From what they are, to whether our sun will become like them one day, join me as I show
you white and black dwarf stars!
There are MANY stars in the universe, that's part of the reason why the universe is so
special.
There are stars of massive sizes, there are ones that are massive and yet don't shine
brightly, or ones that are so small that they can't be seen outside of a certain distance.
This variety makes our universe even more special as a whole.
But when it comes to some of the most unique stars of the set, that would be the White
and Black Dwarf Stars.
So let's ask the basic question, "What are White and Black Dwarf Stars?"
I'll start with the White Dwarfs first because those we know are in the universe right now.
White Dwarfs are also known "degenerate dwarfs", and that's because they are a stellar core
remnant that is made up of highly dense matter of an electron-degenerate variety.
In short, the star is one that is very small, and yet very dense in terms of its makeup.
A great way of thinking about it is that a White Dwarf can have the size of our planet,
but its mass is more equivalent to that of our own sun.
And if you didn't know, you could fit 1.3 MILLION of our Earths into the sun.
So imagine having that much mass in something the size of the Earth.
That's one of the major reasons why White Dwarfs are so special.
Here's the rub though, despite having all of that mass and energy, a White Dwarf honestly
doesn't shine that brightly.
This is because unlike most other stars in the universe, it doesn't have any nuclear
fusion going on within itself (our own sun does this for the record).
Instead, the light it produces is Thermal Energy built up from the stores of it from
within the core.
What might surprise you though is that while there are only said to be about 8 White Dwarf
stars within the hundred star systems nearest our own sun...many believe that the White
Dwarf is the "final fate" of many dying stars.
Specifically, "White dwarfs are thought to be the final evolutionary state of stars whose
mass is not high enough to become a neutron star."
If you're curious, that definition would apply to about 97% of the stars in the Milky Way
Galaxy!
Which means that having that many White Dwarf stars would cause some serious problems down
the road, but that's something we'll get into a bit later.
It should be noted though that one of the 8 White Dwarf stars we know about is only
8.6 light years away at SIrius B. Which is one of the main reasons we even known about
it at all.
So how does something like our own sun go from being like that to a White Dwarf?
Well it's not an instant thing if that's what you're wondering.
It's very much a thing of "phases."
"After the hydrogen-fusing period of a main-sequence star of low or medium mass ends, such a star
will expand to a red giant during which it fuses helium to carbon and oxygen in its core
by the triple-alpha process.
If a red giant has insufficient mass to generate the core temperatures required to fuse carbon
(around 1 billion K), an inert mass of carbon and oxygen will build up at its center.
After such a star sheds its outer layers and forms a planetary nebula, it will leave behind
a core, which is the remnant white dwarf.
So as you can see, this is something that takes billions of years to complete, and considering
our sun (which is a Yellow Dwarf star if you recall) has likely a couple billion years
before it goes into the Red Giant phase of its life (which will eradicate the Earth,
Mars and many other things until it gets WAY closer to Jupiter), we'll be fine, and thus
we won't get to see a White Dwarf in our lifetime.
That's not to say that other star systems won't get to see it happening sooner, and
it's possible if we find the right star that we could watch a White Dwarf being born...theoretically
of course.
Speaking of theoretically...let's dive into the other side of the spectrum...the Black
Dwarf stars because this may not be exactly what you're thinking it is.
Before we dive into that Black Star topic and such, be sure to like our video and subscribe
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Ok, so what exactly is a Black Dwarf Star?
To answer that, we actually have to go back to the White Dwarf star, don't worry though...it
won't be that long though.
You see, because of the fact that White Stars don't do nuclear fusion to maintain its heat
and shine, and thus relies on stored Thermal Energy, that means that eventually...they're
going to run out of power.
In this case, they gradually cool over time.
Granted, because of the density of White Dwarfs that's a long, LONG, time, but when they do,
their surfaces will start to crystalize until eventually...they're a Black Dwarf star...theoretically.
"What do you mean, theoretically?" you're asking, well that's because as of right now,
we don't know if a Black Dwarf star is in the universe.
I know that sounds weird, but let me explain.
You see, the White Dwarf stars take their sweet time in cooling off.
We're talking billions upon billions of years.
To the extent that more than likely, any white star that was born near the beginning of the
universe (which is of course an assumption as we don't know exactly what was around at
the beginning of the universe) hasn't had enough time to cool off enough to turn into
a Black Dwarf.
In fact, we really don't know just how long it WOULD take for such a White Dwarf to turn
into a Black Dwarf.
And obviously it's not something we can just wait around on because...well...it's very
likely that we're not going to be around to witness one.
I'm just saying.
Then again, it's also possible that Black Dwarf stars are an impossibility, and that
White Dwarfs will do something else when they've cooled down enough.
There are honestly a lot of things about stars that we don't understand.
And if you think about it, that's not too much of a surprise.
After all, the only real star we can study is our own sun, and that means that everything
we're guessing or stating about these other stars in the sky, including the White Dwarfs
and the potential Black Dwarfs, is technically theoretical.
Sure, we have basis for most of it, including the transformation into other phases like
the Red Giant, and more, but other aspects are a bit more of a "up for interpretation"
kind of thing.
It's not the best of situations obviously but we make it work.
But let's picture a Black Dwarf star in the sky, what exactly would it look like?
Well, not unlike a Black Hole, you likely wouldn't be able to see it unless you're looking
right at it, and even then.
After all, at this point in the stars life, there is no more heat in it, and there's no
more light being emitted from it.
Which would go to mean that it's basically a potentially massive black husk just staying
there in the space its within.
Not exactly the most fulfilling of lives, wouldn't you say?
Again, this is theoretical, but it would be something that many scientists would love
to observe one day...if life of any kind is around to see such a thing.
So, now that you know what White and Black Dwarf Stars are, aren't, and whether they're
around or not, what is there left to talk about?
Well how about this?
Do you want to know if we could actually LIVE around a White Dwarf star?
Now to be clear I'm not talking about our own solar system, as humanity likely would
be long gone from that system in one form or another (I.E. colonization of other worlds
or the destruction of all life via the sun being a Red Giant).
But for the sake of argument, let's say that we found a planet that was in the habitable
zone (where the suns light and heat was enough to allow the potential for water and life
sustainability) of a White Dwarf Star, would it be possible to truly live there?
Based on what scientists have found out about the White Dwarfs...yes, with a few catches
though.
I want you first to think about our own star.
Our sun.
Think about how far we are away from it (93 million miles) and what that allows to do
on Earth.
Our sun really is the "perfect star" for what we try and do in terms of life.
We get the perfect amount of heat, light, radiation output and more that affects us
just enough to live...and yet doesn't weigh us down with too many negatives.
For a White Dwarf star, a lot of that is up for debate.
Not the least of which is that to get the light and heat to survive (because remember,
White Dwarfs run off Thermal Energy and not Nuclear Fusion) we'd need to be WAY closer
to the White Dwarf than we are with our own sun.
How much closer?
Well instead of 93 million miles away, we'd need to be about...say...1.8 million miles
away?
Which I know still feels like a LONG way away from a sun...but it's really not.
Furthermore, scientists speculate that while this COULD work, the planet would likely have
to be tidally locked (always having one side face the sun) in order to get the consistent
sun and heat needed to maintain the status quo of life.
While this may not sound so bad at first, scientists have also pointed out some problems
in trying to live in this kind of an area or zone.
First and foremost, given the amount of time needed to get a star into the White Dwarf
phase of its life, the "sanctity" of the planets would be in question.
Severe question in fact.
And not just about what's on their surface, but what's within their cores.
Many feel that by the time such a White Dwarf was born that the planets around them would
have such less mass than something like Earth that it wouldn't make it worth it to try and
live there for any period of time.
Even though theoretically we could live in such a place by that star for about 3 billion
years before things get so cooled off in regards to the star that we feel the effects on the
planet we're on.
This is why the study of stars like this is so important, because right now we're working
really hard to try and find a place outside of our own solar system to live should we
need to evacuate Earth in a hurry.
YEs, we're already doing plans to get to Mars, and possibly even some of the moons of Saturn
and Jupiter, but those are more temporary solutions.
They're likely not long-term answers because of the fact that we'd have to build things
to make life sustainable rather than just being on a planet that is sustainable.
We're looking at places like Alpha Centauri for the answer of "where we can go next",
but to understand what planets MIGHT be the next place for us to live, we need to know
more about the stars in the sky.
Sometimes we just don't realize how much the stars impact our lives, and I would wager
that you didn't know that White Dwarfs were a thing.
Or even if you did, I bet you didn't know their importance or what they were in the
life cycle of said star.
And though Black Dwarfs are theoretical, it's important to think about what stars do when
they die, because sometimes they transform into other stars like White Dwarfs, Neutrons,
etc., and sometimes they transform into black holes.
So in many ways, we should be grateful that White Dwarfs exist, because they're a good
"middle ground" if you will for the dangers of Neutron Stars and Black Holes as a whole.
Then again, what would the universe be like if 97% of the stars (just referencing the
Milky Way Galaxy for now) were White Dwarfs?
Well first and foremost, the night sky would be a lot darker.
Again, White Dwarfs are one of the kinds of stars that don't emit a lot of light, and
so they go and do their thing with very minimal output.
And since you need stars to pour out lots of light in order to make it shine in the
universe as whole, if the majority were White Dwarfs, then that would mean the night sky
would be pretty much blank.
Especially if you viewed it from something like Earth.
The other problem that it would cause is that a lot of the planets in the universe are directly
changed or altered by the sun itself.
So, if you have say a planet that was next to a Red Giant, and its climate and weather
effects were directly affected by the mass and the heat of that star, and then it turned
into a White Dwarf, that planet would be DRASTICALLY changed.
And the effect would be near immediate due to the degrees of change.
So yeah, while we may not have a White Dwarf directly near us, and our sun likely won't
become one until we're long gone, we're good in that we don't have to face these kinds
of effects.
But it's always good to know what might happen should one come our way.
Thanks for watching everyone!
What did you think of this look at the white and black dwarf stars that are a part of our
universe?
Did you know that these stars existed before you came and watched the video?
Do you think that the universe will be full of these kinds of stars one day?
Let me know in the comments below, be sure to subscribe, and I'll see you next time on
the channel!