Per. 5 Table 5

1. Per. 5 Table 5 WWK Unit 15How gravitational condensation of the solar nebula lead to the accretion of planetesimals and protoplanets

2. Solar Nebula • The solar system began as a massive cloud of interstellar dust and gases. The cloud collapsed into its own gravitational force, and in the center of all the high pressure material the sun formed. Most of the masses in the cloud formed the sun, but the rest of the particles flattened out and began rotating around the newly formed star. This massive circulating cloud of dust and gas is known as the Solar Nebula and formed approximately 4.6 billion years ago.

3. Planetesimals Theory • Viktor Safronov proposed this theory of how planets were formed. • The theory states that material such as gas, dust, and space rock spinning in the nebula are what starts the process. This material is gradually pulled together by gravity to form small chunks. These chunks get larger and larger until they form planetesimals. • Many of the objects break apart when they collide, but some continue to grow. Some of these planetesimals go on to become planets and moons.

4. From Planetesimals to Protoplanets • At approximately 1 kilometer in diameter these planetesimals begin to form their own gravity because of their increasing size. • Once the large mass has its own gravity it begins to “feed” off of smaller bodies that happen to cross its path by colliding and absorbing them, and they continue to increase in size and also increase their energy. These planetesimals that have increased drastically are called protoplanets. • They are theorized to be small celestial bodies that are formed at the beginning stages of planet formation.

5. Terrestrial Planets • These planets are comprised of mostly rock and various metals. These are the planets that form from the accretion of planetesimals and protoplanets. • They have various layers because the gravity in the center pulls in the denser material such as iron and the outer layer is mostly the least dense materials. • Examples are Mercury, Venus, Earth, and Mars

6. Asteroids and Comets • Other celestial bodies formed during planetary accretion are asteroids and comets. • They are planetesimals that never collected enough material to begin the process of becoming a planet.

7. KS • What are two examples of a terrestrial planet?

8. Video • http://www.youtube.com/watch?v=TUjJTNKO9FU

9. WWK: how the sun and other stars transform matter into energy through nuclear fusion Danny Aguilar Period 5 Table 5 Unit 15

10. Nuclear Fusion • Nuclear fusion is when a nuclear reaction in which two or more atomic nuclei collide at a very high speed and join to form a new type of atomic nucleus. During the nuclear fusion process, matter is not conserved because of some of the mass of fusing nuclei is converting into photons which is released through a cycle that the sun uses.

11. Nuclear Energy • Energy is indirectly observed quantity which comes in many forms. • A release of nuclear energy happens when the nuclei of an atom is changed. Hydrogen and uranium are two kinds of matter (generally is a substance often a particle that has rest mass and also volume.) used to produce nuclear energy. In a nuclear reaction, the big binding of energy inside a hydrogen or uranium nucleus would be released.

12. The Sun • The Sun is a main sequence star, and it generates it’s energy by nuclear fusion of hydrogen nuclei into helium. In it’s core, the Sun would fuse 620 million metric tons of hydrogen every second.

13. Stars • Nuclear fusion separates the stars. Stars are powered by the fusion of elements lighter than iron, particularly of hydrogen.

14. Nuclear Transformation • Nuclear transformation is what happens to an unstable atom nuclei while striving to reach stability. The nucleus of any element atom should have a specific neutron/proton ratio to be a stable nucleus. Also, the absolute number of protons should not exceed a certain limit.

15. KS • What is Nuclear Fusion?

16. http://www.youtube.com/watch?v=pusKlK1L5To

17. We will know about the various processes which are thought to allow the differentiation of protoplanets into layers

18. Differentiation • Differentiation is the process by which protplanets are allowed to form and get distinct layers • The process by which they form takes place during the formation of a solar system • The dust surrounding a star collide with other particles that collide with other particles and continue to grow to eventually form protoplanets

19. Protoplanets • A protoplanet is a small celestial object that is similar to our moon, but the moon is not a protoplanet • They are essentially small planets similar to asteroids but are structured like planets • They have layers and an atmosphere

20. Kinetic Heat of Impact Accretion • When clumps of material collide they form larger clumps, this process is called impact accretion • The kinetic heat from the collisions causes the cold materials to heat up • This is how protoplanets form and create layers

21. Gravitational Compression • Iron from the clumps sink to the core and generate gravitational energy • The gravity melts silicate rocks within the protoplanet allowing the protoplanet to form further • Through the process of gravitational compression gravity also compresses the protoplanet to where it is tightly packed, allowing it to solidify and have finalized layers

22. Radioactive Decay • The radioactive heat generated by the impact melts the ice on the planet making the protoplanet smoother and more liquified, this process is called radioactive decay • Once the ice was melted, the minerals in the protoplanet were meshed together to form rocks

23. K.S. • What is the third step in the differentiation process?

24. Video • Coming Soon!

25. Unit 15 By: Tyler Tucker WWK: Aging stars and their connection to supernovas

26. White Dwarves • A white dwarf is a small and very dense star that has ahigh temperature and glow. It is thought to be a star in its final stage. It is either used up all of its nuclear fuel or shed its outer layer, leaving only the core. Only about 10 percent of stars in the Milky Way are white dwarfs. They’re so small, they are not visible to the naked eye.

27. Red Giants • A red giant is a very large star that has a low surface temperature, which makes it glow red or orange. Red giants are non-main-sequence stars. They are not massive stars but just expanded stages of lower-mass main-sequence stars that exhausted the hydrogen in their core and fuse the hydrogen remaining into helium in a glowing red/orange outer shell. The Sun is expected to become a red giant in about 5 billion years, which would cause the expanding of 70 times its current size bringing it dangerously close to Earth.

28. Supernovas • A supernova is a star that erupts into an enormous explosion caused by either instabilities after it exhausts its nuclear fuel or gravitational collapse that happens after the addition of matter from another star, which, for a few days, makes it about one hundred million times brighter than the sun. The expanding shell of debris creates a a shell of space dust that gives off radio waves, X-rays, and light, for hundreds or thousands of years.

29. KS: • Which vocab word from the presentation describes a large explosion?

30. Video • http://www.youtube.com/watch?v=e-91PbbaKI8

31. WWK: Evaluate the evidence concerning the Big Bang model such as red shift and cosmic microwave background radiation and current theories of the evolution o f the universe, including estimates for the age of the universe. Andrew McAllisterPeriod 5

32. The Big Bang Theory • The Big Bang theory is the prevailing cosmological model that describes the early development of the Universe.  According to the theory, the Big Bang occurred quite some time ago. • After this time, the Universe was in an extremely hot and dense state and began expanding rapidly. After the initial expansion, the Universe cooled sufficiently to allow energy to be converted into various subatomic particles. • Big Bang-theory that deduces a cataclysmic birth of the universe from the observed expansion of the universe, cosmic background radiation, abundance of elements, and the laws of physics. • Universe-the totality of known or supposed objects and phenomena throughout space.

33. Red Shift and Cosmic Microwave background Radiation • Redshift happens when light seen coming from an object that is moving away is proportionally increased in wavelength, or shifted to the red end of the spectrum. • When it is redder this means lower frequency and photon energy. • The cosmic microwave background radiation is a way to see things in space easier. • Most telescopes can only see so far and this helps you identify stars, galaxies, and other objects by using a type of thermal radiation. • Radiation-the emission or transfer of radiant energy as particles, electromagnetic waves and sound.

34. Theories about the evolution of the Universe • The Big Bang Theory is the most prominent. • The steady state theory is another that says that the mass of the universe is the same at all times, because of new galaxies and old ones dying. • Another one is the pulsating theory, which says that the universe pulsates and right now the universe is expanding.

35. Elements involved • The first element that was produced was hydrogen. • Soon after that more were created, such as helium and lithium. • Giant clouds of these primordial elements later combined due to gravity to form stars and galaxies, and the heavier elements were synthesized either during supernova or within stars.

36. New Theories • A new theory from the University of Melbourne says that it was not a big bang, but a giant freeze. • Some people say that the universe was frozen and the big bang was just the universe becoming unfrozen by an explosion.

37. K.S. • What is a theory that explains how the universe might have started or works?

38. Video • http://www.youtube.com/watch?v=OdTTwtVcYjU