Science with Sam: Do aliens exist?

Do aliens exist? It’s a query that has spawned numerous movies and TV sequence, books, podcasts, art work and conspiracy theories, however the query of whether or not or not we’re really alone within the universe stays unanswered. On this episode of Science with Sam, we clarify the continuing hunt for extra-terrestrial life and whether or not or not they could already be right here.

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Video transcript

We people are obsessive about the concept that we’re not alone, that someplace on the market within the universe, there are different life varieties clever sufficient to speak with us.  Or possibly even destroy us. But when there may be life on the market, why haven’t we heard from them but?  Or have we?


In 1961, the astronomer Frank Drake devised a calculation that predicted the existence of hundreds of thousands of civilisations on the market among the many stars. His Drake Equation used some pretty speculative assumptions, but it surely ignited our curiosity.  Are we only one small a part of an enormous, cosmic zoo?

For physicist Enrico Fermi, the contradiction between this prediction and actuality made no sense, and it got here to be referred to as the Fermi Paradox. “The place is everyone?”, he needed to know. There might be an infinite variety of solutions to this query. Listed below are a couple of:

There isn’t a paradox and we actually are alone within the universe

Miserable although it could be, typically the best solutions are probably the most believable.

They’re ghosting us

Perhaps aliens have a coverage to not intervene with much less superior cultures.  A bit just like the “prime directive”, on Star Trek.

They don’t reside lengthy sufficient to get in contact

This concept, referred to as the Nice Filter, says that no superior civilisation survives lengthy sufficient to nonetheless be round when its neighbours are thriving. For us, threats like nuclear battle, local weather change or pandemics would possibly spell our doom.

They’re already right here

From Roswell to The Lubbock Lights, there have been loads of UFO sightings on Earth. Is the federal government hiding the proof? Or is it pretend information?

If there are any aliens watching, why not say hello within the feedback under? Higher but, click on like and subscribe. You would possibly study rather a lot about human behaviour from our movies. And, each Aliens and earthlings can get 20 per cent off a New Scientist subscription by utilizing the code SAM20.

The silence from different civilisations isn’t for need of wanting on our half.  In 1960, Drake pointed a radio telescope in the direction of two close by stars, and waited for that hotline bling. As a substitute of clever messages he received a load of static, and interference from a secret navy experiment. Nonetheless, the Seek for Further Terrestrial Intelligence, or SETI, was born.

Then, on 15 August, 1977, one other SETI program recorded a quick radio sign coming from the course of Sagittarius. Jerry Ehman, the astronomer analysing the information at ‘Massive Ear’ telescope that day, was so excited that he wrote “Wow!” within the margin of the print-out. Up to now, that ‘Wow!’ sign stands as our most hopeful signal of alien communication but.

However listening for ET to cellphone house is a bit like standing by the payphone, ready for the cellphone to ring. Perhaps we’ve to make the primary transfer.

Drake tried this too, sending a radio message in the direction of globular star cluster M13. Referred to as the Arecibo message, it confirmed potential aliens our DNA construction, photo voltaic system and a number of the biochemicals of earthly life. We additionally tried sending aliens a greeting onboard house probes Pioneer 10 and 11, which included photographs of people and instructions to our planet.

Then, in 1977, we despatched a extra bold message, stuffed with audio and pictures, on board the Voyager probes. We even included a mixtape of a few of our favorite tunes, together with Bach, Beethoven, Louis Armstrong and Chuck Berry, to impress any pleasant lifeforms – or at the very least those with ears. And if that didn’t entice them to get in contact, possibly this illustration of people consuming, licking and ingesting would possibly?!

By now aliens would possibly know quite a bit about us – together with what we have to survive and how one can attain us. And also you is likely to be questioning whether or not it’s such a good suggestion to be broadcasting our location everywhere in the galaxy, after we don’t know who’s listening.

“It’s like shouting in a forest earlier than you already know if there are tigers, lions, and bears”, says Dan Werthimer, a SETI researcher. Worse nonetheless, these bears might need planet-destroying interstellar missiles.

Placing apart the query of whether or not we must always attempt to contact aliens, are we even doing it proper? These alien societies is likely to be hundreds of thousands of years previous, so to them our radio messages would possibly look as outdated as flip telephones, pagers, and, effectively, radio.

Loads of different methods to search for life have been tried or steered. Listed below are a couple of choices:

Search for biosignatures

Over time, the biochemistry of billions of creatures can remodel a world in distinctive methods. By analysing the wavelengths of sunshine that come by the planet’s environment, we will search for gases that recommend the presence of life.

Search for technosignatures

if we do see indicators of life on one other planet, that gained’t inform us whether or not it’s inhabited by senseless inexperienced slime or sentient city-builders. A extra dependable method to search for kindred spirits is to search for chemical compounds that solely clever civilisations can produce.

Metropolis lights

Aliens with evening imaginative and prescient as restricted as ours would possibly festoon their constructed surroundings with synthetic lighting. So possibly we may spot cities lit up on the planet’s darkish facet.

Aliens on the go

Alien spaceships is likely to be simpler to identify than their house planets. Perhaps, we will search for high-powered lasers used to push optical sails, or intense plumes of sunshine generated by an antimatter engine, like these imagined in Star Trek.


Aliens might need constructed gargantuan engineering initiatives like Dyson spheres, named after the physicist and engineer Freeman Dyson, that are swarms of units round a star that harvest its vitality, and nothing to do with vacuum cleaners

The Ozymandias Impact

The ruins of superior civilisations doomed by their very own know-how might need their very own telltale signatures. If we discover useless civilisations earlier than we discover dwelling ones, that may not bode effectively for our personal future.

If we do make contact with aliens, it will be a decisive blow to the concept that people are the centre of the universe. However how a lot cooler wouldn’t it be to find that we’re only one department of an enormous galactic tree of life?


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