This is the 100th video I've made for this channel since I first began uploading these
videos in April of 2016.
At the time, I only expected to make one video and did not expect to end up with many subscribers,
needless to say, the numbers continue to amaze me.
Thanks to all of you for that, the channel truly is something that I love and I look
forward to many more years of making science videos.
So, time for some fireworks in celebration, but not the normal kind.
Here are three stars, two visible in our night sky and one too dim to see but potentially
very dangerous, that in the future are going to explode.
The first star is Antares in the constellation of Scorpius, the 15th brightest star in the
night sky, which is expected to go supernova sometime after about 10,000 years from now,
though estimates there vary.
A red supergiant star, it has long been gazed at by astronomers throughout history because
while it is not only bright, it is also visibly reddish in color unlike most other stars.
Oddly, the universe is full of red stars, but the naked human eye is not great at detecting
the color red if it's from a dim point source like a star.
As a result, we see astronomical objects with red in them, such as the great Orion nebula,
as bluish-green or white until we either have a telescope large enough to bring out the
reddish hues or we have a red object that's really bright.
Antares is one such object.
But Antares is living on borrowed time and is expected to explode with enough intensity
to reach or exceed the brightness of the full moon as viewed here on earth, perhaps enough
to cast shadows at night before dimming back down.
And while it will be spectacular for future observers, it should pose no threat to Earth
due to Antares being fairly distant at about 600 light years.
But there is an even more prominent star that's set to go supernova.
The constellation of Orion is dominated by yet another red star, bright Betelgeuse.
It's the 9th brightest star in the sky, and its name, though weird, is actually a distortion
of what Arab astronomers called it long ago to denote it as, well, what it is: the armpit
of Orion the hunter.
But for me it's my favorite star due to its very obvious orangish-red glare and its place
as a prominent winter star here in the Northern Hemisphere.
I've been looking at it since I was a kid, and still gaze up at it to this day on cold,
dark winter nights, usually while fumbling with my keys.
Betelgeuse also happens to be one of the few stars we've been able resolve and directly
image its disc.
This is due to the star appearing absurdly huge due to it tossing off layers of itself
into space.
It is a roiling, crazy star that is known to have shrunk by 15 percent in less than
two decades.
And it doesn't have long to live, probably less than 100,000 years though it could go
at any moment, and when it does, like Antares the explosion will be prominently visible
from earth.
But signs Betelgeuse's end are apparently already evident.
The 2nd Century Astronomer Ptolemy working in the then Roman controlled city of Alexandria
described the star in the Greek of the period as hypokirhhos, meaning ruddy or reddish.
It looks like that now.
But not so to Chinese astronomers three centuries before Ptolemy.
They made it clear that the star was yellow.
And it is indeed possible that the star was, at the time, a yellow supergiant that has
since evolved.
Betelgeuse, like Antares, is too distant to pose a threat, but one very unusual even more
distant star could go sometime within the next few hundred thousand years.
This star is called WR 104, and it's too dim to see with the naked eye.
It's a type of star known as a wolf-rayett star located about 7500 light years away.
We don't yet have a solid understanding of what a star of this type would do during a
supernova leaving open a small chance that it could do damage to earth.
It comes down to gamma ray bursts.
Some scientists think that a supernova from this star could produce one, and if the star's
poles are aligned with earth, we could receive a dose of gamma radiation that could cause
a mass extinction on earth, though the odds are very low for this happening.
There is no consensus on this star, and other scientists think that it's unlikely for a
gamma ray burst to be produced at all, and the odds of the star's poles being aligned
with us are low.
Plus, at that great distance, the geometry of the burst would play a major role.
If the jet of gamma rays is wide, it will diffuse over distance and won't do any damage
even if it is pointed at us.
If it's more focused, it could pose a threat, but the narrower the beam, the less chance
there is of it lining up with earth.
The chances are low, but it is possible, that WR 104 could damage our planet sometime over
the next few hundred thousand years.
That may seem like a long time, but for perspective, in 100,000 years certain species of earthworms
on the North American continent will have just recovered their former range in Canada
after having been driven out by the advances of the Laurentide Ice Sheet thousands of years
ago.
Thanks for listening!
I am futurist and science fiction author John Michael Godier currently feeling sorry for
the earth worms, there are some predictions that a new ice age will occur in about 50,000
years completely thwarting their not-so-lightning advance and be sure to check out my books
at your favorite online book retailer and subscribe to my channel for regular, in-depth
explorations into the interesting, weird and unknown aspects of this amazing universe in
which we live.