Just How Old is the Milky Way Galaxy? | How the Universe Works | Science Channel

[Music] Earth our home just one of 100 billion planets orbiting 400 billion stars that make up an immense Galactic spiral the Milky Way galaxies are stars for form and of course planets form around Stars so the story of the earth of yourself of the solar system has everything to do with the story of the galaxies the story of the Milky Way begins 13.6 billion years ago just after the big bang it's a time when there are no planets and no stars just a vast lumpy soup of superheated hydrogen gas over millions of years the temperature

drops and gravity compresses the lumps down until eventually the hydrogen molecules fuse and ignite a star in time billions of stars burst into life and the Milky Way begins to take shape you can think of a galaxy as sort of like a human being when you're young and in your adolescent stage you're vibrant and active that's a young Galaxy forming stars in a crazy way and it's not even fully formed yet at certain point Galaxy reaches middle age and a middle-aged Galaxy really is what it's going to be it has its shape but in the

long run a Galaxy will stop forming stars and eventually just like we all die our galaxy will die so at what stage of life is the Milky Way is it a healthy active youngster or is it heading for its deathbed scientists can determine each Galaxy's stage of Life by its color so we see different colors of galaxies in the universe we see galaxies that are tinted blue and galaxies that are tinted red when we see a blue Galaxy that tends to be a younger Galaxy full of bright hot newly formed Stars when we see a

redder Galaxy that tends to be a dimmer older Galaxy that isn't forming new stars in the present moment all its stars are are aged and older and redder and so the entire galaxy cast a different Hue so what color is our galaxy it's a simple question but the answer is hard to come by even though we've been looking at the Milky Way for thousands of years the term Milky Way is ancient it goes back to a time when in the dark sky people noticed there was this light band that actually went from Horizon to Horizon

and that band turned out to be made of thousands and thousands of stars actually too far away to see individually but it took us a long time to realize what the shape and the scale of the Milky Way galaxy is the amazing thing to think about is that we actually don't know our home Galaxy very well at all we actually live in the middle of this disc of gas and dust and that obscures our view of the larger Milky Way using visible light we C see to the center let alone the other side of the

Milky Way galaxy the solution is to use a form of light that passes through the gas and dust infrared this is the Sloan digital Sky survey telescope at the Apache Point observatory in New Mexico it's mapping the Galaxy using infrared and giving scientists unprecedented insights the first sensitive infrared observations really weren't done until the last 15 years and each of these new windows on the universe teach us different things in the last 15 years Sloan has surveyed more than 250 million stars analyzing their light to work out the color of the Milky Way and what

scientists saw shocked them until very recently we thought the Milky Way was a young healthy Galaxy but now there's evidence that we may be entering the pathway to death the Sloan telescope reveals that star production in our galaxy is falling through the floor the Milky Way is dying and when it stops forming new stars its time will be up paradoxically our galaxy still has star forming gas in the tank so it should be healthy but something is killing it off so the Milky Way galaxy is this wonderful disc filled with Rich hydrogen gas lots of

dense dust clouds it has everything you need there for Star formation but it seems to be slowing down and even turning off and right now we don't really understand what the culprit is with a Galaxy killer at large scientists Embark upon the biggest murder investigation in the history of the universe everything in science when you're when you're exploring a problem is a bit like uh a crime scene you've got the evidence laid out in front of you and we have to figure out who done it our home in the universe is dying not the Earth

but our galaxy The Milky Way it's been producing stars for billions of years but soon it will stop our own Sun formed about 4 and a half billion years ago in the Milky Way galaxy and we are not the oldest star by far and yet tragically we actually seem to be one of the last generations of new stars in the Milky Way current projections suggest that in about 4 billion years star formation may have ceased altogether which is almost just the blink of an eye in the life cycle of the universe to find out why

science scientists launch an investigation the most crucial question how is the Milky Way dying to kill a Galaxy you have to get rid of the cold gas because that's what stars form from there are many ways you can do this you can blast it out from the inside you can draw it out from the outside you can heat it up so it's no longer cold you can use it all up and there's even more ways you can stop it what we have to do is figure out which way is happening and our Galaxy perhaps the

culprit is inside the Milky Way itself a clue comes from another galaxy entirely this is w2246 d526 scientists call it a hot dust obscured Galaxy or hot dog for short this galaxy is 12 A2 billion light years away it's the most luminous Galaxy we know of in the universe and has a light of 300 trillion [Music] Stars the source of the intense light is not at stars but a mysterious object at the Galaxy's center it's a million times smaller than the Galaxy itself there's only one thing that small and that powerful a super massive black

hole