Ask Me Everything 9

Ho w big is the

universe?

• * .

The universe is very big; in fact, it is bigger than anything

else we know about. We can see that it exists as far as around

• • •

13.7 billion light-years (ly) from us. We also know that there is ‘ ■:'

morę beyond the edge of the observable universe,-

but we don’t know how much. The universe is

expanding all the time—it is bigger now than    •

when you started reading this sentence! *• * ,    .    •

Atoms 4.6%

Expanding

Universe

RECORD BREAKER

The largest structure in the universe is the Sloan Great Wall. Around one billion ly away from Earth, it is a giant wali of galaxies that stretches for 1.37 billion ly across the universe.

01: When the universe started in the explosive event called the Big Bang around 13.7 billion years ago, it was smaller than a period on this page.

02: Within one trillionth of a second it ballooned to around the size of a soccer field.

03: The young universe was incredibly hot and madę up of tiny particles of matter. It has been

expanding, cooling, and changing ever sińce.

04: In 1998, astronomers discovered that the universe’s expansion ratę is not slowing down as they thought, but accelerating.

05: For the past 5-6 billion years, the universe has been getting bigger at a faster and faster ratę.

matter

23%

Dark energy 72%

Calculatlng the scalę

We can’t see the universe's large-scale structure easily because we are inside it.

Computers have been used ‘•‘iw to simulate a cube-shaped region (above) that is two billion ly across and populated by around 20 million galaxies.

.;.•&. Superclusters are groupings of galaxy clusters, which are themselves collections of galaxies.

ujfc The universe is madę of a huge ‘•w weblike network of chains and sheets consisting of superclusters separated by huge voids.

What about me?

^VV1 _t aicitant object that most The most^dista _{th nake}d eye is

people can see    2 5 million ly

away. In 9    _the Triangulum

^pe°g^Palaxy. 3 million IV away.

Galaxy gang

Barnard’s galaxy

10,000 ly wide

Milky Way galaxy

100,000 ly wide

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