The Big Bang
Physics: Cambridge International GCSE Supplement, topic 6.2.7
The Big Bang
The Big Bang theory says that the universe began from a single point.
The Big Bang
- The universe began from a very small region that was hot and dense.
- This region ‘exploded’ and started expanding.
- This expansion is still happening.
Evidence
- There are many forms of evidence to support the Big Bang model of the universe.
- An example is the observation of red-shift in distant galaxies.
- This suggests that the universe has expanded from a single point and continues to expand today.
Gaps in Knowledge
Although science can explain so much of what we see in the universe, there is still a lot we cannot currently explain.
How expansion happens
- Scientists still don’t understand everything about the universe.
- They don’t understand much about how the universe is expanding.
Dark matter and dark energy
- Some scientists think that the universe is mostly made up of dark matter (an unknown substance that holds galaxies together but doesn’t emit electromagnetic radiation) and dark energy (the thing that causes the universe to quickly expand).
- But no one really knows what these are - they are just theories.
Test yourself on The Big Bang
Which of these describe the universe at the time of the Big Bang?
How much can science explain about the universe?
Which of these do scientists not yet fully understand about the universe?
What do we call an idea a scientist comes up with to explain something?