SCIENCE 3

Module 2

2.01FORMATION OF HEAVENLY BODIES Big Bang The formation of the universe started with the Big Bang. Clouds of Dust After the Big Bang, the universe contained pockets of dust. Dust Starts to Condense The Law of Universal Gravitation says that all objects

attract each other. Because of this, the pockets of dust started to attract to each other. The dust then became more packed together. You can think of this idea kind of like a spiral. The center of the spiral is closely packed and it gets less packed as you move away from the center.

Planet or Star is formed Eventually the dust clouds became so packed they formed

a planet or star. Large clouds of dust became stars and smaller clouds became planets.

02.01 FORMATION OF HEAVENLY BODIES - GRAVITY CREATES STARS They postulated that the life cycle of a star is

dominated by a single factor ...(long pause).. gravity. Gravity is significant at the birth of a star. Stars are born in giant nebulae when, under the pull of gravity, its gases begin to coalesce in areas here and there. It is the beginning of a process which will last several million years, and during which, evermore matter is collected until, eventually, a sphere of gas begins to take form. As mass increases, so does gravity. It compresses the gas at the center of the embryonic star and that heats it up until it becomes incandescent. Once the interior temperature reaches 15 million degrees Centigrade the nuclear fusion process begins with hydrogen being converted into helium.... ...and a star is born.

2.02 GALAXIES The Universe is Huge A galaxy is a group of stars, planets, gas, and dust

that is held together by gravity. Our galaxy, The Milky Way, is thought to have

around 100,000,000,000 stars and there is thought to be about 100,000,000,000 other galaxies in the Universe. That leaves the universe with trillions and trillions of stars!

Many scientists estimate that the universe has 400,000,000,000,000,000,000,000. stars.

Let’s take a second to talk about how big this number really is. It is important to understand the magnitude of how many stars this is for you to really understand the size of galaxies and the universe.

2.02 GALAXIES Types of Galaxies There are three different types of galaxies. Watch the

presentation below to learn about these different types of galaxies.

There are three types of galaxies: Spiral: Spiral galaxies revolve around a single point. Our galaxy, the

milky way is an example of a spiral galaxy. Elliptical: Elliptical galaxies are circular in shape. Most of the objects in

an elliptical galaxy are concentrated around the center of the galaxy. From far away these galaxies look like one big star.

Irregular: Irregular galaxies are galaxies that are not spiral or elliptical.

These galaxies have an irregular shape.

2.02 GALAXIES Galaxies and stars The names of the different types of galaxies describe the shape of the

galaxy. The type of the galaxy can also tell us about the age of the stars and the amount of space dust in the galaxy.

Irregular Galaxies Irregular galaxies are young galaxies. Because of this, they contain mostly

young stars. These galaxies have many stars that are still forming. Irregular galaxies also contain lots of gas and dust. This gas and dust can

form into new stars or planets. Spiral Galaxies Spiral galaxies are medium aged galaxies. Because of this, they contain

some older stars and some younger stars. They still have a few stars that are still forming.

Spiral galaxies also contain some gas and dust. This gas and dust could condense to form new stars and planets.

Elliptical Galaxies Elliptical galaxies are old galaxies. Because of this, they contain mostly old

stars and they do not have new stars forming. Because elliptical galaxies do not have new stars forming, they do not have

much gas and dust.

2.03 DISTANCES IN SPACE

Cool Graphics for your Presentation….

2.03 DISTANCE IN SPACE Speed of Light Have you ever noticed that during a thunderstorm you can

see the lightning a long time before you hear the thunder? The reason for this is light travels 800,000 times faster than sound. In fact, light is the fastest thing in the universe that we know of.

How long do you think it will take light to travel the following distances?

To Earth-0.13 sec. To Moon- 1.3 sec. To Sun- 8 min. Other than the sun, the nearest star to us is called Proxima

Centauri . It takes light 4.2 years to travel from this star to our eyes. Think about how fast light is. Proxima Centauri must be very far away for light to take 4.2 years to travel from its surface to the earth!

2.03 DISTANCE IN SPACE Light Years Because light is so fast, it is used to measure

distances in space. A light year is the distance that light can travel in

one year. So if an object is one light year away, it will take light one year to get there.

1 light year = 9,461,000,000,000 km or 5,879,000,000,000 miles

Light years are used to measure distances in space because their large size allows us to talk about vast distances using smaller numbers. For instance, it is much easier to talk about three light years, than it would be to talk about 17637000000000 miles!

2.04 PROPERTIES OF STARS Star Size Scientists use four different characteristics to

help them classify and describe stars. Neutron Star A neutron star is the smallest type of star.

Neutron stars have a diameter that is about 10 to 20 km. This is probably less than the total distance that you travel on a daily basis.

Even though Neutron Stars are very small, they are very massive. One teaspoon of a Neutron Star would weigh about 10 million tons. These stars are very tight and compact.

2.04 PROPERTIES OF STARS Dwarf Star Dwarf stars are stars that are about the same

size as the Earth, but they weigh as much as the Sun. Dwarfs are not as compact as Neutron stars. A teaspoon of a Dwarf Star would weigh 5 tons.

Medium-sized Star The majority of the stars in the universe are

medium-sized stars. Medium-sized stars are about the same size as the Sun. The Sun is a medium-sized star.

2.04 PROPERTIES OF STARS Giant Star Giant stars are stars that are 10 to 1000 times bigger

than the sun. The following image is of a red giant star called Mira A. It is sometimes called Mira’s Football because of its football like shape. This star is 700 time bigger than the sun.

Supergiant Star A supergiant star is a star that is more than 1000 times

bigger than the sun. Below is a picture of Betelgeuse. Betelgeuse is a supergiant that can be seen with the naked eye in the night sky.

If we were to replace our sun with Betelgeuse as the center of our solar system, it is so big that it would extend past the orbit of Jupiter.

2.04 PROPERTIES OF STARS Star Brightness Imagine that you had a small candle and a big spotlight. If a friend held

these about ten feet from you, which of these would be the brightest? The spotlight right? Now imagine the candle is ten feet from you and the spotlight is one mile away from you. Which one would be brighter? The candle would appear brighter. This helps to illustrate that there are three things that affect star brightness.

The distance light source is from your eye. The size of the light source. The strength of the light source. Since not all stars are the same distance from your eye, size, or strength,

every star will have a different brightness when you look up into the night sky. The brightness of a star as it appears from the earth, without the effect of the earth’s atmosphere, is called apparent magnitude . Since the earth’s atmosphere causes stars to look different, the apparent magnitude takes this effect out.

If we could take two stars and put them side by side, we could tell easily which star is brighter because they are the same distance from your eye. Absolute magnitude is the amount of light that a star gives off.

Both apparent and absolute magnitude are important when studying stars.

2.04 PROPERTIES OF STARS Star Temperature Every star has a different temperature. The

temperature of the stars can be different based on the size of the star and the type of elements that make up the star.

The temperature of a star is very important because it determines the color of the star. Roll over the temperatures below to see how the temperature and star color are related.

Cool Star – Red/ Orange Warm Star- Yellow Hot Star-White Very Hot- Blue

2.04 PROPERTIES OF STARS Star Composition By studying the light that comes off stars,

scientists can determine what the star is made of. Every star gives off a different fingerprint of light and this light gives scientists a clue as to what elements are located in the star.

The most common element in stars is hydrogen. The second most common element in stars is helium. Stars do contain other elements but these two are the most common.

2.04 PROPERTIES OF STARS

2.04 PROPERTIES OF STARS REVIEW

Supergiant- More than 1000 times bigger then the sun

Giant- 10 to 1000 times bigger then the sun Medium Size- Majority of the stars in the

universe are Medium size. About the size of the sun. The sun is a medium size star.

Dwarf- About the size of the earth but weight about as much as the sun.

Neutron Star-Smallest star that is very tight and compact. Diameter of about 10 to 20 km.

2.04 PROPERTIES OF STARS REVIEW The Four Characteristics of Stars

Temperature - Determines the color of the starStar composition-Provides a "fingerprint" for

starsStar Brightness- Is determined by star size,

distance away, and strength of lightStar Size-Dwarf, medium, giant and supergiant

2.04 PROPERTIES OF STARS REVIEW

Apparent Magnitude- The brightness of a star as it appears from the earth, without the effect of the earth’s atmosphere

Absolute Magnitude- the amount of light that a star gives off. (brightness)

2.05 HR DIAGRAM The main reason that the HR Diagram is so

useful is you can tell the size of the star by plotting it on the HR Diagram. The different sizes of stars form a pattern on the HR diagram.

The HR diagram is a graph with the Absolute magnitude on the y – axis. Absolute magnitude is measure in comparison to the sun. Absolute magnitude is the brightness of a star as compared to the sun. We assign the sun an absolute magnitude of 1.

The temperature on the x-axis. The Surface temperature of the sun is measured in degrees Celsius.

2.06 LIFE CYCLE OF STARSStages of a Stars Life

Protostar – The birth of a star

Fusion Ignition to Main Sequence – Infancy to Childhood ages

2.06- LIFE CYCLE OF STARSRed Giant or Supergiant- Middle age stars

Dwarf or Black Hole- Old age to Death of a star

2.06LIFE CYCLE OF STARS Protostar-Fetus A nebula is a region of gas and dust in space.

Over time the gas and dust collects in a spinning cloud. This condenses more to from a protostar.

A protostar is the birth place of a star. It is similar to the fetus stage in the human life cycle.

Fusion Ignition/Main Sequence=Infancy and Adult

As the gases in a protostar become more and more compact, the pressure and heat will get to a point where the gas will ignite and a star is born. The main sequence is when the star is in its youth. These stars are of average size.

2.06LIFE CYCLE OF STARS Red Giant/Red Supergiant- Middle Age After a star has burned for awhile, it will become a giant or

supergiant. Giants and supergaints are stars that are middle aged.

Black Hole/Dwarf-Old Age/Death At the end of a stars life, it will become a dwarf or a black

hole. The giants will turn into dwarfs and the supergiants will turn into blackholes.

Black Holes A black hole is formed when a supergiant star dies. Black holes are hard for scientists to study because they

are black and hard to see. Select to Open Fun Fact: It is estimated that a 100 lb person would weigh

9,200,000,000,000 lbs on a black hole.

2.06 ADVANCE: MASS DETERMINES FATE Betelgeuse started like every star. A nebula condensed into a protostar. The protostar formed a main sequence star. The main sequence star turned into the supergiant that

we see today. Since Betelgeuse has so much mass, it will soon explode

in a giant supernova . When the gravity of supergiants gets too big, the star will explode. This is called a supernova.

After stars explode in a supernova, they have two options to spend the rest of their life. Again depending on the mass left after the supernova, the star will either become a neutron star or a black hole.

High mass stars will become neutron stars. Extremely high mass stars will become black holes.

2.06 ADVANCE: MASS DETERMINES FATE Fate of an Average Sized Star A nebula condensed into a protostar The protostar formed a main sequence star The sun is currently a main sequence star. More specifically

the sun is in the middle of its main sequence stage. At some point in the future, the sun will end its main sequence stage and it will begin to swell to form a red giant. When this happens the sun will swell all the way out to the orbit of Jupiter. All the inner planets will be destroyed. Don’t worry this won’t happen for a very long time.

After the sun becomes a red giant, it will then expel its outer shell of gas and form a planetary nebula. The gases that are let off by the sun glow with all sorts of brilliant colors. The planetary nebula stage only lasts a few thousand years.

2.06 ADVANCE: MASS DETERMINES FATE Planetary nebula will eventually collapse into

a white dwarf. Once white dwarfs have all burnt out, it is

thought that they will form a black dwarf. At this point there are not black dwarfs found in our universe. The reason for this is our universe is not old enough and there has not been a white dwarf that has burn out yet. At some point in the future, a white dwarf will burn out and possiblity for a black dwarf to form will happen.

2.06 ADVANCE: MASS DETERMINES FATE High mass stars will not live as long as low

mass stars. The high mass stars will be hotter and

brighter. Because of this they will burn through their fuel faster.

Small mass stars will live for 100 billion years.

Average mass stars will live for 10 billion years.

Large mass stars will live for 5 billion years or less.

2.07 SOLAR PROPERTIES Solar prominences are flame-like arcs into

space, which are associated with sunspots and magnetic fields. Some solar prominences last for many days, others for only minutes.

Solar Flares- Flares, of all solar events, are the shortest…lasting only minutes..(pause).. and the most violent… creating a fusion explosion equal to millions of hydrogen bombs. The explosion of a solar flare is so violent that, like an earth quake, pressure waves race across the entire immense surface of the sun in just a few hours.

2.07SOLAR PROPERTIES Sunspots-If you were to look at the surface of

the sun through a solar telescope, you would see areas of dark spots. These are sunspots. These regions are dark because the temperature within a sunspot is lower than the rest of the sun. Over time these sunspots will come and go.

Even though the sun is so far away, these sunspots can have an effect to us on earth. When there are a large number of sunspots, the magnetic activity that comes from these sunspots can disrupt communication systems on earth. Cell phones, radios, and TV antennas will not work as well.

2.07SOLAR PROPERTIES Corona-The corona is the outermost part of

the suns atmosphere. The temperature of the corona exceeds one million ºC.

The corona can only be seen during an eclipse, where the moon covers up the sun leaving only the corona exposed, or through a special solar telescope.

ELECTROMAGNETIC SPECTRUM

2.08 ELECTROMAGNETIC SPECTRUM Electromagnetic Spectrum-the part of light that we can see is only a

small part of light. The electromagnetic spectrum is the range for light. The frequencies visible to us, we see as this range of colors. All visible frequencies mixed together appear as white light until

separated by a prism. The color of objects comes from the balance of frequencies in the light

striking them. The frequencies the objects absorb and finally, the non-absorbed

frequencies they reflect, which we call their color. Beyond the light visible to humans, are ultra-violet frequencies visible to

insects: and infra-red waves, that snakes can sense, and weather satellites too. Radio waves- coming from matter deep in outer space, that radio

telescopes can picture and x-rays that easily pass right through a body revealing structures deep inside a living person and so the frequencies the human eye can see, have been vastly expanded by technology from just visible light, to the entire range of the electro-magnetic spectrum.

2.08 ELECTROMAGNETIC SPECTRUM Gamma Rays Description: Gamma rays are light that is given off

of radioactive substances. X-rays Description: X-rays are light that is used in the

medical field to look at people’s bones and insides Ultraviolet Light Description: Ultraviolet light is radiation that is

given off by the sun that causes sunburns. Visible Light Description: Visible light is all the light that

humans can see.

2.08ELECTROMAGNETIC SPECTRUM Infrared Light Description: Infrared light is heat. The

military uses infrared to see how many people are in buildings or to see people at night.

Microwaves Description: Microwaves are light that is used

in radar and to heat up our food. Radio Waves Description: Radio waves are light that is

used for radio, TV antennas, and cell phones.

2.08 ELECTROMAGNETIC SPECTRUM :REVIEW 1. All of the following are types of light

except Visible light Microwaves Plasma X-rays 2. The electromagnetic spectrum is A magnetic field. A device that puts out a magnetic

field. The study of electricity. The range of all the types of light.

2.08 ELECTROMAGNETIC SPECTRUM REVIEW 3. Which of the following types of light can

humans see with their eyes? Microwaves Radio Waves Gamma rays Humans cannot see any of the above

with their eyes. 4. Which colors are contained in white light? All of the colors No colors All the light colors All the dark colors

2.08 ELECTROMAGNETIC SPECTRUM REVIEW 5. Which type of light can cause sunburns? Visible Light Ultraviolet Light Infrared Light X-rays

2.08 ELECTROMAGNETIC SPECTRUM REVIEW 6. Heat is what type of light? Visible Light Ultraviolet Light Infrared Light Gamma Rays 7. Which type of light transmits cell

phone conversations? Radio Waves Ultraviolet Light Infrared Light Gamma Ray

2.08 ADVANCE: CHARACTERISTICS OF LIGHT Where does sound fit in? This is a great

question! And though the electromagnetic spectrum includes various types of radio waves to broadcast sound, sound is not part of the electromagnetic spectrum.

Sound is a totally different form of energy than light represented by the electromagnetic spectrum. The biggest difference is that all types of light can travel through empty space, while sound requires matter to travel through, like air or water. Isn't that cool?

2.08 ADVANCE: CHARACTERISTICS OF LIGHT Light is a Wave Light behaves in two ways - like a wave and like a

particle. With this in mind, we learned that there are more kinds of light than just what you can see. There are many different types of light, but what determines the kind of light? There are two properties of light that will determine the type of light.

Wavelenght-is the distance between two wave crest Frequency-is the number of times a wave crest passes

by one point in one second. Light does not travel in a perfectly straight line. It

moves like a wave does on the ocean. There are two important properties of waves that determine the type of light. Explore the properties to learn more about them.

2.08ADVANCE: CHARACTERISTICS OF LIGHT Wavelength and Frequency are Related When we say that wavelength and frequency

are related, that does not mean that they are brothers or sister. It means:

if you change the wavelength of a wave it will affect the frequency,

if you change the frequency of a wave it will affect the wavelength.

2.08ADVANCE: CHARACTERISTICS OF LIGHT These two different waves show: when the wavelength increases, the

frequency will decrease, when the wavelength decreases, the

frequency will increase. Wavelength and frequency are opposites.

2.09 LIGHT: FINGERPRINT OF STARS Emission Spectrum The light “fingerprint” is called an emission

spectrum . When an atom lets off or emits light it does not let off just one color. It emits a combination of a few colors. The emission spectrum is all the colors that the atom emits. Here is the emission spectrum for iron.

Spectroscopes are the instruments that scientists use to see the atoms emission spectrum. They take the light and bend it through a prism. Spectroscopes take the light coming off objects and break them down into their colors.

2.09LIGHT: FINGERPRINT OF STARS Stars and planets are made up of many

different atoms. When scientists pass the light coming from the star or planet through the spectrometer they get an emission spectrum. We can compare this emission spectrum to a situation where many people have put their fingerprints in the same spot. The scientist is like a police officer that has to sort them all out.

2.09LIGHT: FINGERPRINT OF STARS Review Spectrum White Light White light is light that contains every color

of the rainbow. Notice that every color is in white light’s emission spectrum.

Hydrogen Hydrogen’s spectrum has some different

shades of violet, some shades of blue and a red. Hydrogen is the most abundant element in the universe.

2.09LIGHT: FINGERPRINT OF STARS Sodium Sodium’s spectrum contains two shades of yellow. Helium Helium is another very abundant element in the

universe. Helium’s spectrum contains some different shades of blues, a yellow and a red.

Neon Neon is the atom that is contained in a neon light.

Can you see why a neon light looks orange? Mercury Mercury’s spectrum contains purple, blue, green

and two shades of yellow.