Physical Science 10/16 Stars and Galaxies Bell work: What Galaxy are we in? What kind of Galaxy is it? What measurements do we use to measure distances between objects in space? Agenda: Stars and Galaxies Learning Target: I can describe how scientist search the skies. I can describe the different properties of various star groupings. I can draw the EM spectrum and list the major parts. Homework/Important Dates: 15.1 + 15.2 Book Notes & vocab due Thursday Last day to turn in late or makeup work = 10/27 Unit 2 test = Oct 31st

Physical Science Notes Stars and Galaxies

Telescopes The most common way scientists view celestial bodies is with a telescope. Telescopes are instruments that collect and focus light and other forms of EM radiation. The simplest kind of telescope is an optical telescope. Optical telescopes use mirrors and lenses to collect and focus visible light from distant objects. There are reflecting and refracting telescopes.

Telescopes Radio telescopes detect the radio waves emitted by objects in space. Radio telescopes can be one very large dish, or several smaller radio dishes. Other telescopes can detect other types of EM radiation, such as x-rays. Observatories are complexes that contain one or more telescopes. Many observatories are on mountains or in space because Earth’s atmosphere blurs visible light that passes through it.

Measuring Distances in Space An astronomical unit is the distance from the Earth to the sun. An AU is about 93,000,000 miles. A light-year is the distance that light travels in a year. Since light travels about 186,000 miles per second, a light-year is about 6,000,000,000,000 miles. A parsec is about 3.26 light years.

The Electromagnetic Spectrum Light is a form of electromagnetic radiation, energy that can travel through space in the form of waves. All the different forms of EM radiation make up the electromagnetic spectrum. The type of EM radiation is determined by its wavelength, the distance between the crest of one wave and the crest of the next.

The Electromagnetic Spectrum The electromagnetic spectrum goes from radio waves with the longest wavelength, to gamma rays with the shortest wavelength. In the middle is visible light, the types of radiation humans can see.

Sound travels through matter as a wave A standing wave – Rubens tube: https://www.youtube.com/watch?v=ynqzeIYA7Iw

Spectrographs A spectrograph is a device that breaks light into colors and produces an image of the resulting spectrum. Different elements have different spectrographs. Scientists can use the spectra of stars to determine how much of each element there is in the star.

Stars When humans look up at the stars, they often see patterns. We call those patterns constellations. Constellations are made of many different star, of all types. Stars are classified according to color and size. Color of the star tells how hot the star is. Red is coolest, blue is hottest. Size of stars vary greatly. The sun is a medium-sized star.

Brightness The brightness of a star depends on both its size and temperature. There are two measure of brightness: Apparent brightness is the star’s brightness as seen from Earth. Absolute brightness is the star’s brightness as it would be seen from 10 parsecs away.

Parallax In order to measure the distances to stars, astronomers use parallax. Parallax is the apparent change in position of an object when you look at it from different angles. Parallax works on stars that are within a few hundred light years of Earth.

Measuring Parallax To measure parallax, scientists look at a nearby star when Earth is on one side of the sun. Then they look at the same star six months later when the Earth is on the other side of the sun. They measure how much the star appears to move against the background and then use that info to calculate the distance.

Star Systems Most stars are member of groups of two or more stars, called star systems. Star systems that have two stars are called binary stars. Often one of the stars in the system is much brighter than the other, meaning one cannot be seen from Earth. The dimmer star can be inferred from the wobble its gravity puts onto the brighter star. Star systems with more stars are called multiple stars. Most stars we see from Earth are actually multiple stars.

Physical Science 10/17 How does a telescope work? Bellwork: How does a telescope work? What does an astronomer use a spectrograph for? Agenda: Bill Nye “Outer Space" Galaxies Foldable Learning Target: I can describe how scientists search the skies. I can describe the different properties of various star groupings. I can draw the EM spectrum and list the major parts. Homework/Important Dates: 15.1 + 15.2 Book Notes & vocab due Thursday Last day to turn in late or makeup work = 10/27 Unit 2 test = Oct 31st

Star Clusters Many stars belong to larger groupings called star clusters. Open clusters have a loose disorganized appearance, and contain no more than a few thousand stars. Globular clusters are large groupings of older stars and are very densely packed, often containing millions of stars.

Galaxies A galaxy is a huge group of single stars, star systems, star clusters, dust, and gas bound together by gravity. Quasars are a special type of galaxy that are enormously bright and have giant black holes at their centers.

Galaxies There are three main types of galaxies. Spiral galaxies have a bulge in the middle and arms that spiral outward like a pinwheel. Elliptical galaxies are round or oval in shape and are mostly made of old stars. Irregular galaxies do not have a regular shape and are generally smaller.

The Milky Way Our solar system is located in a spiral galaxy called the Milky Way. The solar system orbits the center of the Milky way, taking about 225 million years to make the trip. We are about 25,000 light-years away from the center of the galaxy.

Exo and Rogue Planets Exoplanets are planets that orbit a star other than the sun. There are over 3000 confirmed exoplanets, 51 of which may have Earth-like conditions. Millions more may exist, but have not been discovered. Rogue planets do not orbit a star, they instead orbit the center of the galaxy directly. There are 8 rogue planet candidates, but likely many more exist.

Physical Science 10/18 How do we measure the distance to stars? Bellwork: How do we measure the distance to stars? List 5 Astronomy topics that interest you. Agenda: Research Project Learning Target: I can research an astronomy topic and create and deliver an informative presentation about my topic. Homework/Important Dates: 15.1 + 15.2 Book Notes & vocab due Thursday Last day to turn in late or makeup work = 10/27 Unit 2 test = Oct 31st

Galaxy Foldable Complete foldable using complete sentences and color pictures Make the example match the picture. Pictures may be printed. Pg. 618

Topic Selection Person + Vehicle Place Program Other 1st Man/woman Saturn V Planets Race to the moon Eclipses Animals Apollo Galaxies Mission to Mars Astronaut Training 1st American Man/woman Space Shuttle Stars Explorer Spacesuit Apollo11 astronauts ISS Nebulae Surveyor Twin Study Apollo 13 astronauts Rovers Asteroid belts and Oort cloud Cassini Orbiter Space Program Disasters Teachers Exoplanets and Rogue Planets New Horizons SETI Famous Explorers Rocket Development Jupiter’s Moons Viking Living in Space

Physical Science 10/19 Bellwork: What is the difference between absolute and apparent brightness? Agenda: Quiz Review Research Project Learning Target: I can research an astronomy topic and create and deliver an informative presentation about my topic. Homework/Important Dates: Research Last day to turn in late or makeup work = 10/27 Unit 2 test = Oct 31st (correction)

Last day to turn in late or makeup work = 10/27 Unit 2 test = Oct 31st Physical Science 10/20 Bellwork: What is an astronomical unit and when would you use it? What is a light year and when would you use it? What is a parsec and when would you use it? Bellwork: Agenda: Quiz Friday Weekly Assignments: Bell Work Notes Book Notes & Vocab. Homework/Important Dates: 15.3 + 15.4 Book Notes due Thursday 10/26 Last day to turn in late or makeup work = 10/27 Unit 2 test = Oct 31st

Nebula Protostar Red/Super giant Planetary nebula Supernova White dwarf Neutron star Pulsar Black hole Hertzsprung-Russell diagram Main sequence star