the universe is one giant box of mystery
and we've been discovering exoplanets
all the time since we sent telescopes
powerful enough to detect them to space
one of the most intriguing exoplanets is
the proxima and as such scientists
including the ones employed by nasa have
spent lots of time studying it whatever
they learned about this fascinating
planet is life present on it join us to
explore nessa's study of proxima b that
reveals its secrets
less than six years ago news broke of
the discovery of another planet due to
its location big outside the solar
system this planet known as proxima
centauri b or simply proxima b is an
exoplanet in the past several years
astronomers have found a large and
growing number of earth-sized exoplanets
orbiting distant stars some are in the
habitable zones of their stars where
temperatures might allow liquid water to
exist on their surfaces however one
reason scientists were very excited by
proxima centauri b is that the sun it
orbits is the closest star to our sun
only 4.2 light years away proxima b was
detected by guillermo glada equidae and
a team of astronomers from the pale red
dot campaign its existence was further
confirmed using the high accuracy radial
velocity planet searcher or harps
spectrograph on the esl 3.6 meter
telescope using a method known as
doppler spectroscopy or the radial
velocity method this method consists of
observing the spectra of stars for signs
of a wobble where the star is moving
closer and farther away from earth this
is caused by the gravitational influence
of planets that orbit the star the
extent of which is used to infer the
mass of the planets in the case of
proxima b astronomers obtained a minimum
mass estimate of 1.24 and a maximum
estimate of 2.06 earth masses proxima
b's presence was confirmed again in 2020
using the eso's very large telescope vlt
and it's a shell spectrograph for rocky
exoplanet and stable spectroscopic
observations espresso most exoplanets
discovered to date were found using the
transit method but for a star like
proxima centauri a low-mass and less
bright m-type or red dwarf star that
method was not workable proxima centauri
b is very similar in size to earth with
a mass of 1.17 earth masses it orbits
its star in only 11.2 days in contrast
to our earth's year-long orbit around
our sun that means proxima centauri b is
a lot closer to its star than earth is
to the sun but because the star is a red
dwarf which is much smaller and cooler
than our sun its orbit is indeed within
the habitable zone of proxima centauri
interestingly proxima centauri b
receives about the same amount of solar
energy from its star that earth does
from our sun this implies the proxima
centauri b could have water on its
surface it could be habitable but of
course we don't yet know all the details
about habitability for exo worlds but
then many factors affect a planet's
habitability such as temperature the
composition of the planet and atmosphere
water or lack of it and radiation from
its sun red dwarfs like proxima centauri
are known to emit flares and these
flares make habitability for red dwarf
exoplanets even more complex and
interesting as you shall see in this
video when astronomers confirmed its
existence back in 2016 scientists
attempted to determine if this exoplanet
could harbor life sure it sat in its
star's habitable zone but some studies
soon cast the prospect of possible alien
life into doubt as such the subject of
whether life could exist on proxima b
has always divided the scientific
community however all of these studies
indicate that this question cannot be
answered until astronomers characterize
proxima b's atmosphere ideally by
observing it as it passes in front of or
transited its host star but in a new
nasa supported study a team led by
astrophysicists at the university of
chicago determined that this is an
unlikely possibility the study that
describes their findings was led by
emily a gilbert a graduate student with
the university of chicago's department
of astronomy and astrophysics she was
joined by researchers from the older
planetarium the center for space science
and technology the university of
maryland and the exoplanets and stellar
astrophysics laboratory at the nasa
goddard space flight center however even
if life exists on proxima b there is
something that will make it very
difficult it is known as space weather
as an earth dweller when you hear about
the weather you naturally think in terms
of the sun clouds rain wind and so on if
you are familiar with conditions on
other planets or moons that have
atmospheres you might think of that kind
of weather too however space weather
isn't related to any of that it's the
sort of weather that originates in stars
including our own sun and that permeates
the space near a star space weather
consists of ionizing radiation released
during flares on the sun or other stars
the radiation can be deadly for any life
forms on distant planets that's
especially true astronomers say for red
dwarf stars which have more frequent
flares than our sun red dwarf stars can
be very volatile and proxima centauri
happens to be a red dwarf star
astronomers at the university of sydney
in australia used radio waves to detect
and probe the space weather in proxima's
vicinity this our sun's nearest neighbor
is known to have at least two planets
orbiting it one proxima centauri b which
as we have said is almost the same as
earth and the other proxima centauri c
is about seven times more massive
proxima centauri b also orbits within
its star's habitable zone where
temperatures might allow liquid water to
exist on the planet's surface if you're
nodding you're ahead of these as a sign
of life you would be disappointed the
findings of flares on stars like proxima
suggest a grim prospect for life on the
planets in this system proxima centauri
b is subject to intense outbursts of
ionizing radiation from its star because
proxima centauri b is close to the star
proxima centauri it is important to know
that an exoplanet existing within the
habitable zone does not necessarily mean
it can be actually inhabited this is the
case with proxima b proxima centauri is
a cool small red dwarf star meaning the
habitable zone is very close to the star
in fact much closer in than mercury is
to our sun research shows that this
makes the planets very vulnerable to
dangerous ionizing radiation that could
effectively sterilize the planets mind
you our sun regularly emits hot clouds
of ionized particles during what is
called coronal mass ejections but given
the sun is much hotter than proxima
centauri and other red dwarf stars our
habitable zone is far from the sun's
surface meaning the earth is a
relatively long way from these events so
this radiation doesn't affect us as
powerfully further the earth has a very
strong planetary magnetic field that
shields us from these intense blasts of
solar plasma with the result of studying
the space weather around proxima
centauri scientists may assume that all
red dwarf stars are not the friendliest
places for life however there could be
other factors at play here for any given
planet such as just how far it is from
the star how strong its magnetic field
is if it has one and so forth some red
dwarves are probably also more active
than others relatively speaking so
making a blanket statement regarding
situations surrounding red dwarfs is
difficult in further research of the
possibility of life on proxima b
scientists have also tried to determine
what the earth as a planet would look
like if it was orbiting proxima centauri
they relied on modeling to work out what
the situation would look like again we
return to the concept of habitable zones
just because proxima b's orbit is in the
habitable zone which is the distance
from its host star where water could
pool on a planet's surface doesn't mean
it's livable it doesn't take into
account for example whether water
actually exists on the planet or whether
an atmosphere could survive in that
orbit atmospheres are also essential for
life as we know it because it allows for
climate regulation the maintenance of
water friendly surface pressure
shielding from hazardous space weather
and the housing of life's chemical
building blocks the scientists computer
model used earth's atmosphere magnetic
field and gravity as proxies for proxima
b's they also calculated how much
radiation proxima centauri produces on
average based on nasa's chandra x-ray
observatory observations with these data
their model simulates how the host stars
intense radiation and frequent flaring
affect the exoplanet's atmosphere an
active red dwarf star like proxima
centauri strips away the atmosphere when
high energy extreme ultraviolet
radiation ionizes atmospheric gases
knocking off electrons and producing a
swathe of electrically charged particles
in this process the newly formed
electrons gain enough energy that they
can readily escape the planet's gravity
and race out of the atmosphere opposite
charges attract so as more negatively
charged electrons leave the atmosphere
they create a powerful charge separation
that pulls positively charged ions along
with them out into space in proxima
centauri's habitable zone proxima b
encounters bouts of extreme ultraviolet
radiation hundreds of times greater than
earth does from the sun that radiation
generates enough energy to strip away
not just the lightest molecules hydrogen
but also over time heavier elements such
as oxygen and nitrogen the model shows
proxima centauri's powerful radiation
drains the earth-like atmosphere as much
as ten thousand times faster than what
happens at earth to understand how the
process can vary the scientists looked
at two other factors that exacerbate
atmospheric loss first they considered
the temperature of the neutral
atmosphere called the thermosphere they
found that as the thermosphere heats
with more stellar radiation
atmospheric escape increases
let's hear what you think of life
existing on proxima b in the comments
section below