Which of the following is/are cited by the scientists as evidence/evidences for the continued expansion of the universe?
- Detection of microwaves in space
- Observation of redshift phenomenon in space
- Movement of asteroids in space
- Occurrence of supernova explosions in space
Select the correct answer using the code given below:
- 1 and 2
- 2 only
- 1, 3 and 4
- None of the above can be cited as evidence
Explanation
Detection of microwaves in space is correct
- With a traditional optical telescope, the space between stars and galaxies is completely dark. However, a sensitive radio telescope shows a faint background glow. This glow is strongest in the microwave region of the radio spectrum, and hence it is called a Cosmic Microwave Background (CMB).
- CMD, also known as relic radiation (thermal radiation left over from the “Big Bang”), is fundamental to observational cosmology because it is the oldest light in the Universe and can be found in all directions. Its discovery is considered a landmark proof for the concept of “accelerating expansion of the universe” and the Big Bang Theory.
Observation of the redshift phenomenon in space is correct
- Redshift and Blueshift describe how light changes as objects in space (such as stars or galaxies) move closer or farther away from us. American astronomer Edwin Hubble was the first to describe the redshift phenomenon (galactic redshift) and tie it to an expanding universe (galaxies are drifting apart).
- Hubble’s law: the farther away galaxies are, the faster they are moving away from Earth ― also known as accelerating the expansion of the universe.
Movement of asteroids in space is incorrect
- The movement of asteroids is governed by local gravitational forces within the solar system and is unrelated to the universe’s large-scale expansion.
Occurrence of supernova explosions in space is incorrect
- While supernovae are important for studying cosmic distances and verifying the accelerated expansion of the universe, their mere occurrence is not direct evidence of expansion. This statement is incorrect in this context.
