strong- nothing can escape even light No real evidence they exist only study the effects High mass stars are believed to form black holes when they collapse Black Hole

30. The Milky Way Galaxy • Earth and the solar system are in a galaxy called the Milky Way. • It might contain as many as one trillion stars You can see the brightest part of the Milky Way if you look low in the southern sky on a moonless summer night. • Like many other galaxies, the Milky Way has a super-massive black hole at its center. • This black hole might be more than 2.5 millions times as massive as the Sun. • Evidence for the existence of the black hole comes from observing the orbit of a star near the galaxy's center. • Additional evidence includes X-ray emissions detected by the ChandraX-ray Observatory. • Countless other galaxies also exist.

31. The Milky Way Galaxy A giant disk of more than 100 billion stars 160,000 light-years across and 1,000 light-years thick. The Sun is 30,000 light-years from the center It takes 250 Million years for the Sun to complete one orbit The Spiral arms are the locations of new star formation

32. The Solar System Sun blows a wind of charged gas into space: the Solar Wind Boundary between Solar Wind and interstellar space 100 AU from the Sun 8 planets, dozens of moons, 100s of dwarf planets, 100,000s of asteroids, trillions of comets and meteoroids, …? Mostly distributed in a disk about the Sun

33. Size of the Solar System • Earth is • about 150,000,000 km from the Sun. • This distance is referred to as • 1 astronomical unit or 1 AU. • used to measure distances between objects within the solar system. Video of solar system scale. http://www.youtube.com/watch?v=aY_NfuZlFxc The significance of a phenomenon is dependent on the scale, proportion, and quantity at which it occurs. (HS-ESS1-1)

34. The Sun—An Average Star • Sunspots • Areas of the Sun's surface that appear dark because they are cooler than surrounding areas are called sunspots • Using the movement of individual sunspots they found that the Sun rotates. • Sunspot maximums occur about every 10 to 11 years. • The Prominences and Flares • intense magnetic fields associated with sunspots might cause prominences, which are huge, arching columns of gas. • Some prominences blast material from the Sun into space at speeds ranging from 600 km/s to more than 1,000 km/s. • Gases near a sunspot sometimes brighten suddenly, shooting outward at high speed. • These violent eruptions are called solar flares.

35. Sun Very active w/ • Prominences & solar flares are solar storms caused by changes in magnetic field of sun • (like bar magnet) • Suns magnetic poles switch about every 11 years • Compare inner & outer planets • The star called the sun is changing and will burn out over a lifespan of approximately 10 billion years.

36. CMEs • Coronal mass ejections (CMEs) occur when large amounts of electrically-charged gas are ejected suddenly from the Sun's corona. • CMEs can damage satellites in orbit around Earth. • They also can interfere with radio and power distribution equipment • High energy particles contained in CMEs and the solar wind are carried past Earth's magnetic field. • This generates electric currents that flow toward Earth's poles. • CMEs often cause auroras • These electric currents ionize gases in Earth's atmosphere • When these ions recombine with electrons, they produce the light of an aurora

37. Space Weather & Generating Energy • Mass can be converted into energy. • This was stated as the famous equation E=mc2. • In this equation, E is the energy produced, m is the mass, and c is the speed of light. • The small amount of mass "lost" when hydrogen atoms fuse to form a helium atom is converted to large amount of energy • Nuclear Fusion processes in the center of the sun release the energy that ultimately reaches Earth as radiation.

38. The sun’s radiation varies due to sudden solar flares (“space weather”), the 11-year sunspot cycle, and non-cyclic variations over centuries • It takes from 1 – 5 days for a CME aimed in our direction to reach Earth. • The solar wind, solar flares, and CMEs bring an increase in radiation to astronauts and electronics in space. • The sudden increase in power can damage sensitive electronic equipment. Power transformers can overload, causing long-lasting blackouts

39. The 11-year sunspot cycle • can affect the intensity of the sunlight that reaches Earth’s surface. • can cause either warming or cooling. • The sun follows a natural 11-year cycle of small ups and downs in intensity • The effect on Earth’s climate is small.? • Changes in the sun’s intensity have influenced Earth’s climate in the past and appear to be the primary cause of past cycles of ice ages, as well as shorter interglacial periods (periods between ice ages) of relatively warmer temperatures.. • Low solar activity between 1645 to 1715 may have caused the so-called “Little Ice Age” between the 17th and 19th centuries

40. Use mathematical or computational representations to predict the motion of orbiting objects in the solar system. • Kepler’slaws describe common features of the motions of orbiting objects, including their elliptical paths around the sun. Orbits may change due to the gravitational effects from, or collisions with, other objects in the solar system. • Newtonian gravitational laws govern orbital motions, which apply to human-made satellites as well as planets and moons. • The force of gravity on Earth is the resultant (vector sum) of two forces: • (a) The gravitational attraction in accordance with Newton's universal law of gravitation, • (b) inertia- movement will not change unless acted on by outside force

41. Newton's law of gravity • accounts for the detailed information we have about the planets in our solar system, the mass of the Sun, the distance to stars, quasars and even the theory of dark matter. • Although we have not traveled to all the planets nor to the Sun, we know their masses. These masses are obtained by applying the laws of gravity to the measured characteristics of the orbit. • In space an object maintains its orbit because of the force of gravity acting upon it. Planets orbit stars, stars orbit Galactic Centers, Galaxies orbit a center of mass in clusters, and clusters orbit in superclusters. • The force of gravity exerted on one object by another is directly proportional to the product of those objects' masses and inversely proportional to the square of the distance between them.

42. reconstruct the early history of Earth. • The earth formed along with the rest of the solar system 4.6 billion years ago. • Examples of evidence include the • absolute ages of ancient materials (obtained by radiometric dating of meteorites, moon rocks • Continental rocks, which can be older than 4 billion years, are generally much older than the rocks of the ocean floor, which are less than 200 million years old. • Spontaneous radioactive decays follow a characteristic exponential decay law. Nuclear lifetimes allow radiometric dating to be used to determine the ages of rocks and other materials • compositions of solar system objects • objects in the solar system, such as lunar rocks, asteroids, and meteorites, have changed little over billions of years and can provide information about Earth’s formation and early history. • Impact cratering record of planetary surfaces.

43. Moon FormationAt present, the giant impact hypothesis seems to be the best model to fit the scientific evidence for how the moon was created Giant Impact - Collision Theory – According to the giant impact hypothesis, a bodies that never made it to full planetary status from the leftover cloud of dust and gas orbiting the young sun crashed into Earth not long after the young planet was created. Known as Theia, the Mars-size body collided with Earth, throwing vaporized chunks of the young planet's crust into space, creating a moon that is the largest in the solar system in relation to its host planet. This would explain why the moon is less dense than Earth — the material that formed it came from the crust, while leaving the planet's rocky core untouched. Co-formation theory Moons can also form at the same time as their parent planet. Gravity would have caused material in the early solar system to draw together and would have a very similar composition to the planet. This would explain the moon's present location. However, the moon is much less dense than our planet, which would likely not be the case if both started with the same heavy elements at their core. Capture theory Perhaps Earth's gravity snagged a passing body, as happened with other moons in the solar system, such as the Martian moons of Phobos and Deimos.. A rocky body formed elsewhere in the solar system could have been drawn into orbit around the Earth. This theory would explain the differences in the composition of the Earth and its moon. However, such orbiters are often oddly shaped, rather than being spherical bodies like the moon. Their paths don't tend to line up with the ecliptic of their parent planet, also unlike the moon.

44. Early history of Earthformed along with the rest of the solar system 4.6 billion years ago. Examples of evidence of Earth’s formation and early history include the • Impact cratering record of planetary surfaces.] Impact craters are the remains of collisions between an asteroidormeteorite and a planet or moon. • Active geologic processes, such as plate tectonics and erosion, have destroyed or altered most of the very early rock record on Earth • Other objects in the solar system, such as lunar rocks, asteroids, and meteorites, have changed little over billions of years. Studying these objects can provide information about Earth’s formation and early history. • Giant Impact Video http://www.space.com/19275-moon-formation.html

45. Examples of evidence of Earth’s formation and early history include the Absolute Ages • absolute ages involves the radiometric dating of meteorites, moon rocks, & Earth’s oldest minerals). • The far side of the moon is rougher than seen from this side due to impact craters. We never see the back side of the moon since one side always faces us. • Spontaneous radioactive decays follow a characteristic exponential decay law. Nuclear lifetimes allow radiometric dating to be used to determine the ages of rocks and other materials. • So far, oldest dated Earth rocks are 3.96 billion years. • Older rocks include meteorites and moon rocks, where Moon rocks from the Lunar highland are about 4.5 billion years old • mare basalt rocks are 3.2 - 3.8 billion years old. • Meteorites are all older than 4.5 billion years. • http://bwbearthenviro2011.wikispaces.com/Homework+Due+Monday+29th+Oct

46. Milky way collision

47. Period of revolution- time it takes a planet to complete 1 revolution= 1 yr One rotation on axis = 1 day on planet Year vs. day

48. Europe Takes Aim at Space Junk Menace • – March 6, 2013 • There are about 600,000 objects larger than 1 cm (0.39 inches) and at least 16,000 larger than 10 cm (3.9 inches).  • Space junk is man-made debris — spent rocket stages, dead satellites and even lost spacewalker tools — orbiting Earth which pose a risk to orbiting satellites, which even a small piece of space trash could damage or destroy. • . The European Union has launched a new program to tackle the threat of space junk • March 2014

49. 3D Printers Could Build Futuristic Moon Colony • Feb 2, 2013 • The European Space Agency (ESA) study is investigating how practical constructing a manned base on the moon only using 3D printing technology could be, given that it would rely primarily on lunar dirt for building materials

50. Warp Drive By Clara Moskowitz | SPACE.com – September 17, 2012 http://news.yahoo.com/warp-drive-may-more-feasible-thought-scientists-161301109.html • Warping space-time • An Alcubierre warp drive would involve a football-shape spacecraft attached to a large ring encircling it. This ring, potentially made of exotic matter, would cause space-time to warp around the starship, creating a region of contracted space in front of it and expanded space behind. [Star Trek's Warp Drive: Are We There Yet? | Video] Meanwhile, the starship itself would stay inside a bubble of flat space-time that wasn't being warped at all. "Everything within space is restricted by the speed of light," explained Richard Obousy, president of Icarus Interstellar, a non-profit group of scientists and engineers devoted to pursuing interstellar spaceflight. "But the really cool thing is space-time, the fabric of space, is not limited by the speed of light." With this concept, the spacecraft would be able to achieve an effective speed of about 10 times the speed of light, all without breaking the cosmic speed limit. • The only problem is, previous studies estimated the warp drive would require a minimum amount of energy about equal to the mass-energy of the planet Jupiter. But recently White calculated what would happen if the shape of the ring encircling the spacecraft was adjusted into more of a rounded donut, as opposed to a flat ring. He found in that case, the warp drive could be powered by a mass about the size of a spacecraft like the Voyager 1 probe NASA launched in 1977. Furthermore, if the intensity of the space warps can be oscillated over time, the energy required is reduced even more, White found. "The findings I presented today change it from impractical to plausible and worth further investigation," White told SPACE.com. "The additional energy reduction realized by oscillating the bubble intensity is an interesting conjecture that we will enjoy looking at in the lab.“ • Laboratory tests White and his colleagues have begun experimenting with a mini version of the warp drive in their laboratory.