# Explain why scientists believe the universe will continue to expand forever, and describe one piece of evidence that supports the idea that the universe began from a single point.

> AQA A-Level Physics (7408) — 3.9.3 Cosmology · Explain · 5 marks

## Mark scheme (5 marks)

1. The universe is currently expanding (galaxies are moving apart)
2. If there is not enough mass/gravitational pull is too weak, expansion will continue indefinitely
3. Dark energy accelerates the expansion, making it more likely to continue forever
4. Cosmic microwave background (CMB) radiation is detected uniformly across the universe
5. CMB radiation is the remnant heat/energy from the Big Bang, showing the universe started from a very hot, dense single point

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