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  • Aliens contacting us might seem like science fiction but now, new mysterious

  • signals from outer space are intriguing scientists around the world.

  • This signal is so bright that it was completely unlike anything we'd ever seen before.

  • It's not crazy to think that radio bursts could be created on another planet.

  • What causes them is one of the biggest mysteries in physics.

  • Now linking strange signals from space with aliens sounds a bit like something cooked up

  • by a conspiracy theorist.

  • Yes this is real science.

  • It's the job of an astrobiologist to figure out where in the universe is habitable and

  • if possibly intelligent life could have developed there and then contacted us.

  • In fact, in 1961 pioneering astronomer Frank Drake organised and now infamous secret

  • meeting to try and figure out how many

  • civilisations like this exist outside of our own.

  • So we start out with the rate of star formation.

  • Multiply that by the fraction of stars which actually have planets, habitable planets in

  • each system, by the fraction on which life develops, the fraction by which intelligence appears.

  • By the fraction of

  • Those which actually give a detectable technology.

  • This rate times the average time

  • that these civilizations remain detectable.

  • N equals about 10,000 detectable civilisations at present

  • in our galaxy the Milky Way.

  • Calling themselves the Order of the Dolphin,

  • this group of award winning scientists, set out on the hunt for this huge number of

  • civilisations that they thought could be out there.

  • Oh I believe very strongly that they are out there.

  • We can be very very wrong and yet there will be many many detectable civilisations.

  • From secret government agencies to Nobel Prize winning scientists,

  • the search was on for weird

  • First there was the Wow signal in 1977, detected by the Big Ear radio telescope in Ohio.

  • The signal was strong about 72 seconds.

  • But more importantly it was detected in something known as the Hydrogen Line.

  • That was significant because at the time astronomers thought that if extraterrestrials

  • did exist they would use that frequency.

  • The astronomer Jerry Ehman was so excited that he actually wrote the term 'Wow!' on the

  • print out.

  • Very quickly it was dismissed by astronomers as actually coming from a comet.

  • Then in 2007 came a detection of what would become the biggest mystery in physics,

  • something that could have been a game changer in the search for aliens.

  • My student showed me this signal that was so bright and apparently so far away that it

  • was completely unlike anything we'd ever seen before.

  • Then we realise this is just impossible.

  • Unless a civilisation is way more advanced than we are.

  • Scientist Duncan Lorimer and his team had found what we now call Fast Radio Bursts.

  • They're incredibly bright radio signals so bright that they can't be coming from any

  • naturally occurring phenomena on earth.

  • They have to be coming from outer space.

  • Quite frankly it was unlike anything I'd ever seen before.

  • Yet it had all the hallmarks of a signal that was coming from deep space.

  • I did think that it could be a signal from an extra terrestrial civilisation.

  • We create signals like that on Earth,

  • so it's not crazy to think that radio bursts could be created on another planet.

  • So it was a groundbreaking time for physicists and with this new data from Lorimer the

  • burning question everyone still had was

  • Now the problem with the Lorimer Burst was that it was just a one off

  • and how do you prove a one off is real and not just some noise or some random signal in

  • your detector.

  • Well it helped when other scientists around the world started detecting signals just

  • like it.

  • They were coming from all over the sky and they were clearly real.

  • So it was a breakthrough moment.

  • Now although this seemed really exciting it meant that there were probably much more

  • likely explanations for what was going on.

  • We observe binary systems of two neutron stars that are in orbit around each other.

  • And when we observe these systems we see them getting closer and closer together all

  • the time.

  • So what will happen eventually is that they'll going to collide.

  • And when they merge the neutron stars will be completely destroyed and form a blackhole.

  • When you look at the energetics of these events you can easily explain the FRB

  • energies with them.

  • You can also explain the durations of the FRB pulses with the expected durations of

  • these merger events.

  • So it's quite a plausible explanation.

  • Neutron stars are some of the most energetic objects in the universe.

  • Second only to black holes and you need something really energetic to produce a fast

  • radio burst.

  • Now astronomers recently have discovered a fast radio burst coming from a magnetar in

  • our own Milky Way galaxy.

  • A magnetar is a special type of neutron star that has a very high magnetic field.

  • And while this is really exciting that we finally might have an explanation,

  • it means that aliens producing FRBs is becoming a lot less likely.

  • Now that fast radio bursts are real.

  • It comes back to the point where they could be caused by aliens.

  • So if I were looking for a signal from an extraterrestrial civilisation I'd be looking

  • for it coming from a single point in the sky.

  • Here we have a population of sources all over the sky which implies that the aliens are

  • all over the place, all over the universe.

  • That just seems highly unlikely to me.

  • So we're one step closer to solving the mystery of fast radio bursts even though it's

  • looking likely that they're not the alien signals that everyone was secretly hoping for.

  • But as a scientist I reckon.

  • Never say never.

  • We'll always keep observing the sky and I think in our lifetimes we've got a great

  • chance of discovering alien life somewhere out there in the universe.

  • We've done a great deal of searching in the last 50 plus years and we've learned that

  • we're going to have to search perhaps a million stars and countless frequency channels

  • before we have a good chance of success.

  • If I had this to do all over I would still do it.

  • And in fact I'd probably put more time into it because I've come to realise that's what's

  • required to succeed.

  • And to me that time is not time wasted because the eventual discovery is of such

  • importance. That it justifies

  • not just one human life being dedicated to succeeding but many.

Aliens contacting us might seem like science fiction but now, new mysterious

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