the mention of a rogue planet may
conjure up images of the death star but
we should be happy that what astronomers
have found is nothing of the sort
up to 170 of these vagrants are in our
cosmic backyard and surprised
researchers say there may be several
billion of them floating around our
milky way completely free of host stars
what does this mean
for one what was recently thought to be
a rather rare find now seems like
anything but
so how did astronomers locate this
treasure trove of celestial oddities in
our neighborhood and what can we hope to
learn from them
welcome the fact nominal in today's
video we look at what we know about
these planets and what we don't which is
astronomical
how do we learn more about these
outcasts and what can the study of rogue
planets tell us about our own origins
most of us have some general vision of
the order of the universe in our
imaginations at last in that satellites
orbit planets and planets travel around
stars it fits into a logical pattern and
is comfortable
and then there are rogue planets
rogue planets are free floating worlds
that either became detached from their
original host star or formed far away
from existing stars
they wander aimlessly like a cosmic
flying dutchman charting its own course
through space
they are cold and dark and it is forever
night on these worlds the sky must be a
brilliant sight without an atmosphere or
nearby star to cast what we call light
pollution here on earth
astronomers first detected one of these
rogue planets in 1998 in the chameleon
constellation some 554 light years from
earth
named ots 44 this object is estimated to
have 11.5 times the mass of jupiter and
a radius as large as 23 to 57 percent
that of the sun
ots-44 is one of the lowest mass objects
in the known universe and astronomers
believe it is a disc composed of dust
rocks and ice that may someday form a
solar system of its own
this relative newbie in the pantheon of
celestial objects is possibly a brown
dwarf an object trapped in astronomical
purgatory between being an extremely
large gaseous planet and the smallest of
small stars
these misfits are often alone in space
with nothing to orbit though it is
speculated that some miniature solar
systems exist with planets orbiting
their own brown dwarf
before this recent groundbreaking
discovery of our swarm of wandering
neighbors astronomers had found less
than two dozen of these oddities in 20
years of searching
but now in this exciting time of
seemingly exponential expansion of our
cosmic knowledge we once again get to
throw out the old books and fill new
ones with discoveries and the
possibilities they present
[Music]
astronomers cannot look at individual
objects in space for the time it takes
to notice a slight variation in a star's
brilliance and they don't have to thanks
to ogle the optical gravitational
lensing experiment project that began
almost 30 years ago
a team from the university of warsaw in
poland monitors millions of stars near
the center of our milky way
the process is called gravitational
microlensing and requires the light
source the lensing object such as a
rogue planet and the observer to be
perfectly aligned
using microlensing to search for rogue
planets since it does not depend on the
brightness of the lensing object led to
the exciting discovery of an earth-sized
planet roaming freely through the milky
way
here's how this needle was found
in june 2016 ogle detected a faint star
in sagittarius that brightened a bit for
about five hours before dimming back to
normal
astronomers collected enough data to
determine that the object lensing the
starlight is in fact a rogue world
between the size of earth and mars with
further study favoring a size closer to
mars
as exciting as this discovery was it
only set the table for what astronomers
were to discover next
so how exactly did we find this trove of
hard to detect neighbors anyway
and can we even call them planets the
international astronomical union which
decides these things defines a planet as
among other things an object that orbits
a star
which by definition these do not
and finding a rogue planet is different
from looking for exoplanets of which
there are approximately 5000 confirmed
as of december 2021.
this band of unaligned worlds was
discovered using over 20 years of data
compiled from the european southern
observatory's very large telescope the
visible and infrared telescope for
astronomy the vlt survey telescope and
other facilities
the team based in france and austria
took an almost unfathomable amount of
data and merged it into a new picture of
nearby space
some of this data also came from the
european space agency's gaia satellite
in a collaboration of ground and
space-based observatories
according to herve boy an astronomer and
project leader for the team at the
laboratory astrophysique de bordeaux
france
we use tens of thousands of wide-field
images from eso facilities corresponding
to hundreds of hours of observations and
literally tens of terabytes of data
astronomers searched for needles in the
cosmic haystack pouring through
mountains of observation and data to
chart the tiniest motions colors and
brilliance of targets in a large area of
space
what they found was startling
in the upper scorpius and ophiuchus
constellations there are up to 170
signatures of free-floating worlds
will they all turn out to be exiles
ejected from their solar system or
remnants of star materials that never
reach star status
not likely but best estimates say at
least 70 of the suspects are in fact
free floating worlds at least the size
of jupiter
why the uncertainty
current observations do not give
astronomers exact masses of the bodies
and it is possible that many of them are
failed stars or brown dwarfs
some are detectable by their brief
distortion of background starlight much
in the same way as exoplanets however
unlike exoplanets these distortions
caused by crossing the path of a star's
brilliance do not repeat themselves
working in astronomers favor is that
many of these rogues are thought to be
much newer planets due to being found in
areas of new star formation
their relatively young age means they
still have residual heat and are
detectable in ways that exoplanets are
not
so these are neighbors we've just
discovered
what can they tell us and more
importantly could they have
life-supporting conditions
these rogue planets do not orbit stars
but it is very conceivable they have
moons that orbit them researchers from
the university of concepcion in chile
created a mathematical model of these
free worlds and their possible exomoons
and determined conditions may exist on
both for liquid water and atmosphere
basing their model on a jupiter-sized
rogue planet with an earth-sized moon
scientists in chile and germany focused
on the satellite while factoring in the
thermal structure and composition of the
two bodies
they found that while the level of water
would be much less than on earth the
conditions may provide enough for life
to develop and flourish
also by studying these vagabond planets
in relatively early stages of
development it may be possible to grasp
more clues about the formation of
planets such as our own billions of
years ago
so how are we going to find out more
about these hard to detect nomads
i'm glad you asked
we live in exciting times for new
discoveries about our universe the
successful launch of the james webb
space telescope foretells a treasure
trove of new data that with any luck
will begin pouring in during summer 2022
and by the mid-2020s presumably no later
than 2027
nasa's nancy grace roman space telescope
or roman space telescope is planned to
launch with a very specific mission
component concerning rogue planets
remember gravitational lensing the
method of finding untethered worlds that
emit little or no light by observing
their movement between the observer and
a distant object
roman will conduct a massive
microlensing survey which is the
narrower focus on gravitational effects
of smaller objects on far away light
sources
the trick is and always has been to be
watching at the right time since the
microlensing event lasts from only a few
hours to a couple of days nasa believes
roman will detect rogue worlds as small
as mars and by doing so narrow down the
chaotic process of planetary formation
different models proposed by scientists
will be tested by roman which
researchers say will be capable of
detecting at least 10 times the number
of these breakaway worlds that are
currently possible
the roman space telescope will have a
field of view a hundred times greater
than hubble's meaning much more data in
much less time
it should also provide high contrast
imaging of nearer rogue planets and give
astronomers a more accurate estimate of
their numbers
some believe we will find there are more
rogue planets in our milky way than
there are stars want more excitement
astronomers also await the completion of
the european southern observatory's
extremely large telescope which is under
construction in chile
featuring a 130-foot segmented primary
mirror this project will give humanity
another eye into deep space one that can
expand our knowledge of these mysterious
planets that roam our cosmic
neighborhood
so what do you think about these newly
discovered rogue planets and what can we
learn about and from them
are you excited about the new ways in
which we are about to be able to peer
into the universe and search for these
and other mysterious objects
tell us in the comments and as always
thank you for watching fact nominal