Unit 1: Astronomy, Part 1: The Big Bang

Transcription

1 Earth Science Notes Packet #1 Unit 1: Astronomy, Part 1: The Big Bang 1.1: Big Bang The universe is How do we know this? All matter and energy in the universe was once condensed into a single point bya Moments after the Big Bang, the universe was very hot and dense Protons, neutrons, and electrons formed formed There was enough energy to start formed Evidence Background radiation Space is...space! Composition of matter in the universe hydrogen helium

2 1.2: Expansion of the Universe The Doppler Effect The change in of a wave for an observer relative to its motion Moving toward you: Waves are Moving away: Waves are Redshift When the light of a distant object (star, planet, etc.) is viewed through a prism, the spectrum is not Black lines appear: lines Determine which are present When the object is moving away from us, the absorption lines are shifted toward the end of the spectrum (stretched): Redshift! Hubble s Law Hubble s Law: The further an object is from Earth, the faster it is moving If a galaxy is twice as far from Earth as another, it is moving as fast

3 1.3: Structure of the Sun Our sun is just one of billions of stars in the Milky Way galaxy. Only star whose surface we can study. Through spectroscopic analysis of the sun, scientists know that most of the known elements are found in the sun Hydrogen makes up of the sun s mass Helium makes up The core Nuclear Radiative Zone Energy is transferred through (particles of light) travel very slowly through this layer As a photon travels, it hits many other photos on its way, slowing it down Convective Zone Energy is transferred through The Photosphere most of the sunlight we see The part of the Sun we see! Has a grainy texture Granules move by convection (heat currents) The Chromosphere This layer of hot gas appears as a red rim around the sun (due to ) Located above the photosphere The Corona layer of the Sun Prevents most of the Sun s atomic particles from escaping Some particles DO escape, however. These particles travelling away from the Sun are called. This layer can ONLY be seen from Earth during a.

4 1.4: Surface Features of the Sun Sunspots: Dark areas on the sun areas The magnetic field breaks through the surface, causing a disruption in heat transfer The number of sunspots varies every years. This is known as the solar cycle. Solar Flares Brief outbursts releasing HUGE amounts of energy/electrically charged. Sometimes the particles reach Earth s atmosphere and produce (Northern and Southern Lights). Prominences Clouds of glowing gases that form huge arches. Jump from one to another. Very violent eruptions of chromospheric gases. 1.5: Gravity in the Universe Gravity The force of between two bodies in the universe Newton s Law of Universal Gravitation The law stating that the force with which bodies are attracted to each other is directly proportional to the of the objects and inversely proportional to the square of the by which they are separated. 1.6: Life Cycles of Stars A star s life cycle can last billions of years. 1. Dark, cool clouds of interstellar gas and dust. Often referred to as. Stars begin to form as gas and dust collide. 2. Developing star Not yet hot enough for fusion reactions (10x10 6 K) 3. Hydrogen to Helium fusion has begun! The hotter, larger stars burn H 2 fastest. This stage makes up 90% of a star s life.

5 4. Hydrogen at core is depleted and it begins to contract. The contracting core heats up and causes the outer edges to heat up and expand. Results in a star hundreds to thousands of times its normal size. 5. Depends on the of the star. Low mass stars: Main Sequence White Dwarf (No Red Giant) Medium mass stars: Main Sequence Red Giant White Dwarf OR outer gases leave to form a Planetary Nebula Massive stars: Main Sequence Super Giant Supernova Neutron Star OR Black Hole Stellar Remnants Extremely small stars with huge. Cools and dims over time until it becomes a small cold body known as a Black Dwarf (never seen). Leftovers in supernova events. Smaller and more dense than White Dwarfs. Pea sized sample=100 million tons! : Source of bursts (or pulses) of radio energy. Stars three times our Sun can collapse after a supernova into objects more dense than Neutron Stars. Such high mass and gravity that even light can t escape. Possibly detected by strong X-ray sources.