For the very first time astronomers in a groundbreaking study now believe that our
search for extraterrestrial life has been severely limited by assuming that habitable
worlds must resemble our earth and we even have a great candidate to study a nearby alien
world extremely different and larger than ours high sea and planets with vast liquid
water oceans and a hydrogen-rich atmosphere and possibly life welcome the Factnomenal
in today's video we explore the chances that these wondrous exoplanets are not only abundant
but have life quite different from what we see around us
as we close in on Webb opening its golden eye to the universe an equally golden opportunity
to search for extraterrestrial life is coming with it and now we know just where to look
Astronomers for decades have used earth as a model for what is needed to sustain life
and that is understandable at first however some now believe this search is far too limited
enter a new class of exoplanets the Hycean these are in between a rocky world and a gas
giant with thick atmospheres covering vast oceans the name hycean which combines hydrogen and ocean
has not been formally adopted by astronomers who decide that kind of thing but it'll do
for now Nikku Madhusudhan of Cambridge’s Institute of Astronomy began suspecting
while studying super earths that potential life-sustaining worlds are being overlooked
theorizing that the heavy atmospheres and sizes of these alien exoplanets may enable liquid water
to abound at higher temperatures than previously theorized Madhusudhan who both led the research
and coined the name says these worlds are a whole new avenue to search for life away from earth
essentially when we've been looking for these various molecular signatures
we have been focusing on planets similar to earth which is a reasonable place to start he explains
but we think high sea and planets offer a better chance of finding several trace bio signatures
when astronomers previously established if an exoplanet is habitable they cut off the
list with any that are above the boiling point because as they quickly note you will
evaporate the entire ocean but the new study shows that with hydrogen-rich atmospheres
these worlds with large amounts of water can exist even at enormously high temperatures
extremes where life can also be found on earth
despite being very unearth-like Madhusudhan's team concluded these exoplanets could host microbial
life of our own extremophiles after all our home world features beings that thrive in acids salt
extreme cold and even radiation some can suspend their metabolism for years when conditions are
too radical or toxic and then revive themselves when their environment becomes livable again
these organisms are already known to develop and survive in extreme conditions and hycean
planets feature both water and hydrogen-rich atmospheres that are potentially life-sustaining
the study placed exoplanets in this category that are up to 2.6 times larger than earth
and with atmospheric temperatures ranging from earth-like up to almost 392 degrees Fahrenheit
hyceans have at least 10 percent of their mass in water with massive and even planet-wide oceans the
study concluded that these conditions are likely to allow for biological organisms
throw out what you think you know about life-sustaining planets
the hyceans are anything but ordinary and are an incredibly diverse class of alien worlds
some are so close to their host star that they are tidally locked as the moon is to earth with
one side blazing hot in perpetual daylight and the other brutally cold and dark others orbit so far
from their star that they receive precious little radiation so far out that the slightest nudge
might bump them into the cosmos as eternal wanderers of the thousands of exoplanets now
discovered many are between the size of earth and Neptune so astronomers refer to them as
super earths and many Neptunes some are rocky and others are ice giants or anywhere in between
and until recently researchers thought they were uninhabitable due to extreme conditions
many orbits small and dim red dwarf stars which are far more common than those like our sun
the search for extraterrestrial life has centered on exoplanets that occupy what astronomers call
the Goldilock Zone meaning not too hot and not too cold for liquid water
and if looking for cosmic duplicates of ourselves that's a great place to start
but what if that focus is instead preventing us from finding life elsewhere in the universe
the Cambridge Institute of Astronomy team decided to expand the horizons of worlds to study
to include those with temperatures up to 248 degrees Fahrenheit and under
pressures of about 1,000 bar think barometric pressure that weather forecasters like to use
not precisely the same but very close earth for comparison has a standard pressure of 1.01325 bar
adopting these new parameters for extraterrestrial life brings an incredible number of exoplanets
into the search for example if earth were moved just beyond the orbit of Mars
the Cambridge team says our greenhouse gases would freeze out and we would be in
for a snowy winter to put it mildly habitable high sea in worlds have no such limitations
they can even be what astronomers call rogue planets not tied to a star at all their hydrogen
atmospheres would theoretically enable life to exist even in the cold and dark cosmos
here's some great news they are much easier to find than worlds like our own
they are mostly larger and their habitable zone is far wider than our own because of that size
normally astronomers search for exoplanets using the tried and true transit method which watches
for signs that a planet passes between its star and the earth observer causing the light to dim
there is a bonus to this method in that researchers can study the light of the star
as it passes through the exoplanet's atmosphere and learn a great deal about the atmosphere's
chemical makeup water vapor is a molecule that gives tell-tale signs to the observer as do
certain biosignatures like oxygen and methane the James Webb space telescope is expected to
make tremendous advances in the study of exoplanet atmospheres nothing researchers have used up until
now comes close to bringing home the precise data from the infrared spectrum that Webb will provide
the transit method however presents challenges when limiting observations to earth-like
exoplanets orbiting sun-like stars the size differential between the two means the planet is
quite difficult to first detect and then study this has reduced the search for signs
of atmospheres on exoplanets to those of similar size as earth but orbiting much smaller dwarf
stars the quest to find hycean and exoplanets is easier for several reasons including their vast
numbers but also their size relative to their host's stars also the hycean exoplanets higher
atmospheric temperatures and larger radii make the biomarkers astronomers look for easier to
find than in earth-sized rocky worlds and for the first time we have found a very viable candidate
in 2019 strong buzz erupted around the first discovery of water vapor in the atmosphere of a
potentially habitable super earth k2-18b located a relatively nearby 124 light years from us
astronomers quickly countered media reports breathlessly announcing a prime candidate
for life elsewhere they clarified that k2-18b is more of a mini Neptune than a super earth
meaning that even though it does have confirmed water vapor in its atmosphere it likely has a deep
atmosphere of hydrogen and or helium and may also lack a solid surface so not very earth-like and
the old life as we know it parameters require a rocky surface with oceans of liquid water
but that was then now astronomers believe k2-18b not only has water vapor but also liquid water on
its surface using the Kepler Space Telescope the Hubble Space Telescope and the now decommissioned
Spitzer Space Telescope astronomers found clues of a rocky core on k2-18b in a study published
in the astrophysical journal letters the research team at the Cambridge institute of astronomy used
atmospheric data to determine that while k2-18b may be closer to the size of a mini Neptune
it very likely is a rocky world or even an ocean world both of which point to habitability for life
the hydrogen envelope of k2-1ab became their focal point a study co-author Matthew Nixon details
we wanted to know the thickness of the hydrogen envelope how deep the hydrogen goes
while this is a question with multiple solutions we've shown
that you don't need much hydrogen to explain all the observations together
meaning our focus has been far too narrow in searching for life elsewhere
it may not be long before Webb shows us just how crowded our galaxy really is is it exciting to
contemplate that nearby countless neighbors of ours may harbor microbial life what do you think
about these potentially habitable worlds will Webb be able to pinpoint a super earth and if so
will we ever find out tell us in the comments and as always thank you for watching Factnomenal