Exploring SpaceExploring Space

Looking from EarthLooking from Earth

Telescopes are used to see objects that Telescopes are used to see objects that are far away. are far away.

The largest telescopes are up to 300m The largest telescopes are up to 300m widewide

There are 3 typesThere are 3 typesReflectingReflectingRefractingRefractingRadioRadio

Optical TelescopesOptical Telescopes

Refracting and Refracting and reflecting telescopes reflecting telescopes are both types of are both types of optical telescopesoptical telescopes

They use lenses and They use lenses and mirrors to produce mirrors to produce magnified imagesmagnified images

Professional Professional astronomers house astronomers house the telescopes in the telescopes in observatoriesobservatories

The Hubble Space The Hubble Space Telescope was Telescope was launched in 1990 in launched in 1990 in order to get better order to get better quality picture of the quality picture of the universe.universe.

Radio TelescopesRadio Telescopes

All stars radiate energy throughout the All stars radiate energy throughout the electromagnetic spectrumelectromagnetic spectrumLight, x-rays, radio waves, microwaves, etc…Light, x-rays, radio waves, microwaves, etc…

Radio telescopes study the radio wavesRadio telescopes study the radio wavesA computer takes data about the radio A computer takes data about the radio

waves and makes a mapwaves and makes a mapThe largest radio telescope in the world is The largest radio telescope in the world is

300m wide300m wide

SatellitesSatellites

Space exploration began in 1957 with the Space exploration began in 1957 with the Soviet satellite Sputnik ISoviet satellite Sputnik I

Today thousands of artificial satellites orbit Today thousands of artificial satellites orbit the Earththe Earth

Space probes carry instruments to gather Space probes carry instruments to gather information and send it back to Earth.information and send it back to Earth.

There have been several important probes There have been several important probes sent out by the National Aeronautics and sent out by the National Aeronautics and Space Administration (NASA)Space Administration (NASA)

Mariner 2Mariner 2 Viking 1Viking 1

Launched in August Launched in August 19621962

First successful First successful planetary probeplanetary probe

Verified high Verified high temperatures in temperatures in Venus’ atmosphereVenus’ atmosphere

Launched August Launched August 19751975

Mapped Martian Mapped Martian surfacesurface

Searched for life on Searched for life on the surfacethe surface

Pioneer 10Pioneer 10

Launched March 1972Launched March 1972First probe to encounter JupiterFirst probe to encounter JupiterSent back photographs and dataSent back photographs and data

VoyagerVoyager

2 probes were launched in 19772 probes were launched in 1977

Voyager 1Voyager 1Flew past Jupiter & SaturnFlew past Jupiter & Saturn

Voyager 2Voyager 2Flew past Jupiter, Saturn, Uranus, and Flew past Jupiter, Saturn, Uranus, and

NeptuneNeptuneSent back information from all the planets Sent back information from all the planets

it visitedit visited

GalileoGalileo

Launched in 1989Launched in 1989Reached Jupiter in 1995Reached Jupiter in 1995

Sent a probe in to the atmosphereSent a probe in to the atmosphereReturned data on composition, Returned data on composition,

temperature, and pressuretemperature, and pressureAlso studied Jupiter’s moon’s, rings, and Also studied Jupiter’s moon’s, rings, and

magnetic fieldsmagnetic fields

Race to the moonRace to the moon

In 1961, President John F. Kennedy called In 1961, President John F. Kennedy called for the US to put a person on the moon for the US to put a person on the moon and began the space race.and began the space race.

The race to the moon was undertaken in 3 The race to the moon was undertaken in 3 projectsprojectsProject MercuryProject MercuryProject GeminiProject GeminiProject ApolloProject Apollo

Project MercuryProject Mercury

Goal: To orbit a piloted spacecraft around Goal: To orbit a piloted spacecraft around the Earth and bring it back safelythe Earth and bring it back safely

Significant EventsSignificant EventsMay 5, 1961 – Alan Sheppard became the May 5, 1961 – Alan Sheppard became the

first US citizen in spacefirst US citizen in space1962 – John Glenn became the first US 1962 – John Glenn became the first US

citizen to orbit the Earthcitizen to orbit the Earth

Project GeminiProject Gemini

2 astronauts in the same Gemini 2 astronauts in the same Gemini spacecraft orbited the Earthspacecraft orbited the Earth

One team met and connected with another One team met and connected with another space craft in orbit.space craft in orbit.

RangerRanger & Surveyor – & Surveyor – Proved we could Proved we could land on the moonland on the moon

Project ApolloProject Apollo

Goal: to reach the moonGoal: to reach the moonJuly 20, 1969: Apollo 11 landed on the July 20, 1969: Apollo 11 landed on the

lunar surfacelunar surfaceNeil Armstrong became the first man to set Neil Armstrong became the first man to set

foot on the moon.foot on the moon. ““One small step for man, one giant leap for One small step for man, one giant leap for

mankind.”mankind.”

Beyond our Solar SystemBeyond our Solar System

Characteristics of StarsCharacteristics of StarsColorColorTemperatureTemperatureBrightnessBrightnessMassMass

Color and TemperatureColor and Temperature

Color tells us temperature of a starColor tells us temperature of a starVery hot stars = temperatures above Very hot stars = temperatures above

30,000 K are blue30,000 K are blueStars between 5,000 K and 6,000 K Stars between 5,000 K and 6,000 K

appear Yellowappear YellowCooler stars under 5,000 K appear RedCooler stars under 5,000 K appear Red

Stellar MassStellar Mass

Binary stars- 2 stars pulled together in Binary stars- 2 stars pulled together in orbit by the force of gravityorbit by the force of gravity

They orbit each other around a center of They orbit each other around a center of massmass If the center of mass is known than we can If the center of mass is known than we can

calculate mass of the starscalculate mass of the starsExample- if the stars have equal mass the Example- if the stars have equal mass the

center of mass is exactly halfway between center of mass is exactly halfway between themthem

Measuring Star DistanceMeasuring Star Distance

Shifting of a nearby star due to the orbital Shifting of a nearby star due to the orbital motion of Earthmotion of Earth

How is it done?How is it done?Photograph a nearby starPhotograph a nearby starPhotograph the same star 6 months laterPhotograph the same star 6 months laterCalculate distance from star by the amount Calculate distance from star by the amount

and angle of the shift and angle of the shift

Light YearsLight Years

Distances to stars are so large that we Distances to stars are so large that we need a special unit to measure themneed a special unit to measure them

1 Light Year is the distance light travels in 1 Light Year is the distance light travels in one years timeone years time9.5 X 109.5 X 1012 12 KilometersKilometers

Or 9.5 trillion KilometersOr 9.5 trillion KilometersProxima Centauri is 4.3 light years awayProxima Centauri is 4.3 light years away (9.5 trillion kilometers X 4.3)(9.5 trillion kilometers X 4.3)

Stellar BrightnessStellar Brightness

MagnitudeMagnitude = measure of star’s brightness = measure of star’s brightnessApparent magnitude – how bright a star Apparent magnitude – how bright a star

appears from Earthappears from EarthFactors that effect apparent magnitudeFactors that effect apparent magnitude

How big it isHow big it isHow hot it isHow hot it isHow far away it isHow far away it is

Absolute magnitudeAbsolute magnitude

Actual brightness of a starActual brightness of a star2 stars with the same absolute magnitude 2 stars with the same absolute magnitude

may not necessarily have the same may not necessarily have the same apparent magnitudeapparent magnitude

Stellar EvolutionStellar Evolution

Stars start off as dark clouds of 92% hydrogen, 7% helium, < 1% heavier elements

Gravity squeezes matter inward and the interior heats up

Protostar- early phase where star is heating up (spans 1 million years)

Star BirthStar Birth

When the core of the Protostar reaches 10 million K, pressure is so great that nuclear fusion occurs- a star is born

Heat from fusion of hydrogen is releasedWhen balance is maintained from inward

pressure (gravity) and outward pressure (heat) the Main-Sequence stage is reached

Main-Sequence StageMain-Sequence Stage

Hydrogen fusion occurs for a few billion years

Stars age at different ratesBlue stars- burn so hot they deplete hydrogen

quickly (few million years)Red/Yellow stars- burn cooler so their

hydrogen lasts longer (our sun 10 billion years)

Red Giant StageRed Giant Stage

Hydrogen depleted in core leaving a helium core

Core loses outward heat pressure and begins to collapse

As core contracts it grows hotter by converting gravitational energy into heat energy- this energy starts to fuse hydrogen in outer layers

Red Giant StageRed Giant Stage

The heat energy expands stars outer layer resulting in a giant body hundreds to thousands of times larger than its main sequence size

Previous events are all well documented- what happens next is based on theory

Burnout and DeathBurnout and Death

Stars eventually run out of fuel and collapse due to gravity

Death of different size starsLow-mass stars

Remain in main-sequence until fuel runs out and than collapse into white dwarf

White dwarf- extremely dense remains of starsBlack dwarf- a white dwarf that has cooled down

Medium mass starsReach giant phase fusing hydrogen and

heliumThen collapse from red giants to white dwarfs

White dwarfs are extremely dense remains of stars

Cast the outer layer creating an expanding cloud of red gas (called planetary nebula)

Massive stars Have short life spans and die out with a

brilliant explosion (supernova)During a supernova the outer layer of the star is

ejected while the core collapsesStar becomes a million times brighter than the

prenova phaseIf one of the nearest stars to Earth went into

supernova it would be brighter than our sun

Black HolesBlack Holes

During a supernova remnants of stars 3X the size of the sun collapse into small dense objects (Black Holes)

These black holes have gravitational energy so strong that even light cannot escape their surface

How do we find them? Look for the heat emitted as matter is being

pulled in

GalaxiesGalaxies

Group of stars, dust, and gases held Group of stars, dust, and gases held together by gravitytogether by gravity

Billions of stars in our galaxy- The Milky Billions of stars in our galaxy- The Milky WayWay100,000 light years across100,000 light years acrossSpiral galaxySpiral galaxy

Types of GalaxiesTypes of Galaxies SpiralSpiral

Great concentration of stars Great concentration of stars near the centernear the center

Large galaxies containing Large galaxies containing billions of starsbillions of stars

EllipticalElliptical Round to oval in shapeRound to oval in shape Smaller galaxiesSmaller galaxies

IrregularIrregular Composed of mostly young Composed of mostly young

starsstars

Hubble’s LawHubble’s Law

Red shifts- Hubble observed that most Red shifts- Hubble observed that most galaxies have red shiftsgalaxies have red shiftsRed shifts show that light waves are being Red shifts show that light waves are being

stretchedstretchedThis means that Earth and the source of the This means that Earth and the source of the

light waves are being moved away from each light waves are being moved away from each otherother

Greater red shifts mean faster speedsGreater red shifts mean faster speeds

Hubble’s LawHubble’s Law

Galaxies further away have greater red shifts Galaxies further away have greater red shifts and therefore are moving fasterand therefore are moving faster The Universe is Expanding!!!!The Universe is Expanding!!!!

This discovery led to the Big Bang TheoryThis discovery led to the Big Bang TheoryAt one time the entire universe was confined to a At one time the entire universe was confined to a

dense, hot, supermassive ball. 13.7 billion years dense, hot, supermassive ball. 13.7 billion years ago a violent explosion occurred hurling this ago a violent explosion occurred hurling this material in all directionsmaterial in all directions

Evidence- 1) red shifts 2) cosmic radiation Evidence- 1) red shifts 2) cosmic radiation produced during the explosionproduced during the explosion

What is the fate of our What is the fate of our Universe?Universe?

Expansion lasting forever as stars die out Expansion lasting forever as stars die out and the universe is filled with dense black and the universe is filled with dense black dwarfs and black holesdwarfs and black holes

The Big Crunch- will gravity pull everything The Big Crunch- will gravity pull everything back into a high density, high energy mass back into a high density, high energy mass as it was before the big bang?as it was before the big bang?