How do astronomers know that the luminous regions of active nuclei of active galaxies are very small?
a. Their nuclei are much brighter than expected.
b. The orbits of stars near the center of the galactic nuclei are faster than expected.
c. The luminosity of the nuclei varies over short times.
d. The color of the nuclei is different than expected.
Question 2
Synchrotron radiation is produced
a. in planetary nebulae.
b. by red dwarfs.
c. in massive stars as their iron core collapses.
d. in supernova.
e. by neutrinos.
The regions of the brain.
Interacting and Colliding Galaxies
World Climate Regions and Climographs
Landform Regions
To satisfy the inequality, sketch the following function by hand and shade the graph regions.
New patterns of gene expression can be generated by overlapping regions containing two different gen