since we've been talking how stars formed and the evolution of stars
i thought it was about time that we looked at some cool pictures of stars
forming or stars themselves, or evolution of stars.
so this right here is from the Eagle Nebula,
Just so you know, the word Nebula is kind of a general word for any interstellar cloud of gas or dust
so when we're talking about the Eagle nebula, we're actually talking about a huge nebula
and actually, it's a nebula that expands.
and so that you have a sense, this is just one of the pillars of the "Pillars of creation"
This is just a small part of the actual Eagle Nebula
And just this pillar right over here, just this pillar here
so that you have a sense of how large it is, just this pillar itself is 7 light years
it is 7 light years talls
so this is an enormous amount of distance
remember, the distance from earth to the nearest star was about 4 light years
it would take voyager, if it were pointed in the right direction
moving at 60 thousand kilometers per hour
it would take Voyager 80 thousand years to go 4 light years
just this pillar is 7 light years
but i wanted to show you this because these type of nebulae, the plural of nebula
are where stars can form.
so this right here, you actually see, is actually a breeding ground for the birth of new stars
this gas is condensing, just like we talked about a couple of videos ago. Until it gets to that critical
temperature, the critical density, where you can actually get
fusion of hydrogen
so this is just a huge interstellar cloud of hydrogen gas
and over here you can see its just this breeding ground for stars
and we don't even, we think that this structure doesn't even exist anymore
because remember, this thing is very very far away from us
in fact is, just so you have the number, this thing is 7000 light years away
7000 light years away
which means that what we are seeing now, the photons that are reaching our eyes or telescopes right now
left this region of space 7000 years ago
so we're seeing it as it was 7000 years ago
so a lot of this gas, a lot of this hydrogen, may have already condensed into many many more stars
so the structure might not be the way it looks right now
and actually there was another
super nova that happened that might have blown away a lot of this stuff
and we won't even be able to see the effects of this super nova
for another thousand years
but anyway, this is just a pretty amazing photograph in my opinion
especially, and its beautiful at any scale
and it's even more mindblowing when you think that this is 7, this is a structure
that is 7 light years tall
and this is really just part of the Eagle Nebula
one of the pillars of creation
this right here is a star field, and this is as we're looking towards the center of our galaxy
the milkyway
this is the Sagittarius star field
the neat thing here you see is such a diversity in stars
this is also kind of mind numbing because every one of these stars, are inside of our galaxy
this is looking towards the center of our galaxy
this isn't one of those where we're looking beyond our galaxy or looking at clusters of galaxies
this is just stars here
but the thing here is that you see a huge variety, you see some stars that are
shining red, right over here
and obviously, the apparent size, you cannot completely tell
because the different stars are at different distances and at difference intensities
but the redder stars, these are stars in their red giant phase
or they're probably at their red giant phase
i haven't done specific research on these stars
but that's what we suspect
those are in their red giant phase
the ones that are kind of in the yellowish white part of the spectrum
these are stars that are probably in their main sequence
probably not too different than own sun
the ones that are in the yellowish white, closer to orange-yellowish-white part of the spectrum
and the ones that look a little more bluish, or a little bit more greenish
these are burning super fast
let me see if i can find, this one looks a little big bluish to me,
these are burning super super fast, and so
the super massive stars, they burn kind of fast and furious and then just die out
but the smaller stars, the ones with less mass
they burn slower over a much much longer period of time
so the ones that are burning fast
are emitting a lot of energy at the smaller wavelength part of the light spectrum
that's why they look bluer or greener and these are going to be more massive stars
the ones that look white or bluer or greener
while the redder ones
the redder ones are less massive stars that are kind of in their super giant phase
and so they are at this point cooler than the main sequence stars
this right here, this right here is the cat's eye nebula
and the word nebula, this is actually a planetary nebula
this one here is a planetary nebula
and it's called a nebula because it is kind of this gas that's kinda floating out in space
but it's at a completely different kind of scale than this Eagle nebula
that we drew over here
so when people talk about nebulas, they normally talking about something like the eagle nebula
these huge masses of interstellar gas
when people talk about planetary nebulas; this is actually still a huge radius
but no where near 7 light years
but this is the bi-product of a star shedding all of its outer material
so at the center of this, we see kind of a mature star here
and it's shed of kind of its outer layers
and it did that in its red giant phase
so the core would keep flaring up, having these hot explosions
and every time you have one of these hot explosions, you had more and more of its outer layers getting
pushed off, pushed off into space
forming this planetary nebula
so this as we see it right now
its still not yet a white dwarf, it is still an active star
fusion is still occurring in this star, but it is well on its way onto becoming a a white dwarf
once all its fuel runs out
it's past its red giant phase, it's thrown all of this material into space and it's on its way onto becoming
a white dwarf
anyway hopefully you enjoyed that
i actually find all of these images to be pretty captivating
especially the star field one
because this just inside of our galaxy
hopefully it gives more appreciation for how many stars there are
i mean this is just a small fraction of the 200 to 400 billion stars inside the milky way