GRAHAM LOVELAND

WWK: Understand the leading theories of the evolution of the universe including the big bang, redshift, and the age of the universe.

Redshift

Redshift is an effect that light undergoes through long distances.

All light changes in wave length through distances but is only noticeable through long distances. The further away something moves the longer the wave length. By using redshift scientists have determined that galaxies are expanding away from each other in acceleration. Scientists have concluded by rewinding this process that the universe must have come from a singularity giving rise to the big bang theory.

The age of the universe

Using triangulation and brightness variations scientists can calculate the distance of stars and galaxies.

The furthest scientists have ever scene is from cosmic microwave background radiation and was 13.7 billion light years away.

The big bang

In order to explain the big bang scientists believe a force called inflation released huge amounts of energy through the expansion of the universe which latter settled to matter.

Plank time

To measure the first instances after the big bang scientists use plank time which is equal to 10 to the -43 seconds. This unit of time is also used in particle accelerators in order to discover new sub atomic particles.

String theory

There is no definite answer for what came before the big bang but one of the leading theories is string theory.

String theory has mathematically sound since 1984 but is not testable to this day. This theory proposes a possible explanation for what was before the big bang yet also proposes some radical ideas such as 11 dimensions and multiple universes.

K.S.

According to the cosmic microwave background radiation what is the minimum age for the universe?

Video

http://www.youtube.com/watch?v=fyPNvxCqJ0M

WWK:WE WILL KNOW THE CHARACTERISTICS AND LIFE CYCLE OF

STARS

WHAT IS A STAR?

• A star is a massive ball of gas which produces heat and light through nuclear fusion.

• A star's life cycle is determined by its mass: The larger the mass, the shorter the life cycle.

• A star's mass is determined by the amount of matter that is available in its nebula, the giant cloud of gas and dust in which it is born.

STAR FORMATION:• Stars are formed by clouds of dust. The cloud of

dust is called a nebula. Nebulas are made up of helium, and hydrogen.

• Over time, gravity pulls the hydrogen gas in the nebula together and it begins to spin. When the gas spins faster, it begins to heat up and becomes known as a protostar.

• The temperature of the star eventually reaches 15,000,000 °C and nuclear fusion occurs in the cloud’s core. This is the main sequence of the star and it stays this way until it dies.

HOW ARE STARS FUELED

• Stars are fueled by the nuclear fusion of hydrogen which forms helium deep in its core. The outflow of energy from the central regions of the star provides enough pressure to keep the star from collapsing under its own weight. This energy is the reason stars shine.

CHARACTERISTICS OF STARS

Stars are characterized by their brightness, color, surface temperature, size, and mass

A Stars brightness is measured by its magnitude and luminosity compared to our sun.

Stars come in a wide variety of colors: from reddish to yellowish to blue the color depends on the surface temperature of the star.

CHARACTERISTICS CONT.

The surface temperature of a star is measured by the kelvin unit.

The size of stars is measured in terms of the radius of our sun.

The mass of stars is also measured in terms of the solar mass of our sun.

THE DEATH OF STARS

• A star begins to die when the hydrogen supply in the core of the star runs out. This causes the core to become unstable and it contracts. The outer shell of the star, compromised mostly of hydrogen, begins to expand. As the star expands, it cools and glows red: at this stage the star is known as a Red Giant. The amount of mass a star has determines which of the following cycle the star goes through after the Red Giant phase:

THE DEATH CONT.

Average/ Medium sized stars: Throughout the red giant phase, the hydrogen gas in the outer shell

continues to burn and the temperature in the core continues to increase. Helium atoms in the core fuse to form carbon atoms. The last of the hydrogen gas in the outer shell is blown away to form a ring around the core. When the last of the helium atoms in the core are fused into carbon atoms, the medium size star begins to die. Gravity causes the last of the star's matter to collapse inward and compact. This is the white dwarf stage. At this stage, the star's matter is extremely dense. White dwarfs shine with a white hot light. Once all of their energy is gone, they no longer emit light.

THE DEATH CONT.

Large stars Once large star reach the red giant phase. The temperature of

the core increases as carbon atoms are formed from the fusion of helium atoms. Fusion stops and the iron atoms formed by carbon start to absorb energy. The energy held by the iron atoms is released in a powerful explosion known as a supernova. From a supernova, stars can end up as neutron stars: a spinning star that gives of radio waves. Large stars can also end up as black holes after the super nova because the lack of nuclear fusion to support the core causes gravity to swallow up the star, creating a black hole. Black holes swallow any matter and energy that come near them.

VOCAB

• Nuclear fusion: a nuclear reaction in which two or more atomic nuclei collide at very high speed and join to form a new type of atomic nucleus.

• Nebula: any of numerous clouds of gas or dust in interstellar space.

• Red Giant: a luminous giant star of low or intermediate mass in late phase of stellar evolution.

• White dwarf: a stellar remnant composed mostly of electron-degenerate matter.

• Supernova: an explosion of a massive supergiant star

• Black hole: region of space-time from which gravity prevents anything, including light, from escaping.

KS

•What is a white dwarf?

VIDEO

• http://www.dnatube.com/video/28727/Formation-of-Stars

How the sun and other stars are

fueled.By Nika Patthana

The sun is fueled by hydrogen, this is a process by hydrogen atoms, which bonds form helium to create Nuclear Fusion deep in the sun core.

But can happen only under very hot condition which creates heat and light through nuclear fusion.

How is the sun fueled?

Star’s are fueled by the same thing as the sun nuclear fusion. hydrogen atom to form helium deep into the interior of star’s.

The outflow of energy from the central regions of the star provides the pressure necessary to keep the star from collapsing under its own weight, and the energy by which it shines.

How are star’s fueled?

Nuclear fusion is a process where two or more nuclei combine to form an element with a higher atomic number. Fusion is the reverse process of nuclear fission which fusion reactions power the Sun and other stars.

The fusion releases energy. The energy released is related to Einstein's famous equation, E=mc2.

For a nuclear fusion to occur it is necessary to bring the nuclei so close together that nuclear forces become important and glue the nuclei together. The nuclear force only acts over incredibly small distances and has to counteract the electrostatic force where the positively charged nuclei repel each other. For these reasons fusion most easily occurs in a high density, high temperature environment.

What’s a nuclear fusion?

Hydrogen is a colorless, tasteless, odorless gas. It is found only in very small amounts in the Earth and its atmosphere. But hydrogen combines very easily with other elements. Water, H2O, for example, is the most important and abundant hydrogen compound. It is made up two atoms of hydrogen for every one atom of oxygen. Hydrogen and carbon combine in various ways to form hydrocarbons, such as petroleum products, coal products, and rubber.

Helium is a chemical element with symbol He and atomic number 2. It is a colorless, odorless, tasteless, non-toxic, inert, monatomic gas that heads the noble gas group in the periodic table. Its boiling and melting points are the lowest among the elements and it exists only as a gas except in extreme conditions.

What’s Hydrogen and Helium

What’s a nuclear fusion?

KS

http://www.youtube.com/watch?v=MUR3hmW6Ydw

Video

Madeleine Flores

SUPERNOVAE AND NEBULAE

WWKHOW SUPERNOVAE CONTRIBUTE TO THE FORMATION OF

PLANETS AND STARS AND HOW NEBULAE CONTRIBUTE TO THE FORMATION OF PLANETISMALS AND PROTOPLANETS.

WHAT ARE SUPERNOVAE?• When a star reaches its last stage in their cycle the star can either implode on itself

causing a supernova or it can turn into a white dwarf.

• There are two types of a supernova:

Type I:is the complete destruction of a white dwarf but only if the white dwarf is made up of carbon and it is a member of a binary system

Type II: As a massive star gets older, its core shrinks as its outer layers expand. As the outer layers are expanding, the core creates energy and creates outward pressure. When the core becomes mainly iron and cannot create any more fusion (to create energy), it cannot create outward pressure to resist the gravitational pull of the star. The gravity of the star overpowers the outward pressure of the core, and the star collapses. The star’s outer layers rebound off of the star’s core and eject into space as an enormous cloud of gas and dust, creating a gigantic explosion

• A supernova can result into a black whole

HOW A SUPERNOVA FORMS STARS AND PLANETS• Supernovae destroys the star and forms heavy elements because of the high temperature

and then spews those elements out into space.

• Our sun and planets (any star and or planets) incorporated those heavy elements

• Our solar system was most likely formed by a nearby supernova and caused a cloud of gas and dust to collapse.

• The heavier elements in the human body were formed in supernovae that exploded before our solar system formed.

WHAT PLANETISMALS AND PROTO PLANETS ARE

• A planetismal is an object formed from dust, rock, and other materials.

• It can range anywhere from a few meters to hundreds of kilometers it refers to a term of small celestial bodies formed during the creation of planets.

• A protoplanet are small celestial objects that are the size of a moon or a bit bigger. They are small planets, like an even smaller version of a dwarf planet

• These objects form during the creation of a solar system.

WHAT A NEBULA IS • Nebula is a Latin word that means cloud

• A nebula is an interstellar cloud in outer space that is made up of dust, hydrogen and helium gas, and plasma

• It is formed when portions of the interstellar medium collapse and clump together due to the gravitational attraction of the particles that make them

• Outer space is made up of gas and dust known collectively as the interstellar medium or ISM. It is this dispersed matter that eventually collapses and forms a nebula. There are five different types of nebulae:

Emission: an emission nebula is a cloud of high temperature gas. Within this type of nebula, a star energizes the atoms in the cloud with ultraviolet radiation. As these atoms fall back to lower energy states, they emit radiation. Usually red. (Orion nebula)

Reflection: it does not emit radiation of its own. It is a cloud of dust and gas that reflects the light energy from a nearby star or group of stars. Reflection nebulae are frequently the sites of star formation. They usually tend to be blue in color because of the way that the light is scattered. (Trifid nebula)

Dark Hole: A dark nebula is a cloud of dust that blocks the light from objects behind it. They are very similar to reflection nebulae in composition and look different primarily because of the placement of the light source. Dark nebulae are usually seen together with emission and reflection nebulae. (Horsehead nebula)

Supernova: The explosion blows a large amount of the star's matter out into space. This cloud of matter glows with the remains of the star that created it. (Crab nebula)

Planetary: - A planetary nebula is a shell of gas produced by a star as it nears the end of its life cycle. Their name can be a bit misleading. They actually have nothing to do with planets. These nebulae were given this name because they often look like planets due to their round shape. The outer shell of gas is usually illuminated by the remains of the star at its center. (Ring nebula)

HOW NEBULAE FORM PLANETISMALS AND PROTOPLANETS • In the nebular theory of the formation of the solar system, a large cloud of dust and gas—

the solar nebula—began to collapse under its own gravity. As it did so, it began to spin faster, to conserve angular momentum, eventually forming a disk. Protoplanets formed in the disk and became planets, and the central protosun eventually evolved into the Sun.

• The condensation theory builds on the nebular theory by incorporating the effects of particles of interstellar dust, which helped cool the nebula and acted as condensation nuclei, allowing the planet-building process to begin.

• Small clumps of matter grew by accretion, gradually sticking together and growing into moon-sized planetesimals, whose gravitational fields were strong enough to accelerate the accretion process. Competing with accretion in the solar nebula was fragmentation, the breaking up of small bodies following collisions with larger ones. Eventually, only a few planet-sized objects remained. The planets in the outer solar system became so large that they could capture the hydrogen and helium gas in the solar nebula, forming the jovian worlds.

VIDEO • http://www.youtube.com/watch?v=qVA7R9z4fpU

K.S.• How many different types of nebulas are there?