<p>The universe is expanding, so <span class="math-container">$a$</span> is getting larger. In the past it was smaller. Extrapolating back to a classical, General Relativistic big bang, it goes to zero.</p>

CC BY-SA 4.0
2024-02-13T06:24:45.860Z
2024-02-13T06:24:45.860Z
ProfRob
<p>If the FRLW scale factor is 1 now, was it smaller or larger  at earlier times? Does it asymptotically approach zero or infinity as you look back closer to the big bang? Or what?</p>

CC BY-SA 4.0
2024-02-13T04:17:35.377Z
It was smaller in the past. By definition the Big Bang is the time at which it goes to zero.
Sir Cumference
<cosmology>
Hubble Expansion: scale factor change
Miss Understands
# Hubble Expansion: scale factor change

(Asked by: username_0 on 2024-02-13)

If the FRLW scale factor is 1 now, was it smaller or larger at earlier times? Does it asymptotically approach zero or infinity as you look back closer to the big bang? Or what?

**Tags:** cosmology

> **Comments:**
> **username_1**: It was smaller in the past. By definition the Big Bang is the time at which it goes to zero.  

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## 1 answers

### Answer by username_2 on 2024-02-13. Score: 3

The universe is expanding, so $a$ is getting larger. In the past it was smaller. Extrapolating back to a classical, General Relativistic big bang, it goes to zero.


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