“We are all connected; To each other, biologically. To the earth, chemically. To the rest of the universe atomically.” ~ Neil deGrasse Tyson.

• “We are all connected; To each other, biologically. To the earth, chemically. To the rest of the universe atomically.” 

~ Neil deGrasse Tyson

Stars & GalaxiesStars & Galaxies

Even on the clearest night, the human eye can only see about 3,000 stars. There are an estimated 100,000,000,000 in our galaxy alone!

If you could travel at the speed of light (186,000 miles per second) it would take 100,000 years to cross our galaxy

StarsStarsConstellationsConstellations

• Patterns of stars representing Patterns of stars representing mythological characters, mythological characters, animals, or familiar objects.animals, or familiar objects.

• Most constellations come from Most constellations come from the Greeks.the Greeks.

• The stars in a constellation may The stars in a constellation may appear close, however each star appear close, however each star can be millions of light-years can be millions of light-years away from each other.away from each other.

• There are 88 constellations used There are 88 constellations used to divide the night sky.to divide the night sky. Vega was the

north star around 12,000 BC and will be so again around AD 13,727

Circumpolar ConstellationsCircumpolar Constellations Constellations that appear to circle around the Constellations that appear to circle around the

North Star, Polaris.North Star, Polaris. These constellations are visible all year and These constellations are visible all year and

never go below the horizon.never go below the horizon.Ursa Major, Ursa Minor, Draco, Cepheus, Ursa Major, Ursa Minor, Draco, Cepheus,

Cassiopeia, CamelopardalisCassiopeia, Camelopardalis

Zodiac ConstellationsZodiac Constellations 12 constellations that line up on the 12 constellations that line up on the

ecliptic with the planets.ecliptic with the planets. For about a month, one of these For about a month, one of these

constellations is hidden behind the Sun.constellations is hidden behind the Sun.

Vega is rotating rapidly with a velocity of 274 km/s at the equator.

Absolute & Apparent MagnitudeAbsolute & Apparent Magnitude• Absolute Magnitude refers to the measure of light Absolute Magnitude refers to the measure of light

that a star actually gives off.that a star actually gives off.• Apparent Magnitude refers to the amount of light Apparent Magnitude refers to the amount of light

the Earth receives from the star.the Earth receives from the star.

The largest recorded starquake occurred on the neutron star SGR 1806-20. It was a 22.7 on the Richter scale. The quake released enough gamma radiation that had it been within 10 ly of Earth (it is 50,000 ly away) it would likely have caused a mass extinction.  

Measurement in SpaceMeasurement in Space• Parallax- the apparent shift in the position of an Parallax- the apparent shift in the position of an

object when viewed from two different positions.object when viewed from two different positions.» The closer the object is to the observer, the greater The closer the object is to the observer, the greater

the parallax.the parallax.

Light-years- the distance light travels in one year Light-years- the distance light travels in one year (9.5 trillion km in one year.)(9.5 trillion km in one year.)»Proxima Centauri is the closest star to the Sun Proxima Centauri is the closest star to the Sun

at 4.3 ly.at 4.3 ly.

Properties of StarsProperties of Stars• Temperature- determined by the star’s “surface” Temperature- determined by the star’s “surface”

color.color.

From hottest to coolest:From hottest to coolest:

BlueBlue

Blue-whiteBlue-white

WhiteWhite

Yellow-whiteYellow-white

YellowYellowRed-orangeRed-orange

RedRed

CompositionComposition Observed from the light given off by the star Observed from the light given off by the star

using a spectroscope.using a spectroscope. A prism in the spectroscope divides the light A prism in the spectroscope divides the light

into its component colors.into its component colors. The colors present/absent in the The colors present/absent in the spectrum spectrum

indicate the elements present in the star. Similar indicate the elements present in the star. Similar to a fingerprint.to a fingerprint.

The telescope on Mount Palomar, California, can see a distance of 7,038,835,200,000,000,000,000 miles.

HydrogenHydrogen

HeliumHelium

CarbonCarbon

The SunThe Sun

The Sun’s LayersThe Sun’s Layers• The Sun is a giant ball of gas/plasma.The Sun is a giant ball of gas/plasma.Core- hydrogen is fused into helium giving off Core- hydrogen is fused into helium giving off

massive amounts of energy massive amounts of energy (Nuclear Fusion.) (Nuclear Fusion.) above 15 million K.above 15 million K.

Radiative/Convection Zones- area through which the Radiative/Convection Zones- area through which the energy travels outwards.energy travels outwards.

Atmosphere- outermost region of the SunAtmosphere- outermost region of the Sun

If a pinhead-size piece of the Sun were placed on Earth, one would have to stand as far as 145 kilometers (90 miles) away to be safe.

The sun is….109 Earths across93 million miles away176 years away at 60 mph

Temperatures on the sun range from 7000 to 27,000,000° F

Gravity on the sun is 30 times stronger. 70 lbs on Earth would be 1 ton on the sun

It would take 1,300,000 Earths to fill the sun.

You could string 340 Earths around the equator of the Sun

The Sun’s AtmosphereThe Sun’s AtmospherePhotosphere- lowest layer of the Sun’s Photosphere- lowest layer of the Sun’s

atmosphere. atmosphere. This is considered the “surface” because this is This is considered the “surface” because this is

the part we see from Earth. the part we see from Earth. Sun’s photosphere is yellow at 6000KSun’s photosphere is yellow at 6000KChromosphere- layer above the photosphere.Chromosphere- layer above the photosphere.

Corona- highest & largest layer.Corona- highest & largest layer. Charged particles reach 2 million KCharged particles reach 2 million K

The Earth orbits the sun at an average speed of 107,220 kms per hour.

1.1. CoreCore2.2. Radiative ZoneRadiative Zone3.3. Convection ZoneConvection Zone4.4. PhotospherePhotosphere5.5. SunspotSunspot6.6. ChromosphereChromosphere7.7. CoronaCorona

The light hitting the earth right now is 30 thousand years old. The energy in the sunlight we see today started out in the core of the Sun 30,000 years ago – it spent most of this time passing through the dense atoms that make the sun and just 8 minutes to reach us once it had left the Sun! The temperature at the core of the sun is 13,600,000 kelvins. All of the energy produced by fusion in the core must travel through many successive layers to the solar photosphere before it escapes into space as sunlight or kinetic energy of particles.

If the sun were the size of a dot on an ordinary-sized letter 'i', then the nearest star would be 10 miles away.

Mass of the sun is 330,000 bigger than Earth. Sol has 600 times more mass than all the planets put together!

““Surface” FeaturesSurface” FeaturesSunspots- cooler dark areas Sunspots- cooler dark areas

Appear & disappear regularly Appear & disappear regularly Magnetic stormsMagnetic stormsProminences- huge, arching columns of gas.Prominences- huge, arching columns of gas.Flares- violent eruptions of particles near Flares- violent eruptions of particles near

sunspots.sunspots.Solar Winds- particles ejected from the Sun’s Solar Winds- particles ejected from the Sun’s

corona.corona. Bounce of the Earth’s atmosphere causing the Bounce of the Earth’s atmosphere causing the

auroras.auroras.

There is a current scientific hypothesis that the sun possibly has a companion which is currently about 1-1.5 light years away. It is believed that it has an elliptical orbit which, every 26 million years, sends matter towards the earth causing mass Extinction events. The star is predicted to be most likely a red or brown dwarf and has been named Nemesis or “Death Star”.

SunspotsSunspots

Solar FlaresSolar Flares

ProminencesProminences

The Sun loses up to a billion kilograms a second due to solar winds

Scientists haven’t been able to work out how Stradivari (famous violin maker) made his violins but they think it is due to the wood he used. From 1500s to 1800s the earth underwent a mini ice age due to volcanic activity and decreased solar activity. As a result of the cooling, the trees he used were particularly hard (due to slow growth). If he hadn’t had those trees to work with, his violins might now have been so highly prized.

The Sun – An Average StarThe Sun – An Average Star• Middle-aged star, average absolute magnitude, & Middle-aged star, average absolute magnitude, &

average temperature.average temperature.Multiple star systemsMultiple star systems The Sun is NOT part of a multiple star system The Sun is NOT part of a multiple star system

unlike most stars.unlike most stars.2 stars is a binary system, 3 stars is a triple-star 2 stars is a binary system, 3 stars is a triple-star

system (Alpha Centauri system (Alpha Centauri system)system)Star ClustersStar ClustersStars that are so close that they move together as Stars that are so close that they move together as

a unit.a unit.

III. Evolution of StarsIII. Evolution of StarsClassifying StarsClassifying StarsHetrzsprung-Russell DiagramHetrzsprung-Russell Diagram

• Ejnar Hertzsprung & Henry Ejnar Hertzsprung & Henry Russell independently charted Russell independently charted the relationship between a the relationship between a star’s temperature to its star’s temperature to its absolute magnitude.absolute magnitude.

• It showed that the hotter stars It showed that the hotter stars are also the brightest stars, are also the brightest stars, with a few exceptions.with a few exceptions.

• 90% of all stars fit into a 90% of all stars fit into a diagonal line in the middle of diagonal line in the middle of the graph (Main Sequence.)the graph (Main Sequence.)

The Main SequenceThe Main Sequence Contains hot, blue giant stars that are very bright Contains hot, blue giant stars that are very bright

to cooler, red dwarf stars that are very dim.to cooler, red dwarf stars that are very dim. Yellow, medium sized stars are in the middle of the Yellow, medium sized stars are in the middle of the

Main Sequence like the Sun.Main Sequence like the Sun.

Dwarfs, Giants, & SupergiantsDwarfs, Giants, & Supergiants 10% of stars are not main sequence.10% of stars are not main sequence. Stars that are very hot (white-blue,) but are dim are Stars that are very hot (white-blue,) but are dim are

called the White Dwarfs.called the White Dwarfs. Stars that are cooler (red-orange,) but are very Stars that are cooler (red-orange,) but are very

large and bright are called the Red Giants.large and bright are called the Red Giants. The biggest, coolest, & brightest stars are the Red The biggest, coolest, & brightest stars are the Red

Supergiants.Supergiants.

Medium to Red GiantMedium to Red Giant

The Solar SystemThe Solar System

The star "Lucy" in constellation Centaurus is actually a huge cosmic diamond of 10 billion trillion trillion carats.

Giants to SupergiantsGiants to SupergiantsThe star Antares is 60,000 times larger than our sun. If our sun were the size of softball, the star Antares would be as large as a house.

Nuclear FusionNuclear Fusion

• Four hydrogen nuclei combine to create Four hydrogen nuclei combine to create one helium nucleus.one helium nucleus.

• The mass of one helium nucleus is much The mass of one helium nucleus is much less than 4 hydrogen nuclei, so some of the less than 4 hydrogen nuclei, so some of the mass is lost in the reaction.mass is lost in the reaction.

• The lost mass is converted into large The lost mass is converted into large amounts of energy in the form of light. amounts of energy in the form of light. (Temps in the core exceed 15 million K)(Temps in the core exceed 15 million K)

ProtostarProtostar

Evolution of Stars (Cosmology)Evolution of Stars (Cosmology)

Step 1. Nebula-stars start out as clouds of dust & Step 1. Nebula-stars start out as clouds of dust & gas. Gravity pulls it together.gas. Gravity pulls it together.

Step 2. Protostar-the mass of gas gets bigger & Step 2. Protostar-the mass of gas gets bigger & bigger eventually heating up to 10 million K bigger eventually heating up to 10 million K causing fusion.causing fusion.

Step 3. Main Sequence- when the pressure formed Step 3. Main Sequence- when the pressure formed by the heat balances the attraction due to gravity it by the heat balances the attraction due to gravity it reaches equilibrium.reaches equilibrium.

NebulaNebulaMainMain

SequenceSequence

Pillars of Creation refers to a photograph taken by the Hubble Telescope of elephant trunks of interstellar gas and dust in the Eagle Nebula, some 7,000 ly from Earth

The Pillars of Creation no longer exist. In 2007, astronomers announced that they were destroyed about 6,000 years ago by the shock wave from a supernova.  Because of the limited speed of light , the shock wave's approach to the pillars can currently be seen from Earth, but their actual destruction will not be visible for a 1000 years.

Gomez’s Hamburger is a young star surrounded by a protoplanetary disk about 900 light-years away.

Step 4. If it has:Step 4. If it has:Small MassSmall Mass

» Red dwarf stars with eventually run Red dwarf stars with eventually run out of hydrogen and will collapse out of hydrogen and will collapse into a hot, White Dwarf.into a hot, White Dwarf.

Medium MassMedium Mass» Yellow or white stars that will run Yellow or white stars that will run

out H causing the atmosphere to out H causing the atmosphere to expand and cool into a Red Giant.expand and cool into a Red Giant.

» He will fuse into a carbon.He will fuse into a carbon.» It will eventually collapse into a It will eventually collapse into a

White DwarfWhite Dwarf

Because the Sun is hottest at its center, it will use up the hydrogen at its center first. Then, over the next few hundred million years, it will fuse hydrogen in a spherical shell around the center of the star. In this phase, the Sun will turn into a red giant. The center of the Sun will not be hot enough to fuse helium, and will be surrounded by a layer where there is hydrogen still burning. After a few hundred million years, the helium core will grow large enough that the temperature and pressure near its core will be hot enough to start burning helium.

List of things that fuse in a star. All but the fusion of iron is exothermic.

Large Mass StarsLarge Mass Stars» Blue stars will expand into Red Giants when they Blue stars will expand into Red Giants when they

run out of hydrogen and helium fuses into carbon.run out of hydrogen and helium fuses into carbon.

» Carbon will then fuse into heavier & heavier Carbon will then fuse into heavier & heavier elements causing the star to expand further into a elements causing the star to expand further into a Red Supergiant.Red Supergiant.

» When iron is formed from fusion, iron can’t be When iron is formed from fusion, iron can’t be

fused so the star collapses violently in a fused so the star collapses violently in a Supernova.Supernova.

SN 2006gy was an extremely energetic supernova , sometimes called a hypernova,  that was discovered on September 18, 2006. SN 2006gy occurred in a distant galaxy, approximately 238 million light years away. Therefore, the event occurred about 238 million years ago. Preliminary indications are that it was around 150 solar masses. 

»Depending on the mass of the core, one of the Depending on the mass of the core, one of the following will occur:following will occur:

Neutron Star- smaller cores will produce a dense Neutron Star- smaller cores will produce a dense core of neutrons about 20km in diameter.core of neutrons about 20km in diameter.

A neutron star is the strongest magnet in the universe.

Neutron stars are so dense, that a soup can full of neutron star material would have more mass than the Moon.

4 to 8 times the size the sun -supernovae. This blows a star's outer layers into space, the core remains—but it no longer produces nuclear fusion. With no outward pressure from fusion to counterbalance gravity's inward pull, the star condenses and collapses in upon itself.

At 12.5 miles (20 kilometers)—neutron stars boast nearly 1.5 times the mass of our sun, and are thus incredibly dense. Just a sugar cube of neutron star matter would weigh about one hundred million tons on Earth.

There is a neutron star that spins on its axis at 1,122 times every second.

compression from the star's gravity will be so great the protons fuse with the electrons to form neutrons

Black Hole- larger cores will Black Hole- larger cores will collapse to a super dense collapse to a super dense point. The gravity near this point. The gravity near this mass is so strong nothing can mass is so strong nothing can escape from it, not even light. escape from it, not even light. Locate using X-rays.Locate using X-rays.» Event Horizon is the area » Event Horizon is the area where nothing can escape.where nothing can escape.

Black holes can’t suck up all of the matter in the Universe. Each black hole has its own event horizon, much like the gravitational field of a planet. If matter is not in that horizon it will never get sucked into the black hole.

there is a super massive black hole at the center of the Milky Way galaxy. It weighs about 4 million solar masses (it’s over 30,000 light years away.)

Centaurus A is the nearest example of an active galactic nucleus (AGN), located only 10 million light years from us. The black hole at the center of this galaxy is thought to be around 60 million times the mass of our Sun; material around it gets shot off in the form of huge jets which travel at nearly the speed of light and are easily visible in this Chandra x-ray image. Many of the small dots surrounding the central AGN are thought to be microquasars, smaller black holes which shoot off jets of their own as they rip material from companion stars.

Galaxies & the UniverseGalaxies & the UniverseGalaxies Galaxies • Large group of stars, gas, and dust held together Large group of stars, gas, and dust held together by gravity.by gravity.

-Spiral Galaxies- galaxies with spiral arms that wind -Spiral Galaxies- galaxies with spiral arms that wind outward from the center. They can be normal or outward from the center. They can be normal or barred.barred.

The cosmos contains approximately 50,000,000,000 galaxies.

When you look at the Andromeda galaxy (which is 2.3 million light years away), the light you are seeing took 2.3 million years to reach you. Thus you are seeing the galaxy as it was 2.3 million years ago.

Tadpole Galaxy

 Time is relative

The closer an object gets to the speed of light, that object actually experiences time at a significantly slower rate. If the you were traveling safely at close to the speed of light to the center of our galaxy from Earth, it would take 25,000 years of Earth time. For the you, however, the trip would probably only take 10 years.

It is now thought that almost all galaxies contain gigantic black holes in their centers, millions or even billions of times more massive than the Sun

-Elliptical Galaxies- common -Elliptical Galaxies- common type of galaxy that are oval or type of galaxy that are oval or egg shaped.egg shaped.

-Irregular Galaxies- galaxies -Irregular Galaxies- galaxies that have no distinct shape.that have no distinct shape.

cosmic year is the amount of time it takes the Sun to revolve around the center of the Milky Way, about 225 million years.

Hubble Deep Field

You are looking back into the past by 13 billion years in this picture

Each spot of light isn’t a star….

It’s an entire galaxy. About 1500 of them

Deep Field Video

with ~ 100 billion stars per galaxy

how arrogant would it be to think we are the only life in the universe.

The Milky WayThe Milky Way• Spiral galaxy that is about 100,000 ly across.Spiral galaxy that is about 100,000 ly across.• Out solar system is located about half-way out on Out solar system is located about half-way out on one of the spiral arms.one of the spiral arms.

• Like many galaxies, the Milky Way has a super Like many galaxies, the Milky Way has a super massive Black Hole at its core.massive Black Hole at its core.

Sun is 23,000 light-years from it's centerWe are moving through space at the rate of 530km a second

On average, every star in the Milky Way is accompanied by 1.6 planets. That’s at least 100 billion planets

Origin of the UniverseOrigin of the Universe• Steady State Theory- the Universe has Steady State Theory- the Universe has always been the same as it is today.always been the same as it is today.

• Oscillating Model- the Universe expands Oscillating Model- the Universe expands and and contacts in a cycle.contacts in a cycle.

• Big Bang Theory- the Universe started with Big Bang Theory- the Universe started with a bang and has expanded ever since.a bang and has expanded ever since.

Expansion of the UniverseExpansion of the Universe•Doppler Shift- the changing of the wavelength of Doppler Shift- the changing of the wavelength of sound or light as an object gets closer or further sound or light as an object gets closer or further away.away.

•Red Shift- as a star or galaxy gets further away from Red Shift- as a star or galaxy gets further away from the Earth, its light will expand (stretch) producing a the Earth, its light will expand (stretch) producing a longer wavelength (red) in the spectroscope. longer wavelength (red) in the spectroscope.

Blue Shift-as a star or Blue Shift-as a star or galaxy gets closer to the galaxy gets closer to the Earth, its light will get Earth, its light will get compressed (squeezed) compressed (squeezed) producing a shorter producing a shorter wavelength (blue) in the wavelength (blue) in the spectroscope.spectroscope.

» Most galaxies show red shift, therefore the » Most galaxies show red shift, therefore the Universe is expanding. Universe is expanding.

The Big Bang TheoryThe Big Bang Theory• All energy & matter was created in an instant All energy & matter was created in an instant with an initial explosion.with an initial explosion.

• The matter rapidly expanded throughout space The matter rapidly expanded throughout space in a swirling, dense mass.in a swirling, dense mass.

• Matter began to collect into clumps. As matter Matter began to collect into clumps. As matter cooled, hydrogen & helium gases formed.cooled, hydrogen & helium gases formed.

• Eventually the first stars will form followed by Eventually the first stars will form followed by galaxies, etc while still expanding.galaxies, etc while still expanding.

Quasars are extremely distant objects in our known universe. They are the furthest objects away from our galaxy that can be seen. Quasars are extremely bright masses of energy and light. The name quasar is actually short for quasi-stellar radio source or quasi-stellar object.

A quasar is believed to be a supermassive black hole surrounded by an accretion disk.

When we look at quasars which are 10-15 billion light years away, we are looking 10-15 billion years into the past.

Evidence of a black hole