The Sun
Earth is bombarded with particles and radiation after violent eruptions from the Sun's surface called _______.
What are solar flares?
Absolute magnitude takes distance into account when indicating the _______ of a star.
What is brightness?
The unit of measure that is the average distance between the Sun and Earth.
What is Astronomical Unit?
A star that starts with more than about 20 times the Sun's mass will end in what.
What is collapse forever and become a black hole?
Most galaxies in the inner region of a large cluster are _______ .
What is ellipticals?
A mysterious, invisible substance that makes up about 27% of the universe
What is dark matter?
Based on the best value for H that has been calculated, the age of the universe is hypothesized to be about
What is 13.7 billion years?
Edwin Hubble sorted galaxies according to their shapes. Which letter notation below corresponds to a "normal spiral" galaxy shape
What is S?
Who first proposed the heliocentric model of the solar system?
Who is Nicolaus Copernicus?
Sunspots activity reaches a maximum every _______ years.
What is 11?
Using the parallax technique, astronomers can accurately measure the distance of stars up to _______ away.
What is 300 parsecs?
Defines a planet's elliptical orbit as the ratio of the distance between the foci and the length of the major axis.
What is Eccentricity?
A star beings with a mass 8 to 20 times that of the Sun's mass lifecycle ends in what.
What is end up with a core too massive to be supported by pressure and come to a violent end?
Galaxies that are not flattened into disks and do not have spiral arms are called.
What are elliptical galaxies?
The universe began as a point and has been expanding ever since is called the
What is the Big Bang theory?
Cosmic background radiation provides information about conditions _______ in the expansion of the universe
What is very early?
Edwin Hubble sorted galaxies according to their shapes. Which letter notation below corresponds to a "Barred spiral" galaxy shape
What is SB?
What is retrograde motion?
The top layer of the Sun's atmosphere is the low-density _______ .
What is Corona?
Stars are assigned a spectral type, with M being the ________ stars.
What is coolest?
Scientists measure distances to stars and observe how stars interact with one another to
What is determine which stars are gravitationally bound to each other?
The resistance of a star's core to being squeezed halts the collapse of the core and the core becomes a
What is a neutron star?
Disk like galaxies with spiral arms are divided into which of the following two subclasses.
What are normal and barred spirals?
The three possible outcomes for the universe.
What are open universe, closed universe, and flat universe?
When the rate of expansion of the universe is known, it is possible to calculate the
What is the age of the universe?
Edwin Hubble sorted galaxies according to their shapes. Which letter notation below corresponds to a "Tightly wound arm and large, bright nucleus" galaxy shape
What is a?
Objects that collided and merged to form other various objects in the solar systems
What is a Planetesimal?
Why do sunspots appear dark.
What is they are cooler than their surroundings?
The mass of a star determines the star's temperature, luminosity, and _______ .
What is diameter?
A key goal of the _______ is to gather data that would help to pinpoint the value for H, the Hubble constant
What is the Hubble Space Telescope?
The question about other objects existing in the sky as answered by Edwin Hubble in 1924. What did he discover in the Great Nebula in the Andromeda constellation.
What are Cepheid variable stars?
Observations of visible galaxies reveal a(n)
What is average density is much less than critical density?
All three possible outcomes for the universe are based on the premise that the rate of expansion has
What is increased since the beginning of the universe?
One way to estimate the fate of the universe is to measure how much _______ has occurred in its expansion
What is acceleration?
Edwin Hubble sorted galaxies according to their shapes. Which letter notation below corresponds to a "Loosely wound arms and a small, dim nucleus" galaxy shape
What is c?
The oval shape centered on two points instead of one point.
What is an Ellipse?
The _______ is not solid, but gaseous, because of its high temperature.
What is solar interior?
When estimating the distance of stars from Earth, astronomers use the fact that nearby stars shift in position as observed form Earth, which is called
What is a parallax?
Edwin Hubble measured the redshifts and distances of many galaxies and found that the redshift of a galaxy depends on its _______ .
What is distance from the Earth?
Astronomers can identity binary stars by what.
What is measuring the position of the visible star in the pair and noting shifts as it orbits the center of mass between it and the unseen companion star?
Edwin Hubble sorted galaxies according to their shapes. Which letter notation below corresponds to a "Irregular galaxy" galaxy shape
What is Irr?
The total amount of matter in the universe is expressed in terms of the
What is the critical density of matter?
Studies provide evidence that there is a great amount of unseen matter called dark matter composed of dim stellar remnants that _______ .
What is have mass?
Edwin Hubble sorted galaxies according to their shapes. Which letter notation below corresponds to a "Flat disks that do not have spiral arms" galaxy shape
What is S0?
The average distance of a planet to the Sun.
What is the Semi Major Axis?