Star Field and Nebula Images

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