Are We Alone in The Galaxy? Brian Cox on Alien Life

[Music] it is one of the most intriguing  questions in all of science are we alone   with the launch of the james webb space telescope  we might be closer than ever to answer this   question a recent study shared on a pre-print  server showed that the telescope could discover   signs of atmospheres capable of supporting life on  alien worlds beyond our solar system in only about   20 hours a means of studying distant worlds is via  the wobble method as a planet orbits its host star   it tugs on that star ever so slightly with its  gravity this causes a tiny wobble a subtle rocking   back and forth that can be measured by using  precision instruments however the transit method   has proven to be the most robust so far it's  used for detecting and studying the properties   of a planet via the dip in the brightness of its  host star as the planet passes between it and us but the james webb telescope will possibly  transform exoplanet studies in the search   for biosignatures in the atmospheres of alien  worlds via transmission spectroscopy it is the   most basic technique for analyzing samples in the  infrared light from the host star passes through   the exoplanet to be registered by the james webb  telescopes detector for the first time in human   history we are on the verge of finding whether  life exists elsewhere in the galaxy i think there   must be even in the solar system i would  not be surprised if we find microbes on mars   or on some of the moons of jupiter or saturn  where there's liquid water and the reason is   if you think about the reason i think that it's  a guess is because if you look at the history of   life on earth then so earth formed and it was  just a there was no life it was a ball of rock   and almost as soon as it cooled down we see  evidence of life so certainly 3.8 billion   years ago possibly even further back than that  we see evidence of life on earth so somewhere   along the line geochemistry active geochemistry  became biochemistry on earth and we have some idea   that if you get gradients of temperature and  acid and alkaline and the conditions that are   naturally present on the surface of oceans then  complex carbon chemistry spontaneously happens   so we know that life almost certainly we know that  life began on earth i mean the other option is it   came from space or something like that but  it probably didn't um so that means that at   least here that happened and that we know that the  conditions that led to the origin of life on earth   were present on mars 3.8 4 billion years ago and  we know that they're present on europa today so   i don't see that there's anything special life  is just chemistry and the idea that geochemistry   becomes biochemistry is not fanciful because  it happened here so i think that given the same   conditions it would be surprising to me if the  same thing didn't happen in that life begins so to   test that is one of the great frontiers of science  now it's one of the great challenges which is why   another reason we're interested in mars  because we know those conditions were there   we know there were what's called hydrothermal  vent systems on the floors of oceans on mars   3.8 or 4 billion years ago so it would be  good to know if what i've said is right   and the way we find out is to  find life or evidence of past life   there are about 300 million planets in our galaxy  alone that might support life as we know it   by the sheer number of these planets it can be  argued that we are most likely not unique in the   galaxy however even if life exists elsewhere it  can be expected that the vast majority of it will   be simple organisms such as microbes of course  the most exciting life forms will be intelligent   multicellular organisms such as us but among the  many attributes of life on earth intelligence is   the rarest all species of animals land plants  and most fungi on earth are multicellular as   are most algae whereas few organisms are uni amply  multicellular like slime molds and social amoebi   multicellular organisms arise in various ways for  example by cell division or by aggregation of many   single cells but going from single cell life to  multicellular life forms is one thing attaining   intelligence is a different thing entirely  and if the evolution of life on earth reflects   that of life in the galaxy it can be argued  intelligent civilizations are extremely rare what we do know about earth is that although  life began let's say 3.8 billion years ago   it wasn't until around 600 million years ago or so  that or maybe at most 700 that you see any complex   multicellular organisms at all so for something  like 3 billion years it was single-celled   alone and that's one of the reasons why i would  guess if i had to guess i would say that microbes   would be common because life began very quickly on  earth and i would be surprised to find it on mars   but complex life multi-cellular life insects   plants intelligence i would guess would be very  rare because it took so long on earth to get there   a new analysis concludes that roughly  half of the galaxy's sun-like stars   post rocky worlds in habitable zones where  liquid water could pool or flow over the planet's   surfaces perhaps some of the rocky worlds are  the home planets of distant alien civilizations   the drake equation uses seven factors to estimate  the number of detectable civilizations in our   galaxy it considers variables such as the number  of sun-like stars with planetary systems and the   number of habitable planets in each of those  systems from there it considers how often life   evolves on worlds with the right conditions and  how often those life forms ultimately develop   detectable technologies it took more than half  a century for scientists to start pinning down   how many planets could feasibly host life but  now there is an even harder question to answer   how often can extraterrestrials develop  technologies that we can detect and the length   of time such civilizations are detectable even  if there were countless intelligent civilizations   through the billions of years of the galaxy's  evolution we have no way of knowing about their   existence if we don't have the right timing if  civilizations are common or even slightly common   then there should be civilizations ahead  of us because there's been so much time   you imagine the time scales we've been around as  a civilization let's let's give say 40 000 years   i don't know how long our civilization's been  around let's say that the galaxy is pretty much   as old as the universe it's 13 billion years  worth of time so the idea that there are no   civilizations arose you know 100 million years  ago 200 million years ago one billion years ago   and imagine what they'd be like if they'd survived  i mean we've been around we've had science for   let's say since newton or copernicus 500 years at  most we've had and look what we've done we've gone   beyond the solar system with voyager we've walked  on the moon um we're about to go to mars i would   think so we're about to begin colonizing our own  solar system um we've done that in 500 years so   imagine a million years it's one of the arguments  often used to say there aren't any civilizations   out there in the galaxy it's called the fermi  paradox because if you imagine a civilization   that's a million years ahead of us they should  have written their presence across the sky by now   they should see him if we survive a million years  into the future actually even a few thousand   years into the future we will be exploring the  galaxy we will have spacecraft that are going   through with the stars we will be doing it so our  signature will become visible i'm sure if we last   english science fiction writer  arthur c clarke once said   two possibilities exist either we are alone in the  universe or we are not both are equally terrifying   imagine intelligent civilizations are  prevalent throughout the lifespan of the galaxy   there had to be a first civilization asking are we  alone only in their case the answer would be yes   indeed terrifying when you think about it but  maybe that civilization is us there are many   people who believe we've already been visited  by extraterrestrials especially with recent   ufo footage that has been circling  on the internet over the past years   but scientifically speaking the data shown so far  does not qualify as extraordinary evidence for   the extraordinary claim that we are definitely  not alone the fermi paradox remains a problem   regardless of how many people believe  it's extreme hubris for us to expect to   find evidence of intelligent alien life when we  cannot possibly imagine the most efficient ways   an intelligent civilization millions of  years ahead of us could traverse the galaxy there is an argument as well that technology so  advanced would be difficult for us to detect i   mean we tend to think of starship that you can  see the signature of but actually maybe the   the civilization just becomes a nano civilization  but because that's more efficient it's a better   way to do things so it's possible i suppose  that there are space probes all over the   place that are so small and it's so efficient  and use so little energy that we just don't   see them i suppose that is possible [Music]  thanks for watching did you like this video   then show your support by subscribing and  ringing the bell to never miss videos like this [Music]

Channel: Science Time

Views: 765,075

Keywords: Are We Alone in The Galaxy? Brian Cox on Alien Life, brian cox, space, physics, universe, aliens, alien, intelligent aliens, intelligent life, fermi paradox, life on earth, are we alone, galaxy, europa, mars, scientists, jupiter, saturn, alien life, life in the solar system, science, science time

Id: 06jlaYGBh08

Length: 10min 15sec (615 seconds)

Published: Sat Nov 27 2021