Physical SciencePhysical Science

UniverseUniverse

Slides subject to changeSlides subject to change

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Job 3814 Where were you when I laid the Earth’s

foundation?

31 Can you bind the beautiful Pleiades?

Can you loose the cords of Orion?32 Can you bring forth the constellations in their

seasons

or lead out the Bear with its cubs?

North Pole

South Pole

Equator

Celestial SphereNorth Celestial Pole

South Celestial Pole

Celestial Equator

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The Sun: Our Nearest StarThe Sun: Our Nearest Star

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SunSun

Diameter: 109 EarthsDiameter: 109 Earths Mass: 333,000 EarthsMass: 333,000 Earths Density: Avg. 1.4 g/cmDensity: Avg. 1.4 g/cm33 Sun exists as a plasma, and Sun exists as a plasma, and

is not solid.is not solid. Gravity: 27.9 gGravity: 27.9 g

Solar Day: 25 daysSolar Day: 25 days

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Solar and Heliospheric ObservatorySolar and Heliospheric Observatory

ESA/NASA CollaborationESA/NASA Collaboration

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SunSunTemperatureTemperature

15,000,000 K15,000,000 K

6,000 K6,000 K

50,000 K50,000 K

1,000,000 K1,000,000 K

Nuclear reaction at CoreNuclear reaction at CoreBright visible surface Bright visible surface

“Photosphere”“Photosphere”Thin layer of hotter gas Thin layer of hotter gas

“Chromosphere” “Chromosphere” White halo “Corona”White halo “Corona”

Sun is hotter as you rise Sun is hotter as you rise above the surface.above the surface.

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Sun's PowerSun's Power

Nuclear fusion of hydrogen into helium in Nuclear fusion of hydrogen into helium in its core.its core.

Normally (at Earth temperatures) Normally (at Earth temperatures) hydrogen nuclei (protons) repel each hydrogen nuclei (protons) repel each other. other.

At Sun's core, At Sun's core, TT =15,000,000 K, protons =15,000,000 K, protons collide with such energy they fuse.collide with such energy they fuse.

Energy released as hydrogen goes Energy released as hydrogen goes through several steps to become stable through several steps to become stable helium.helium.

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Nuclear Fusion

Every second in the sun’s interior mass is converted to energy:

hydrogen (H) → helium (He) + energy

6.0x1011 kg H → 5.96x1011 kg He + energy

Enough fuel to last another five billion years.

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Solar FlaresSolar Flares

Charged particles in the midst of intense magnetic fields.

Photo March 18, 2013 by NASA Solar Dynamics Observatory

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SunspotsSunspots

Cooler areas on the sun (Cooler areas on the sun (T T ≈ ≈ 4600 K).4600 K).

NASA

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SunspotsSunspots Sunspot intensity cycles every 10-11 years.Sunspot intensity cycles every 10-11 years. Emitted radiant energy varies with sunspot activity.Emitted radiant energy varies with sunspot activity. Significant influence on Earth’s climate.Significant influence on Earth’s climate.

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Effect of SunspotsEffect of Sunspots Red curve illustrates Red curve illustrates

solar activity.solar activity. Black curve, Earth's Black curve, Earth's

average temperature.average temperature. Over last 100 years,Over last 100 years,

average globalaverage global temperature has increased by approx 0.7 temperature has increased by approx 0.7 °°C.C.

Earth’s climate is closely associated with Earth’s climate is closely associated with Solar activity – correlates with colder Solar activity – correlates with colder temperatures. temperatures.

ScienceScience, 254, 698-700, 1991, 254, 698-700, 1991

14Today’s Activity

2009 had 260 spotless days

2010 had 51 spotless days,

2011 had 2 spotless days

Since then there have been sunspots every day. www.almanac.com/sunspotupdate

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Climate ChangeClimate Change

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StarsStars

Like the Sun, other stars are massive, Like the Sun, other stars are massive, luminous balls of plasma. luminous balls of plasma.

Most stars between 0.1 and 5 solar masses.Most stars between 0.1 and 5 solar masses. Size is a balance of thermal and radiant Size is a balance of thermal and radiant

pressure outward, and gravity inward.pressure outward, and gravity inward. Once regarded by astronomers as a small Once regarded by astronomers as a small

and relatively insignificant star, our Sun is and relatively insignificant star, our Sun is now thought to be brighter than about 85% now thought to be brighter than about 85% of the stars in the Milky Way galaxy.of the stars in the Milky Way galaxy.

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Measure Star BrightnessMeasure Star Brightness

More More negativenegative the number, the more bright ! the number, the more bright ! Apparent magnitude of the Sun is −26.74, and the Apparent magnitude of the Sun is −26.74, and the

mean apparent magnitude of the full moon is mean apparent magnitude of the full moon is −12.74. The Sun is the brighter of the two objects.−12.74. The Sun is the brighter of the two objects.

The apparent magnitude of Sirius is −1.44, and The apparent magnitude of Sirius is −1.44, and the apparent magnitude of Polaris is 1.97. Sirius the apparent magnitude of Polaris is 1.97. Sirius is the brighter of the two stars.is the brighter of the two stars.

Hubble Space Telescope can see stars of Hubble Space Telescope can see stars of magnitude 30.magnitude 30.

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Star Magnitude ScaleStar Magnitude Scale

Sky Map

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Star DistancesStar Distances

1 light year1 light year——the distance light goes in one yearthe distance light goes in one year——approx. six trillion miles.approx. six trillion miles.

1 light year = 9.46x101 light year = 9.46x101515 meters. meters. Closest star to us: Proxima Centauri (4.3 light Closest star to us: Proxima Centauri (4.3 light

years).years).

Keep in mind it only takes 8 minutes for light to Keep in mind it only takes 8 minutes for light to come from the Sun to Earth.come from the Sun to Earth.

About 17 hours from Earth to Voyager 1 (125 About 17 hours from Earth to Voyager 1 (125 AU from Sun)AU from Sun)

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View of StarsView of Stars

Long photo exposure Long photo exposure of stars from Oregon.of stars from Oregon.

Center of concentric Center of concentric circles is Polaris, the circles is Polaris, the “North Star” at the “North Star” at the North Celestial Pole.North Celestial Pole.

Polaris is 431 light Polaris is 431 light years from Earth.years from Earth.

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5:00 am 9/22/12

VenusJupitor

Uranus

Big Dipper

Polaris

Orion

Sirius

Betelgeuse

WestEast

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6:00 am 9/22/12

Venus JupitorUranus

Polaris

Orion

Big Dipper

Sirius

Betelgeuse

WestEast

237:00 am 9/22/12

SunVenus Jupitor

Uranus

Polaris

Orion

Sirius

Big Dipper

Betelgeuse

WestEast

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Ursa Major

Ursa Major The Great Bear

Ursa Minor The Little Bear

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Big DipperBig Dipper

The Big Dipper is formed The Big Dipper is formed by seven major stars by seven major stars within Ursa Major.within Ursa Major.

In the U.S. this group of seven stars is called In the U.S. this group of seven stars is called the “Big Dipper.” UK and Ireland, the the “Big Dipper.” UK and Ireland, the “Plough.” American Indians referred to it as a “Plough.” American Indians referred to it as a bear and three cubs.bear and three cubs.

In 19In 19thth century, runaway slaves would follow the century, runaway slaves would follow the “drinking gourd” to head north and freedom. “drinking gourd” to head north and freedom.

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Where is Polaris in the Sky?Where is Polaris in the Sky? Find the Big Dipper Find the Big Dipper

within Ursa Major.within Ursa Major. Two end stars point Two end stars point

to Polaris, to Polaris, approximately seven approximately seven lengths.lengths.

Polaris is in the Polaris is in the handle of Little handle of Little Dipper (Ursa Minor).Dipper (Ursa Minor).

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SiriusSirius Brightest star in the sky, magnitude −1.4. Brightest star in the sky, magnitude −1.4.

Bright because it is relatively close, 8.6 Bright because it is relatively close, 8.6 lightyears, and hot (10,000 K vs Sun 6,000 K).lightyears, and hot (10,000 K vs Sun 6,000 K).

Find it by following the “belt of Orion” southward.Find it by following the “belt of Orion” southward.

Known as the "Dog Known as the "Dog Star", in its constellation, Star", in its constellation, Canis Major (Big Dog). Canis Major (Big Dog). Faithful dog of Orion the Faithful dog of Orion the Hunter.Hunter.

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BetelgeuseBetelgeuse Betelgeuse (“beetle-Betelgeuse (“beetle-

jooz”) is a red supergiant jooz”) is a red supergiant star approaching end of star approaching end of its life cycle.its life cycle.

Ninth brightest, reddish Ninth brightest, reddish tinge.tinge.

641 light years away.641 light years away. Located in constellation Located in constellation

Orion. Near the belt.Orion. Near the belt. If put in place of our Sun, If put in place of our Sun,

would reach to Jupiter.would reach to Jupiter.

Hubble telescope, VisibleHubble telescope, Visible

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End of a Star’s LifeEnd of a Star’s Life

The future of BetelgeuseThe future of Betelgeuse——In larger stars, In larger stars, nuclear fusion continues until the heavier nuclear fusion continues until the heavier core has grown so large that it can no core has grown so large that it can no longer support its own mass. longer support its own mass.

This core will suddenly collapse.This core will suddenly collapse. The shockwave formed by this sudden The shockwave formed by this sudden

collapse causes the rest of the star to collapse causes the rest of the star to explode in a supernova.explode in a supernova.

Most of the matter in the star is blown Most of the matter in the star is blown away by the supernova explosionaway by the supernova explosion

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NebulaeNebulae

Crab Nebula 6,300 ly – Crab Nebula 6,300 ly – HubbleHubble

Crab Nebula first observed Crab Nebula first observed 1731.1731.

Corresponds to bright (6x Corresponds to bright (6x Venus) supernova recorded Venus) supernova recorded by Chinese and Arab by Chinese and Arab astronomers in AD 1054. astronomers in AD 1054.

At center is the Crab At center is the Crab PulsarPulsar, a rotating neutron , a rotating neutron star roughly 20 km in star roughly 20 km in diameter. diameter. ρρ=10=101414 g/cm g/cm33

Pulsar blinks light, 30 times Pulsar blinks light, 30 times per second.per second.

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Edwin HubbleEdwin Hubble Up to the early 1900’s the Milky Up to the early 1900’s the Milky

Way was considered the Way was considered the universe.universe.

Edwin Hubble collected data from Mt. Edwin Hubble collected data from Mt. Wilson Observatory, and announced in Wilson Observatory, and announced in 1925 that there were other galaxies 1925 that there were other galaxies beyond the Milky Way (in particular the beyond the Milky Way (in particular the Andromeda GalaxyAndromeda Galaxy))

His announcement changed our view of His announcement changed our view of the universe.the universe. Mt Wilson Webcam

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Andromeda Spiral Galaxy - Andromeda Spiral Galaxy - Amateur TelescopeAmateur Telescope

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Andromeda GalaxyAndromeda Galaxy

Andromeda Spiral Galaxy - Andromeda Spiral Galaxy - HubbleHubble

Nearest Galaxy to Milky WayNearest Galaxy to Milky Way

34 The Hubble Space Telescope is named in honor of Edwin Hubble.The Hubble Space Telescope is named in honor of Edwin Hubble.

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GalaxiesGalaxies

A galaxy is a massive system consisting of A galaxy is a massive system consisting of stars, gas and dust, and “dark matter.”stars, gas and dust, and “dark matter.”

Range from ten million to one trillion stars, Range from ten million to one trillion stars, average 100 billion.average 100 billion.

Stars orbit a common center of mass.Stars orbit a common center of mass. Our Sun is one of the stars in the Our Sun is one of the stars in the Milky WayMilky Way

galaxy.galaxy. Classified according to their shape, elliptical, Classified according to their shape, elliptical,

spiral, starburst, ...spiral, starburst, ...

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Milky Way GalaxyMilky Way Galaxy Milky Way spiral galaxy. Sun is on the “Orion” arm. 100,000 ly in diameter. 200 billion stars. One of a cluster of 40 galaxies called the

Local Group. Includes Andromeda Galaxy.

Artist concept→

Artist concept

37M104 Sombrero Galaxy - M104 Sombrero Galaxy - Hubble , VisibleHubble , Visible

38 Nearby Spiral Messier 81 Galaxy, Nearby Spiral Messier 81 Galaxy,

12 million light-years - 12 million light-years - NASA Spitzer NASA Spitzer Space Telescope, InfraredSpace Telescope, Infrared

39 A Full Ring Galaxy - A Full Ring Galaxy - NASA HubbleNASA Hubble

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Black HoleBlack Hole

A Black Hole is at the center of each A Black Hole is at the center of each galaxy, and its size correlates to the size galaxy, and its size correlates to the size of each galaxy.of each galaxy.

A black hole is a place in space where the A black hole is a place in space where the gravity is so strong that nothing—not even gravity is so strong that nothing—not even light—can escape it. light—can escape it.

This is not a black hole.This is a Black Hole

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Observable UniverseObservable Universe

100 billion galaxies in the observable 100 billion galaxies in the observable universe.universe.

Approximately 100 billion stars in each Approximately 100 billion stars in each galaxy.galaxy.

Galaxies range from 3 to 300,000 light Galaxies range from 3 to 300,000 light years in diameter.years in diameter.

““Dark matter” is an invention to explain Dark matter” is an invention to explain why galaxies rotate as if they are much why galaxies rotate as if they are much heavier than they appear. heavier than they appear. Unseen mass. Unseen mass. Galaxy may be up to 90% dark matter.Galaxy may be up to 90% dark matter.

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Low

er F

requ

enci

esLo

wer

Fre

quen

cies

Red ShiftRed Shift Dark lines from Dark lines from

absorption of specific absorption of specific light colors by the gases light colors by the gases in the Sun’s in the Sun’s photosphere.photosphere.

H and He.H and He.

Stellar Doppler effectStellar Doppler effect

Light from stars Light from stars moving away moving away from Earthfrom Earth

Doppler effectDoppler effect

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Universe Is ExpandingUniverse Is Expanding

Formulated in 1929 based on Hubble’s Formulated in 1929 based on Hubble’s additional measurements from Mt. Wilson.additional measurements from Mt. Wilson.

Most cited evidence for the “Big Bang” Most cited evidence for the “Big Bang” model of the universe.model of the universe.

Sometimes the energy for this expansion Sometimes the energy for this expansion is called “dark energy.” Not understood.is called “dark energy.” Not understood.

Hubble’s Law (1929):Hubble’s Law (1929):

“ “The redshift in light coming from The redshift in light coming from distant galaxies is proportional to distant galaxies is proportional to their distance.”their distance.”

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Big BangBig Bang

Cosmological model of the universeCosmological model of the universe Supported by all lines of scientific Supported by all lines of scientific

evidence and observation. evidence and observation. Essential idea is that the universe has Essential idea is that the universe has

expanded from a primordial hot and dense expanded from a primordial hot and dense initial condition at some finite time in the initial condition at some finite time in the past and continues to expand.past and continues to expand.

Extrapolation of the expansion of the Extrapolation of the expansion of the universe backwards in time helps fix a universe backwards in time helps fix a date ~ 13 billion years ago.date ~ 13 billion years ago.

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1990 Voyager 1990 Voyager photo taken as photo taken as Voyager exits Voyager exits Solar System.Solar System.

Earth is 4 billion Earth is 4 billion miles away.miles away.

Mote of DustMote of Dust

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Compare Carl Sagan’s view of Earth Compare Carl Sagan’s view of Earth http://obs.nineplanets.org/psc/pbd.htmlhttp://obs.nineplanets.org/psc/pbd.html

With God’s:With God’s: Isaiah 45:18 “For this is what the LORD Isaiah 45:18 “For this is what the LORD

says— he who created the heavens, he says— he who created the heavens, he is God; he who fashioned and made the is God; he who fashioned and made the earth, he founded it; he did not create it earth, he founded it; he did not create it to be empty, but formed it to be to be empty, but formed it to be inhabited.”inhabited.”

Romans 5:8 But God demonstrates his Romans 5:8 But God demonstrates his own love for us in this: While we were own love for us in this: While we were still sinners, Christ died for us.still sinners, Christ died for us.

Earth and Moon Earth and Moon seen from Mars by seen from Mars by

MGS on 8 May MGS on 8 May 20032003