For a long time, scientists have been looking for exoplanets where humanity could potentially
exist outside of Earth.
Despite the fact that we know there isn't another planet like Earth where life might
exist, there are hundreds of millions of those planets out there, and more are being discovered
every day.
Everything is beginning to change, especially now that scientists claim to have discovered
exoplanets that may be more livable than Earth.
But, the most important thing to know is whether these planets actually exist.
In this video, we'll figure out what those planets are and whether life is truly conceivable
there, so we can decide whether we should book a trip there, just kidding.
I know you have a lot of questions in your mind now, so let’s get this started!
To begin, we must define an exoplanet.
Any planet that orbits a star outside of our solar system is known as an exoplanet or extrasolar
planet.
Keep in mind that these exoplanets range in size from massive gas giants like Jupiter
to small rocky worlds like Mars and Earth.
The majority of planets that have been identified are found in a small region of the Milky Way
galaxy.
According to NASA's Kepler space telescope mission findings, there are more planets than
stars in this galaxy.
It was in the year 1990 when the first exoplanet was discovered, and thousands more have been
discovered since then using a variety of approaches.
However, finding them is not a simple feat.
In our Milky Way galaxy alone, there could be at least three hundred million possibly
habitable exoplanets.
Before the US space agency's Kepler space telescope ran out of fuel in 2018, it spent
nine years searching for planets where life could possibly exist.
It was successful in identifying hundreds of exoplanets in our galaxy.
After reviewing all of the data acquired by Kepler, the three hundred million exoplanets
it recorded may be capable of maintaining liquid water on their surfaces, making it
also possible that life could exist there.
However, keep in mind that this is only a rough estimate, as the Milky Way Galaxy contains
between one hundred and four hundred billion stars.
And since each of those stars is expected to have at least one planet, there are likely
trillions of planets out there.
You might believe that all you need to find exoplanets is a telescope, but that is not
the case.
In fact, seeing an exoplanet is as rare as seeing Saturn from Earth.
Luckily, there is a method of identifying planets known as direct imaging, and very
few exoplanets have been discovered this way.
However, the transit method was utilized to discover the majority of exoplanets.
The fading of a star as a planet passes in front of it is measured using this method.
Exoplanets can also be discovered by monitoring the star's light spectrum.
It detects signs of a planet pulling on the star, which makes the light to change, or
by employing gravitational lensing.
If scientists use these three methods to find exoplanets, they will be able to find more
exoplanets every day in the huge universe.
If we're looking for exoplanets that potentially support life, what we need to do is to study
a region where planets orbit their host stars in the habitable zone, also known as the Goldilocks
Zone by some scientists.
The Goldilocks Zone is an area surrounding a star where the temperature is neither too
hot nor too cold to support liquid water.
However, the planet must also have the appropriate size, and the star around which the exoplanet
revolves must be of a specific type and stable existence.
Our sun, which is a yellow dwarf star, has been around in the system for nearly 4.5 billion
years, however, other stars in other systems are not as stable as our sun.
Keep in mind that there are other types of stars, but we’re going to touch on those
later.
At 4.2 light-years from Earth, Proxima b was discovered by the Harps telescope in 2016.
Proxima b is the exoplanet that is considered the closest one to our solar system.
It is thought to be at least 1.3 of the Earth's weight, and is located in the habitable zone
of its red dwarf star Proxima Centauri.
However, it was recently discovered by a new telescope called Espresso to be only 17 percent
more massive than our planet, meaning Proxima b is more Earth-like than it was previously
thought.
Because of this, this exoplanet has the potential to sustain life.
Additionally, it has the appropriate distance from its host star to be able to produce liquid
water.
Scientists felt that the planet could be livable, and that future generations that can create
speedy spacecraft could visit it in search of life.
A gigantic solar flare, however, had erupted from the exoplanet's red dwarf star, and the
explosion created a thousand times brighter light than the star itself.
It emitted four thousand times more Ultraviolet than the Earth would receive from our sun's
solar flare.
According to scientists, this event may have wiped out all possible life on the planet.
However, Proxima b is not the only possible habitable exoplanet.
According to scientists, they have discovered 24 livable planets or exomoons that may be
more suited for the origin and evolution of life.
Renee Heller and John Armstrong are the two researchers who coined the term "superhabitable"
in 2014.
According to them, being in the habitable zone is not enough for an exoplanet to be
livable.
An exoplanet must be older, larger, warmer, wetter, have higher amounts of oxygen, and
have a longer surviving star for life to exist in it.
According to Heller and Armstrong, the necessary size of a super-earth would have to be double
the mass of the Earth.
Because it is only in this way that radioactive decay in the planet's interior would last
longer for it to supply heat.
The size would also help in increased gravity that would keep the atmosphere in place for
a longer period of time.
Scientists chose the 24 superhabitable exoplanets because they have the correct size of the
star, the right lifespan, and are located in the habitable zone.
Many of these exoplanets orbit around G-dwarf stars, stars that are like our sun.
However, researchers are also examining exoplanets that move around K stars and Orange dwarf
stars, which are colder, less massive, and less bright.
In the Milky Way, there are fifty more orange dwarfs than yellow dwarfs.
I know that planets orbiting around K-stars may not seem suitable for life to exist, but
they have a considerable advantage: their lifetimes range from seventeen billion to
seventy billion years, whereas our sun was estimated to be alive for about ten billion
years lifespan.
That only means if life began on a planet orbiting a K star, it would have had considerably
more time to evolve than life on Earth has had thus far.
Given that complex life evolved on Earth over 3.5 billion years and advanced species, such
as humans, over 4 billion years, a larger exoplanet could mean more space for landmass
and habitat.
These highly livable planets would also have higher gravity and a thicker atmosphere, allowing
useful organisms to spread life through the air.
According to planetary scientists, the age of a highly livable exoplanet is between five
and eight billion years.
We all know that water is required for humans to be able to survive, as well as with other
organisms.
This means that planets with higher moisture levels and average surface temperatures that
are around eight degrees Fahrenheit higher than Earth may be more livable.
Additionally, more life forms can be found in warmer and wetter places, so some of these
livable planets may mirror Earth in the early Carboniferous period, which occurred around
three hundred and fifty-nine million years ago, when the planet had a tropical rainforest
climate.
Proxima B is followed by Gliese 667CC, another nearby superhabitable planet that orbits a
red dwarf star in the Glie667 triple star system.
Gliese 667CC is 23.62 light-years away and comprises 3.7 percent of the Earth's mass.
Kepler-452b, sometimes known as Earth 2.0, is another possible superhabitable planet.
It circles a G-type star, which is comparable to our sun but 1.5 billion years older and
slightly larger.
Some researchers suggest that an ancient civilization may have existed on Kepler-452b or on the
moon orbiting it.
However, some believe that we are already witnessing a glimpse of Earth's potential
fate through this exoplanet.
This is due to the star it orbits running out of fuel and exploding into a red giant.
However, there is still no technology that can discover the presence of oxygen in the
atmospheres of these exoplanets.
Everyone is hopeful that the James Webb Space Telescope, which will be sent into space on
an Aryan 5 rocket, will answer the unanswered questions.
Many people claimed that the telescope's technology was unlike anything ever developed.
It is the Hubble Space Telescope's successor and will be a formidable new tool in the search
for exoplanets that potentially sustain life.
The James Webb Space Telescope will launch 940 million miles from Earth, well beyond
the orbit of the moon.
It will be the largest observatory ever sent into space, employing cutting-edge optical
science and engineering to glimpse the unknown.
Researchers claim to have devised a new method that will enable the James Webb Space Telescope
to identify a distinct signal produced when oxygen molecules collide.
If this signal was discovered in an exoplanet's atmosphere, it would imply that the planet's
surface contains oxygen and possibly life as we know it.
Despite all of this incredible equipment, if a planet orbiting a red dwarf star had
an atmosphere equivalent to Earth's, the Webb Telescope would need sixteen light-years for
it to detect the oxygen signal.
Aside from that, the Nancy Grace Roman Telescope will also be launched in the late 2020s.
It will delve into the mysteries of dark matter and dark energy, which make up the vast majority
of the universe.
The most fascinating aspect is that it will be able to take direct photos of exoplanets,
which will be impossible from Earth.
The major purpose of its mission, however, is to stare into the interior of the Milky
Way galaxy, where gravitational microlensing could lead to the discovery of thousands more
exoplanets.
With all of this knowledge, it is evident how interesting the vast universe is.
It's very mysterious that so-called superhabitable planets may exist, and that they might not
be like the Earth that we know.
With the capacity of human technology, we're likely to discover life on a distant planet
somewhere in the distant future.
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