Panspermia The Origin of Life on Earth

[Applause]

the origin of life on earth is one of

our greatest mysteries

could life on earth have originated

elsewhere from our universe

could the comets that brought water to

earth have also brought the bacteria

that evolved into the rich variety of

life we see around us

today panspermia is a radical theory

that was first proposed by the ancient

greeks

it suggests that life can spread from

planet to planet in our universe and

could mean that our ancestry traces back

to an as yet undiscovered world

the theory suggests that tiny microbes

or bacteria can become embedded in rocky

debris which is then ejected into space

following collisions between planets

asteroids and comets

these asteroids and comets can then

travel to other habitable worlds crash

land on the surface and kickstart the

evolution of life once more

panspermia is certainly not a proven

process and not widely accepted by the

scientific community

but with thousands of distant planets

now detected in our galaxy the hunt is

on to detect a signal of life from one

of these distant worlds

i’d like to take you on a short journey

today exploring how life may be much

more widespread than previously thought

and how life may regenerate to populate

the universe

for many years the ingredients for life

have been discovered inside rocks

orbiting the solar system

and inside some rocks that have crash

landed on earth

these ingredients are formed of the same

elements as life on earth elements like

carbon nitrogen oxygen hydrogen

in 1969

meteorite landed in australia called the

merchants and meteorite

several studies since then have found

the evidence for amino acids the

building blocks for proteins and dna

buried within fragments of this

meteorite

another study was conducted last year

that found more evidence of complex

organic matter within fragments of this

meteorite

in 2014 the european space agency’s

filet lander probe surveyed a distant

comet in our solar system called comet

67p

as it was orbiting the comet it detected

the signs of organic matter in the

atmosphere around the comet

just before it touched down on the

surface of the comet

it sent its signals back to earth

reporting that the majority of the comet

was formed of water ice with a thin

layer of dust around the outside

in 1990 a meteorite fell in algeria

just last year a team in america

reported the first ever detection of a

long complex protein inside a fragment

of this meteorite

this is the first ever complex protein

detected inside a meteorite ever

the findings of these chemicals inside

rocks in our solar system suggests that

that they could be responsible for for

transferring matter across our solar

system

but could these rocks also transmit life

around our solar system or even further

afield

how far would life have to travel

between planets and what is the chance

of it surviving such a brutal trip

well space is a pretty inhospitable

place you won’t find many five-star

reviews on tripadvisor for outer space

the launch is pretty harsh you’ve got to

survive the intense vacuum and radiation

of your journey and then the landing at

the other end is almost as harsh

what kind of life forms could survive

such a journey

could life-forms have began life

elsewhere and traveled towards earth

for panspermia to have any scientific

merit

we need proof that life can survive

these types of extreme journeys

and we know of several life forms that

can indeed survive such a journey

one of the cutest animals that can

survive in outer space

is a tiny micro animal called a

tardigrade also known as a water bear

these are tiny microscopic eight-legged

animals discovered about 150 years ago

these animals can survive extreme

conditions here on earth the hottest

temperatures the coldest temperatures

the highest pressures at the bottom of

the ocean and they can even survive in

the vacuum of space

despite being known as water bears they

can actually survive for decades without

any water at all in a state of suspended

animation

many years ago hundreds of tardigrades

or water bears were flown into orbit

around earth for 12 days mounted to the

outside of a rocket a pretty

uncomfortable trip

this would have killed any other animal

but not the humble tardigrade most of

them survived completely unharmed and

unfazed

just this year more tardigrades water

bears were launched to the international

space station to investigate how their

genomes may help them survive the harsh

conditions of outer space

whilst the water bears are perhaps the

cutest animals that could survive in

outer space it’s much more likely that

tiny microscopic bacteria are the

passengers responsible for spreading

life in our universe

the most interesting type of bacteria

that could survive this trip is called

danococcus radiodurans

this is an extremophile bacteria you can

put it in any harsh conditions you like

and most of them will survive in

addition to surviving in extreme

temperatures and pressures they have a

special skill

they can withstand intense bursts of

radiation like the kind they experience

in outer space

and they can automatically repair their

own dna a feature not yet found in any

other life forms

many of these bacteria were launched

onto the international space station

this year as part of a japanese space

agency program called tan popo tan popo

is the japanese word for dandelion

and the word dandelion was chosen for

the experiment because it was thought

that the seeds of the dandelion drifting

through space resembled the seeds of

life spreading throughout our galaxy

but what happened to these these

bacteria on the space station

they were exposed to the harshness of

space for one two and three years

the vast majority of them survived by

using a thin layer of dead bacteria

almost like an umbrella to protect the

colony belief from the harmful radiation

so we know that these bacteria can

survive for at least three years

but scientists think that in fact they

can survive long enough to travel

between any two locations in the solar

system

certainly from earth to mars to venus to

the moons of saturn or the moons of

jupiter

but instead of bacteria traveling from

earth to another location

what about bacteria that’s traveled from

another location to earth

well we may all have martian ancestry

and it may not be just the men who are

from mars

hundreds of rocks on earth have been

traced back to the red planet via their

chemical composition

just this year nasa’s perseverance rover

touched down in the jezero crater on

mars

the rover is looking for signs of life

in addition to surveying the martian

climate and the martian geology

we think that mars was once a very

habitable world

full of liquid water stable warm

temperature and a thick atmosphere

the jezero crater itself where the rover

is currently was once a large lake with

its own river system

the rover is looking for signs either

that life once existed on mars billions

of years ago or is still there buried

beneath the surface

if life did exist on mars perhaps it all

died out after the evaporation of the

martian atmosphere

but perhaps it survived by going

underground later being transported to

earth via panspermia

such a trip from mars to earth would

take a couple of years not too long on

the cosmic scale

again the bacteria would have to

withstand the intense pressures of being

launched into space following a

collision the intense radiation and the

vacuum of space and then the harsh

landing at the other end

and we know that bacteria can in theory

survive this trip

but what about a longer journey

our milky way galaxy could be exchanging

life across vast distances

this depends on a number of factors

including the distance between the stars

and the planets how fast the comets or

the asteroids are traveling

how much material gets ejected into

space after a collision and of course

how long the organisms can survive for

the most likely place to find this kind

of interstellar panspermia is in

clusters of stars really dense groups of

stars and we find several of these

within our own milky way galaxy

if we’re looking for panspermia anywhere

these are the locations that we might

find it

we have evidence for these longer

distance transits within the last few

years

in 2017 a small rocky object named

umuamua which i believe is hawaiian for

traveler was found entering our solar

system

it passed our sun

past the planet and return to the cold

dark space

between the stars

in 2019 another small rocky object was

detected entering our solar system a

small comet a few kilometers wide

nicknamed borisov

these two objects could not have been

created within our own solar system

they’re moving far too fast around two

hundred thousand kilometers per hour

they must have come from a different

star system

comet borisov came probably from a

relatively close red dwarf star system

named kruger 60.

it began life as an icy remnant orbiting

around its home star

came slightly too close to another

planet or a comet

was ejected out of its orbit and

traveled and accelerated towards our own

solar system

this journey could have taken millions

of years

but we think some bacteria could survive

this trip by going into a state of

hibernation and coming back into life at

the opposite end

we need more evidence if we’re going to

believe any such crazy theory

there are currently two probes

investigating whether the theory of

panspermia could be true

the nasa probe osiris-rex and the

japanese craft hayabusa ii are currently

orbiting the solar system looking for

more evidence of organic matter in

distant asteroids and comets and they

may return more evidence that our solar

system really is littered with the

ingredients for life itself

panspermia is quite a novel theory and

again it’s not widely accepted in the

scientific community

but if it is responsible for spreading

life around our cosmos there may be a

huge number of life forms out there

waiting to be discovered

depending on who you are and what you

believe some people think that life is

rare and can only form here on earth

some people believe that life can form

on any planet given the right conditions

entirely independently

but some people believe

that life can all form from the same

primordial seed scattered across the

galaxy via panspermia

i wonder how that might change the

opinion here on earth if we discovered

distant life on another planet

well with thousands of habitable planets

now detected many of which full of

liquid water the hunters on to be the

first to detect a signal of life from

one of these distant worlds

i wonder how that might change things on

earth

it’s amazing to think

that the story of life on earth many

billions of years in the making

could have begun with our distant

ancestors on a far away planet a long

long way away thank you

[Applause]