How Astronomers Know — Evidence Lab

Evidence for the Big Bang

Estimated time: ~35 min

Learning goals

Scientific theories are strengthened when independent observations, made with different techniques, agree with a single underlying model.
HS-ESS1-2 — Students weigh multiple independent evidence lines for the Big Bang.

Help & glossary

Use the hint ladder before checking your answer — hints get more specific.
Incorrect answers can be retried. Feedback explains why.
Constructed responses (CER) are self-checked — nothing is sent to a server.

Question 1 of 3

Select every observation below that provides independent evidence supporting the Big Bang model. Pick at least three.

Multiple lines of independent evidence, each measured with different instruments, converge on the Big Bang model of an expanding, cooling early universe.

Sources

The Universe — NASA Science — NASA · NASA Science · Accessed 2026-09-01
Cosmic Microwave Background — NASA — NASA · NASA Science · Accessed 2026-09-01