Cosmology 7.2

A collection of flashcards covering key concepts in the Edexcel GCSE Physics 7.2 Cosmology topic.

What is the Big Bang Theory?

The Big Bang Theory states that the Universe began around 14 billion years ago from a very small, hot, and dense region that exploded, causing the Universe to expand and cool.

What does the Steady State Theory propose?

The Steady State Theory suggests that the Universe has always existed as it is observed now and maintains a constant density by suggesting that new galaxies form as existing ones move apart.

What evidence supports the Big Bang Theory?

Evidence for the Big Bang includes Galactic red-shift, Cosmic Microwave Background (CMB) radiation, and the observation of galaxies receding from each other.

What is Galactic Red-shift?

Galactic Red-shift refers to the phenomenon where light from galaxies that are moving away from us is shifted towards the red end of the spectrum due to the Doppler effect.

What is Cosmic Microwave Background (CMB) radiation?

CMB radiation is the thermal radiation filling the Universe, thought to be the remnants of the initial heat from the Big Bang, now observed as microwaves.

What does a redshift indicate about a galaxy's motion?

A redshift indicates that a galaxy is moving away from the observer.

What happens during the Doppler Effect?

The Doppler Effect describes the change in wavelength and frequency of waves emitted by a source moving relative to an observer—waves are compressed in front of the source and stretched behind it.

How does wavelength relate to frequency in the context of the Doppler Effect?

As wavelength increases, frequency decreases, and vice versa.

What role did the development of modern telescopes play in astronomy?

Modern telescopes allow for the observation of a wider range of wavelengths in the electromagnetic spectrum and provide clearer and more detailed images.

Why are space telescopes advantageous compared to ground-based telescopes?

Space telescopes avoid atmospheric interference, can detect a greater range of electromagnetic waves, and produce clearer images unaffected by light pollution.