From evidence of a giant ninth planet lurking in the outer solar system

to the invention of reusable rockets, the last10 years have certainly been full of

excitement and unprecedented progress when it comes to space exploration.

We marvelled as scientists announced the possible discovery of a 12 mile long

underground lake of liquid water below the surface of Mars.

We said goodbye to Cassini as it plunged directly into Saturn's violent atmosphere after nearly

20 years of incredible service.

and we watched as Elon Musk's SpaceX company made history

by launching the first-ever commercial spacecraft to resupply the ISS.

Accomplishments such as these and many others are helping to improve our

understanding of the universe that surrounds us.

So as 2020 approaches let's look back at some of the biggest space discoveries

breakthroughs and stories during the last 10 years!

More than a hundred years ago Albert Einstein predicted the existence of

gravitational waves and in October 2015 the us-based Observatory LIGO detected

them for the first time.

Gravitational waves are ripples in space-time that are

caused by violent and energetic processes within the universe.

When massive accelerating objects such as black holes orbit each other they

disrupt the space-time around them causing invisible waves of distorted

space to radiate out at the speed of light, similar to ripples on the surface of a pond.

The gravitational distortions detected by LIGO in 2015

originated from the collision of two black holes nearly 1.3 billion light

years away and since then they have observed multiple other waves, including

those from two colliding neutron stars.

LIGOs discovery will help scientists

study the universe in a completely new way and will go down as one of

humanity's greatest scientific achievements.

In July 2015 eight years after its launch NASA's new Horizons became the

first spacecraft to visit the distant dwarf planet Pluto.

Equipped with an array of instruments New Horizons pointed it cameras

spectrometers and other sensors at the mysterious world and revealed Pluto to the earth.

It exposed the complexity of its icy uneven surface it's thin hazy

atmosphere and it's multiple strange moons.

After its flyby was complete

New Horizons then went on to a new target a Kuiper belt object that was

previously nicknamed Ultima Thule but is now known as Arrakoth.

In January 2019

the spacecraft finally arrived at the unusual object while capturing photos

that feature a large flat lobe that is connected to a smaller rounder lobe.

Arrakoth was the most distant flyby ever attempted however the New Horizons

mission has been extended through to 2021 so that the incredible spacecraft

can explore another mysterious Kuiper belt object.

In April 2019 teen Scientists accomplished what was previously thought

to be impossible when they captured the first ever image of a supermassive black hole.

The image was obtained by using eight ground-based radio telescopes that

were operating together as if they were one massive telescope the size of a planet.

The network was called the event horizon telescope and revealed the

silhouette of a black hole that is outlined by the glowing gas that

surrounds its event horizon the precipice beyond which light cannot escape.

The colossal structure is 6.5 billion times more massive than the Sun

and is located at the center of the galaxy Messier 87 which is about 54

million light-years away from Earth.

What you see in this image has been described

by scientists as an absolute monster of the universe.

Although they were launched more than 40 years ago Voyager 1 and 2 are still

collecting data and exploring regions where nothing from Earth has flown before.

They were originally designed to visit Jupiter and Saturn with an

extended mission for Voyager 2 to also fly by Uranus and Neptune.

But their mission didn't end there because after the historic encounters were complete

the twins continued to explore the outermost edge of the solar system.

In August 2012 Voyager 1 became the first spacecraft

ever to cross the boundary of the heliosphere the bubble of charged

particles that the Sun produces.

Then in November 2018 it's twin Voyager 2 also

entered interstellar space while capturing groundbreaking data along the way.

Both Voyager 1 and 2 have been flying longer than any other spacecraft

in history and are still providing humanity with groundbreaking data from a

truly uncharted region

For centuries planets beyond our solar system existed only in theory or

science-fiction.

But in more recent times scientists have successfully developed

detection methods that have enabled the discovery of thousands of exoplanets.

NASA's Kepler space telescope for example which is now retired was

responsible for discovering about half of the currently confirmed exoplanets.

Over the past decade, it revealed rocky world's the size of Earth that may have

the right conditions to harbor life as we know it.

It found hundreds of super-Earths which are planets bigger than earth but smaller than Neptune and it

discovered thousands of gas giants similar to Jupiter or Saturn.

Although Kepler is no longer searching the cosmos in 2018 NASA launched a new

spacecraft called transiting exoplanet survey satellite or Tess for short that

will search every star within 100 light years of Earth.

But it seems that we may not have to explore too far away from home to find the next habitable planet

because in August 2016 the pale red dot projects confirmed the existence of an

exoplanet orbiting within the Goldilocks zone of the red dwarf star Proxima

Centuri the closest star to the Sun.

The decade also brought us the most detailed study of a comet ever attempted

when ESA's Rosetta probe encountered comet 67p churyumov-gerasimenko

approximately 372 million miles away from Earth.

Comets are considered the primitive building blocks of the solar system and

likely helped seed the Earth with water possibly even life.

Rosetta arrived at comet 67p in November 2014 where it followed and studied its nucleus its

environment and its surface as it drifted towards the inner solar system

becoming the first spacecraft ever to orbit and land a probe on a comet.

The mission Lander was called Philae and photographed its surface after it

unexpectedly bounced twice before ending up in a shadow near a cliff but it did

capture part of the comet strange alien landscape.

In September 2016 after two

years of orbiting the mysterious object Rosetta and the comet was heading

towards the outer solar system where the spacecraft would not be able to continue

to operate under solar power and so it's made a controlled final plunge into the

surface of the comet ending the historic mission.

In October 2017 astronomers observed the first known interstellar object to visit our solar system.

The mysterious object was named Oumauamua and was

discovered by the University of Hawaii's pan star s1 telescope.

Oumauamua was

originally classified as a comet however the strange object did not

display any comets like traits as it passed by the Sun leading astronomers to

second-guess themselves some researchers argued it was an unusually shaped rocky

asteroid while others say it's a new type of object altogether or even an

alien spaceship.

The object appeared to have a rocky cigar-shaped body with a

reddish hue and is up to 1/4 of a mile long. Observations of Oumauamua

suggest that it had been wandering the Milky Way galaxy for hundreds of

millions of years before its chance encounter with our solar system.

It was tumbling end over end on a u-shaped hyperbolic orbit that took it around the

Sun and back out into interstellar space where we will likely never see it again

What an amazing 10 years it's been when it comes to space discoveries and

breakthroughs. What will the next decade bring us? Who knows but I for one cannot

wait to find out.

Thank you all so much for watching I really hope you enjoyed

the video have a brilliant Christmas break if you celebrate it and I'll see

you all soon with a new video all about the elusive planet 9.