In an expanding universe, what exactly is expanding?
A. velocities
B. galaxies
C. space but not time
D. spacetime
Answer: D. spacetime
You might also like to view...
Enzymes are catalysts which means that they
A) speed up biochemical reactions which would normally occur too slowly B) slow down biochemical reactions which would normally occur too quickly C) prevent unwanted biochemical reaction occurring D) destroy harmful chemical species
Is gasahol a good idea? Explain
What will be an ideal response?
When light reflects from a polished surface, there is a change in its
A) frequency. B) wavelength. C) speed. D) all of the above E) none of the above
The Kepler mission has searched for Earth-like planets by looking for the dip in the brightness of a star as a (potential) planet transits across it
Why will this technique actually miss the vast majority of planets around the stars it observes?