Which statement best describes the galaxies closest to the Milky Way? (1 point)
These galaxies are independent of and unaffected by the Milky Way's gravitational pull.
These galaxies are all identified as spiral.
These galaxies include irregular, spiral, and elliptical types.
These galaxies consist of mostly old stars.
These galaxies include irregular, spiral, and elliptical types.
Where could scientists look to observe a black hole? (1 point)
the center of the sun
the center of the Milky Way
the edge of the solar system
the solar system asteroid belt
Scientists could look to observe a black hole at the center of the Milky Way.
Which of these characteristics of a star make it most likely to become a black hole? Select the two correct answers. (1 point)
Its mass is equal to that of the sun.
It has an abundant supply of hydrogen.
It is dying.
Its mass is greater than 20 times the mass of the sun.
The two characteristics that make a star most likely to become a black hole are:
1) Its mass is greater than 20 times the mass of the sun.
2) It is dying.
What is the main challenge astronomers face when trying to directly detect black holes? (1 point)
O Black holes are too small.
Black holes trap all light.
Black holes are empty.
Black holes are too black.
The main challenge astronomers face when trying to directly detect black holes is that black holes trap all light.
How do emission and reflection nebulae differ? (1 point)
hard line edges
interactions with light
the presence of young stars
contain remnants of stars