Galaxy + Sun Test review

   What is the doppler effect and how does it work as an object is moving towards or away from the observer?

Change in sound, when the object approaches the noise gets higher pitched because the waves are shortened, and vice versa when the waves are moving away.

What layer of the Sun radiates most of the energy that reaches the Earth?

The photosphere

Describe the chromosphere.

the reddish, middle layer of the Sun’s atmosphere, located between the photosphere and the corona, extending roughly 400 to 2,100 km above the surface

1.      From which part of the Sun does the solar wind originate?

The corona (outer layer)

1.      Why are sunspots darker than the surrounding areas of the Sun?

They are cooler than the rest of the surface of the sun

1.      What is the difference between nuclear fusion and nuclear fission, and which one do stars perform?

Stars preform fusion, where molecules are combining whereas fission is when they are separating.

1.      What does the stars color tell you about its temperature?

Blue stars are very hot, whereas the red ones are the coolest. It gradients from Blue, white, yellow, orange, and red

1.      What is a light year?

unit of distance, not time, representing the total distance light travels in a vacuum in one Julian year 

What are the three types of spectra and what is the difference between them?

1. Continuous Spectrum: An uninterrupted range of wavelengths emitted by solid, liquid, or densely packed gases, showing all colors.

2. Emission Spectrum: Produced when gases or elements emit light at specific wavelengths, appearing as bright lines on a dark background.

3. Absorption Spectrum: Occurs when light passes through a cooler gas, absorbing certain wavelengths and resulting in dark lines on a continuous spectrum.

1.      What type of spectra is used to determine the composition of stars?

Absorption line spectra

1.      What are the things that affect the apparent brightness of a star?

The temperature and size of a star

1.      The H-R Diagram shows the relationship between what two things?

The luminosity of a star versus their surface temperature (Kelvin)

1.      On the H-R Diagram what percentage of stars are on the main sequence?

90%

1.      What is contained in a nebula?

Dust and gases

What is the Acronym for OBAFGKM?

Only Bonnie And Frankie Got Kind Moms

 When does a star actually become a star?

when its core temperature and pressure become high enough to ignite nuclear fusion

 What is the primary force that begins a star’s formation?  (this is controlled by mass)

Gravity

 What is a supernova?

The explosion at the end of a giant star’s life

 Carbon is created when what element combines in nuclear fusion? (like when one hydrogen combines with another to form helium?

Helium nuclei

 When a star like the Sun leaves the main sequence it will move into which branch of the H-R Diagram?

The red giant branch

 What type of star is the Sun?

A yellow dwarf planet

 Describe a black hole?

a region of space with gravity so intense that nothing, not even light, can escape

How is it known that the universe is expanding?

The space between stars is getting farther apart at a faster pace.

 What is significant about the number 13.7 billion years?

That is how old the universe is

When fusion is taking place on many levels within a star, what branch of the H-R Diagram is that star located?

AGB branch (Asymptotic Giant Branch)

What are the types of galaxies?

Bar spiral galaxy, spiral galaxy, Irr galaxy, Elliptical galaxy, and lenticular

 Describe a variable star?

a star whose brightness, as seen from Earth, fluctuates over time (absolute magnitude)

 What are the parts of a spiral galaxy and where are each of them located?

Nucleus is the center of the galaxy, Central Bulge: Located at the very center of the galaxy, this is a large, tightly packed,  galactic disk thin disk around the buldge, Spiral arms are long thin concentrated reigons and extend out. Galactic Halo: A near-spherical, sparsely populated region surrounding the entire galactic disk, Dark Matter Halo: A massive, invisible component that surrounds the entire galaxy, the thin disk is the most condensed part of the disk. It is extremely hot and bright.

 What is the center of the Milky Way galaxy in relation to Earth?

The black hole named Saggattarius A (Sgr A)

 What type of galaxy is the Milky Way and how many light years is it across?.

Barred Spiral galaxy, 100,000 to 120,000 light-years across

Supermassive black holes are usually located is what parts of galaxies?

Center of large galaxies

 What is dark matter?

Matter we cannot see that makes up a majority of the universe

 Edwin Hubble put galaxies into categories, what was the basis for each category?

the degree of flattening for ellipticals, the size of the nucleus and tightness of arms for spirals, and the presence of a central bar

The mass of galaxies and the luminosity of galaxies each reveal the rotational speed of the galaxy, however, the results are not the same.  What is said to be causing this difference?

This means that dark matter takes up a lot of space

 The fact that objects further away from Earth have a greater redshift than those that are closer is a clue that the universe is doing what?

Is constantly expanding faster and wider

 What is Hubble’s constant and how is it used?

the unit of measurement used to describe the current expansion rate of the universe, quantifying how fast galaxies are receding from us based on their distance

  What is the core of an active galaxy where highly energetic objects or activities are located?

Active Galactic nucleus

Describe a quasar.

the intensely luminous, compact active nucleus of a distant galaxy, powered by a supermassive black hole accreting large amounts of matter

 Describe a radio galaxy.

a type of active galaxy that emits10⁵–10⁷ times more power in radio wavelengths than a normal galaxy, often powered by a supermassive black hole at its core