What Would Happen if Betelgeuse Exploded?
Intro A violent explosion awaits every star in our
universe, and Betelgeuse is no different.
The cycle of life and death is a constant that is ever present in the universe.
It is common for planets, stars, and even entire galaxies to fulminate as they reach
the end of their life.
However, to witness an act of such extreme celestial violence from Earth is a rare sight.
Today, let’s talk about what would happen if Betelgeuse exploded.
Celestial Explosion A supernova is what happens when a star has
reached the end of its life and explodes in a brilliant burst of light.
Supernovae can briefly outshine entire galaxies and radiate more energy than our sun will
in its entire lifetime.
They're also the primary source of heavy elements in the universe.
According to NASA, supernovae are "the largest explosion that takes place in space."
Various civilizations recorded supernovae long before the telescope was invented in
the 17th century.
The oldest recorded supernova is RCW 86, which Chinese astronomers spotted in A.D. 185.
According to NASA, records show that this "guest star" stayed in the sky for eight months.
The Crab Nebula, arguably the most famous supernova, was first spotted by Chinese and
Korean astronomers who recorded this star explosion in their records in 1054.
Native Americans may have seen it as well, according to rock paintings found in Arizona
and New Mexico.
The supernova that formed the Crab Nebula was so bright that those early astronomers
could see it during the day.
Other supernovae that were observed before the telescope was invented occurred in the
years 393, 1006, 1181, 1572, and 1604.
famed astronomer Tycho Brahe who observed the 1572 event wrote about his observations
of the "new star" in his book, "De nova Stella," which gave rise to the name "nova."
The term "supernova" was first used by Walter Baade and Fritz Zwicky at Mount Wilson Observatory,
who used it concerning an explosive event they observed, called S Andromedae, located
in the Andromeda Galaxy.
Scientists suggested that supernovas happen when ordinary stars collapse into neutron
stars.
According to research by the European Space Agency, on average a supernova will occur
once every 50 years in a galaxy the size of the Milky Way.
The U.S. Department of Energy estimates that a star explodes every 10 seconds or so somewhere
in the universe.
About 10 million years ago, a cluster of supernovae created the "Local Bubble," a 300-light-year
long, peanut-shaped bubble of gas in the interstellar medium that surrounds our solar system.
Exactly how a star dies depends in part on its mass.
Our sun, for example, doesn't have enough mass to explode as a supernova, but with the
right amount of mass, a star can burn out in a fiery explosion.
Types and Causes A supernova may occur in one of two ways.
In a type I supernova, a star accumulates matter from a nearby neighbor until a runaway
nuclear reaction ignites.
A type II supernova happens when a star runs out of nuclear fuel and collapses under its
gravity.
A type II supernova is arguably the more exciting of the 2.
For a star to explode as a Type II supernova, it must be several times more massive than
the sun, estimates run from 8 to 15 solar masses.
Like the sun, it will eventually run out of hydrogen and then helium fuel at its core.
However, it will have enough mass and pressure to fuse carbon.
Next, gradually heavier elements build up at the center, and the star forms onion-like
layers of material, with elements becoming lighter toward the outside of the star.
Once the star's core surpasses a certain mass, it begins to implode.
For this reason, these Type-II supernovae are also known as core-collapse supernovae.
Eventually, the implosion bounces back off the core, expelling the stellar material into
space, and forming the supernova.
What's left is an ultra-dense object called a neutron star, a city-sized object that packs
the mass of the sun in a small space.
Type II supernova sub-categories are classified based on their light curves, which describe
how the intensity of the light changes over time.
The light of Type II-L supernovae declines steadily after the explosion, while the light
of Type II-P supernovae stays steady for a longer period before diminishing.
Both types have the signature of hydrogen in their spectra.
Astronomers think that stars much more massive than the sun might not explode as a supernova,
instead, they collapse to form black holes.
Type I supernovae lack a hydrogen signature in their light spectra and are generally thought
to originate from white dwarf stars in a close binary star system.
As the gas of the companion star accumulates onto the white dwarf, the white dwarf is progressively
compressed and sets off a runaway nuclear reaction inside that eventually leads to a
cataclysmic supernova outburst.
Astronomers use Type Ia supernovae as "standard candles" to measure cosmic distances because
all are thought to blaze with equal brightness at their peaks.
Type Ib and Ic supernovae also undergo core-collapse just as Type II supernovae do, but they have
lost most of their outer hydrogen layer.
In 2014, scientists detected the faint, hard-to-locate companion star to a Type Ib supernova.
The search consumed two decades, as the companion star shone much fainter than the bright supernova.
Recent studies have found that supernovae vibrate like giant speakers and emit an audible
hum before exploding.
In 2008, scientists caught a supernova in the act of exploding for the first time.
While peering at her computer screen, astronomer Alicia Soderberg expected to see the small
glowing smudge of a month-old supernova.
But what she and her colleague saw instead was a strange, extremely bright, five-minute
burst of X-rays.
With that observation, they became the first astronomers to catch a star in the act of
exploding.
The new supernova was named SN 2008D.
Further study has shown that the supernova had some unusual properties that are being
studied to this day.
Consequences At about 950 times bigger than our Sun, Betelgeuse
is one of the biggest stars in our Universe.
But that comes with a price.
Just like us, stars have a life expectancy, and Betelgeuse is no different.
It's a ticking time bomb that's ready to go, but we're not sure when.
So, what if today was the day Betelgeuse went out with a bang?
How would the Earth be affected?
And will our Universe ever be the same?
Betelgeuse is one of the closest stars to Earth, at a distance of only 650 light-years
away.
This makes it a fan favorite with professional and amateur astronomers alike.
Betelgeuse is a red giant star, which means that when it reaches the end of its life,
it will explode in a spectacular supernova, possibly even becoming a black hole in the
process.
Let's imagine that today Betelgeuse calls it quits, and puts on one heck of a cosmic
light show.
But, before getting good seats for Betelgeuse's grand finale, what sort of damage could an
exploding star do to Earth?
Well, think of stars as being like nuclear power plants.
If they explode, you're looking at a disaster of cosmic proportions.
Anything within 50 light-years of the exploding Betelgeuse will suffer massive shockwaves,
and be inundated with dust and radiation.
However, astronomers predict that humanity would probably survive this celestial eruption.
Down here on Earth, we're going to see a very bright light in the sky.
It could even be visible during the day, and bright enough to rival a full moon at night.
This light show is expected to go on for quite some time.
This is because the light has to travel 650 light-years from its place in the Universe
to ours.
The event will be breathtaking to behold, but will not affect life on Earth except for
the light show at night.
We're about 10 times too far away to feel any repercussions from the explosion.
If we weren't, well, that would be another story.
If we were too close to Betelgeuse when it explodes, our atmosphere and cells would be
fried by the radiation and gamma waves.
When you're exposed to high doses of radiation, it can burn and scar your skin, cause genetic
mutations, and can ultimately be lethal.
Gamma radiation, in particular, is incredibly powerful.
It's pure energy, even more intense than light itself.
If Betelgeuse were closer to Earth, it would be a literal and figurative "lights out" for
all of us.
Humans, animals, plants, you name it – it would all be toasted.
An explosion that big, from a star that immense, would destroy life on Earth in seconds once
the radiation hits us, even though the process of going supernova takes years.
And even if we did have interplanetary ships to evacuate in time, Betelgeuse is so huge
that there wouldn't be a planet in our Solar System that's safe from the explosion.
Thankfully, we're much too far from Betelgeuse to have any direct, observable, or harmful
effects from the explosion.
Betelgeuse is going to explode, but it will likely take another 100,000 years.
When it does go, astronomers are going to have to rethink the structure of Orion.
Bright Lights If you stargaze on a clear winter night, it's
hard to miss the constellation Orion the Hunter, with his shield in one arm and the other arm
stretched high to the heavens.
Betelgeuse marks Orion's shoulder, and this star's strange dimming has captivated sky
gazers for thousands of years.
Aboriginal Australians may have even worked it into their oral histories.
Today, astronomers know that Betelgeuse varies in brightness because it's a dying, red supergiant
star with a diameter some 700 times larger than our Sun.
With all the speculation about what a Betelgeuse supernova would look like from Earth, astronomers
at the University of California have come up with simulations of the star's dying days.
The astronomers say there's still uncertainty over how the supernova would play out, but
they were able to augment their accuracy using observations taken during Supernova 1987A,
the closest known star to explode in centuries.
The simulations show that the explosion will shine as bright as the half-moon for more
than three months.
Humans would be able to see the supernova in the daytime sky for roughly a year, and
it would be visible at night with the naked eye for several years, as the supernova aftermath
dims.
By the time it fades completely, Orion will be missing its left shoulder.
While there is no worry of any harm to life, the supernova could still impact Earth in
some surprising ways.
For example, many animals use the Moon for navigation and are confused by artificial
lights.
Adding a second object as bright as the Moon could be disruptive.
It's not only wildlife that would be disturbed, either; ironically, astronomers themselves
would have a hard time.
Astronomical observations are already difficult when the Moon is bright, and adding another
bright light in the sky could hinder progress for years.
And if Betelgeuse does defy the odds and blow up in our lifetimes, astronomers say there
will be ample warning.
Instruments on Earth would start detecting neutrinos or gravitational waves generated
by the explosion as much as a day in advance.
But for scientists, Betelgeuse doesn't have to explode to be interesting.
It's big and bright, making it relatively easy to study.
The star provides a unique opportunity to study a celestial body at the end of its life.
Some fascinating physics is going on in the internal structure of Betelgeuse, and the
best guess astronomers have as to what's going on stems from what they already know about
the star and others like it.
Outro If you liked this video, you may also enjoy
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Do you think Betelgeuse will explode in our lifetime?
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