Question

If the cosmic microwave background radiation (CMBR) is the remnant of the Big Bang’s fireball, we expect to see hot and cold regions in it. What are two causes of these wrinkles in the CMBR? Are the observed temperature variations greater or less than originally expected?

a) Inflation and dark energy; greater than expected
b) Quantum fluctuations and dark matter; less than expected
c) Gravitational waves and dark energy; greater than expected
d) Cosmic strings and dark matter; less than expected

Answer 1

Temperature variations in the CMBR, which are less than originally expected, were caused by quantum fluctuations and cosmic inflation, stretching these imbalances to cosmological scales.

The correct answer to the question is (b) Quantum fluctuations and dark matter; less than expected.

Step-by-step explanation:

The cosmic microwave background radiation (CMBR) does exhibit hot and cold regions, known as 'wrinkles'. These wrinkles in the CMBR signify temperature variations that correlate with areas of different densities in the early universe.

These early fluctuations are crucial because they are thought to be the primordial seeds from which galaxies and other large-scale structures eventually emerged due to the influence of gravity. One cause of these fluctuations is quantum fluctuations, which happened during the very early moments of the Big Bang, creating uneven distribution of matter.

The other reason for these fluctuations is related to cosmic inflation, a period of rapid expansion that the universe underwent fractionally after the Big Bang. During this phase, tiny quantum fluctuations were stretched to cosmological scales.

The observed temperature variations in the CMBR are actually less than originally expected, but are still detectable with precise measurements. The correct answer to the question is (b) Quantum fluctuations and dark matter; less than expected.