If you collect everything there is in the universe, (wow that’d be a lot of stuff)
but what color would it be?
It isn’t possible to answer that, but we can at least go back in time far enough to
see how it looked when it all began to exist.
Yes, this is apparently possible.
We all know about this mysterious and fascinating moment called the Big Bang, which gave birth
to all that we can see around us right now.
Now containing red dwarfs, white dwarfs, seven dwarfs, emerald supernovas, blindingly bright
quasars and everything in between – the Universe is as colorful as it gets.
But of course, it wasn’t like that at the time of its birth.
It originally had just one color.
As it expanded and cooled down, it formed more and more tangible matter and started
to morph into all the colors we’re used to seeing today.
To be able to see through time to the very first moment 13.8 billion years ago -- I wasn’t
around then -- you would need a time machine!
But even then, you won’t see anything.
Just black nothing.
And it’s not like the clocks on your time machine are off – this is the moment the
Big Bang is happening.
You just can’t see it because our eyes are sensitive to photons, and none of them exist
at this point.
The universe is simply too hot now to allow even something as basic as photons to form.
But seconds later – it’s already a different story.
During these first seconds, the universe is expanding so fast and with such power that
the temperature drops by trillions and trillions of degrees before it reaches the end of the
first minute of its life.
Approximately 14 seconds from the beginning, it’s already at 5 and a half billion kelvins,
and 48 seconds later it loses another 3 and a half billion degrees.
If, from the sheer epic of this universal scale, these numbers sound humble to you,
that’s my fault – they’re anything but humble.
And the best proof of that would be that you can’t see anything at all.
How is that?
Well, photons already exist, in fact, as well as protons and neutrons; Morons – we’ll
talk about some other time -- cand they’re already busy forming the various nuclei of
gases like helium and hydrogen.
Congratulations, by the way: these gases give us our first forms of tangible matter!
And when gas is heated up like that, it’ll take the form of plasma.
Everything is a blazing plasma right now, and that’s bad news for photons because
they can’t move freely in such extreme environments.
And if photons can’t move how they want, you won’t be able to see anything.
To see something, you’ll have to wait; and not another minute, but another 380,000 years,
when the universe cools down.
Until then, this epoch in the history of everything is what scientists refer to as “The Dark
Age”.
And while our time machine is reconfiguring, let’s figure out how scientists even know
all this if they don’t have a secret time machine like this one.
They use a method called cosmic microwave background scanning.
That moment, 380,000 years after the initial Big Bang, the universe got so hot that subtle
traces of that heat and light still persist in the space around us.
They form an imprint, which shows the whole process of the universe’s creation.
Scientists learned to study this imprint like an ancient map of a world that no longer exists.
Fun fact: astronomers figured out that the age of the universe is exactly 13.8 billion
years because they can see this imprint from a distance as huge as 13.8 billion light-years
away.
But remember, at the time we’re talking about, (380,000 years after the Big Bang)
the universe was still quite small.
That’s if you can call something like 84 million light-years across small.
But in comparison – yes, it’s 164 times smaller than the universe we know now.
And it wasn’t all plasma anymore.
Finally, photons were given the green light (ha the “green” light!) to move wherever
they want and that means that we can see something here.
And that something is a colossal blob of blindingly bright light.
You wouldn’t be able to clearly make out anything, actually, because the color of everything
is dictated by the temperature alone.
This phenomenon is also sometimes called blackbody radiation.
This radiation is as bright as the matter it irradiates is hot.
And the term blackbody doesn’t mean that whatever emits this colorful thermal radiation
is necessarily black per se.
It means that this irradiating object is unreflective to light.
Or at least its own appearance, including its color, won’t mean much to an observer
because of this radiation that obscures everything.
To draw a picture of it in your mind, remember how lava looks.
It’s red, yellow and orange glow isn’t representative of the matter itself, because
in places where it already cooled down, it’s ashy black or grey.
But of course, you would say that lava is bright in its fiery colors.
This is how the whole universe looked back then, 380,000 years after the moment it was
born.
It looked like fire because the temperature made it look that way.
As the universe continued to expand, it also continued to lose the heat.
This process is in action to this very day, and scientists say that it won’t stop any
time soon; possibly not even until the universe consists of mostly nothingness between celestial
bodies, and its temperature will be a tiny bit higher than absolute zero.
You can even imagine it like one supernova explosion so massive that it takes billions
of years to happen.
And fascinatingly enough, we happen to live somewhere around the middle of its timeline.
With the loss of temperature, the glow of its thermal radiation has gone through several
metamorphose.
From blindingly bright yellow, it went to fiery orange and then became red, which was
replaced by black.
Mostly.
These relatively modern times in the life of the universe became the dawn of its spring,
as more and more stars emerged from the cooling matter.
They were born from hot gas clouds, and they were aging, cooling, turning orange, and then
red as the universe did before.
Then the stars were exploding into supernovas with every color imaginable; or collapsing
into black holes, where no color is possible at all.
Fun fact, black holes are what scientists call perfect black bodies, and they emit radiation
powerful enough to be seen as a ring of orange heat.
If you remember the first photos of a black hole that came out recently, this is what
you saw on them in the most basic terms.
In some way, asking about the color of the universe during the Big Bang is like asking
about the color of a black hole.
The first and only visible thing that ever appeared in the universe was so heated that
it looked like an orange glow and nothing more.
Today it’s another matter completely.
There are from 100 billion to 200 billion galaxies around us and they’re all full
of motion, so colors are uncountable and everchanging.
When ancient astronomers looked into the skies and saw part of our own galaxy, the Milky
Way, they didn’t name it this just for kicks.
They meant it: it looked as if someone had spilled milk over the dark skies.
And one of them thought: What a great name for a candy bar!
The other ancient astronomers asked: What’s a candy bar?
Anyway, there’s one rough estimation about what color the universe is today.
It’s well known that our galaxy isn’t that dense, and its appearance to us is only
what we’re limited to from our planet’s perspective.
Yet this perspective matters because it blurs all stars, and all matter in general, into
something homogenous.
And this is the key to knowing what colors a galaxy, or even the universe, would be if
it was just one separate object.
And the answer is probably in your cup every morning.
This color is Cosmic Latte.
And the analogy between the universe and coffee is a surprisingly good one.
Just like a good latte, the universe will get darker with time and it is the lightest
and brightest right after it was made; or appeared, in the case of the universe.
Um, I’d like a low-fat, no-foam, de-caf double shot universe please, and hold the
whip.
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