Is The Universe Already Ending?

How much of the universe is already

dead?

At first glance, it's a difficult

question to answer. Except for the

occasional supernova blast or colliding

black hole, at the very largest scales,

the cosmos appears static and

unchanging, a frozen snapshot in a long

and unknowable history. But Swedish

physicist Eric Holberg decided he wanted

to know more.

Today his name is largely unknown even

to astrophysicists. But in 1940 in a

darkened gymnasium in Stockholm he

crafted perhaps the most ingenious

experiment since the Renaissance days of

Galileo. In the process becoming the

first scientist to watch millions of

years of cosmic history unfold.

The idea was simple.

[Music]

In the gymnasium, he and his students

set to work placing 74 stations, each

one equipped with a bright light bulb

and a photo receptor that could measure

the light being received by that

station. The stations represented

portions of a galaxy, an individual bit

of mass that could influence its

surroundings and be influenced by it in

return. The light stood in for the

gravitational force, each reducing as

the distance squared. He divided the

stations into two camps, drawing the

rough figures of two spiral galaxies

just before a merger.

Then slowly, methodically, he set the

lamps in motion. He measured the amount

and direction of light at each station

and used that to estimate where the

station should be placed as if that

portion had advanced forward a million

years in time. After moving all the

stations, he repeated the measurement

and movement again and again and again.

Holberg had created the world's first

simulation of the cosmos built with an

analog computer.

In watching the evolution of galaxies

unfold before his very eyes, Holberg saw

exquisite beauty, the stretching the

galaxies undergo and the graceful

arching of tidal tales that arise during

a merger. But he also saw something else

in the form of light bulbs and photo

receptors arranged carefully on a

gymnasium floor. He witnessed how

galaxies die.

Holberg witnessed a universe that

changes. And he saw that the cosmos we

have learned to know and love, a

universe filled with vibrant galaxies

arranged in a grand cosmic web, will not

last forever.

There was a time billions of years ago

when the universe was plunged into

darkness before the first stars awoke.

And by the harsh laws of cosmic

expansion, there will be a time in the

distant future when the cosmos returns

to that darkness.

In his shadowfilled gymnasium, Holberg

had witnessed that impermanence.

But what he didn't see, what he couldn't

see without more advanced tools was that

the wider universe was already well on

its way to oblivion, well past its peak.

For today, following in H Homeberg's

pioneering footsteps, we have combined

advanced computer simulations with

comprehensive observations to learn that

much of the universe is already dead. We

are already in the age of twilight. What

we face in the long future is nothing

but decline.

In a sense, then this is a story of

betrayal because in a changing universe,

the very forces that give rise to star

formation eventually turn their backs on

their creations and kill them from the

inside out.

In the 1930s, Gro Reeber was rejected

from a post at Bell Labs, where he'd

hoped to work on scanning the sky for

radio signals. And so instead, he built

an entire radio telescope in his garden,

the most advanced in the world at that

point, from among other things, spare

parts from a Ford Model T truck. Pretty

impressive. And so what would your

passion project be? Whether you want to

create documentaries, a podcast, a

company that sells services, or a brand

that sells products, Squarespace can

help. Squarespace is super simple to use

and easily allows you to build a totally

unique online presence for your project.

But one great, less well-known feature

of Squarespace are the in-built email

campaigns. Here you have all the tools

you need to engage with your world. You

can schedule emails to arrive at the

perfect moment for your recipients and

set up email automations to save you

time. And all of this seamlessly

integrates back into booking, sales, or

promotional pages that have beautifully

well-designed templates. So head to

squarespace.com/history

of the universe to save 10% off your

first purchase of a website or domain

using the code history of the universe

and start your passion project today.

[Music]

4 and a half billion years ago, just

after its birth, our Earth was a literal

hell.

There is an earthshaking rumble

permanently echoing across the young

globe as the very crust itself shifts

and cracks. Molten rock spurts and oozes

over the constantly shifting landscape.

Temperatures reaching a thousand° on the

surface. The atmosphere almost

non-existent, barely different in its

makeup to the inside of a solar nebula.

And in the sky above this molten chaos,

is the moon, but not the moon we know.

[Music]

15 times as large as we see it today and

glowing a dull red, this young satellite

would have filled the horizon like a

dreadful portent. And so what happened

between then and now to give us the moon

of today, placid and distant? Well, it

is very slowly moving away. We know this

from what is called lunar laser ranging,

a technique where scientists shine laser

pulses at the moon and measure the

length of time they take to arrive. The

accuracy of these measurements improved

by optical receptors placed on its

surface during the Apollo missions.

Scientists have calculated that our moon

is receding at a speed of 1 in per year

and would only finish its journey in

roughly 15 billion years were that not

well after the time at which the sun

will have consumed the earth. Our

night sky is far from static. And on

cosmic scales, our retreating moon is

just a tiny example. Our entire universe

is full of change at scales great and

small.

Indeed, the astronomers of the

Renaissance were astonished to discover

that the heavens were just as tumultuous

as our lives here on Earth. Once they

realized that the Earth itself moved,

the idea of the permanent, fixed, and

unchanging cosmos

crumbled,

comets were discovered not to be just

strange atmospheric phenomena. They were

temporary visitors from the outer solar

system. The bright guest stars that

flickered and flared in the night sky

were really the deaths of massive suns.

The nebula were not mere clouds. They

were either the birthplaces or the

cemeteries of stars.

The universe was revealed to be

constantly shifting. And because of that

change, there are things that have not

yet had enough time to be born and

things whose time has passed. Things

that we will never see again.

To start with, the extremely early

universe was very different to today.

Due to the immense energies present, it

may have fashioned exotic particles like

magnetic monopoles or even stranger

topological defects like cosmic strings.

They are all gone now. There was a time

when the universe itself was capable of

creating new elements. Primordial

hydrogen and helium condensed out of the

thick nuclear soup within minutes after

the big bang. Generation after

generation of stars lived and died,