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  • On October 19, 2017

  • at the Haleakala Observatory in Hawaii,

  • human beings detected the first-ever

  • visitor from interstellar space:

  • an object from outside our own solar system.

  • A pair of Harvard scientists say a massive,

  • fast-moving visitor to our solar system

  • may have been a probe

  • sent by an advanced alien civilization.

  • It's an alien spacecraft.

  • Some sort of alien technology,

  • perhaps exploring the cosmos.

  • It's called Oumuamua,

  • which roughly translates as messenger from the past

  • reaching out to us in Hawaiian.

  • Everything in our solar system is on a closed loop.

  • You know, some orbits are nearly circular,

  • some are elongated.

  • This one was an open-ended orbit,

  • which means it's coming from outside the solar system.

  • Then something even more strange happened.

  • Upon leaving the inner solar system,

  • astronomers reported an unexpected acceleration,

  • only adding to the hypothesis that Oumuamua

  • was some sort of alien creation.

  • It would be exciting to think this is an alien spacecraft.

  • You know, one of the burning questions on many minds is:

  • Are we alone?

  • But you have to be responsible about it.

  • And if there is a perfectly common explanation,

  • you shouldn't go to the exotic explanation.

  • After observing the object,

  • most astronomers agree that it's probably a comet.

  • Like 2I/Borisov,

  • the other interstellar object seen a year later.

  • But we may never know for sure.

  • Things that come in on these type

  • of very elongated orbits move really fast

  • when they're close to the sun,

  • and then they're much slower as they move out

  • of the solar system.

  • So when you looked at the brightness of this object,

  • it was going to only be easy to observe for about a week.

  • In that short window of time

  • with just a pinpoint of light,

  • scientists were able to make guesses on the object's shape,

  • its size, how fast it was spinning and its color,

  • which is thought to be reddish.

  • But there are a lot of questions about Oumuamua

  • and space that'll remain unanswered

  • unless we're able to act more quickly.

  • Right now, many of the teams are saying

  • we need the capability

  • to have reactive missions,

  • fast missions that can respond to a discovery.

  • Because right now, the missions,

  • the way NASA works with the small missions,

  • is you put in a proposal and it takes many years

  • to get that approved.

  • And then it might be a decade between proposal

  • and actually launching a mission.

  • And obviously for Oumuamua,

  • that would have been pointless.

  • So we would like to have missions that are maybe ready

  • to go, built and in orbit,

  • waiting for a new discovery

  • or something that could be launched immediately.

  • That's why teams of scientists

  • are planning missions to wait for objects in space,

  • and spring into action as soon as

  • something interesting is detected.

  • It may be humanity's only chance to see an object

  • from another solar system up close.

  • The space between solar systems is huge.

  • Unless warp drives become a reality,

  • traveling from one to another any time soon is

  • probably not possible.

  • Well, I mean, I'm a "Star Trek" fan,

  • and according to "Star Trek" in 2063,

  • I think, Zefram Cochrane invents the warp drive.

  • Zefram Cochrane?

  • Of Alpha Centuri?

  • The discoverer of the space warp?

  • That's right captain.

  • So if that happens, definitely.

  • If not, I think it's quite difficult

  • to reach anything within my lifetime.

  • Currently, the only way that we have to see

  • some of the material from these other star systems

  • is stuff that is in interstellar space that gets to us.

  • Although we've never gone near

  • an interstellar object,

  • we've learned a lot from approaching objects

  • from within our solar system.

  • In 2014, the European Space Agency's Rosetta probe

  • rendezvoused with Comet 67P.

  • Rosetta is the first mission

  • that ever delivered a lander to the surface of a comet.

  • This had never been done before.

  • It's the first mission that went into orbit

  • around a comet,

  • and it accompanied it for two years and a bit,

  • from 2014 to 2016.

  • And from this mission, the European Space Agency made a lot

  • of interesting observations.

  • I think this shape was one of the major surprises

  • that we had at the beginning.

  • No one really expected that.

  • Another really big discovery, I think, was that

  • the water that came off Comet 67P

  • is not that kind of water that we have on Earth.

  • And if it's not the same, you know that

  • they're probably not from the same source.

  • So I think this was quite unexpected

  • because people really thought

  • this comet could be a real possibility

  • to bring water to Earth.

  • Scientists are still looking at the data

  • from the Rosetta mission

  • and making exciting new discoveries about 67P.

  • And those discoveries in turn

  • give us hints about the early days of our solar system.

  • I think comets are very interesting

  • because they can actually tell us where we come from.

  • The comets are always thought as kind of

  • leftovers from the solar-system formation.

  • And if we explore comets,

  • we can understand how the solar system formed,

  • how Earth formed and basically

  • how humans in the end came to be

  • because without Earth we wouldn't be here.

  • While the Rosetta mission was a success,

  • Comet 67P orbits the sun every seven years

  • and is affected by the heat,

  • losing gases and changing its composition with each orbit.

  • Scientists at ESA recognized the need to study a comet

  • with a pristine surface,

  • one that's never been near the sun,

  • and that's largely unchanged

  • since the formation of our solar system.

  • This is known as a new comet.

  • They were talking about this problem

  • of pristine surface versus changed surface.

  • And they said, "Well, you know what we should do?

  • We should try and get to one of those new comets."

  • And so the Comet Interceptor idea was born.

  • This is very different from previous missions

  • that we've done where we've always gone to comets

  • that go round and round in the solar system.

  • And the reason why we go to these is that

  • we know where they are.

  • We can observe them and then get

  • their position very accurately.

  • But Comet Interceptor doesn't want to do that.

  • Comet Interceptor wants to go to a very new comet

  • and observe it with three different little spacecraft:

  • one mother spacecraft, as we call it,

  • and two sub-spacecraft.

  • And we want to basically observe everything we can.

  • We'll take pictures of the comet's nucleus,

  • which is a little thing in the middle.

  • We'll take pictures of the gases around it,

  • the dust that comes off of it, the environment.

  • Interstellar objects

  • are not Comet Interceptor's primary target.

  • Since we've only ever detected two,

  • we don't know when or if we'll detect another one.

  • This mission is mainly going after

  • unknown new comets from beyond Neptune in the Oort cloud.

  • This is the spherical, outer part of the solar system

  • and is believed to contain trillions of comets.

  • The majority have never entered the inner solar system.

  • But every once in a while,

  • one of these icy bodies gets a gravitational bump

  • from another object, flinging it

  • into the inner solar system.

  • And Comet Interceptor hopes to be ready for the next one.

  • And there is another very interesting target family,

  • let's say, which is interstellar objects.

  • So if there is an interstellar object

  • like Oumuamua or Borisov,

  • that's obviously where we we will be going

  • because that's by far the most interesting thing

  • that we can explore.

  • And Comet Interceptor is the only mission

  • that has the capability to explore

  • such an interstellar object.

  • But to catch up to a new comet

  • from our solar system or an interstellar object,

  • they needed to come up with a way to deal

  • with the short lead time,

  • something that's never been done before.

  • The problem is that

  • these dynamically new comets are usually detected

  • just a couple months before they get close to Earth.

  • And a couple months as everyone involved

  • in any space mission knows

  • is not enough to build a spacecraft

  • and go somewhere with it.

  • So we're actually more looking at a timeframe of five years

  • for the mission, where we have five years of waiting time

  • and we can choose whenever we detect a suitable comet.

  • And we think that the chance of detecting

  • a suitable, dynamically new comet

  • that we can reach is over 90% over these five years.

  • To be able to wait for a comet out in space

  • for up to five years, they'll send a small probe

  • to the Earth-Sun Lagrange point,

  • a place where the gravitational pull

  • from both bodies cancel each other out,

  • creating a stable orbit.

  • And when Comet Interceptor gets there,

  • it will just wait for five years.

  • And once we detect the comet we'll be

  • setting off towards rendezvous point,

  • and this will be done with chemical propulsion.

  • Data gathered by the interceptor

  • could be compared to other comet missions,

  • so scientists will be able to predict the effects

  • of the sun on comets,

  • giving them clues as to what the formation

  • of our solar system was like,

  • and in turn teach us about how Earth came to be.

  • It is a very ambitious mission.

  • That's, I think, why it's so exciting.

  • I mean, if you just do things that are easy,

  • it's a bit boring.

  • So this mission is very difficult to pull off.

  • And I think that

  • the team here at ESA has done a very good job

  • in kind of reminding everyone

  • of the constraints of the mission

  • while still getting the best science out of it

  • that we can expect at the end.

  • Although not as far along

  • as ESA's Comet Interceptor,

  • which is set to launch in 2029,

  • there is a team at MIT in its initial planning stages,

  • designing a mission specifically

  • targeting interstellar objects.

  • We see interstellar objects

  • as the new frontier in

  • planetary sciences.

  • And now that we detected them,

  • it really opens up the door of like, oh,

  • what new things can we discover?

  • And how do these new discoveries frame

  • our thinking about the formation of this star system

  • and other star systems?

  • So it's really science in a nutshell.

  • Their proposal is called

  • Dynamic Orbital Slingshot for Rendezvous

  • with Interstellar Objects.

  • Much like the Comet Interceptor,

  • it will wait in space and spring into action

  • at the right time.

  • So the unique part about our concept

  • is that using the solar sail,

  • our payload remains stationary.

  • We can completely cancel out this force of gravity.

  • Of