NATS From the Cosmos to Earth Spiral Galaxies Similar to the Milky Way View from above Edge view

NATS From the Cosmos to Earth The Milky Way The Sun is located on the Orion spiral arm about 30,000 LY from the galactic center It takes about 230 million years for the sun to complete one orbit around the galactic center

NATS From the Cosmos to Earth Other Galaxies in Our Local Group The Andromeda Galaxy 2.3 million LY away A Ring Galaxy

NATS From the Cosmos to Earth Deep field view - about 10 billion LY away

NATS From the Cosmos to Earth  In our galaxy there are about 200 billion stars  In our universe there are over 100 billion galaxies There are more stars in the universe than there are grains of sand on the Earth

NATS From the Cosmos to Earth If the Universe was one year old (instead of 15 billion years) The Cosmic Calendar (Carl Sagan)

NATS From the Cosmos to Earth meters = 1000 yottameters 100 Billion Light Years This image represents the size of the known universe -- a sphere with a radius of 13.7 billion light years.

NATS From the Cosmos to Earth meters = 100 yottameters Ten Billion Light Years Light from galaxies on the edge would require 5 billion years to reach the center. Observers at the center are seeing light that was emitted by these galaxies before the solar system formed. The largest scale picture ever taken. Each of the 9325 points is a galaxy like ours. They clump together in 'superclusters' around great voids which can be 150 million light years across.

NATS From the Cosmos to Earth meters = 10 yottameters One Billion Light Years Astronomers have determined that the largest structures within the visible universe - superclusters, walls, and sheets - are about 200 million light years on a side.

NATS From the Cosmos to Earth meters = 1 yottameter 100 Million Light Years Clusters of Galaxies

NATS From the Cosmos to Earth meters = 100 zettameters 10 Million Light Years Within the Virgo Cluster

NATS From the Cosmos to Earth meters = 10 zettameters 1 Million Light Years The Local Group - Our galaxy with the Magellanic Clouds - two companion galaxies on the right.

NATS From the Cosmos to Earth Our galaxy - the Milky Way - looks rather like a whirlpool. It has spiral arms curling outwards from the center and rotates at about 900 kilometres per hour. It contains about 200 billion stars meters = 1 zettameter 100,000 Light Years

NATS From the Cosmos to Earth meters = 100 exameters 10,000 Light Years Our Spiral Arm

NATS From the Cosmos to Earth meters = 10 exameters 1,000 Light Years The Stars of the Orion Arm

NATS From the Cosmos to Earth meters = 1 exameter 100 Light Years Stars within 50 Light Years

NATS From the Cosmos to Earth meters = 100 petameters 10 Light Years The Nearest Stars

NATS From the Cosmos to Earth meters = 10 petameters 1 Light Year The Oort Cloud

NATS From the Cosmos to Earth meters = 1 petameter 0.1 Light Year Sol - our Sun

NATS From the Cosmos to Earth meters = 100 terameters Our Sun and a few rocks

NATS From the Cosmos to Earth The solar system. Only the orbit of Pluto, the furthest planet from the Sun, is off the picture meters = 10 terameters

NATS From the Cosmos to Earth Within the orbit of Jupiter - the orbits of the inner four planets : Mercury, Venus, Earth and Mars. All four have rocky crusts and metallic cores meters = 1 terameter

NATS From the Cosmos to Earth Six weeks of the Earth's orbit. The orbits of Venus and Mars are just visible on either side meters = 100 gigameters

NATS From the Cosmos to Earth Four days of the Earth's orbit meters = 10 gigameters

NATS From the Cosmos to Earth The moon's orbit around the Earth, the furthest humans have ever traveled meters = 1 gigameter

NATS From the Cosmos to Earth 10 8 meters = 100 megameters Earth

NATS From the Cosmos to Earth North and Central America 10 7 meters = 10 megameters

NATS From the Cosmos to Earth 10 6 meters = 1 megameter California

NATS From the Cosmos to Earth 10 5 meters = 100 kilometer The San Francisco Bay Area

NATS From the Cosmos to Earth 10 4 meters = 10 kilometers San Francisco

NATS From the Cosmos to Earth 10 3 meters = 1 kilometer Golden Gate Park

NATS From the Cosmos to Earth Japanese Tea Garden - one hectare (10,000 m 2 ) 10 2 meters = 100 meters

NATS From the Cosmos to Earth A pond with lily pads 10 1 meters = 10 meters

NATS From the Cosmos to Earth A one-meter square 10 0 meters = 1 meter

NATS From the Cosmos to Earth meters = 10 centimeters A bee on a lily pad flower

NATS From the Cosmos to Earth A bee's head meters = 1 centimeter

NATS From the Cosmos to Earth A bee's eye meters = 1 millimeter

NATS From the Cosmos to Earth Pollen meters = 100 micrometers

NATS From the Cosmos to Earth Bacteria meters = 10 micrometers

NATS From the Cosmos to Earth Virus on a bacterium meters = 1 micrometer

NATS From the Cosmos to Earth A virus meters = 100 nanometers

NATS From the Cosmos to Earth The structure of DNA meters = 10 nanometers

NATS From the Cosmos to Earth The molecules of DNA meters = 1 nanometer

NATS From the Cosmos to Earth Carbon's outer electron shell meters = 100 picometers

NATS From the Cosmos to Earth The inner electron cloud meters = 10 picometers

NATS From the Cosmos to Earth Within the electron cloud meters = 1 picometer

NATS From the Cosmos to Earth The nucleus meters = 100 femtometers

NATS From the Cosmos to Earth The nucleus of carbon meters = 10 femtometers

NATS From the Cosmos to Earth A proton meters = 1 femtometer

NATS From the Cosmos to Earth Within the proton meters = 100 attometers

NATS From the Cosmos to Earth Quarks and gluons meters = 10 attometers

NATS From the Cosmos to Earth We are “Star Stuff”

NATS From the Cosmos to Earth The Orion Nebula Located in the sword of the constellation Orion.

NATS From the Cosmos to Earth The Orion Nebula

NATS From the Cosmos to Earth The Orion Nebula

NATS From the Cosmos to Earth Proplyds or Proto Solar Systems in the Orion Nebula

NATS From the Cosmos to Earth Gaseous Pillars - Stellar Nursery

NATS From the Cosmos to Earth Science What is Science? –Observation and experimentation directed toward understanding of the natural world. Why study science? –We live in a world surrounded by science and technology. –Our problems and their solutions are bound up with science. –We are called upon to make decisions, to vote, hopefully informed, on issues affecting our lives. –Many of these issues have a significant scientific component.

NATS From the Cosmos to Earth Why study science? (Continued) –For the convenience of the study of science, the subject is frequently divided into neat packages called biology, chemistry, geology, physics, astronomy --- –Nature is not so divided - Each scientific discipline views nature from a different perspective, but all are studying the same world. –This course will focus on a fundamental or general look at nature. It will be based on physics, the study of the principles that govern the natural world.

NATS From the Cosmos to Earth Why are we able to study nature? Fundamental assumptions about nature: –Order exists in nature – in the universe. –Order can be discovered by observation and experimentation. –Laws of nature are constant in time and place. Philosophical approach to the study of nature. Aristotle, Plato –Senses cannot be relied on –Must use reason and insights of human mind.

NATS From the Cosmos to Earth Scientific approach to the study of nature Copernicus and Galileo introduced observation and experimentation in the 16 th century. Science is not a set of facts. It is a way of conducting a dialogue about our physical surroundings. The scientific method consists of careful observation of nature and an open-minded creative search for general ideas that agree with and predict those observations. To be scientific, a statement must be capable of being proven wrong.

NATS From the Cosmos to Earth Scientific approach to the study of nature. Observation and experimentation set science apart from other ways of knowing - ways that are not less important - just different –Philosophy – Reason – Logic –Art – Appreciation of form – Beauty Pseudoscience statements: – Hypothesis that cannot be tested with reproducible results; Cold fusion, ufo's, astrology...

NATS From the Cosmos to Earth Scientific approach to the study of nature. Scientific Law: –Statement of observed regularity in nature - attempts to describe the observations –has a well documented history of successful replication and extension to new conditions Scientific Theory: –Statement of observed regularity in nature - attempts to explain the observations –General principle offered to explain a set of phenomena or observed facts. –Not all scientific predictions can be tested directly Core of earth Sun—energy Expansion of the universe Require models—creative thought –No ultimate truths—all Provisional Ok as long as they are not contradicted

NATS From the Cosmos to Earth Scientific approach to the study of nature. Model: –Simplified version of reality used to describe aspects of nature. –Not synonymous with reality. –Based on assumptions that may simplify some aspects of nature, or may be incomplete statements about nature –Useful to make predictions that can be verified by experimentation or observation.

NATS From the Cosmos to Earth The Scientific Method

NATS From the Cosmos to Earth Hallmarks of Science Modern science seeks explanations for observed phenomena that rely solely on natural causes. Science progresses through the creation and testing of models of nature that explain the observations as simply as possible. A scientific model must make testable predictions about natural phenomena that would force us to revise or abandon the model if the predictions do not agree with observations.

NATS From the Cosmos to Earth The idea that scientists should prefer the simpler of two models that agree equally well with observations - the second hallmark - after medieval scholar William of Occam ( ). For instance, original model of Copernicus (Sun-centered) did not match the data noticeably better than Ptolemy's model (Earth-centered). Thus, a purely data-driven judgment based on the third hallmark might have led scientists to immediately reject the Sun-centered idea. Instead, many scientists found elements of the Copernican model appealing, such as the simplicity of its explanation for apparent retrograde motion. Was kept alive until Kepler found a way to make it work. Occam’s Razor

NATS From the Cosmos to Earth The most exciting words in science are not “Eureka (I found it)” but “Now that’s funny”.

NATS From the Cosmos to Earth MOTIONS OF EARTH 1. ROTATION ON ITS AXIS - Day 2. REVOLUTION ABOUT SUN - Year 3. PRECESSION - Wobble of spin axis

NATS From the Cosmos to Earth MotionTypical Speed rotation1,000 km/hr or more around axis, with one rotation taking 1 day orbit of Sun100,000 km/hr around Sun, with one orbit taking 1 year motion within local solar neighborhood 70,000 km/hr relative to nearby stars rotation of the Milky Way Galaxy 800,000 km/hr around galactic center, with one galactic rotation taking about 230 million years motion within Local Group300,000 km/hr toward Andromeda Galaxy universal expansionmore distant galaxies moving away faster, with the most distant moving at speeds close to the speed of light Motions of Earth

NATS From the Cosmos to Earth The Earth rotates about its axis axis once per day - one rotation equals one day. The axis goes through the north and south poles and through the center of the Earth. It rotates counterclockwise when looking down on the north pole which means that the sun rises in the east and sets in the west. Rotation

NATS From the Cosmos to Earth The Rotation of the Earth From Space

NATS From the Cosmos to Earth Earth’s rotation causes the stars - the celestial sphere - to appear to rotate around the Earth. Viewed from outside, the stars (and the Sun, Moon, and planets) therefore appear to make simple daily circles around us. The red circles represent the apparent daily paths of a few selected stars.

NATS From the Cosmos to Earth The Celestial Sphere Envisioned by the ancients, the celestial sphere had Earth at the center with the stars emblazoned on the sphere. They thought the stars rose and set because the celestial sphere (the sky) rotated, carrying the stars from east to west. All stars appear to move around two points on the celestial sphere, the north and south celestial poles—projections of earth’s axis of rotation. Earth's equator projected on the celestial sphere becomes the celestial equator.

NATS From the Cosmos to Earth Our lack of depth perception when we look into space creates the illusion that the Earth is surrounded by a celestial sphere. Thus, stars that appear very close to one another in our sky may actually lie at very different distances from Earth.

NATS From the Cosmos to Earth Constellations Constellations - groupings of stars named after mythical heroes, gods, and mystical beasts - made up over at least the last 6000 years - maybe more - used to identify seasons: - farmers know that for most crops, you plant in the spring and harvest in the fall. - in some regions, not much differentiation between the seasons. - different constellations visible at different times of the year - can use them to tell what month it is. For example, Scorpius is only visible in the northern hemisphere's evening sky in the summer. - many of the myths associated with the constellations thought to have been invented to help the farmers remember them - made up stories about them

NATS From the Cosmos to Earth Picture at right shows a start chart of the region around the constellation Orion. Picture at the left is an ornate star chart printed in shows the great hunter Orion. He is holding a lion's head instead of his traditional bow or shield. He is stalking Taurus, the Bull in the upper right hand corner. Behind him, his faithful dog, Canis Major, is chasing Lepus, the Hare.

NATS From the Cosmos to Earth In modern world - constellations redefined so now every star in the sky is in exactly one constellation. In 1929, the International Astronomical Union (IAU) adopted official constellation boundaries that defined the 88 official constellations that exist today. Constellations Western culture constellations originated in Mesopotamia over 5000 years ago - added to by Babylonian, Egyptian, and Greek astronomers - current list based charts of Roman astronomer, Claudius Ptolemy (~140 AD)