PHYS 170 Test 3

At the center of our galaxy scientist have noted since the _______very complex system of ____ waves suggesting strong magnetic fields

1960's, radio waves

Evidence for black holes was not well accepted and/or understood until the

1990's

What are the correct percentages for dark energy, dark matter and regular matter in the universe

70, 26, 3.5

In a galaxy the Dark Matter makes up ____ of galaxy and was initially hypothesized when scientist sought to explain ______

90-95%, rotation curves

Hydrostatic Equilibrium is

A balance between the gravity and internal pressure pushing out on a star

As a ______ star forms it can begin to rotate causing_______

A protostar; gases to be ejected at the poles is called bipolar flows

Both a neutron star and black hole

Are left after a supernova, Are the end results for a massive star, Are extremely compact objects with ;large gravitational fields

In the 1960's and 1970's Hawking and Roy and others developed theories about

Black holes

What steps do stars go through on their path to becoming stars

BokGlobule (molecular cloud), protostar, premain sequence , cross the zero age main sequence line, main sequence

Who cataloged and categorized the smears of light in the sky before the 20th century

Both Meissner and the Herschel's

What are the parts of our galaxy

Bulge, halo, disk (spiral arms)

What are the conditions for a star to form in a molecular cloud

Cool and dense

Which is a remnant of the supernova seen in the 1000's in China

Crab nebula

Scientist believe that there must be ________ because the arms of the galaxy move faster than the center.

Dark matter

Shapley used the luminosity and periods of stars in clusters to determine the

Distance

A black hole's strong gravitational field can pull in material and an accretion disk will form creating a great deal of energy that can result in

Emission of X-rays

We know the galaxy is _____ because____

Flat ,of how the stars are distributed

Scientist realized that pulsars must be neutron stars when they

Found a pulsar in the center of the Crab nebula

A star that is above 30Msun will

Fuse to iron, supernova and form a black hole

For the range of stars between 0.8 - 2Msun they undergo which fusion steps:

H => He => He flash => C => O

Stars that move off of main sequence first are

High Mass stars since the gravity is so great their Hydrogen gets used up faster

What technique is used to determine the distance of the farthest objects and how does it work

Hubble's Law, graph of recession velocity versus distance

The discovery of the pulsar occurred in what decade and by whom

In the 1960's by Jocelyn Bell

A black hole

Is a dense compact object whose gravity is so great that light cannot be emitted

Once a star runs out of the majority of its H what is true

It expands and forms a Giant, It moves off of main sequence to the upper right

Earth is composed of rock made of Silicon and metals where is this material come from

It was produced by nuclear fusion in stars and through supernova

If a galaxy begins to run out of hydrogen what does this suggest

It's very old and stars have gone through several deaths and reformations

The supernova of 1987 showed scientist that even a ____ star could supernova

Large blue

LGM stood for ______and was actually a ______

Little green men, pulsar (neutron star)

How have scientist searched for black holes

Looking for effects of event horizon, Look for another star orbiting something invisible, x-rays emanating as object goes into the black hole

What abbreviations did they use to categorize these smears of light

M+ number (M22) and NGC (new general catalog)

Henrietta Leavitt in the 1920's discovered a relationship between these and were called

Period of fluctuations and luminosity, Cepheid's

At what stage will fusion begin

Pre-Main sequence star after accretion ceases

A star will move from a position of higher luminosity to lower luminosity as it moves from being a _______ and crosses______

Protostar , main sequence

Scientist used ____ to study the center of the galaxy because it has a _____wavelength that won't be scattered by all the dust and gases

Radio, long

What type of star fuses its H and the is left mostly with He burning slowly

Red dwarf

Which type of stars are most abundant

Red dwarfs

What are the three types of nebula?

Reflection, emission, dark

It is hypothesized that all AGN's are in fact

SMBH with accretion disk

The scientist believe the center of the galaxy is located near _________ constellation because of the dense concentration of _____ clusters

Sagittarius, globular

In a high mass star _____ fuses in a shell while _____ migrates to center where it builds up eventually resulting in a super nova

Si,Fe

As you get close to a black hole the time _____ and the size of an object ___

Slows down , stretched

The theory of general relativity describes how gravity (large mass) affects ______ and was developed by

Space and time, Einstein

The hypothesis for dark energy comes from

The accelerating expanding Universe

As a star runs out of H it undergoes a series of fluctuations caused by

The idea that as one material fuses and moves out consecutive layers of fusing elements cause expansions and the contractions

The 1987 supernova gave scientist their first experience

To test their theories, To use modern equipment to make measurements, To see if they could detect neutrinos

On March 20th will be

Vernal Equinox

What is the best working hypothesis for what dark matter is

WIMPs (weakly interacting massive particles)

Protostars that are below 0.08 Msun

Will not change since they do not begin to fuse in first place, these stars are Brown Dwarfs

When a low mass star sloughs off its outer layer

You are left with a White Dwarf that is composed of mostly C/O it is hot but not luminous

An E0 is

a compact circular ellipse sphere

Out of the four models for how the Universe will evolve the one that fits best with data is

accelerating

AGN stands for

active galactic nuclei

What kind of galaxy? hurricane

barred spiral

There are 3 models for the Universe

closed, flat, open

What is used as an explanation for this acceleration

dark energy

Outside of the Milky Way is the large and small Megallanic clouds which are actually

dwarf galaxies

What major astronomical information was released recently

first image of a supermassive black hole

Calculations show that the best theory for the Universe is it best matches with actual CMB

flat

What were the two problems with the initial Big Bang theory and what was the solution

flatness and horizon, a period of rapid inflation

Hubble developed the ______ as an organizing tool for all of the galaxies

fork

As was verified by the CMB discovery in the beginning the Universe was actually ____ but appears ____ due to _____

hot, cool, red shift

What type of galaxy? typical

irregular

The biggest effect of interacting galaxies

is their tidal affects

What is gravitational lensing

it is in accordance with Einstein's theory of gravity that light is affected by mass

In the early part of the 20th century we finally realized that the smears of light in the sky are actually

other galaxies

The theorist starting as early as the 1940's and working into the 1960's

predicted that the early universe would emit a low energy radiation

Where did the name quasars come from?

quasi-stellar radio sources

The Universe was initially governed by ___ and later by ____

radiation, matter

Which AGN emits mostly in the radio range and has large jets

radio

Hubble's law

receding velocity and distance

What is the evidence for a dark matter

rotation curves, lensing and galaxy clusters

The AGN discovered in the 1940's and is a spiral galaxy is

seyfert galaxy

Which galaxies are most plentiful

spiral

What are the 3 main types of galaxies

spiral, elliptical, and irregular

What is the edge problem

that if there is an edge what would be on other side so there is no edge

The Big Bang

the beginning when all that existed was energy (EM) radiation that expanded and cooled eventually leading to formation of matter

What discovery led to the expanding Universe suggesting a beginning

the farther we look back in time the more red shifted objects are suggesting they are expanding an once we're close together

What is cosmology

the study of the evolution of the Universe across all time

What sets AGN's apart from other galaxies

they are very far but very luminous

A nova can occur with a white dwarf

when they pull material from a neighboring star