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‘Oumuamua: Was Our First Interstellar Visitor Alien Technology? · Lost Civilizations: Ancient Aliens & Forgotten History

0:00
Imagine discovering an object that is already on
0:03
its way out.
0:04
You never get close to it, you never
0:06
see its surface, you never get a photograph
0:09
where you can zoom in and say, there,
0:12
that's what it looks like.
0:14
All you have is a tiny point of
0:16
light against the black sky, but you can
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measure where the point is again and again
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and again, and after a while you notice
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something.
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The point isn't exactly where it should be.
0:29
Something is pushing it, not by much.
0:32
There is no dramatic change of direction, no
0:35
an engine suddenly turning on or anything like that.
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Nothing that looks like a scene from a
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science fiction movie, just a small extra acceleration.
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But in astronomy, a small difference can matter.
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If the measurements are good enough, even a
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tiny change can tell you that something is
0:56
happening.
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Gravity tells us how an object should move around
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the Sun, and this object was not following
1:02
that prediction perfectly.
1:05
That alone is not necessarily strange.
1:08
Comets do that all the time.
1:09
the Sun heats the ice inside a comet,
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material turns into gas, and gas and dust escape
1:15
from the surface, and that gives the comet
1:18
a small push.
1:19
You can think of this as a very
1:21
weak rocket engine made by nature.
1:24
So if this object is a comet, maybe
1:28
we already have the answer.
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There is just one problem.
1:32
Astronomers cannot see the tail they would
1:35
normally expect.
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They do not see a clear cloud of
1:41
material around it.
1:42
They do not see the obvious dust activity
1:45
we normally connect with an active comet.
1:47
And still, there is an extra push.
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The object is already unusual for another reason.
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It did not come from our Solar System.
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Its path tells us that the Sun had
2:02
never owned it.
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It came from the space between the stars, passed
2:07
around the Sun, and continued back out
2:10
again.
2:11
And we discovered it only after the best time
2:15
to study it had already passed.
2:17
Then, in 2018, two researchers asked a different question.
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If gas was not pushing it, could
2:23
the light itself be doing it?
2:25
Because light can actually push things.
2:28
Photons from the Sun carry momentum.
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The effect is very small, but if an
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object is extremely light and has a very
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large surface, sunlight can start to matter.
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That is the basic idea behind a solar
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sail.
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And suddenly, the story moves far outside normal
2:47
comet research.
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Because if the object is as thin and light
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as that calculation would require, what is it?
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An extremely strange natural object, or something that was
3:00
made.
3:01
And this is where the story of ‘Oumuamua
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really begins.
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Not with a photograph of a spaceship, not
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with a radio signal, not with contact
3:08
with aliens, but with a dot and with
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a path through space that did not exactly
3:13
behave the way astronomers expected.
3:19
Why are we still talking about it?
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‘Oumuamua has almost become trapped between two
3:25
stories.
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One story says it was aliens.
3:28
The other says it was just a rock.
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Both are too simple because we actually know
3:34
quite a lot about ‘Oumuamua, and at the
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same time we know far too little.
3:39
That combination is exactly what makes the story
3:41
interesting.
3:42
If we knew nothing, we could attach almost
3:45
any story to the object.
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If we knew everything, there would be no
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mystery left.
3:49
But here, we are right in the middle.
3:51
We know the orbit, we measured the light
3:53
coming from the object, we know that it
3:55
was tumbling, we know we did not see
3:59
any kind of obvious comet activity that we
4:02
would normally expect, and we know that researchers
4:04
later found a small extra acceleration.
4:09
Those are real astronomical observations.
4:12
But we do not know the exact shape,
4:16
we do not know its exact mass, we
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do not know exactly what it was made
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of, we have no sample, and we will
4:24
probably never be able to make a new
4:26
observation of that particular object.
4:29
It is already far away continuing its journey
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out of our Solar System.
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So in a way, ‘Oumuamua is like a
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scientific crime scene where the most important piece
4:41
of evidence disappeared before investigators even understood which
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questions they needed to ask.
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And that makes the debate difficult because when
4:50
data is missing, models take over.
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Models are necessary, but sometimes different models can
4:56
explain the same observations.
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An extremely unusual comet, a fragment from another
5:03
world, a piece of nitrogen ice, water ice containing
5:07
trapped hydrogen, a very light and fluffy object,
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or a thin structure being pushed by the
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sunlight.
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Some of these ideas are supported much better
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than the others, but they are all trying
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to explain the same strange collection of details.
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And then, of course, there is a much bigger
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question.
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If a technological civilization really did send objects
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through interstellar space, how would we recognize one?
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We cannot answer that question by simply laughing
5:39
at it, but we also cannot answer
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it by falling in love with the idea.
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So we are going to do this in
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the right order.
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First, we are going to look at what astronomers
5:50
actually found, then give the technological interpretation the
5:55
space it needs, and then after that, we
5:58
will start trying to break it.
6:03
On October 19th, 2017, astronomer Robert Weryk noticed
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something in images from the Pan-STARRS
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1 telescope in Hawaii.
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Pan-STARRS watches the sky again and again.
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One of its jobs is to find moving
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objects, asteroids, comets, small bodies that may pass
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near Earth.
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At first, the new object received a normal
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catalog name, but then astronomers started calculating its
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orbit.
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Then something became clear.
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It did not fit.
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An object that belongs to the Solar System
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is held by the Sun's gravity.
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Its orbit might be almost circular.
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It might be a long ellipse.
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A comet might travel incredibly far and then
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take thousands of years to return, but it
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is still gravitationally bound to the Sun.
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It comes back.
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This object was different.
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Its orbit was hyperbolic.
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It had enough speed to escape.
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It was only passing through.
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When astronomers calculated its path backward, it led
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out into interstellar space.
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This was not simply a comet from the
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distant edge of our own Solar System.
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It was a visitor from somewhere else.
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For the first time in human history, we
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had clearly observed a large object from another
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star system passing through our own.
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It received the official name 1I.
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Number 1 because it was the first, the
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letter I for interstellar.
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Then came the Hawaiian name: ‘Oumuamua.
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The name is often translated as something like
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a messenger or scout from far away,
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arriving first.
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It's a beautiful name.
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It's also one of those names where the
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Danish mouth, and probably a few American mouths
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as well need a little practice before everything
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agrees on where the sounds are supposed to go.
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But let's go on.
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The astronomers did not have much time.
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When ‘Oumuamua was discovered on October 19th, it
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had already passed closest to the Sun
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more than a month earlier.
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Its closest approach to the Sun happened on
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September 9th.
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At that point, it came inside the orbit
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of Mercury.
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So it had already been exposed to the
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intense heat from the Sun, and now it
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was heading away.
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Every day it became fainter.
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Observatories around the world quickly turned their telescopes
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toward it.
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They measured its spectrum, its brightness, its position,
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and its rotation.
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They tried to learn as much as possible
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while they still could.
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And almost immediately, the first major surprise appeared.
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The brightness changed a lot.
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When an object with an uneven shape rotates,
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the amount of surface we can see changes.
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Imagine a long potato turning through space.
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It reflects more light when we see
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its side and less light when we see
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one end.
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So by watching how the brightness changed, astronomers
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could try to estimate its shape.
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‘Oumuamua showed a huge change in its brightness.
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In some of the early studies, the difference
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was so large that a simple shape model
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suggested that the object might be around 10
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times longer than it was wide.
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And then the idea of the cigar was
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born.
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Illustrations quickly spread around the world.
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A dark red rocky cigar moving between stars.
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There is just one important problem.
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Nobody ever saw that cigar.
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That matters.
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The telescopes could not see ‘Oumuamua as a
9:58
detailed object.
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It was too small and too far away.
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It appeared as a point of light.
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The shape was calculated from the changing brightness.
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And the changing brightness can depend on several
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things.
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Shape, surface reflection, viewing angle, rotation.
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Later studies showed that other shapes also could
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explain the data.
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Including shapes that were much flatter, something closer
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to a disc or a pancake.
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So whenever you see an image online with a
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title like,
10:32
“This is what ‘Oumuamua looked like,”
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you should mentally add a small note underneath:
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artist's impression, because it is not a photograph.
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Still, the extreme change in the brightness was
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real.
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And there is another interesting feature.
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‘Oumuamua was not spinning in a simple, stable
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way around one axis.
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It was tumbling.
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Imagine throwing a shoe, or a book,
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through the air.
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It can spin in more than one direction
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at the same time.
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Something similar can happen with ‘Oumuamua.
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This kind of tumbling is known among asteroids
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or other small objects.
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It can be a sign of an earlier
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collision, or perhaps another violent event in the
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past.
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And because there is very little in interstellar space
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that can slow down the movement, a tumbling
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motion can survive for a very long time.
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The surface also happened to be interesting.
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The color was reddish.
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Not a bright metal structure, but not in
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a way that clearly told us exactly that
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what it was made of either.
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Red surfaces are seen on several kinds of
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small objects in our own Solar System.
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They can be created by long-term exposure
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to radiation and chemical changes.
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So at this point, we have something strange,
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but nothing impossible.
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An interstellar visitor, a huge change in brightness,
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an unusual shape, a tumbling rotation, a reddish
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surface, and then we have something we're missing.
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We have no clear tail, no obvious cloud
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around the object.
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In the first observations, it did not look
12:14
like a normal active comet.
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It was interesting because ‘Oumuamua had just passed close
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to the Sun.
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If normal types of ice were exposed near
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the surface, the Sun would have heated them.
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That could have produced activity.
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One of the early ideas was that the
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surface may have been changed during its long
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journey through interstellar space.
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Maybe a layer of material had formed that
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protected ice deeper inside.
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Already, the simple picture was getting complicated.
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Asteroid? Comet? Maybe neither word fit perfectly.
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And that would make sense.
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We created those categories by studying objects from
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our own Solar System.
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‘Oumuamua did not come from here.
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Maybe the object did not fit our categories
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because our categories were too small.
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Then, almost a year after the discovery, researchers
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published the result that changed the entire story,
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the orbit.
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If you look at the first cracks,
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astronomy can sometimes be surprisingly simple.
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You observe where something is, you wait,
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you observe again, then you ask, does the
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movement match the physics?
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For ‘Oumuamua, astronomers had many accurate measurements of
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its position.
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Some came from observatories on Earth.
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Others came from the Hubble Space Telescope.
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Marco Micheli and his team analyzed those observations.
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Their results were published in the journal Nature
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in June 2018.
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A model using only the expected gravitational forces
14:03
did not fit the observations perfectly.
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But when the researchers added a small extra
14:09
acceleration away from the Sun, then the orbit
14:12
fit better.
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This was not simply a weak, maybe-
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there-is-something-here result.
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The signal was statistically strong.
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There really was a physical effect that needed
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an explanation.
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But there's an important phrase here, non-gravitational
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acceleration.
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It sounds mysterious, but it does not mean
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unexplained.
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It simply means a change in the motion
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caused by something other than gravity.
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And astronomers already knew a very common cause,
14:50
comets.
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When the Sun heats a comet, ice can
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turn directly into gas.
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That gas escapes, often it carries dust with
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it.
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And as material leaves the surface, the nucleus
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receives a small push
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in the opposite direction.
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So outgassing was the first obvious explanation.
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In fact, Micheli and his team considered comet
15:15
-like outgassing to be a physically reasonable explanation
15:19
for the acceleration.
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That is important.
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The acceleration was not discovered as some impossible
15:26
mystery with no known natural process behind it.
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The problem was more complicated than that.
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If the gas was escaping, where was the
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activity?
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Researchers had looked for dust.
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Deep observations did not show the obvious cloud
15:45
or tail normally associated with an active comet.
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Other measurements also placed limits on certain gases.
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So the simplest version, a normal comet doing
15:55
normal comet things, did not fit very well.
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There could still be gas.
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There could still be activity that was hard
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to detect.
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The chemical makeup might be unusual.
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But now we were already building a
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more special explanation.
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Another challenge involved the rotation.
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If gas is escaping strongly from a certain
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area, from a small uneven object, that gas
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should not only affect its path.
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It should also be able to change its
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rotation.
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Think of it as a lawn sprinkler.
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The water shooting out causes the sprinkler to
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turn.
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Astronomer Roman Rafikov argued that the amount of
16:44
outgassing needed to explain the acceleration should also
16:48
have a strong effect on ‘Oumuamua's spin.
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That made the standard comet picture more difficult.
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Not impossible, but difficult.
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Now the list looks like this.
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We have an interstellar object, extreme brightness changes,
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tumbling, no obvious coma, and yet an extra
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acceleration away from the Sun.
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Each individual feature might have a natural explanation.
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The interesting part is its combination.
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And now we change the point
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of view.
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Because if you want to understand why some
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people, including a very well-known Harvard astrophysicist,
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start talking about technology, it's not enough to
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say he thought it was aliens.
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We need to follow the argument from the
17:37
inside all the way.
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If we look at the alternative theory here,
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the first point is that light can move things.
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When we do not notice this in normal
17:52
life, because the pressure from the light is
17:54
incredibly small compared to the other forces around
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us, but photons carry momentum.
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When they hit the surface and it's absorbed
18:03
or reflected, they transfer a tiny amount of
18:05
that momentum.
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In space, tiny forces matter.
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There is no air resistance.
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And if a force keeps acting long enough,
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even a very weak acceleration can change the
18:18
object's speed.
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That's the idea behind the solar sail.
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Instead of carrying large amounts of fuel, a
18:24
spacecraft can open a very large and very
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light surface.
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Sunlight hits the sail and slowly the spacecraft
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accelerates.
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The closer to the Sun, the stronger the radiation
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pressure is.
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Farther away, the effects become weaker.
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And this is not science fiction.
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Humans have already tested solar sails in space.
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And much more extreme light sails have been
18:51
proposed for future missions between the stars.
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Avi Loeb himself has worked in this general
18:57
area through Breakthrough Starshot.
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The basic idea of Starshot is to build
19:03
a very small, very light spacecraft with sails.
19:07
Powerful lasers would push those sails.
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And in theory, the spacecraft would reach a
19:15
meaningful fraction of the speed of light.
19:18
So this was part of the background when
19:21
Shmuel Bialy and Avi Loeb looked at ‘Oumuamua’s
19:24
strange acceleration.
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They asked a simple question.
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What if the gas was not pushing it?
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What if sunlight was?
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If that were true, you could use the
19:36
measured acceleration and work backward.
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How much mass would the object have compared
19:43
with the surface area catching the sunlight?
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The answer was unusual.
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If sunlight was responsible for the acceleration, ‘Oumuamua
19:51
would need a very low mass compared with
19:53
the surface area.
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In other words, a lot of surface.
19:57
And very little mass.
19:59
If you imagine it as a solid sheet
20:03
made of normal materials, the required thickness could
20:07
be less than a millimeter.
20:09
So now we get a very different
20:12
picture.
20:13
Not the famous dark cigar.
20:16
A thin structure, large enough to catch sunlight.
20:19
Light enough for the tiny pressure of photons
20:22
to matter.
20:23
And suddenly, the changing brightness becomes interesting in
20:27
a different way.
20:28
As researchers continued studying the rotation, a long
20:31
cigar was no longer the only possible shape.
20:34
A much flatter object could also fit the
20:37
observations.
20:38
And a flat object naturally sounds more like
20:42
a sail than a giant rock shape like
20:44
a pencil.
20:47
That does not mean that an alien light
20:49
sail would have to be a perfect shiny circle.
20:52
An old technological object might be damaged.
20:55
Bent.
20:56
Broken.
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Folded.
20:58
It could be a piece of something larger,
21:01
or a structure whose original purpose no longer
21:03
matters.
21:04
So the alternative idea does not have to
21:07
be there was an alien pilot inside ‘Oumuamua
21:10
holding a steering wheel.
21:12
In fact, the idea becomes more interesting when
21:14
we remove Hollywood from the story.
21:17
Instead, think about technology as archaeology.
21:22
understand this on Earth.
21:23
A civilization does not need to still exist
21:28
for us to discover it.
21:30
If archaeologists find a Roman sword, there does
21:33
not need to be a Roman soldier standing
21:35
next to it.
21:37
If we find an ancient stone tool, the
21:39
person who made it has been gone for
21:41
thousands of years.
21:43
Technology can survive its creators, sometimes for a
21:46
very long time.
21:48
In space, that time could be even longer.
21:52
There is no rain.
21:53
There is no forest growing over the object.
21:56
There is no normal weather.
21:58
There is no Earth-like atmosphere.
22:01
There are still dangers: radiation, tiny impacts, heat
22:03
and cold, and collisions.
22:05
But an object can in principle survive and
22:07
drift for an extremely long time.
22:09
So imagine a technological civilization around another star.
22:14
Maybe it existed a million years ago, maybe
22:17
100 million years ago.
22:19
It sent objects into space, probes, sails, scientific
22:23
instruments, communication devices, maybe millions of small and
22:27
cheap machines.
22:29
Eventually the civilization disappeared.
22:31
The planet changed.
22:32
Maybe the entire species went extinct.
22:36
But some of the objects kept moving.
22:39
That is one way to understand Loeb's idea
22:42
of space archaeology.
22:44
We may not have to wait for somebody
22:46
to say hello on the radio.
22:47
We might be able to find their objects.
22:50
And if we do, the first thing
22:52
we find may not be a perfect working
22:56
spacecraft.
22:57
It might be debris, a dead probe, a
23:00
broken sail, a machine that has stopped working
23:02
a million years ago.
23:04
It could simply be technological driftwood.
23:08
That idea matters because it changes several questions
23:11
people often ask.
23:13
Why didn't ‘Oumuamua send us a message?
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A dead object does not need to.
23:19
Why didn't it fly toward Earth?
23:21
A drifting object does not need to.
23:25
Why didn't it slow down?
23:27
A passive sail does not need to.
23:30
Why didn't it contact us?
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Maybe contact was never its purpose.
23:35
And why would anyone send objects through the
23:38
empty space between stars anyway?
23:41
Here we can turn the question toward ourselves.
23:43
We are already doing something similar.
23:45
Voyager 1 and Voyager 2 are leaving our
23:48
planetary system.
23:50
The Pioneer spacecraft are also moving outward.
23:54
They were not sent to visit alien civilizations.
23:59
But if they survive long enough, they will
24:02
become human-made interstellar objects, tiny pieces of
24:06
our civilization moving through the galaxy.
24:09
And we have only been a space-
24:11
faring civilization for a very short time.
24:14
Imagine a civilization that has had space technology for
24:17
100,000 years or a million years.
24:20
The amount of material that it could produce
24:23
might be enormous.
24:24
And if some civilizations learned to build small
24:27
probes cheaply, the galaxy could contain technological objects
24:33
without being filled with giant starships.
24:38
This connects to an old question, the Fermi
24:41
paradox.
24:43
If there were many places in the galaxy
24:46
where life could develop, and the Milky Way
24:49
is billions of years old, where is everybody?
24:53
Why don't we see the obvious signs?
24:55
One possible answer is that nobody else is
24:58
there.
24:59
Maybe technological intelligence is extremely rare.
25:04
Another possibility is that civilizations do not last
25:07
very long.
25:08
Another is that the distances are simply too
25:11
great.
25:11
Another possibility is that we are looking in
25:14
the wrong way.
25:15
Traditional SETI has focused a lot on communication,
25:18
radio signals, laser pulses, and other signs of
25:23
technology.
25:25
But communication depends on timing.
25:28
If a civilization sent a signal through our
25:30
part of the galaxy a million years ago,
25:33
that does not help us today.
25:38
A physical object can be more patient.
25:41
It can drift.
25:42
It can wait.
25:43
It can survive its creators.
25:46
So from that point of view, interstellar space
25:50
is not only empty space.
25:53
It could also be an archaeological landscape.
25:57
And then ‘Oumuamua arrives, the first object we
26:00
know for sure came from that space.
26:02
It did not immediately look like the type
26:04
of comet many people expected.
26:06
Its brightness changed dramatically.
26:09
It did not have any obvious comet tail.
26:12
It had an extra acceleration, and perhaps it
26:15
had a very flat shape.
26:17
From inside this technological interpretation, the main point
26:21
is not a single smoking gun.
26:23
It's the combination.
26:26
The first known interstellar object had several features
26:29
that did not immediately look normal compared with
26:32
the small objects we knew from our own
26:34
Solar System.
26:35
One possible physical explanation for the acceleration required
26:40
something very light.
26:43
That creates a question we can ask without
26:46
even using the word alien.
26:50
Do natural objects exist with the right surface
26:53
area to mass ratio?
26:56
If the answer is yes, then we have
26:57
a natural candidate.
26:58
If the answer is no, then what is
27:02
a structure like that doing in space?
27:07
And there are more details.
27:10
One is ‘Oumuamua's speed before it entered the
27:12
Solar System.
27:13
The stars around us do not all move at
27:16
exactly the same speed and direction.
27:18
But astronomers describe an average local
27:22
movement called the local standard of rest.
27:26
You can think of it as a kind
27:27
of an average traffic flow in our part
27:30
of the galaxy.
27:31
‘Oumuamua had a relatively low speed compared with that
27:35
frame.
27:37
Loeb has pointed this out as an interesting
27:41
detail.
27:42
You can imagine an object that is almost
27:44
waiting in this galactic traffic frame.
27:47
It does not have to chase individual star
27:50
systems.
27:51
The stars came to it.
27:54
Imagine a buoy floating in the ocean.
27:57
The buoy does not have to travel to
27:59
every ship.
28:00
The ships pass the buoy.
28:02
In the same way, technological objects could in
28:05
theory exist in interstellar space as markers, relay
28:09
points, or probes.
28:12
the Sun might be the moving part of
28:15
the meeting.
28:16
Our entire Solar System travels through the galaxy.
28:19
And during that journey, it could pass an
28:22
object.
28:23
That is a much quieter idea than
28:26
an invasion.
28:28
And because of that, it also cannot
28:31
be dismissed by simply asking: if it was
28:34
technology, why did it not do anything?
28:38
Maybe doing nothing was exactly the point, or
28:41
maybe it was no longer working at all.
28:45
Then there is the question of survival.
28:48
Could an extremely thin structure really travel between
28:52
the stars without being destroyed?
28:56
Bialy and Loeb studied the effects of interstellar
28:59
material and other physical stresses.
29:02
Their conclusion was that a thin structure made
29:05
from strong enough material could, in principle, survive
29:08
travel over large interstellar distances.
29:14
That does not prove ‘Oumuamua was such a
29:17
structure, but it removed one easy objection.
29:21
You cannot simply say something that thin could
29:23
never survive.
29:25
You have to calculate it.
29:27
And that brings us up to something that
29:29
probably helped explain why Loeb's argument became so
29:32
popular outside astronomy.
29:35
He also challenged a cultural attitude inside science.
29:43
His view is that artificial origin should be
29:48
allowed on the list of possible explanations if
29:52
the data points toward conditions that technology
29:55
could explain.
29:57
Not because technology should be the default answer,
30:01
but because the question should not be banned
30:03
before the evidence is examined.
30:07
If an object behaves in a way that
30:09
reminds us of something we could build ourselves,
30:13
why should we refuse to study that possibility?
30:18
Loeb often uses simple comparisons.
30:22
Imagine walking along a beach and finding a
30:24
plastic bottle.
30:25
If you had never seen technology before, maybe
30:28
you will first try to explain it as
30:30
a strange rock.
30:34
But at some point, the
30:36
shape and the structure would become so specific
30:39
that construction would make more sense than geology.
30:44
The difficult question is, when do we reach
30:47
that point?
30:49
How strange does something need to be?
30:52
That is the whole fight over ‘Oumuamua in
30:56
miniature.
30:57
Someone who supports the technological hypothesis sees several
31:03
unusual features that may point in the same
31:06
direction.
31:07
The missing comet tail, the acceleration, the brightness
31:11
changes, the possible flat shape, the low
31:15
mass compared with the surface area if sunlight
31:18
caused the acceleration, the interstellar path, and the
31:24
unusual speed compared with the local galactic frame.
31:29
Seen from that point of view, the question
31:31
becomes, how many unusual features does an object
31:35
need before the idea of something manufactured is
31:38
allowed on the board?
31:42
There is also the issue of numbers.
31:45
Before 2017, we had never discovered an interstellar object.
31:52
So how many did we expect there to
31:55
be?
31:55
If ‘Oumuamua represents a natural population of small
31:59
objects, there must be enough of them in
32:01
space for Pan-STARRS to have a
32:05
realistic chance of finding one.
32:09
The discovery itself changes our estimate of how
32:12
common these objects might be.
32:15
With technology, we have an even bigger unknown.
32:18
We have zero confirmed examples of alien artifacts.
32:22
So we cannot simply open a textbook and
32:25
look up the correct probability.
32:28
Imagine a civilization sending out one probe.
32:32
That would create almost no objects.
32:35
Imagine a civilization producing trillions of small sails
32:38
over a million years.
32:40
That calculation completely changes.
32:42
We do not know which kind of universe
32:46
we live in.
32:47
And supporters of the technological idea would say
32:49
that we should be careful about declaring it
32:53
impossible based on intuition.
32:56
Then there is the lack of a radio
32:58
signal.
32:59
Researchers did search ‘Oumuamua for artificial
33:03
radio emissions. They did not find a convincing
33:06
transmission.
33:08
But again, if we stay inside the technological
33:10
interpretation, that does not automatically settle the question.
33:15
A sail does not need to transmit.
33:17
A broken piece of technology does not need
33:20
to transmit.
33:21
A million-year-old probe with dead electronics
33:24
board does not need to transmit.
33:28
Human-made objects do not automatically broadcast
33:33
an easy-to-detect radio signal forever either.
33:39
So if we want to test a technological
33:42
hypothesis properly, we need something more.
33:46
A picture, a sample, a close flyby, a
33:49
measurement of the object's mass, better spectroscopy,
33:54
a direct measurement of any gas leaving the
33:57
surface, maybe radar under the right conditions with
34:01
another future object.
34:03
And that leads to what we call maybe
34:07
the strongest point in the entire alternative story.
34:11
Next time, we need to be ready because
34:14
‘Oumuamua was discovered too late.
34:16
It came in, it passed the Sun, and
34:18
only then did we see it.
34:20
If a spacecraft had already been ready to
34:23
go, the story might be very different.
34:26
Imagine sending a camera.
34:29
Then we would not need to argue about
34:32
artistic pictures of cigars and pancakes and so on.
34:36
and so on.
34:37
We might have a real photograph.
34:40
Imagine a rough natural object, rock, cracks, ice,
34:45
a strange geological surface.
34:49
That would have greatly weakened the technological idea.
34:53
Now imagine instead seeing a thin membrane with
34:57
regular structures.
34:59
Then we would have a very different conversation.
35:04
The wonderful thing is that these
35:08
two possibilities do not
35:10
require two different philosophies.
35:12
They need the same instrument, a camera.
35:17
That is where the alternative theory becomes the
35:20
most interesting, not as a belief, but as
35:23
an argument for collecting the kind of data
35:25
that could destroy the theory or make it
35:28
much stronger.
35:29
In that sense, ‘Oumuamua might be more important
35:33
as a warning than as an
35:37
answer.
35:39
We were not ready.
35:40
An object from another star passed through our
35:43
planetary system.
35:44
We discovered it, but we discovered it just
35:47
late enough that we could not
35:52
take a closer look.
35:54
If it was a rock, we missed the
35:57
chance to photograph material from another planetary system
36:00
at close range.
36:01
If it was technology, we missed the chance
36:04
to inspect what would have been the most
36:08
important archaeological discovery in human history.
36:12
And now it is gone, not mysteriously disappeared, just
36:16
continuing on its path out of the solar
36:19
system while we stay behind, arguing about what
36:22
we saw.
36:28
If you go down the rabbit hole, then
36:30
in August 2019, something happened that might have
36:33
made ‘Oumuamua seem less special.
36:37
An amateur astronomer named Gennady Borisov discovered another
36:42
object on a hyperbolic path.
36:45
It became 2I/Borisov, the second known
36:49
interstellar visitor.
36:51
And this time the picture looked much more
36:54
familiar.
36:55
Borisov was clearly a comet.
36:57
There was activity: gas, dust, a visible coma.
37:01
It fits naturally with the idea that planetary
37:05
systems create huge numbers of small objects and
37:08
throw some of them out into interstellar
37:11
space.
37:12
So you could say, fine, now we know
37:15
interstellar objects are comets.
37:18
‘Oumuamua was just an unusual one.
37:21
But one discovery cannot tell us that.
37:25
Borisov shows us that other planetary systems produce
37:29
comets that can reach us.
37:30
It does not automatically tell us what ‘Oumuamua
37:34
was.
37:35
In fact, the comparison makes ‘Oumuamua's missing obvious
37:39
coma stand out even more.
37:41
And then something else happened.
37:43
On July 1st, 2025, a third interstellar object
37:47
was reported.
37:48
It became 3I/ATLAS.
37:52
It also showed clear comet activity.
37:56
So now in 2026, we have three confirmed
38:01
interstellar visitors.
38:02
‘Oumuamua, Borisov, and 3I/ATLAS.
38:06
Numbers two and three look broadly like comets.
38:11
Number one is still the strange member of the
38:14
family.
38:16
That is both important and dangerous.
38:20
Important because we're finally getting something to compare with.
38:22
Dangerous because three objects are still almost nothing
38:25
statistically.
38:27
Three objects cannot tell us what the full
38:30
population of interstellar bodies looks like.
38:33
But they do tell us one important thing.
38:35
These visitors are real.
38:38
Interstellar objects do pass through our Solar System.
38:43
This is no longer only a theoretical idea.
38:49
And if we can discover them earlier, maybe
38:51
one day we can visit one.
38:53
That brings us to Project Lyra.
38:55
Soon after ‘Oumuamua was discovered, researchers and engineers
39:00
began asking whether a spacecraft could ever catch
39:04
it.
39:05
The challenge is huge.
39:07
‘Oumuamua already had a major head start.
39:11
It is leaving the Solar System quickly.
39:13
If we start chasing years later, the spacecraft
39:18
would first need to cover all the distance
39:20
the object has already traveled.
39:23
Then it still has to catch it.
39:27
So it has to move faster.
39:29
Different mission ideas have been studied.
39:32
Gravity assists, flybys of Jupiter, extreme paths near
39:36
the Sun.
39:37
Other ideas try to avoid the most difficult
39:41
close paths near the Sun.
39:45
A published Project Lyra study has shown that
39:48
at least one possible mission path using technology
39:51
based on known spacecraft methods. The trip would
39:54
still take decades.
39:57
That does not mean a mission has been
40:00
approved.
40:01
There is no spacecraft sitting on a launch
40:03
pad waiting to chase ‘Oumuamua.
40:06
Project Lyra is a mission study.
40:09
But the fact that people can seriously calculate
40:11
a possible intercept is fascinating.
40:14
Imagine that mission.
40:15
We launch a spacecraft.
40:17
It travels for decades.
40:19
the Sun becomes smaller and smaller behind it.
40:22
Eventually, the spacecraft reaches a region where almost
40:25
everything made by humans is unbelievably far from
40:29
home.
40:31
And somewhere out there, it has to find an object
40:33
that we first saw as a tiny point
40:36
of light in 2017.
40:41
If we ever received a close-up photograph
40:43
of ‘Oumuamua after decades of chasing it, the
40:46
results would be historic almost no matter what
40:50
it showed.
40:51
A chunk of ice would be historic.
40:53
A fragment of another planet would be historic.
40:57
An extremely light natural structure would be historic.
41:01
Technology would obviously be something else entirely.
41:05
But there is another important point.
41:08
‘Oumuamua has already changed the way people think
41:10
about interstellar objects.
41:12
It turned them into possible mission targets.
41:17
And in that sense, Loeb's idea of space
41:21
archaeology grows beyond the one object.
41:25
If alien technological artifacts exist, we may not
41:30
only need to search hundreds of light years
41:34
away.
41:35
Some could pass through our own neighborhood.
41:38
Some might already be somewhere in our solar
41:42
system.
41:42
Some could even hit Earth.
41:44
The idea later led Loeb toward the
41:49
search for possible interstellar meteors and material recovered
41:54
from the ocean floor.
41:56
That story needs its own careful investigation.
41:59
And the evidence there has to be judged
42:02
separately.
42:03
But the basic idea comes from the same
42:05
question.
42:06
What if SETI is not only about listening?
42:10
What if someday we can actually pick something
42:14
up?
42:15
There is something strange about the idea.
42:18
The classic picture of contact with
42:19
alien intelligence is a message, a signal through
42:23
a radio telescope, numbers, mathematics, a greeting.
42:27
But the first real sign of another
42:30
technology might be much less poetic, a piece
42:35
of trash, a broken machine, a dead probe,
42:39
something that has lost its purpose a long
42:42
long ago and is simply drifting, and maybe
42:45
we never meet the beings who built it,
42:50
that could almost be more unsettling than a
42:53
living spaceship.
42:55
We might find proof that we are not
42:56
the first technological species, and still we will
43:00
be completely alone.
43:01
But before we go too far into that
43:05
darkness, we need to come back to ‘Oumuamua.
43:10
explanation to stand in its strongest form.
43:13
Now we need to ask the same kind
43:14
of hard questions about it, that it asks
43:20
about the traditional explanations.
43:22
What survives? What is assumed? And are there
43:25
natural models that actually explain the observations better?
43:35
If we go to the criticism, then I
43:38
think we should start with the most important
43:40
fact.
43:41
Nobody observed technology on ‘Oumuamua.
43:44
That is a simple sentence, but it also
43:47
clears away a lot of confusion.
43:49
We do not have a photograph of a metal
43:51
sheet.
43:51
We do not see wires, solar panels, bolts,
43:55
engines, an antenna, regular manufactured patterns.
43:59
We did not detect an artificial radio signal.
44:03
We did not observe a controlled intelligent maneuver.
44:08
So the technological idea is based on indirect
44:10
clues.
44:12
That is not automatically a problem.
44:15
A lot of science is based on indirect
44:16
evidence.
44:18
But then we have to ask, is technology
44:20
actually required to explain the observations?
44:24
Right now the answer is no.
44:26
But let's go through the main points.
44:28
First, the shape.
44:29
‘Oumuamua was very uneven or stretched out
44:34
in some way.
44:36
That is strongly supported by the changing brightness.
44:41
But the cigar shape was never seen.
44:43
It was calculated.
44:45
Later studies showed a flatter shape would also
44:48
fit the data.
44:50
So both the famous cigar and the famous
44:53
solar sail are pictures that we have placed
44:56
on top of brightness measurements.
44:59
What we actually observed was a light
45:02
curve.
45:04
When we say it is very flat, we
45:07
have already chosen a model.
45:10
Then there is the missing tail.
45:13
That's also real.
45:15
Deep observations did not find any normal dust
45:18
activity.
45:20
But there is an important difference between the
45:23
two statements.
45:23
No visible tail and no outgassing at all.
45:27
That is not the same thing.
45:28
Gas can be difficult to detect.
45:31
Different molecules produce different signals.
45:35
Dust production can be low.
45:38
The surface might be different from the comets
45:40
we normally study.
45:42
Even in 2017, researchers were considering whether ice
45:47
could survive deeper inside ‘Oumuamua underneath a
45:50
surface changed by its long journey
45:53
through interstellar space.
45:55
So saying it did not look like a
45:58
normal comet does not automatically mean that there
46:02
could not be ice.
46:04
There is also a deeper problem with our
46:06
expectations.
46:07
‘Oumuamua was the first object of its
46:09
kind we had ever seen.
46:11
It may be risky to define normal by
46:14
looking only at objects formed in our
46:17
own Solar System and then expecting everything from
46:20
other systems to look the same.
46:23
Exoplanets have already taught astronomers this lesson.
46:29
When the first planets were discovered around the
46:31
stars, some of them were not what scientists
46:34
expected.
46:37
Hot Jupiters, giant gas planets extremely close to
46:41
their stars, were not something our own Solar
46:45
System had prepared us for.
46:47
Nature had more designs than our local example
46:53
suggested.
46:55
The same could be true for small objects.
46:58
Then there is the acceleration.
47:00
That may be the single most important feature
47:03
of the whole debate.
47:05
But again, non-gravitational acceleration does not mean
47:09
technological acceleration.
47:11
Comets experience it.
47:13
And the original Nature study that measured the
47:18
extra acceleration considered comet-like outgassing to
47:23
be the most reasonable physical explanation among the
47:27
mechanisms the researchers examined.
47:31
So why didn't the story end there?
47:34
Because we were missing the obvious gas and
47:37
dust activity.
47:37
That pushes researchers toward more unusual natural models.
47:43
One of them involves tidal breakup.
47:46
In 2020, Yun Zhang and Douglas Lin modeled what could
47:52
happen if a larger object passed extremely close
47:56
to its star.
47:58
Strong tidal forces could tear the object apart.
48:02
The material could be heated.
48:03
The fragments could develop extreme shapes.
48:08
And some of those fragments could later
48:10
be thrown completely out of the planetary system.
48:14
In that model, ‘Oumuamua would be unusual because
48:17
it went through an unusually violent natural event.
48:21
Not because somebody built it.
48:23
This is important because extreme objects can
48:27
come from extreme natural histories.
48:32
A rock that spent billions of years quietly
48:34
orbiting in an asteroid belt is one thing.
48:37
A fragment that was torn from a larger
48:39
body during a close encounter with a star
48:42
is something completely different.
48:44
Then there is nitrogen.
48:46
In 2021, Alan Jackson and Steven Desch proposed
48:50
‘Oumuamua might be a piece of solid nitrogen
48:53
ice from the surface of a Pluto-like
48:56
world.
48:57
We know Pluto itself has huge areas
49:00
of nitrogen ice.
49:02
So the material is not imaginary.
49:06
Imagine a young planetary system around another star.
49:09
Large impacts strike the surface of the Pluto
49:13
-like world.
49:14
Pieces of nitrogen ice are thrown free.
49:17
The movement of the planets and other
49:19
bodies throw some of them completely out of
49:23
the system.
49:25
One fragment travels through interstellar space for millions
49:29
or billions of years.
49:31
Eventually, it enters our Solar System.
49:34
As it approaches the Sun, the nitrogen turns
49:37
into gas.
49:39
That could create the extra acceleration.
49:44
At the same time, the properties of nitrogen
49:46
ice could help explain why astronomers did not
49:50
detect the specific gases and dust.
49:53
They expected from a more normal comet.
49:57
It is an interesting model because it makes
49:59
‘Oumuamua almost as exotic as the technological idea, but
50:05
without a civilization.
50:11
It could be a physical piece of the
50:15
surface of a Pluto-like planet around another
50:19
star.
50:20
If that were true, a piece of another
50:22
world just flew past us.
50:25
You almost do not need aliens to make
50:29
the story incredible.
50:31
But the nitrogen model has also faced criticism.
50:35
One question is whether enough nitrogen ice fragments
50:39
could realistically be created, survive, and be thrown into
50:43
interstellar space for us to have already discovered
50:47
one.
50:47
Jackson and Desch have tried to address those
50:50
population questions.
50:53
So the debate is not only about whether
50:56
one nitrogen fragment could behave like ‘Oumuamua.
51:00
It is also about whether the universe could make
51:04
enough of them.
51:06
Then there is hydrogen.
51:09
And here we need to separate two different
51:12
ideas.
51:13
One early proposal involved objects almost entirely from
51:17
solid molecular hydrogen.
51:21
That idea faced major problems with how such
51:26
objects could form and survive.
51:29
But in 2023, Jennifer Bergner and Darryl Seligman
51:33
proposed something different.
51:35
‘Oumuamua would not need to be made of
51:37
hydrogen.
51:39
It could mainly contain water ice. During a
51:43
long journey through interstellar space,
51:45
cosmic radiation hits the ice.
51:47
That radiation could change the molecules and create
51:50
molecular hydrogen or H2 inside the ice.
51:55
Some of that hydrogen could become trapped.
51:58
Then ‘Oumuamua enters our Solar System. the Sun
52:01
heats it, the structure of the ice changes, and
52:03
the trapped hydrogen escapes.
52:06
That escaping hydrogen produces
52:11
a push.
52:14
It is an elegant possible answer to one
52:17
very difficult problem: acceleration without a normal dusty
52:20
tail.
52:23
If the model is right, ‘Oumuamua would be
52:26
a fairly ordinary ice-rich object that
52:30
was simply changed by spending a very long
52:33
time between the stars.
52:35
But science did not stop here either.
52:39
Later that same year, Niels Ligterink challenged the model
52:44
in Nature.
52:44
He argued that the proposed process might not
52:47
produce enough hydrogen under the necessary conditions.
52:53
Bergner and Seligman responded, and that is a
52:56
good example of something that also disappears from
52:59
many popular stories about science.
53:03
A paper does not always solve a mystery.
53:05
A paper proposes a model. Other scientists read
53:08
it, do their own calculations, and
53:12
find possible problems.
53:16
The original researchers respond, new data appears, and
53:19
maybe years later, one explanation survives better than
53:22
the others.
53:23
So whenever you see a headline saying that
53:26
‘Oumuamua mystery finally solved, check the date.
53:30
It may be a Tuesday solution.
53:33
By Thursday, another paper may be arguing with it.
53:37
It does not mean that every idea is
53:39
equally good.
53:41
It means that we need to separate a
53:43
promising model from an established fact.
53:46
Now let's get back to the light sail.
53:48
The interesting result from Bialy and Loeb is
53:51
physical.
53:53
If sunlight pressure causes the acceleration, then the
53:57
object needs a very low mass compared with
54:00
its surface area.
54:02
That tells us something about what such an
54:07
object would have to be like.
54:10
But there is a jump between the two
54:12
statements.
54:12
Statement one, a very thin or very light
54:15
object could be accelerated by sunlight in this
54:19
way.
54:20
Statement two, therefore, ‘Oumuamua was an artificial light
54:25
sail.
54:25
Statement two does not automatically follow from statement one.
54:29
Before we can jump to that, we need
54:31
to rule out natural objects with similar physical
54:35
properties.
54:36
Researchers have also looked at very light,
54:40
fluffy structures.
54:41
Extremely loose collections of dust could have large
54:45
surface areas compared with their mass.
54:48
Think less solid rock, and more cosmic cotton candy.
54:54
Those ideas also have problems.
54:56
Can such structures form?
54:59
Can they survive?
55:01
Can they pass close to the Sun
55:04
without falling apart?
55:05
But the most important point is this: just because a
55:08
property reminds us of technology, does not mean
55:10
technology is the only way to create that
55:12
property.
55:14
Next criticism is about probability.
55:18
This part is a little abstract, but stay
55:21
with me.
55:21
Imagine two explanations.
55:23
Explanation A: a natural interstellar object with properties we
55:27
do not completely understand.
55:30
Explanation B, a technological artifact made by an
55:35
alien civilization.
55:36
Both might be made to fit some of
55:38
the observations, but should they start with the
55:41
same probability?
55:43
Many scientists would say no.
55:45
They would begin with A. Not because
55:48
B is forbidden, but because we already know
55:52
natural small objects exist.
55:57
We know planetary systems produce them.
56:00
We have observed huge numbers of asteroids and
56:03
comets.
56:03
And since ‘Oumuamua, we have
56:05
found two more interstellar objects that clearly look
56:07
like comets.
56:09
On the other hand, we still have
56:11
no widely accepted direct detection of alien technology.
56:16
So the two ideas do not necessarily begin
56:18
at the same starting line.
56:21
This is basically a Bayesian question.
56:26
An unusual explanation can absolutely be correct, but
56:31
the evidence has to be strong enough to
56:33
move us away from a lower starting probability.
56:38
If I hear hoofbeats outside a house in
56:42
the United States, I will probably think of
56:45
a horse before I think of a zebra.
56:47
Not because zebras are imaginary, but because I
56:51
know something about where I am.
56:54
On the African savannah, the probability would be
56:57
different.
56:59
The problem with interstellar objects is that we
57:02
still barely know which kind of a zoo
57:05
we are standing in.
57:07
We have three.
57:08
Three. That is all.
57:12
We do not have thousands of examples.
57:15
So some features that look extremely strange
57:18
compared with objects in our own Solar System
57:21
might turn out to be normal among interstellar
57:24
objects, or they might be truly rare.
57:27
We just do not know yet.
57:30
This also affects lists of anomalies.
57:35
Suppose somebody says feature A is very unlikely,
57:39
feature B is very unlikely, feature C is
57:42
very unlikely, feature D is very unlikely.
57:46
Then they multiply those probabilities together and get
57:50
an unbelievably tiny number.
57:53
That only works if those features are independent.
57:57
If the same natural process creates the shape,
58:00
the rotation, and the acceleration, then those are
58:03
not necessarily separate accidents.
58:08
A violent close encounter with a star could
58:12
affect both shape and surface.
58:15
The chemical composition could affect both outgassing and
58:20
brightness.
58:22
The formation history could also affect rotation.
58:26
The unusual features can be connected.
58:29
Then there's also another problem with the technological
58:31
hypothesis.
58:33
It can become extremely flexible.
58:36
If the object is long,
58:38
technology can be long.
58:39
If it is flat, a sail is flat.
58:41
If there is no radio signal, it is dead.
58:43
If there is a radio signal, it
58:46
is active.
58:48
If it moves toward Earth,
58:50
It's a probe.
58:51
If it does not, it is debris.
58:53
If it tumbles, it is damaged.
58:55
If it rotates perfectly,
58:57
It is designed that way.
58:58
A theory that can explain every possible
59:02
result after the fact becomes too hard
59:06
to test.
59:08
Science works best when a theory makes predictions
59:12
that can fail.
59:14
If we can observe one thing, the theory
59:16
should become much stronger.
59:20
If we observe something else, it will become
59:23
weaker.
59:25
And that is why the next interstellar object may ultimately
59:30
matter more than every argument about ‘Oumuamua.
59:34
We cannot take new measurements of ‘Oumuamua now,
59:37
but next time we can decide in advance
59:40
which observation would be truly unusual under natural
59:44
explanations.
59:46
What would a technological object predict?
59:50
Can we measure its mass?
59:51
Can we photograph the surface?
59:54
Can we identify gases?
59:56
Can we measure the acceleration and the outgassing
59:58
at the same time?
1:00:00
Can we send a spacecraft past it?
1:00:03
That is how the idea becomes testable.
1:00:07
And now we are ready to clear the
1:00:09
table. Not spaceship or rock, but point by
1:00:13
point what we actually know.
1:00:20
So what actually holds up?
1:00:22
Let's begin with what is solid.
1:00:25
‘Oumuamua came from interstellar space. That is well
1:00:28
established.
1:00:29
Its orbit was hyperbolic and was not bound
1:00:33
to the Sun.
1:00:34
There's no serious debate about the fact that
1:00:37
it was a visitor from outside our Solar
1:00:39
system.
1:00:40
That alone was historic.
1:00:42
We also know that the brightness changed dramatically.
1:00:46
That is documented.
1:00:48
It means the visible area or reflective properties
1:00:51
changed strongly as the object rotated.
1:00:56
A very uneven shape is a reasonable
1:01:00
conclusion.
1:01:02
But the exact shape is not known.
1:01:06
The cigar is a model.
1:01:07
The pancake is a model.
1:01:09
The solar sail is a model.
1:01:11
We do not have a direct image that
1:01:14
shows the shape.
1:01:17
We know the object was tumbling.
1:01:21
Several studies of the light curve support a
1:01:23
complex rotation.
1:01:25
It is not itself evidence for technology.
1:01:29
A violent natural history could easily produce tumbling.
1:01:33
We know astronomers did not observe a normal
1:01:37
obvious coma or a dust tail.
1:01:39
That is also documented.
1:01:42
It makes ‘Oumuamua unusual compared with classic active
1:01:46
comets.
1:01:47
But it does not prove there was absolutely
1:01:52
no outgassing.
1:01:54
We also know the object experienced a small
1:01:58
extra acceleration.
1:02:01
That is one of the strongest results in
1:02:03
the whole story.
1:02:04
And here the language matters.
1:02:07
The acceleration is not speculation.
1:02:09
The cause of the acceleration
1:02:12
is.
1:02:14
It could have involved outgassing.
1:02:18
It may have involved one of the more specific
1:02:21
natural processes we have discussed.
1:02:24
If the object had the right surface-area-
1:02:30
to-mass ratio, sunlight pressure could also produce
1:02:34
an effect.
1:02:36
But we did not directly measure the
1:02:39
surface-area-to-mass ratio.
1:02:43
And this is where the interpretation begins.
1:02:46
Then we have what is most likely.
1:02:52
one.
1:02:52
Based on the evidence available today, a natural
1:02:55
object is the most cautious and most widely
1:02:59
accepted explanation.
1:03:01
That does not necessarily mean an ordinary
1:03:05
comet exactly like one from our own
1:03:10
Solar System.
1:03:19
‘Oumuamua could be the product of environments and
1:03:21
processes we have never had the chance to
1:03:25
study up close before.
1:03:27
That may be exactly why it looked so
1:03:29
strange.
1:03:30
Then we have what remains uncertain.
1:03:34
Which natural process best explains the acceleration, shape,
1:03:38
and lack of obvious activity together.
1:03:42
There is no single final model that gives
1:03:44
us a photograph of ‘Oumuamua with the answers
1:03:48
written underneath.
1:03:49
The nitrogen ice idea is one possibility.
1:03:53
Hydrogen released from radiation-processed water ice is another.
1:03:59
More normal forms of comet-like activity
1:04:02
are still discussed.
1:04:04
Tidal breakup may help explain an
1:04:07
extreme history and unusual shape.
1:04:10
And finally, we have what is speculative.
1:04:14
An artificial light sail, a probe, a navigation
1:04:18
buoy, technological debris, a piece of a larger
1:04:23
alien structure.
1:04:24
There is no direct evidence for any of
1:04:27
those things.
1:04:28
That does not mean logically impossible.
1:04:30
It means we do not have the observation
1:04:33
needed to move from possibility to discovery.
1:04:37
And that is where the difference really lies
1:04:39
in this story.
1:04:42
The exciting thing about ‘Oumuamua does not have to
1:04:45
be that we discovered aliens.
1:04:48
It may be that for the first time
1:04:49
we saw material from another star system passing
1:04:52
through our own system and realized how little
1:04:56
experience we have with these objects.
1:05:05
So what was ‘Oumuamua?
1:05:07
If I had to choose based on the
1:05:09
evidence we have, I would begin with a
1:05:12
natural explanation.
1:05:15
That is where the total evidence points most
1:05:18
strongly.
1:05:19
But I would be careful with the next
1:05:21
sentence, because natural does not necessarily mean ordinary.
1:05:25
Almost the opposite.
1:05:27
‘Oumuamua could have been part of a
1:05:30
type of world we have never visited.
1:05:33
A fragment created during a violent encounter near
1:05:37
another star.
1:05:39
A strange type of icy body, an object
1:05:42
changed by millions of years in interstellar space.
1:05:46
If even one of those ideas turns out
1:05:48
to be right, the story would still be
1:05:51
incredible.
1:05:53
And the technological possibility? It has not been
1:05:56
demonstrated.
1:05:58
We do not have a technological signature, no
1:06:00
direct observation of a manufactured structure, no confirmed transmitter,
1:06:05
no maneuver that requires intelligence.
1:06:09
So we cannot simply jump from strange to
1:06:14
manufactured.
1:06:15
But one part of the challenge should remain.
1:06:18
If we ever find an object that is
1:06:21
really artificial, we need to have the science
1:06:24
capable of recognizing it.
1:06:26
Not a science that automatically says aliens, but
1:06:30
also not a science that has already decided
1:06:33
that the answer can never be technology.
1:06:36
The real solution is almost annoyingly boring.
1:06:40
We need better data.
1:06:41
And fortunately, we are already in a better
1:06:43
position than we were in 2017.
1:06:48
We know interstellar objects pass through our Solar
1:06:50
system.
1:06:51
We have seen ‘Oumuamua, Borisov, and 3I/ATLAS,
1:06:55
and future sky surveys will find more.
1:06:59
So the next time a truly strange object
1:07:02
arrives, we know which mistakes we do not
1:07:06
have to repeat.
1:07:07
Find it early, measure it quickly, follow the
1:07:10
acceleration, look for gas, determine the rotation, and
1:07:14
if we can, send something after it.
1:07:17
Because one day the answer could be almost
1:07:20
anything.
1:07:21
A comet from another star, a fragment of
1:07:25
an exoplanet, a kind of material that we
1:07:29
have never held in our hands, or something
1:07:32
far less likely.
1:07:34
‘Oumuamua did not give us the answer to
1:07:37
whether we are alone.
1:07:38
It gave us something more modest and maybe
1:07:41
something more useful.
1:07:43
A warning that the next time the question
1:07:47
passes through our neighborhood, we may not have
1:07:51
very long to ask it.
1:07:54
Thank you for listening.