Review Questions Flashcards
Neutron stars
A core with remaining mass of 1.4 to 3 solar mass, composed of tightly packed neutrons
Black Holes
A remaining core with a mass of more than 3 solar mass.
-Will continue to collapse into an infinitely small location in space
_______ cannot escape a black hole
Light
Planets in order Acronym
My Very Educated Mother Just Served Us Nine…
Planets in order
1) Mercury
2) Venus
3) Earth
4) Mars
5) Jupiter
6) Saturn
7) Uranus
8) Neptune
Inner (Terrestrial) Planet Features
small, rocky, have few moons, no rings
Venus Characteristics
1) completely hidden beneath thick atmosphere/clouds
2) extremely high atmospheric pressure
Mars Characteristics
1) once geologically active
2) large storm due to high pressure
In terms of orbital distance, Inner planets are ______ _________ than outer planets
Drastically different.
-much smaller
Jupiter Characteristics
1) Gas Planet
2) largest planet in our solar system
3) has 4 large moons
Saturn Characteristics
1) Has the most extensive ring system
- composed of ice and ice-coated rocks
Neptune Characteristics
1) Brilliant Blue
Uranus characteristics
1) Hazy atmosphere
2) Tilt gives it very exaggerated seasons
The Kuiper Belt is located ________.
outside Pluto
the Kuiper Belt is _____ times as wide as the asteroid belt
20X
The Oort Cloud is located _______.
Outside Pluto
the Oort cloud is home to _______ comets
~ 1 trillion
The Asteroid Belt is located between _________.
Mars and Jupiter
Direct Imaging
Using techniques to block out the host star’s light
Astrometry
Detect planets by measuring the change in a star’s position in the sky
Doppler Affect Definition
the change in wavelength of radiation (light) due to the relative motion between the source and the observer along the line of sight
Astronomers use the Doppler Effect to….
learn about the radial (along the line of sight) motions of stars, and other astronomical objects
when something which is giving off light move towards or away from you, the wavelength of the emitted light is ________.
changed or “shifted”
Redshift
When the source of light is moving away from the observer
Redshifts will cause the wavelength of the emitted light to ______.
Appear to increase
Blueshift
When the source of light is moving towards form the observer
Blueshifts will cause the wavelength of the emitted light to _______.
Appear to decrease
The doppler Effect only happens for motion moving _______.
moving along the line of sight
Objects move faster towards or away from you will exhibit a ________.
larger blue or red shift
Measuring a stars doppler Shift can tell us its _________.
motion toward and away form us
Transit Method
Measuring a planets light as it passes between us and a star as it dims and reappears.
The Drake Equation
The number of civilizations in our galaxy in with which communication might be possible.
The milky way is ________ light years across, but only ________ light years thick.
100,000 ; 1,000
Stars in the disk all orbit _________.
in the same direction.
Stars in the bulge and halo have ________ orbits.
random
Interstellar Medium definition
the term for the material (gas and dust) which resides between the stars
Low mass stars return gas to the ISM by ___________.
blowing off their outer layers
High mass stars return material in two ways:
1) stellar winds blow off much of the outer envelope before the supernovae takes place
2) supernovae return nearly all of the products of fusion to the ISM
Summary of the star-gas-star
1) stars make new elements by fusion
2) dying stars expel gas and new elements producing hot bubbles
3) hot gas cools, allowing atomic hydrogen clouds to form
4) further cooling permits molecules to form, making molecular clouds
5) gravity forms new stars ( and planets) in molecular clouds
Radio (atomic Hydrogen) show______.
where gas has cooled and settled into disk
Radio (CO) waves show________.
where the molecular gas lives
Infrared emissions show ______.
where the dust is and its heat
X- emissions are observed _______.
from hot gas above and below the Milky Ways disk
Gamma-Rays show _______.
where cosmic rays from supernovae collide with atomic nuclei in gas clouds
Halo stars formed ____, disk stars formed ______
first; later
What is at the center of our Milky Way
black hole/supermassive black hole
Cosmology definition
the study of the overall structure and evolution of the universe
the milky way resides in the _______
local group
The local group is home to ________ other galaxies
~ 50
the diameter of the milky way is _________ light years.
~ 10 million
Spiral galaxies are often found in ________
groups of galaxies
Elliptical galaxies are much more common in _______
huge clusters of galaxies
Dark Matter composes about _____ of the galaxy
26%
Hubble’s law
the spectra of nearly all galaxies are redshifted, meaning that they re moving away form us
‘Modern’ Hubble’s Law
Velocity = H0 * distance
How do we measure distance?
the spectra of galaxies
What does redshift mean?
Time between now and a given redshift
Big Bang:
Everything happened at one small point
2 pieces of evidence for the big bang
1) Residual Heat (light) everywhere
2) number of stars
- —we can only see a certain number of stars because the universe began at a certain moment
2 pieces of evidence for Dark Matter
1) Flat velocity curves
- ——speed of stars remain constant
2) Galaxy cluster
- —–the speed galaxies orbit
5th largest planet
Earth
