Sun
Which list correctly orders the layers of the sun from the center outward?
core, photosphere, chromosphere, and corona
Helium fusion requires a higher temperature than hydrogen fusion because ____.
the repulsion between two helium nuclei is much greater
Which terms directly relates to the actual brightness of a star?
Absolute magnitude and luminosity
When we say an object is in orbit, we mean that it is traveling around another object in space. What do planets in a solar system orbit?
A star
Almost two-thirds of the bright galaxies in our region of the universe, including the Milky Way, are what shape?
spiral galaxies
The surface of the sun that we see from Earth is the ____.
corona
All main-sequence stars are composed primarily of ____ and ____.
hydrogen, and helium
The life-cycle path followed by a star is determined by the star’s ____________________________.
Mass
A light year is...
The distance traveled by light in one year
What is larger than a galaxy?
The universe
Stars like the Sun most likely formed directly from what?
Nebula
During which stage does hydrogen fuse into helium?
Main sequence
Which stars are the youngest stars? Super giants, red giants, white dwarfs, or main sequence
main sequence
Which statement explains why galaxies do not fly apart when they rotate?
a.Galaxies rotate very slowly so they stay gravitationally bound.
b.The gravitational force due to dark matter holds matter in place.
c.There are enough stars in galaxies to keep them gravitationally together.
d.Galaxies have a massive black hole with immense gravity at the center.
B. The gravitational force due to dark matter holds matter in place.
A pulsar is a ____ that emits a pulsating radio signal.
neutron star