Our closest star, the Sun, is just one of billions scattered across the Galaxy, but orbiting the Sun
is something unique, possibly the most valuable world in the universe. Planet
Earth, the only place known to support life.
This beautiful, blue marble, is where our human journey began.
But like the brave explorers of old that dared to travel beyond their horizon,
we must leave the comfort of our home, and venture deep into the unknown.
Out there, past that enormous bright band of gas and dust, is our final destination,
the centre of the Milky Way Galaxy.
First, we will pass the moon, the furthest place that human beings have ever walked.
Then we must leave the solar system altogether, and enter the space in between the stars. But In
order to get to the centre of our galaxy, we will have to push beyond the realms of possibility and
break the cosmic speed limit. We must travel faster than anything has ever travelled before.
That ghostly band of light and gas ahead has been the inspiration of many ancient myths
and legends back home. A silver river flowing through the heavens, the backbone of the night,
the pathway of the birds and the spilt milk of a goddess. Until the invention of the telescope,
no human could have known the true nature of the Milky Way Galaxy.
If you could see the Milky Way from above or below,
it would look like an enormous spiral, made up of hundreds of billions of stars,
gas and dust. Our solar system is located on the inside edge of one of its spiral arms,
around 26,000 light-years away from the galactic centre, a journey that would take the interstellar
spacecraft Voyager one more than 450 million years to complete. But we are going much
fastest than any probe launched before us. We are already thousands of light-years away from home.
There's no turning back now. Because we are travelling hundreds of light-years every second.
Each of these blurred, bright dots we are zooming past is a star, and on average,
each star has at least one planet orbiting it, some of which are around the size of Earth
and exist within the habitable zone. Whether there are planets out here capable of hosting life,
is still a mystery. Only time will tell how ordinary or extraordinary the Earth really is.
But as it stands, the Galaxy is silent. The only life we know of exists back home.
At this point, our journey has taken us thousands of light-years away from home.
So far, in fact, the Earth now feels like a distant memory. But we haven't got far to go,
because within that bright mass ahead is the heart of the Milky Way Galaxy.
As we creep ever closer, you will notice that stars are becoming highly concentrated around
the Galactic core. Within this region, stars are typically only a few light weeks away from
each other. Unlike back at home, in our galactic neighbourhood, where they are separated by many
light-years. Around here, stars are so packed together that if you found yourself standing on
one of the orbiting planets, you would witness a blazing light display every single night.
Surrounding the very centre of the Galaxy is a swarm of bright,
giant stars orbiting an invisible object. A sleeping giant. These stars are moving
so fast, that many of them complete one rotation of this mysterious object
in just a couple decades. A journey that takes the Sun more than 200 million years.
After 26,000 light-years, our journey is nearing its end. That dazzling bright light ahead
is Sagittarius a*, our final destination and the very centre of the Milky Way galaxy.
The home of a cosmic monster, a supermassive black hole.
Perhaps the most intriguing object in the Galaxy,
Sagittarius A*, is the ultimate consequence of gravity. It has a mass 4.3 million times
that of the Sun, all concentrated into an area smaller than the orbit of Mercury.
What we are currently observing, however, is not the supermassive black hole itself,
but the swirling, super hot material surrounding it.
That rotating ring of debris is called the accretion disk and is a thin flow of gas
and dust that has not quite fallen into the supermassive black hole. Instead, it forms
a flattened band of spinning matter around the event horizon, the point of no return.
Those powerful jets, blasting out into space are also partly created by the accretion disk,
as it falls towards the supermassive black hole at the centre. The plunging material spins faster
and faster, becoming hotter and hotter, producing magnetic fields, that along with a spinning
black hole, winds up into a twisted cone that reaches thousands of light-years out into space,
extracting torrents of lethal radiation.
Now we have made it to the end of our journey. To the core
of the Milky Way Galaxy and into its chaotic heart.
But just like the material that crosses the event horizon of a black hole, this is a one-way trip.
There's no turning back now. We've come too far.
Did you enjoy this epic journey from Earth to the centre of the Milky Way Galaxy? If you did, then
please tap the like button, let me know In the comment section below and consider subscribing. It
really helps support my channel and allows me to continue creating these epic adventures across the
universe. Thank you so much for watching, if you want some more space, then check out this video
about the hidden dwarf planets at the edge of our solar system, and I'll see you all next time.