Celestial BodiesERAU RETErica Ajder

Andromeda galaxy

Crab Nebula

Sombrero Galaxy

Horsehead nebula

Ultra Deep Field

• Based on the article write 3 interesting facts or comments that you found from the article

• Share 1 interesting fact or comment with the group

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Hubble Telescope

Black Body Radiation

• What you think a blackbody is?• A blackbody is a surface that absorbs all

electromagnetic radiation• All bodies with temperature give off

thermal radiation• As temperature increases, blackbodies

emit visible light from longer wavelength or lower frequency (red) to shorter wavelength or higher frequency (blue)

Star Color/composition

• What is a star made of? • It is made up of various gaseous elements• The center of a star is dense; the outer layers are

less dense and make up the star’s atmosphere• What does the spectrum of a star tell you about

the star? • The spectrum of a star gives information about

the composition and temperature of a star

Emission Spectrum

• What do you think Emission Spectrum means?

• Emission lines are lines made when certain wavelengths, of light, or colors, are given off by hot gasses.

• Each elements produces a unique set of emission lines, which assists in identifying the elements in a star.

• This set of lines is known as the emission spectrum

Absorption spectrum

• What do you think absorption spectrum is? • A star’s spectrum is made of dark emission lines.

A star’s atmosphere absorbs certain colors of light, which causes black lines to appear.

• Because a star’s atmosphere absorbs some colors of light, the spectrum of a star is called an absorption spectrum.

Example of Each Spectrum Type

What do you notice about the absorption & emission spectrum of hydrogen?

Emission Spectrum of Common Star Elements

Kirchoff’s Laws

1. A hot solid object produces light with a continuous spectrum

2. A hot gas at low pressure produces an emission spectrum

3. Light passing through a cool gas will produce an absorption spectrum

Examples of Laws

1. Light passing through Solid Object

2. Hot gas at low temperature

3. Light passing through a cooler gas

Write down which elements are observed in this star

1

Write down which elements are observed in this star

2

Hertzsprung-Russell Diagram H-R Diagram

ParalLax

• the apparent shift in the position of an object when viewed from different locations

Courtesy of Holt Reinhart

Apparent & Absolute magnitude

• What do you think is the difference between Apparent & Absolute Magnitude?

• Apparent Magnitude - the brightness of a star as seen from Earth

• (how bright it looks to you)• Absolute Magnitude is the actual

measured brightness of a star • The absolute magnitude of our sun is 4.8

but because it is so close it appears to be a -26.8 (extremely bright)

Types of Stars• What stage of a star’s life cycle lasts the

longest?• Main sequence -2nd & longest stage

• What stages could a star enter after main sequence?

• Red Giant or Red Supergiant• Red Giants can be 10x larger than our sun• Supergiants can be 100x larger than our

sun

Types of stars Continued

• What stage could a star the size of our sun or smaller enter after being a Red Giant?

• White Dwarf – a small hot dim star that is leftover center of an old star

• White Dwarfs run out of hydrogen and no longer fuse hydrogen to make helium

When stars get old• What happens when a massive star

collapses and throws its outer layers into space?

• Supernova - can be brighter than an entire galaxy for several days

• Particles at the core collapse to form neutrons

• If the mass of this new star is about 2 times the mass of the sun, a neutron star may form

• A pulsar is a spinning neutron star

Name the type of star in each picture below

Sun Sizes compared

3 Types of Galaxies• What are the 3 types of galaxies? • Spiral, Elliptical, Irregular • Identify the 3 types below

Irregular- galaxies that do not fit into any other category

Spiral- galaxies that have a bulge in center & arms

that spiral outward

Elliptical- 1/3 of all galaxies are

massive blobs of stars & contain

mostly older stars

Which of the following forces holds galaxies together?

• A. Electrical• B. Electromagnetic• C. Gravitational• D. Magnetic

Which one of the following properties do astronomers use to determine temperature

& Composition of stars?

• A. the apparent motion of stars

• B. the absolute magnitude of stars

• C. the apparent magnitude of stars

• D. the absorption spectrum of stars

What type of star?

Astronomers estimate that in another 5 billion years, the Sun will burn up all of its hydrogen fuel. At the end of this 5-billion year pd., what kind of star will the Sun change into?

• A. red giant C. white dwarf• B. red dwarf D. red supergiant

Which of the following colors would indicate to an astronomer that a star has a very high surface temperature?

• F. blue• G. orange• H. red• I. yellow

Properties of waves• What does a wave carry? • Energy• What are the 4 properties of a wave?• Frequency – # of waves per sec (Hertz)• Wavelength – distance between any pt

on a wave to identical pt on next wave• Amplitude – distance particles vibrate

from rest position • Wavespeed –

speed a wave travels

wavelength

Types of waves

• What are the 2 main types (not examples) of waves? • Transverse - waves in which the particles vibrate

perpendicularly to the direction wave is traveling; has crest & troughs; medium not required – examples?

• Electromagnetic waves, rope waves• Longitudinal - waves in which the particles vibrate back &

forth along the path that waves move; has compressions and rarefactions; must have a medium – examples?

• Sound waves, seismic waves, spring waves

Electromagnetic (EM) Waves

• Name as many types of EM waves that you can in 2 min with your groups

• Visible Light• Radio waves• Microwaves• X-rays• Gamma • Infrared• Ultraviolet• All waves produced by stars & galaxies

Electromagnetic spectrum

Place the previously discussed electromagnetic waves on the spectrum chart

Use chart to give examples of each type of wave

Insect use to see flowers

Dangers of waves• Which waves are considered dangerous if

exposed to large amounts? • X-rays, Gamma & Ultraviolet• Why?• The higher the frequency and the shorter

wavelength the more dangerous the wave because they have more ENERGY and can travel directly through matter

• Which of the 3 do we have most contact with on a regular basis?

• Ultraviolet

Protection

• How can we protect ourselves from dangerous waves?

• Sunblock• Protective clothing• UV blocking sunglasses • Stay out of the sun• Lead aprons when receiving x-rays

Planet introduction

• All planets are bound to stars because of _?_• Refresher: • All planets move in an __________around a star• Planets move fastest when ____________

(closer/further) to its star• The further a planet is from the sun the

_________ it takes to orbit the sun• The further a planet is from the sun the

_________ the gravitational pull

ellipse

closer

longer

weaker

Solar system sizing

Hodometer Lab

• Follow directions in order to create a scaled down version of the planets in order to envision planet spacing in our solar system

Celestial body project

• Each one of you is going to do a project on one celestial body

• You will be teaching your celestial body to the class through a power point presentation next week