### person | scientist:

Astronomer
* All astronomers can do is look at the light from stars and galaxies
  - watch the sky
* Many astronomers are physicists.
* Many astronomers believe quasars are a more energetic version of nearby active galaxies
  - that the early solar system was a swirling cloud of dust and gas
  - consider the turn of the millennium a golden age for X-ray astronomy
  - now believe that most galaxies have massive black holes at their centres
  - specialise in particular areas of astronomy, called fields
  - theorize that Jovian lightning is also created in clouds containing water ice
  - think that advanced life is widespread in our galaxy
* Many astronomers work at observatories and use powerful telescopes to study the universe
  - with the sole aim of improving scientific knowledge
* Most astronomers are creatures of the night
  - employed by colleges and universities
  - assume that the gas is heated by the magnetic field that pervades the corona
  - believe black holes do exist and are really quite common
* Most astronomers believe that comets originated at the same time as the solar system
  - massive black holes power quasars
  - quasars are unrelated to the peculiar galaxies
  - that, at the centre of an active galactic nuclei, lies a black hole
  - calculate size
  - create diagrams
* Most astronomers describe motion
  - positions
* Most astronomers determine ages
  - orbits
* Most astronomers discover chemical elements
  - nebulas
  - employ scientific methods
  - estimate circumferences
* Most astronomers examine clouds
  - molecular clouds
* Most astronomers have observations
  - space telescopes
* Most astronomers help citizen scientists
  - learn about phenomena
* Most astronomers make calculations
  - discoveries
  - important discoveries
  - measure brightness
  - monitor weather patterns
  - now believe it is made of mostly hydrogen, liquid inside and gas on the surface
  - study different phenomena
  - understand size
* Most astronomers use cameras
  - eyes
  - large telescopes
  - measurements
  - notation
  - optical telescopes
  - radio telescopes
  - scientific notation
  - tools
  - visit observatories
* Most astronomers work full time, and sometimes have to work irregular hours
  - with scientists
* Some astronomers accept big bang theories
  - become photographers
* Some astronomers believe that hundreds of thousands more exist in our Galaxy
  - the halo formed first
  - build detectors
  - calculate brightness
  - come to earth
  - commit suicide
  - compare brightness
* Some astronomers contribute to astronomical discoveries
  - many important astronomical discoveries
  - create maps
  - define measurements
* Some astronomers determine angular diameters
  - develop theories
  - die in prisons
* Some astronomers discover concentration
  - degrees
  - rings
* Some astronomers estimate ages
  - dimensions
  - even watch for meteorite impacts on our moon during meteor showers
  - focus their research on objects in our solar system, such as the sun or planets
  - gather in the sand, under clear, bright skies to look at heavenly bodies
  - guess that comets have low densities, perhaps less than half that of water ice
* Some astronomers have civilizations
  - missions
  - to work in museums housing planetariums
  - identify optical images
  - learn evolution
  - look at positions
  - make measurements
  - measure size
  - point out rings
  - predict existence
  - rely on techniques
* Some astronomers say that comets bombarding the early Earth provided atmospheric gases too
  - they are the result of black holes gobbling up their companion stars
  - think that a gravitational or magnetic disturbance causes the nebula to collapse
* Some astronomers use computers
  - emissions
  - horizons
  - indexes
  - satellites
  - work full time in observatories
* Some astronomers work in business or private industry
  - offices
  - write paper
* act as children.
* adapt the Earth's orbit to make a huge rangefinder.
* advocate lighting that is shielded with reflectors.
* aim for shortest submillimeter wavelengths.
* already know that the early history of the universe was very dynamic.
* also categorize galaxies by how much energy they produce in their cores
  - hope to see jets of dust emerging from the comet's nucleus
  - measure distances, but they are on a different scale from the ones noted above
  - refer to a certain kind of variable star as an eclipsing binary
  - study stars by passing their light through a glass prism or a diffraction grating
  - suspect that many galaxies have extremely massive black holes at their centers
* always try to make things as easy as possible for themselves.
* analyze spectra and images of a celestial body to get a complete picture.
* announce discoveries.
* answer questions about the Sun and the solar eclipse.
* apply the laws of spectroscopy in analyzing radiation from beyond Earth.
* appreciate functions.
* are able to calculate past and future passes of comets based on present behavior
  - gage the mass of the planets if they have an idea of how far away they are
* are able to look back in time, by observing galaxies at ever greater distances
  - in detail only at the sun's closest neighbors
  - artwork
  - eager for observations of the sun's corona, or outer atmosphere
* are especially interested in the voids between the superclusters
  - keen to predict destructive solar storms
  - experts on the properties of light
  - interested in pulsars for a number of reasons
  - likely to know more about astronomy and technology
  - people who watch and study the sky
  - pretty sure in general how stars form
  - scientists that use remote sensing to study the stars
* are still uncertain about how the Earth s atmosphere formed
  - as to where our sun's magnetic field comes from
  - workers
  - wrong about the distances to stars and galaxies
* assert that some stars are a million light-years from the earth.
* attempt to understand the origins and shape of the universe.
* base their studies on research and observation.
* believe a star forms from a rotating cloud of dust and gas
  - some twenty thousand billion billion stars exist in the universe
* believe that Mars once sustained life
  - Titan's atmosphere resembles Earth's, with clouds and rain
  - a single set of equations governs the structure of all stars
  - black holes emit strong amounts of x-rays
  - both types of quasars are fueled by massive black holes
  - many black holes are to be found in the Milky Way
* believe that most comets eventually just disintegrate and disappear
  - galaxies harbor massive black holes at their centers
  - planets form from the swirling debris around nascent stars
  - radio telescopes offer the best way to find intelligent life in space
  - seven binary star systems they have observed probably contain black holes
  - supernovas occur in our galaxy roughly once every hundred years on average
* believe that the atmosphere is being driven by heat flowing from the interior
  - lightning observed in Saturn is the strongest ever seen
  - there vast amount of dark matter surrounding our galaxy
  - the Kuiper Belt is filled with hundreds of thousands of small, icy objects
  - there's no air on there because they've never tryed to breathe up there
* believe they are primordial remnants, left over from the birth of the Milky Way
  - volcanic vents, which are a scant few million years old
  - have calculated the age of the cosmos more accurately than ever before
* calculate orbits based on multiple observations of an object's exact position
* calibrate new telescopes with an image of a point source.
* call apparent magnitude m.
* call it the 'photosphere'
  - small stars dwarfs
* can also calculate Earth's mass by observing the motion of orbiting satellites
  - discover some black holes and neutron stars because they are sources of x-rays
* can estimate that time by measuring how fast the universe is expanding now
  - the age of the universe by studying globular clusters
  - examine the skies constantly and without atmospheric interference
  - explore the global cosmological structure of the universe
  - learn the most about the distant universe from rare and unusual objects
  - look at starlight and tell what the star is made of
* can measure a cluster's age by analyzing the light of the stars within it
  - stars by the amount of energy that they transmit
  - nevertheless study the Venusian surface with radar telescopes
  - now measure differences as small as one-hundredth of a magnitude
  - prove that neutron stars exist, because they give off a unique distress signal
* can tell stars are ringing when their brightness varies in characteristic ways
  - the mixture of elements in a star from the colour of the light it emits
  - then separate stars from quasars by their distinctive colors
  - trace the X-ray jet all the way into the neutron star
* can use a filter on their telescopes to block that color of light
  - telescopes to look at very distant galaxies
  - watch the same phenomena on the sun
* catch glimpses.
* caution observers to never look directly at the sun, including during a solar eclipse.
* challenge aspects.
* characterize the morphology of a globular cluster by means of standard radii.
* choose a fixed point on that circle and measure the motion of the sun from there.
* claim there limit to our universe.
* classify asteroids into two broad groups based on their composition
  - comets based on the durations of their orbits around the sun
* classify galaxies according to their shape and appearance
  - into three major categories
  - most galaxies by shape as either spiral galaxies or elliptical galaxies
* come from many backgrounds and countries and include both women and men.
* consider any chemical element heavier than hydrogen a metal
* construct hypotheses called cosmological models that try to find the answer.
* count the galaxies that are most easy to see.
* deal with quantities ranging from the truly microcosmic to the macrocosmic
  - some of the largest numbers
* decry excessive light levels for obstructing the view of the skies.
* define the reflectivity of an object in space using a term called albedo.
* demonstrate existence.
* describe how most asteroids orbit in a belt between Mars and Jupiter
  - to calculate the age of the universe
* detect gamma-ray bursters almost every day
  - new long-period comets at the rate of about one per month
  - redshift of distant objects by looking at the spectra
  - conditions
  - the distance to a faraway object by measuring the object's red shift
* discover about ten supernovas in distant galaxies each year
  - hundreds of quasars, radio galaxies, and active galaxies
* discover rings around Uranus, making Saturn no longer the only planet with rings
  - unique link between stellar death and birth
* divide stars into different spectral types.
* do it in the dark
  - under the stars
* do it with lenses
  - mirrors
  - young stars
  - something similar when they study the stars
  - the same sort of thing using the inverse square law of light
* draw knowledge.
* employ methods
* encounter statistical issues frequently during their research.
* enjoy books.
* establish existence.
* estimate that the universe is billions of years old
  - there are millions of cold clouds in the Milky Way
  - within that distance the sky holds roughly a million sun-like stars
  - the speed at which a galaxy is moving away by measuring the galaxy's red shift
  - there are roughly a trillion galaxies
  - the positions, motions, and properties of celestial objects
* expect the comet to be as bright as the brightest stars when it passes Earth
  - northern half of the moon to be a richer red than the southern half
* explain how the strength of spectral lines is related to stellar temperatures.
* explain the composition of meteorites and various theories about their origin
  - solar nebula theory that explains how our solar system was formed
* express distance in terms of redshift
  - the brightness of celestial objects in terms of units called magnitudes
* fall in two classes - professionals and amateurs.
* feel that astrology delusion.
* find Saturn-sized planets in other solar systems
  - clumps of galaxies tied together by loose bonds of gravitation
  - evidence
  - examples
  - forms of the cycloidal curves in various coronas
  - no evidence for a systematic rotation of the universe
* function like detectives, looking for clues to solve mysteries.
* generally believe that Jupiter's core was formed by the accumulation of icy volatiles.
* get images.
* go on attacks
  - up into the stratosphere and make sure their instruments work right
* have a model of stars as giant nuclear reactors that burn hydrogen to make helium
  - number of ways to measure the distance to stars
  - different ideas
  - explanations
  - long dreamt of a pristine observing sight with no air turbulence or pollution
  - more than saros periods with which to count
  - no control over the events that they study
  - several coordinate systems and several time measurement systems to choose from
* have the same task when classifying stars
  - unique ability to look back in time as they look far out into space
  - their organizations as well
  - to tax their intellect to justify their value to society
  - wide-ranging opinions on the existence of extraterrestrial intelligent life
* identify numerous types of dwarf galaxies, based on their shape and composition.
* identify the presence of elements millions of light years away by their spectra
  - of light years distant by their spectra
* includes arms
  - body substances
  - cell membranes
  - cells
  - corpi
  - cytoplasm
  - heads
  - human bodies
  - legs
  - material bodies
  - necks
  - personality
  - plasma membranes
  - sections
  - vacuoles
* keep a master list of asteroids with well-determined orbits
  - record of their observations
* know of several variations of supernovas, but they all fall into one of two main types
  - pretty accurately how fast galaxies are moving by their color
* know that the more massive a star is the more rapidly it evolves
  - younger stars are typically hotter and brighter than older stars
  - the universe is awash with the stuff of life
* learn about interest phenomena
  - the final evolutionary paths of massive stars from supernovas
  - ringing truths about the sun
  - to be problem solvers and pick up lots of math and computer skills
* like to measure angles in seconds of arc.
* locate stars by reference to the constellations.
* look for new moons, asteroids and comets by tracking their motion
  - the bright stars that orbit dark partners in the same way
* love to talk about their hobby and are normally happy to explain things at length.
* make calculations based on the sky as it is by observation at the present time
  - computer models of the evolution of stars
  - contributions
  - progress
  - total meteorite-mass measurements in a variety of ways
* measure brightness in units of magnitude
  - the angle of stars in the sky throughout the year
* measure the brightness of stars by their apparent magnitudes
  - in Magnitudes
  - distance from the sun to each planet in astronomical units
  - parallax of a star using Earth's orbital diameter as a baseline
  - resolving power of a telescope in terms of degrees
* monitor patterns
* name some stars by the constellation they are in and their position or brightness.
* need backgrounds.
* normally try to use the largest aperture they can to capture as much light as possible.
* now believe that a nova consists of two stars in tight orbits around each other
  - blue stragglers are created by the merger of two low-mass stars
  - the source cloud of gas from between the stars
  - two are really one great belt filled with particles
  - estimate that there are tens of billions of galaxies in the observable universe
  - exploit wide regions of the full electromagnetic spectrum
  - know the orbits of nearly half a million individual asteroids in the asteroid belt
  - see engineering as a crucial component of making advances in knowledge
  - study comets from a scientific viewpoint
* now think that planets form readily, grow quickly, and for the most part, die young
  - there is 'something' which inhibits internal convection in Uranus
  - when a galaxy has a quasar , the quasar changes the galaxy
  - use the constellations mainly as a convenient way to name regions of the sky
* observe comets in different spectrums in order to measure their chemical content
  - dramatic changes in the system during the months before and after periastron
* observe the apparent magnitude of the stars
  - locations and motions of heavenly bodies
* officially recognize nine major planets.
* often believe that the significance of their work is self-evident
  - choose very faint objects in the sky to study
* often refer to asteroids as minor planets
  - the light bucket of a telescope
* pick up the radio waves only when the pulsar's beam sweeps across the Earth.
* plan projects, make observations, study results, and figure out theories.
* play active roles
  - significant roles
* point telescopes.
* possess ability.
* provide evidence.
* publish paper.
* rate the size of sunspots in terms of millionths of the sun's earth- facing hemisphere.
* reach consensus.
* realize results.
* receive information from the sky.
* record eclipse.
* refer to Venus as Earth's sister planet
  - such couplings of bright planets as conjunctions
  - the aging process as heat death
* repeat calculations.
* report witnessing the largest explosion ever recorded in the universe.
* sample part of the sky to count the number of stars in the whole sky.
* say it's actually a regular occurrence as the Earth travels through the comet's tail.
* say the darkest skies in the world occur in the Australian Outback
  - difference between planets and brown dwarfs is based on how they formed
  - they are mainly made of iron and stony materials
* search the skies for many things.
* see evidence of first light in Universe
  - stars form, because star formation is an ongoing process
  - the emitted radio waves as radio pulses
* seek ever-larger mirrors to increase the power and efficiency of telescopes
  - the recipe of stars, galaxies, and other celestial objects through spectroscopy
* simplify their timekeeping by simply counting the days.
* speak of two kinds of zeniths, astronomical zeniths and geocentric zeniths.
* specialty of Physicists.
* speculate that the dust nearer to the star has been largely consumed in making planets.
* spend most of their lives in the dark
  - weeks or months or years analyzing their data using computers
* still don t understand the origins of gamma ray bursts
  - use the same principle today to find out how far away stars are from the earth
* study black holes by investigating X-rays coming from binary systems
  - movement
  - multiple wavelengths in order to learn more about the objects of the universe
* study the light emanating or reflected from distant objects
  - spectrum of the Sun to determine it's chemical composition
  - stars, the planets, and everything else in our universe
  - sun and other stars using telescopes
  - sun, moon, planets, stars, and galaxies
  - time to seek out the answer
* suggest the supermassive black holes are the remains of fossil quasars.
* take notes.
* talk about heat death when they discuss stars.
* tend to work with industry to extract more from the available technology.
* theorize that the gaseous knots are the results of a collision between gases.
* therefore make heavy use of physics, mathematics, and computer science
  - recognize different kinds of year
  - use a larger unit to measure stellar distances
* think both types of quasars are powered by massive black holes
  - most galaxies harbor a black hole at their centers
  - of infrared in terms of exceedingly long-range signals
* think that massive stars end their existence in titanic explosions called supernovae
  - quasars are located in galaxies which have black holes at their centers
  - stellar black holes are what are left from a burned out star
* think that the black hole glows in X-rays as it swallows nearby clouds of gas and stars
  - elliptical galaxies are older than the spiral ones
* think the rings are dark, because there is no dust for the sunlight to reflect off of
  - solar system is more than four billion years old
  - there are a few times the mass of the Earth in rocky material deep down inside
* think they are created during the universe's most cataclysmic events
  - understand how stars are born
* thus use time to measure distances, and the scale is based on the speed of light.
* to compare patterns
  - gain knowledge
  - measure characteristics
* to study details
  - understand characteristics
* try to measure it all the time.
* use a day called a sidereal day
  - distance unit called parsec
  - logrithmic scale for the brightness of stars called the magnitude system
  - special trick to keep bright flashlights from ruining their night vision
* use a technique called blinking to find objects that move from one image to the next
  - gravity lensing to search for black holes and neutron stars
  - parallax to precisely measure to distance to stars in the sky
  - an effect called parallax to measure distances to nearby stars
  - constellations like location names on the sky map
  - degrees to give the relative placement of objects
  - effects
  - emission lines to identify the composition of stars
  - extensive observations
  - huge telescopes in places called observatories for studying the stars
  - instruments such as bolometers to detect it
  - it to calculate the masses of stars in binary systems
  - lasers and computers to measure the amount of distortion
  - light, which moves in straight lines
  - magnetograms when they study sunspots
  - magnitudes to describe the brightness of an object in the sky
  - measurements of the red shift of stars and galaxies as a distance indicator
  - much the same measurements as do other scientists
* use parallax to find the distances to remote planets or stars
  - when measuring the distances to the planets by triangulation
  - physics and mathematics to learn about the universe and all it contains
  - seconds to measure short periods of time
  - similar coordinate systems to locate objects on the celestial sphere
  - spectroscopes, which separate different wavelengths of light from a single source
  - standard candles to measuring distances
  - star charts to locate stars and other objects
  - supernova data to estimate a distance to the supernova
  - telescopes in space to record the gamma-ray bursts
* use telescopes to collect radiation from astronomical sources
  - look at things that are far away and dim
* use the difference between transmitted and reflected light to observe sunspots
  - magnitude scale for describing the brightness of stars
  - principle of parallax to measure distances to the closer stars
  - principles of physics and math to learn about the nature of the universe
* use the same kinds of angular measurements to find the objects they want to observe
  - principle to calculate the distances to the nearer stars
  - technique to measure the distances to planets and stars
  - sidereal year for comparison purposes
* use the technique in telescopes to grab ever-better photos of the heavens
  - of spectroscopy to analyse the light from individual stars
  - term zenith to describe the point directly overhead
  - triangulation to determine distances within the solar system
  - two basic techniques to measure distances
  - very large telescopes to gather as much of light as they can
+ Astronomy, Fields
  * Astronomy is a very large subject with many different things to study. Many astronomers specialise in particular areas of astronomy, called fields
  - Methodology, Instrumentation
  * Telescopes take all the light in a big area and put in into a small area. This is like making your eyes very big and powerful. Astronomers use telescopes to look at things that are far away and dim. Telescopes make objects look bigger, closer, brighter
+ Quasar: Galaxies
  * Astronomers now think that when a galaxy has a quasar, the quasar changes the galaxy. Gas and dust from the galaxy falls onto the quasar, and the bright quasar heats up gas in the galaxy. This stops new stars from forming in the galaxy, so many of the elliptical galaxies we see in the universe now may have once had a quasar in their centers.
+ Saturn, Exploration
  * Cassini observed lightning occurring in Saturn since early 2005. The power of the lightning was measured to be 1,000 times more powerful than lightning on Earth. Astronomers believe that the lightning observed in Saturn is the strongest ever seen.
  * Astronomers can use telescopes to look at very distant galaxies. Like this they see what the universe looked like a long time ago. This is because the light from distant parts of the universe takes a very long time to reach us. From these observations, it seems the physical laws and constants of the universe have not changed.