Our Universe 3D Page #3

All four of the outer planets Jupiter,

Saturn, Uranus and Neptune are gas giants,

so they share a lot of similarities,

like a lack of a surface.

Saturn looks very special, though.

It is accompanied by a massive ring system.

Saturn is the sixth planet

of our solar system.

Even though it's almost

1 billion miles away,

it's visible to the naked

eye in our night sky.

This is because of its huge size,

over 700 Earth-sized planets

could fit inside it.

Saturn's distinctive ring system

is also gigantic.

Using even the simplest of telescopes,

it can be seen from Earth.

But what are these rings made of?

Once we get closer, we can differentiate

between thousands of sharply-defined rings.

As it turns out, they are not as solid

as they first appear.

In fact, they are made up of asteroids

that circle around the planet.

It's a diverse range of compounds

of different sizes,

from specks of dust up to 10 metres wide.

Some of the smaller moons of Saturn are

ploughing right through these rings.

These moons are called "shepherd" moons,

because their orbits ensure that the rings

are kept nicely in shape,

a shape they have had for millions of years.

Even though Saturn's ring system

really stands out,

the other three gas giants

in our solar system have rings as well.

Those of Jupiter, Uranus and Neptune are

not as visible, though.

They are mostly made up of very

small particles, like cigarette smoke

mixed with some grains of sand.

While Saturn and Jupiter can't

be easily confused,

Uranus and Neptune appear very much alike.

They are the most distant from the sun,

so they don't get too much warmth

and energy.

That's why they are in a subclass

of the ice giants.

And Uranus is the icier one of the two, even

though it is not as far away as Neptune.

But it lacks any form of

internal heat source,

which really is an exception

in our solar system.

Scientists assume this has something to do

with a massive collision

Uranus must have had in the past.

Proof of this is the fact that

the axis of Uranus is severely tilted.

Seen from Earth,

we look at it almost from above.

Neptune, on the other hand,

has an internal energy source

and, therefore,

displays a lot more weather effects.

In the upper layers of the atmosphere,

we see gigantic clouds,

several thousand miles long.

They form in stripes, because of the

high rotation speed of the planet.

At the poles, we have auroras,

northern lights that look much more

complex than those we have on Earth.

This phenomenon occurs

when charged particles

of the solar winds enter the atmosphere.

Jupiter's auroras are even bigger, though.

No surprise, as the planet is

almost too big to be true.

If it had gathered some more mass

during its creation,

it could have ignited to

become a sun all of its own.

In that case,

our solar system would have two suns today.

And while this may sound unusual,

our universe has many systems

with more than one central star.

In the Orion Nebula, we even find

four suns very close to one another.

Also, they are among the biggest suns

in the entire cosmos,

hundreds of times bigger than ours.

Their incredible power has

spawned the creation of thousands

of young stars in their vicinity.

Many of these newborn suns are

surrounded by protoplanetary discs,

where matter is shaped up into asteroids,

moons and planets.

Maybe one of those planets will be home

to intelligent life one day.

Our vast powerful universe certainly offers

limitless possibilities.

New worlds are created

on a literally astronomical scale.

Nebulae like Orion cover distances

of hundreds of light years,

producing thousands of new suns.

But everything that has a beginning,

also has an end.

There is not just birth and creation

on mind-bending scales,

but also chaos and destruction

in the same magnitude.

Even incredibly powerful objects

like a sun have to die one day.

But when they go,

they leave behind sites of new conception,

and incredible sights.

The constellation of

Taurus is home to one of

the most studied objects

in visible space,

the Crab Nebula.

Its torn and furrowed structures

make this nebula look like

a star's explosion frozen in time.

Ancient Chinese astronomers were able to

witness the actual event in 1054 A.D.

The explosion was described as so bright,

it could be seen during

daytime here on Earth.

In the 1,000 years that have passed since,

the remaining core of the crab-sun

has turned into an extremely dense

neutron star.

An even more eerie sight is

provided by the Helix Nebula.

Here, the result of a supernova

resembles a gigantic eye.

This similarity becomes most obvious

when viewed in the infrared spectrum.

This disturbing appearance is

more than fitting

for the fatal events that took place there.

When the sun exploded, all planets and

moons of that solar system were either

torn apart by gravitational forces

or vaporised by the expanding sun.

But at least some comets survived and still

make their way through this galactic rubble.

Even if we know a lot

about these faraway systems,

it's questionable if mankind

will ever reach them.

Considering that even if we could

travel at light speed,

it would take several thousand years

to get there.

For now, it makes sense to concentrate

on the astral objects in our own vicinity.

And scientists have been very busy here.

The first planet that had

a human-built visitor was Venus.

The probe Mariner 2 flew by

in December, 1962.

Venus is the second brightest object

in the night sky, after the moon.

Sometimes we can even see it during daytime.

The reason for this is Venus' dense

light-reflecting atmosphere,

combined with its close proximity to Earth.

And, in addition to being our nearest

neighbour, Venus is even called

the "sister planet" of Earth.

This is because the two of them share

approximately the same size,

density and mass.

Likewise, the gravitational force

on Venus is close to 90% of ours.

But, in spite of these

resemblances, there are

major differences that

spoil any potential

for Venus to serve as a holiday destination.

The number one barrier is Venus' atmosphere.

Comprising almost exclusively

of carbon dioxide, it is toxic for us.

Even worse is the heat.

The temperature on Venus can

reach over 800 degrees Fahrenheit,

making it the hottest place

in our solar system.

Then there is an incredibly high

surface pressure.

The first Russian probes

to arrive here in the 1960s

were literally crushed

by atmospheric pressure.

With the right technology, though, it would

still be possible to land a rover on Venus.

Looking around down here can give you

an idea of what hell might be like.

Sulphuric clouds,

acid rain and active volcanoes

are all on the list of local attractions.

In addition, the heavy clouds are rocked

by lightning and thunderclaps.

The surface is adorned with huge volcanoes.

Among them is Maat Mons,

a giant 5 miles high,

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