the trappist-1 planetary system is
unique among star systems known so far
having seven earth-sized exoplanets
could any of them have life according to
our new toy in space the james webb
telescope they are ideal candidates for
it but how can webb find life there
welcome to fact nominal and today let's
discuss how the james webb telescope
will search for life on seven
earth-sized planets
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last year when the james webb space
telescope was launched in december it
took over the mantle as the world's
premier space telescope from the
legendary hubble this new and flashy
telescope is aiming to provide key
insights into our own solar system as
well as distant worlds around other
stars one of its primary objectives is
trappist-1 an exoplanet system of seven
earth-sized rocky planets around an
ultra-cool dwarf star now when we say
ultra-cool we do not mean you can go
skiing on this star's surface an
ultra-cool dwarf star is still a star
with an effective temperature of less
than 2700 kelvin and that's
approximately 4
400 degrees fahrenheit yeah it's still
blazing hot by our standards but the
exoplanets this dwarf star offers are
different prospects as three of them are
within the habitable zone of this
system's star that's the goldilocks zone
within which planetary surface
temperatures are capable of sustaining
liquid water trappist-1 is located only
39 light years from earth cosmically
speaking that's like being right around
the corner all of its seven planets are
intriguing and have been the subject of
many studies since their discovery but
just because three of these planets are
in the habitable zone doesn't guarantee
that these planets are capable of
sustaining life the habitable zone is
just one of many conditions that need to
be met to make a planet subject to our
next real estate boom these conditions
or indicators are known as biosignatures
the most important of these
biosignatures is the composition of
their atmosphere an exoplanet needs to
have significant quantities of methane
oxygen water vapor carbon dioxide and
many other important gases in somewhat
similar proportions to those observed on
earth until now we didn't have any way
to determine these details of any
exoplanet but according to a study the
james webb space telescope might just be
the game changer we were desperately
searching for astronomers believe that
the webb telescope will be powerful
enough to detect signs of life at the
distance of these earth-sized planets by
analyzing their atmosphere for
biosignatures in fact the webb telescope
is trying to accomplish this task right
now as you're watching this video but
how can webb telescope be successful in
achieving something no other telescope
could accomplish in the past
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the answer lies in the stars literally
these closest potentially habitable
planets are still tens of light years
away from us even from where jwst is
orbiting at l2 but this new telescope
has got some new tricks up its sleeves
you see when a planet is between our
observation point and the exoplanet
system's host star we can use sensitive
telescopes to detect how much of the
star's light is blocked by the planet in
its atmosphere before it reaches us the
proportion by which the light dips is
called the transit depth and will differ
in wavelength since gaseous elements
each selectively absorb certain
wavelengths of light more than others
using a specialized telescope called a
spectrometer telescope we can analyze
light by wavelength to see which signals
are lacking compared to when the star is
not being transited therefore we can
tell which gases are most likely
prevalent in the atmosphere this
technique is called transit spectroscopy
to be fair this is not a new technique
exclusive to the webb telescope transit
spectroscopy was first used with hubble
in 2002 and has been in common use for
well over a decade so then why couldn't
hubble accomplish the same objective why
haven't we already found life-sustaining
planets among the stars what's so
special about jwst that only it can
analyze the atmospheres of obvious
candidates for habitability like
trappist-1 while certain steps of
transit spectroscopy were available with
existing technology the most important
measurement in identifying biosignatures
the shift in transit depth was out of
our reach with other telescopes with
telescopes that predate webb we were
able to determine the size of the star
planet and separate the star angularly
and spectrally from the light emitted
from the multitude of other extrasolar
objects but because planets are
considerably smaller than their host
stars the dip in brightness or the
transit depth observed when a planet
transits the surface of a star dozens of
light years away is also quite small and
that's where the previous telescopes
were lacking they were unable to measure
the minuscule shifts in a transit
depth's wavelength at this distance
telescopes like hubble were able to
detect the atmospheric composition of
exoplanets in categories like hot
jupiters and hot neptunes or in other
words planets much much larger than our
earth and nowhere close to being
habitable the combination of its
location
and advanced instruments grants jwst an
infrared sensitivity greater than any
previous telescope which will allow it
to characterize the atmospheres of
earth-sized exoplanet systems like
trappist-1 for the first time
researchers suggest that the webb
telescope should be able to detect and
analyze any atmosphere fairly quickly
pretty much in a year or so since the
planets are all close to their star that
means their transit times are relatively
short for those who don't know transit
time is the time it takes for a planet
to cross in front of its star from our
viewpoint webb should be able to confirm
the atmosphere or lack of it within 10
transits or less
transit spectroscopy poses an additional
challenge it's that the light we receive
may be partially blocked by objects in
space between our telescope and the star
a prime example of such obstacles is the
huge clouds of gases like hydrogen
carrying tiny solid particles known as
interstellar dust this dust fills much
of the space between stars distorting
most wavelengths of light as they travel
from around the universe through space
towards our telescopes infrared light is
a key exception to this rule as with its
long wavelengths it can penetrate
through most dust unfiltered but
infrared light comes with its own
catch-22 every object including the
telescope machinery emits infrared
radiation if its temperature is above
freezing which makes analyzing it not
that easy this is another reason space
telescopes are better at exploring space
it's possible to maintain such a
temperature in the vacuum of space
rather efficiently jwst has also been
equipped with specialized equipment for
detecting and analyzing radiation in the
near and mid infrared range such as the
near infrared spectrometer and the mid
infrared instrument the webb telescope
is the largest astrophysical space
observatory and the most technically
complex science mission nasa has ever
built and it's just the beginning future
space telescopes are already being
designed with these capabilities firmly
in mind
the james webb space telescope's
capability of detecting the atmospheres
of small rocky planets is exciting since
other telescopes haven't been able to do
this yet there's a big question in the
field right now whether these planets
even have atmospheres especially the
innermost planets if and when we've
confirmed that there are atmospheres
then what can we learn about each
planet's atmosphere and the molecules
that make it up we're expecting a result
within a year but there's a possibility
that might not be the case as it might
depend if the planet's atmosphere has
clouds if a planet has a thick cloudy
atmosphere like venus it could take up
to 30 transits to confirm it so the webb
telescope can still do it it would just
take longer but that is still an
achievable goal one of the other
possibilities is that webb will find
evidence of water that the planets lost
when the system was much younger and the
star was much hotter in such cases an
atmosphere could contain abiotic oxygen
which means not created by life which
might be a false positive signal of
active biology scientists would need to
determine if the oxygen is biotic or
abiotic the james webb space telescope
will be absolutely invaluable for
studying rocky planets like earth and
many more of these rocky worlds are
being discovered all the time in the
vast space of our milky way galaxy it's
estimated that there are billions of
such worlds in our galaxy alone and the
web might provide the first compelling
evidence for life on one or more of them
there's one thing for sure there can't
be a better star system for webb's
telescope to start its search for
extraterrestrial life than trappist-1.
tell us in the comments what are your
expectations from this star system and
as always thank you for watching fact
nominal
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you