Why do stars twinkle?
A. due to their movement across the sky
B. due to the refraction caused by atmospheric irregularities
C. due to rapid changes occurring on their surfaces
D. due to imperfections in the human eye
Answer: B
You might also like to view...
Projectile Motion: A ball thrown horizontally from a point 24 m above the ground, strikes the ground after traveling horizontally a distance of 18 m. With what speed was it thrown, assuming negligible air resistance?
A. 6.1 m/s B. 7.4 m/s C. 8.1 m/s D. 8.9 m/s
The average size of a white dwarf is about the same size as the Earth
a. True b. False Indicate whether the statement is true or false
All Cepheid variables discovered so far lie in other galaxies
Indicate whether the statement is true or false
The element helium was discovered by studying the sun's spectrum
Indicate whether the statement is true or false