Our Universe Objectives Describe characteristics of the universe such as stars and galaxies. Explain how to use light years to describe distances.

Our Universe

Objectives

Describe characteristics of the universe such as stars and galaxies.

Explain how to use light years to describe distances in the universe.

Research and describe historical scientific theories of the origin of the universe.

Analyze and predict the sequence of events in the lunar cycle.

The history of astronomy and early astronomers

The days of Columbus versus

Present day theories

Think about this…

When did the study of space begin?

What do the following astronomers have in common?

What do you think will be revealed through space exploration during your lifetime?

Aristarchus

280 BCE

Greek astronomer & mathematician

Suggested the Earth revolves around the Sun.

Provides first estimation of Earth to Sun distance.

Claudius Ptolemy Greek Astronomer- 140 CE

Formulated the Geocentric theory of the universe (Earth was the center of the universe)

Nicolas Copernicus

Polish Astronomer - 1543

Formulated the Heliocentric theory of the Universe.

Stated that the Sun was the center of the Universe.

Tycho Brahe

Danish Astronomer – late 1500’s

Recorded very precise data on the positions of the sun, moon and planets

Johannes Kepler German Astronomer –

1600’s

Continued Tycho’s work.

Developed new Laws of Planetary Motion

Stated that all planets revolve around the sun in an ellipse

Galileo Galilei

Italian Astronomer – 1600’s

1st to use a telescope to observe objects in space

Discovered 4 moons orbiting Jupiter, craters and mountains on the moon, and sunspots

Isaac Newton

English Astronomer and Physicist – Late 1600’s

Formulated the Laws of motion, force and gravity.

Wrote his book “Principia” which built on the legacy of Copernicus, Galileo and Kepler.

Presented the most accurate model of the Universe and it’s forces.

Edwin Hubble

American Astronomer – Early 1900’s

1st to discover other galaxies beyond the Milky Way

Found evidence for the expansion of the universe

Hubble Space Telescope is named for him

Stephen Hawking British theoretical physicist

– born in 1942 (still alive!)

Famous for black hole research, theoretical cosmology, and quantum gravity

Suffers from Amyotrophic lateral sclerosis known as Lou Gehrig’s Disease in the US. (a motor neuron disease that causes a loss of almost all neurological control

Stephen Hawking's website

With a partner, brainstorm all of the objects in space that you can think of.

Write your ideas down and be ready to report out.

Where is the matter in our solar system?

Sun: 99.85%

Planets: 0.135%

Comets: 0.01% ?

Satellites: 0.00005%

Minor Planets: 0.0000002% ?

Meteoroids: 0.0000001% ?

Interplanetary Medium: 0.0000001% ?

GALAXIES

Large group of stars in space

Spiral Galaxy

Andromeda Galaxy Have a large bulge in the center with spiral arms traveling around

Contains old and new stars

Ex. Andromeda Galaxy and our Milky Way Galaxy

Elliptical Galaxy

M 87 Galaxy

Massive blobs of stars that have very bright centers

Very little gas and dust

Contain mostly old stars.

Ex. M87 galaxy

Irregular Galaxy

Large Megellanic Cloud

Do not fit in any other class.

Contain mostly young stars and lots of gas

Ex. Large magellanic cloud

Light Years

How we measure distances in Space

Light Year

9.46 trillion kilometers

5.87 trillion miles

The distance light would travel in a vacuum (area without interference) within a year.

Used to measure distances to stars Distance across a space like an entire galaxy

How this is figured??

A light year is the distance that light can travel in a year, or:

186,000 miles/second x 60 seconds/minute x 60 minutes/hour x 24 hours/day x 365 days/year = 5,865,696,000,000 miles/year

A light year is 5,865,696,000,000 miles (9,460,800,000,000 kilometers). That's a long way!

Milky Way Diameter 100,000 LY

Andromeda: Our nearest Galaxy=225,000 LY from

Earth

228,000 LY in diameter

How Far are Stars from Each other?

LIGHT YEARSSun=0

Alpha Centauri=4.36

Sirius=8.58

Procyon=11.4

Tau Ceti=11.89

Proxima Cygni=11.37

Practice Alpha Centauri is the closest star to our Sun-about 4

light years away

How far away is Alpha Centauri in kilometers?

9,461,000,000,000 km/light year

X 4 light years

--------------------------------------

37,844,000,000,000 km away

Practice converting light years to other units

What makes up galaxies?

Nebulas – giant clouds of gas and dust where new stars can form.

Stars and star clusters

Quasars – Star like sources of light that are extremely far away.

Black Holes – now believed to be the center of all spiral and elliptical galaxies

Star Clusters

Globular clusters look

like a ball of stars with 20,000 to 100,000 stars on average.

Newly formed open clusters have many bright blue stars with a few hundred to a few thousand stars.

Quasars

Quasars are among the most powerful energy in the universe.

Some quasars give off as much energy as 10 trillion of our own suns.

Quasar FAQ

What exactly are STARS?Huge bright balls of burning gases…mainly hydrogen & helium

How stars “burn”: Nuclear Fusion

This process causes stars to give off heat and light

Star Color

Classifying StarsClass

Color Surface Temp.(degrees Celsius)

Elements detected

Examples of stars

O Blue Above 30,000 Helium 10 Lacertae

B Blue-white

10,000 - 30,000

Helium and Hydrogen

Rigel, Spica

A Blue-white

7,500 - 10,000

Hydrogen Vega, Sirius

F Yellow-white

6,000 - 7,500 Hydrogen and heavier elements

Canopus, Procyon

G Yellow 5,000 - 6,000 Calcium and other metals

The sun, Capella

K Orange 3,500 - 5,000 Calcium and Molecules

Arcturus, Aldebaran

M Red Less than 5,000

Molecules Betelgeuse,Antares

Star Life Cycle

Even though stars are not alive, they have a predictable cycle they follow from “birth” to “death”.

This cycle is often plotted on an HR Diagram

Average stars, like our sun, fall in the main sequence.

Nebulas – Stellar Nurseries

•A cloud of dust particles and gases•Comes from the Latin word for “cloud”•Astronomers believe this is where new stars are created.•Gravity causes the dust & gas to contract and the heat & temperature build up over millions of years to form a new star.

The Lifecycle of Stars

Stages of a Stars Life Cycle

What happens when stars get old?

Supernova – the death of a large star by explosion

Neutron star – a star in which nearly all the particles have become neutrons

Pulsars – a neutron star that spins

Black holes – an object that forms where gravity is so strong that not even light can escape.

Death of a Star

How the star dies depends on how much mass it has.

The most massive stars have the shortest lives

A star will become either a black dwarf neutron star black hole

Death Sequence

Sun-like Stars Mass under 1.5 times the mass of the Sun --> Red Giant --> Planetary Nebula -->White Dwarf --> Black Dwarf

Huge Stars Mass between 1.5 to 3 times the mass of the Sun

--> Red Super Giant --> Supernova --> Neutron Star

Giant Stars Mass over 3 times the mass of the Sun

--> Red Super Giant --> Supernova --> Black Hole

Supernova – Exploding stars

A Neutron Star

The remnants of a planetary nebula where only the hot core of the star remains.The star has nearly exhausted all of their nuclear fuel.Have been detected using X-ray and UV observation

Black holes dragging in space and time

Our sun – the closest star to Earth

150,000,000 Km (93 Million miles) away.

4.5 - 5 billion years old and will last another 5 billion years

So what about our Sun?

The sun is an average size star on the main sequence

The sun only seems large to us because it is the closest star to Earth

The sun will not likely burn out during our lifetime

H-R Diagram Basics

•A scientific tool that shows star relationships•It shows stars of different ages and in different stages, all at the same time. •Each star is represented by a dot.•Stars are graphed on the diagram according to its temperature and magnitude/luminosity.•The “swish” through the middle is the “main sequence” which is the life cycle route most stars follow.

Shows the classification, color, and temperature

Left is hot (blue stars) & Right is cold (red stars)

Luminosity

How bright the star is compared to the Sun.

Top is brighter.

Bottom is dimmer.

Magnitude

How bright the star looks

Top is bright

Bottom is dim

Hertzsprung–Russell (H-R) Diagram- a graph that shows the relationship between a star’s

surface temperature and its brightness

The way things move

ROTATION=day (3 syllables, 3 letters)

REVOLUTION=year (4 syllables, 4 letters) ~ tilt of Earth makes seasons

Lunar Cycle The moon orbits around the Earth

It is our planet's only natural satellite

Cycle lasts about 28 days

Causes the lunar phases - Appearance of the moon from Earth. The sunlit part of the moon is what we see from

Earth.

The Lunar Cycle Phases of the Moon

Lunar Phases

New moon

Waxing crescent

First quarter

Waxing gibbous

Full moon

Waning gibbous

Last quarter

Waning crescent

Lunar Cycle

Waxing vs. Waning

What we see from Earth is the sunlit part of the moon.

Waxing - sun lit part of the moon seen from Earth is growing (getting bigger)

Waning - sun lit part of the moon seen from Earth is getting smaller.

Where do all of these waves come from?

Electromagnetic (EM) Waves

Waves that can travel through matter and empty space

VIBRATE electric and magnetic fields

Transverse waves

Travels FASTER than anything else known: about 300,000 km/sec. (156,000 miles/sec.

Electromagnetic Waves

Radio waves

Microwaves

Infrared waves

Visible Light

Ultraviolet waves

X-Rays

Gamma Rays

Cosmic Rays

Electromagnetic Waves

From lowest to highest frequency (energy)

RADIO

•Longest Wavelength

•Antenna generally receives the signal

•Waves can be up to a mile long

•How astronauts talk in spaceUses:

•Radio

•TV

•Cell Phone

•Radio telescope

Radio waves invade…

What else can radio waves do?

•In 1932 it was discovered that radio waves can detect objects in space

•Radio telescopes look toward the heavens at planets and comets, giant clouds of gas and dust, and stars and galaxies.

•Sunlight, clouds, and rain do not affect observations.

MICROWAVE•Good for transmitting information because microwave energy can penetrate weather (haze, light rain and snow, clouds, and smoke).

•Shorter microwaves are used in remote sensing.

•Doppler radar uses waves just a few inches long.

•Can transmit info like phone calls or computer data between places

What are microwaves good for?

Cosmic Microwave

Background Radiation

•In the 1960's a pair of scientists detected background noise using a special low noise antenna.

•The strange thing about the noise was that it was coming from every direction and did not seem to vary in intensity.

• If this static were from something on our world, like radio transmissions from a nearby airport control tower, it would only come from one direction, not everywhere.

•The scientists soon realized they had discovered the cosmic microwave background radiation.

•This radiation, fills the entire Universe!

INFRARED

•Range of wavelengths

•Vary in size from the size of pin head to microscopic

•Far infrared (closest to microwave) waves are thermal

•Shorter waves are not hot at all--you can even touch them!

Uses of Infrared

FAR INFRARED Used to detect heat Humans can’t see it Snakes can sense it

SHORT INFRARED Control remote controls

VISIBLE LIGHT

•This is actually the colors we see

•Smallest part of the EM spectrum

•The colors that we see in a rainbow - from reds and oranges, through blues and purples.

Colors & Wavelength

ULTRAVIOLET

•Ultraviolet (UV) light has shorter wavelengths than visible light.

•Invisible to the human eye but some insects, like bumblebees, can see them!

•Divided into three sections: the near ultraviolet(NUV), the far ultraviolet(FUV), and the extreme ultraviolet(EUV).

•Too much UV is bad for humans(skin cancer, sunburns

People hunting scorpions use UV light to find them bc their exoskeleton reacts to the rays.

More about UV rays

•The sun emits a lot of UV rays-most are blocked by the ozone layer on Earth

•The Hubble Space Telescope observes stars and galaxies mostly in near ultraviolet light.

•We can use false color photography to see the sun emitting UV rays

X-RAY

Can harm or damage living things

Carry a lot of energy First documented in

1895 X-rays cannot penetrate

from space to Earth The sun, comets, and

black holes emit X-rays

Using X-rays in Space

Locate objects Comets Sun Binary stars Look at Earth Supernova

remnants

Gamma Ray

Carry the most energy of any wave

Produced by nuclear reactions

Produced by violent events like supernova explosions

Used to treat cancer

How we see things in Space

The pretty pictures we see of space objects are actually composite photos…this means many photos are taken in different wavelengths and then put together.

When we look up, we can only see using the visible light but with technology we can “see” other wavelengths.

Images taken by telescopes that observe at the "invisible" wavelengths are sometimes called "false color images.”

That is because the colors used to make them are not "real" but are chosen to bring out important details. The color choice is usually a matter of personal taste, and is used as a type of code in which the colors can be associated with the intensity or brightness of the radiation from different regions of the image, or with the energy of the emission.

Example of composite photography

Several images are combined to make one

The Sun in Various Rays

Visible

UV

Infrared

X-ray

Radio

Moon in Various Rays

Gamma

X-rayVisible light

Microwave

Infrared

Radio

Ultraviolet

Hubble Deep Field: The Most Important Image Ever Taken Follow either link to a short video about Hubble

Deep Field observations.

http://www.metacafe.com/watch/782637/hubble_deep_field_the_most_imp_image_ever_taken/

http://www.youtube.com/watch?v=fgg2tpUVbXQ

Formation of the Universe

Cosmology is the study of the origin, structure, and future of the universe.

Theories on the Origin of the UniverseHow did we get here?

The Big Bang Theory – states that the universe began with a big explosion.

Oscillating Theory– Universe will expand and the fold back in on itself resulting in a “Big Crunch”

Steady State Theory - the universe has always been here and always will.

The Big Bang theory

Most dominant theory

States that the universe was created from a cosmic explosion that hurled matter in all directions

Occurred 10-20 billion years ago

Evidence that supports the big bang

Cosmic background radiation Radiation coming from all directions in space, believed to be left over from the big bang.

The observable and measurable expansion of the universe.