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 course, the materials
that are required for this are exotic.
Some of the materials are currently being developed
at academic labs.
So we think it's within the realm of possibility
for a future mission to do something like this.
We can lay in wait,
watch our local space for any interstellar objects
that might be entering that space
and then spring to action and get a close-up view
of that interstellar object.
Once an object is detected,
it would be allowed to leverage the gravitational force
of the sun in a free-fall trajectory
towards the detected object, matching its path.
The team received phase-one funding from NASA,
which gives them nine months to come up
with a solid plan before applying for the next phases.
We're optimistic about phase two
and we hope to find to eventually get to a phase three.
And if we're able to get there,
then this technology becomes closer to becoming reality.
And both of these missions
are coming at a good time.
Telescopes that are coming online in the next few years
will be able to detect more pristine comets
and interstellar objects than ever before.
Large synoptic survey telescope,
the Rubin Observatory,
is being built in Chile
and that's going to be much bigger.
And scientists are predicting
we might start to see one of these
each year once that is built, because it goes much fainter.
Why is it important to study objects like this?
Well, I think Oumuamua and other interstellar objects
are really important because they are the likely leftovers
of building planets in another solar system.
And right now, we don't have the sensitivity
or resolution to really watch that process unfold.
You know, for example, are all solar systems
chemically the same? Is it the same physical processes
that build planets?
'Cause this is important for the question of, are we alone?
And so some of the ways to answer those questions
require detailed
chemical compositional makeup,
which you can't do remotely.
I think we should be interested in interstellar objects
because it really tells us something about
our own history, whether or not
our star system is unique
or is our star system similar to other star systems?
And if we find out maybe some compositions
of the material around other star systems,
it could inform us what's out there.
If we can explore an interstellar object,
we can explore
by proxy another solar system.
And that's something really exciting
because we know there's so many other solar systems
with exoplanets
and with maybe
even exoplanets that are kind of like Earth.
And understanding those systems better
I think is really interesting.